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Terms modified by QRS Selected AbstractsPredictive Value of Admission Electrocardiography in Patients With Heart FailureCONGESTIVE HEART FAILURE, Issue 4 2008Karolina M. Zareba MD Admission electrocardiography (ECG) in heart failure (HF) patients provides important diagnostic information; however, there are limited data regarding the prognostic significance of ECG parameters for predicting cardiac events (CEs). The ECGs of 246 patients admitted with acute HF were evaluated for heart rate, rhythm, QRS and ST-T wave abnormalities, QTc duration, QT peak corrected (QTpc), T amplitude, and axis. The end points included rehospitalization for a CE or death during 30-day follow-up. There were 71 (29%) patients with CEs. In patients with CEs, atrial fibrillation (AF) was observed more frequently (27% vs 13%, respectively; P=.009) and QTpc was shorter (370±43 vs 386±44 ms, respectively; P=.020). Multivariate logistic regression analysis revealed that QTpc ,360 ms and AF were predictive of CE after adjustment for clinical covariates. In conclusion, apart from AF, the presence of short QTpc ,360 ms is independently associated with increased risk of rehospitalization or death in HF patients. [source] T-Wave Amplitude Attenuation/Augmentation in Patients With Changing Edematous States: Implications for Patients With Congestive Heart FailureCONGESTIVE HEART FAILURE, Issue 5 2007John E. Madias MD Since peripheral edema impacts the entire electrocardiographic curve, it was hypothesized that it would also affect T waves. The amplitude of T waves were measured in all electrocardiographic leads and a sum (,T) was calculated in 28 patients with and 28 patients without peripheral edema (controls). For patients with peripheral edema, ,T on admission was 21.9±10.6 mm and ,T at peak weight was 8.3±6.3 mm (P=.0005). For patients with peripheral edema who subsequently lost weight, ,T at peak weight was 7.2±6.1 mm and ,T at the lowest weight was 14.1±12.2 (P=.006). For controls, ,T from admission and ,T from discharge were 24.4±16.9 mm and 24.7±15.7 mm (P=.82), respectively. Percent change (,%,T) from admission to peak weight correlated with ,% in weight (r=0.58; P=.001) and ,% in the sum of QRS complexes (,QRS) (r=0.71; P=.00005). ,%,T from peak weight to the lowest weight correlated with the corresponding ,%,QRS (r=0.65; P=.02). Changes in T waves with development and alleviation of peripheral edema mirror the changes shown by the QRS complexes and may be useful in the treatment of patients with congestive heart failure or other edematous states. [source] Feasibility of Biventricular Pacing in Patients With Recent Myocardial Infarction: Impact on Ventricular RemodelingCONGESTIVE HEART FAILURE, Issue 1 2007Eugene S. Chung MD To test the hypothesis that biventricular pacing after a myocardial infarction with reduced ejection fraction can attenuate left ventricular (LV) remodeling, the authors studied 18 patients (myocardial infarction within 30,45 days, ejection fraction ,30%, narrow QRS) randomized to biventricular therapy (biventricular therapy + defibrillator) (biventricular group) or implantable cardioverter-defibrillator alone (control group). At 1, 6, and 12 months, there were no differences in functional or clinical parameters (New York Heart Association, quality of life, 6-minute walk). Twelve-month LV volume remained stable in the biventricular group, but increased in the control group (median LV end-diastolic volume increase, 6.5 mL in biventricular vs 35 mL in control; P=.03; median LV end-diastolic volume decrease, 5.5 mL in biventricular vs 30.5-mL increase in control; P=.11). Biventricular therapy also prevented an increase in sphericity index at 12 months (median, ,2% in biventricular vs 37% in control; P=.06). Delivery of biventricular therapy early after myocardial infarction appears safe and feasible and may attenuate subsequent LV dilation. [source] ABSENCE OF CORRELATION BETWEEN QRS DURATION AND ECHOGRAPHIC PARAMETERS OF VENTRICULAR DESYNCHRONIZATION.ECHOCARDIOGRAPHY, Issue 2 2004CAN WE STILL TRUST THE ELECTROCARDIOGRAPHIC CRITERIA? Background: Identification of the responder candidates for multisite pacing is still difficult and severe heart failure, dilated left ventricle with reduced ejection fraction, prolonged QRS with left bundle branch block (LBBB) are still considered the principal indicators of ventricular desynchronization. The aim of the study was to assess if echographic ventricular desynchronization parameters measured in patients with dilated cardiomyopathy and severe heart failure are correlated with the duration of the QRS on surface electrocardiogram. Methods: This study included 51 patients aged 58.8 ± 7.4 years with idiopathic DCM. The following parameters were measured: QRS duration; effective contraction time (ECT) measured as the interval between QRS onset and closure of aortic valve, interventricular delay (IVD) measured as the time between onset of aortic and pulmonary flow, left ventricular mechanical delay (LVD) as the time from maximal interventricular septum contraction and posterior wall contraction, posterior (P), lateral (L), and posterolateral (PL) wall delays, as the time from QRS onset to maximal wall contraction. Regional post-systolic contraction was defined in a given wall as the difference (contraction delay , ECT)> 50 ms. Results: 29 patients presented complete LBBB, 22 patients had QRS duration < 120 ms. 39 patients had a post-systolic contraction of the PL wall (32 patients of the L wall and 26 patients of the P wall). 16 patients with QRS duration <120 had a post-systolic contraction of the PL wall (as for the LBBB the rest of 39 patients). In 40 patients the sequence of regional ventricular contraction was: P-L-PL wall (16 patients with QRS < 120). LVD was > 100 ms in 36 patients (26 patients with LBBB and 10 with QRS < 120). 27 patients with LBBB and 6 with QRS < 120 ms presented IVD > 30 ms. There was no correlation between the QRS duration and the parameters listed above. Conclusions: In a population of patients with severe heart failure and dilated cardiomyopathy there is no correlation between the duration of the QRS and echocardiographic parameters of ventricular desynchronization. These results show that mechanical ventricular desynchronization can be observed in patients with a QRS duration < 120 ms. Further studies are needed to evaluate if this population could beneficiate of multisite pacing therapy. [source] Echocardiographic Features of Patients With Heart Failure Who May Benefit From Biventricular PacingECHOCARDIOGRAPHY, Issue 3 2003Amgad N. Makaryus Background: Recent studies suggest that cardiac resynchronization therapy through biventricular pacing (BVP) may be a promising new treatment for patients with advanced congestive heart failure (CHF). This method involves implantation of pacer leads into the right atrium (RA), right ventricle (RV), and coronary sinus (CS) in patients with ventricular dyssynchrony as evidenced by a bundle branch block pattern on electrocardiogram (ECG). Clinical trials are enrolling stable patients with ejection fractions (EF) , 35%, left ventricular end-diastolic diameters (LVIDd) , 54 mm, and QRS duration ,140 msec. We compared echocardiography features of these patients (group 1) with other patients with EF , 35%, LVIDd , 54 mm, and QRS < 140 msec (group 2 = presumably no dyssynchrony). Methods: Nine hundred fifty-one patients with CHF, LVID 54 mm, EF 35% by echocardiography were retrospectively evaluated. One hundred forty-five patients remained after those with primary valvular disease, prior pacing systems, or chronic atrial arrhythmias were excluded. From this group of 145 patients, a subset of 50 randomly selected patients were further studied (25 patients [7 females, 18 males] from group 1, and 25 patients [7 females, 18 males] from group 2). Mean age group 1 = 75 years old, mean age group 2 = 67 years old. Mean QRS group 1 = 161 msec, mean QRS group 2 = 110 msec. Each group was compared for presence of paradoxical septal motion, atrial and ventricular chamber sizes, LV mass, LVEF, and RV systolic function. Results: Of the initial group of 951 patients, 145 (15%) met inclusion criteria. In the substudy, 20/25 (80%) of group l and 7/25 (28%) of group 2 subjects had paradoxical septal motion on echo (Fisher's exact test, P = 0.0005). The t-tests performed on the other echocardiography variables demonstrated no differences in chamber size, function, or LV mass. Conclusions: Cardiac resynchronization therapy with BVP appears to target a relatively small population of our advanced CHF patients (15% or less). Although increasing QRS duration on ECG is associated with more frequent paradoxical septal motion on echo, it is not entirely predictive. Paradoxical septal motion on echo may therefore be more sensitive at identifying patients who respond to BVP. Further prospective studies are needed. (ECHOCARDIOGRAPHY, Volume 20, April 2003) [source] Initial Clinical Experience with Cardiac Resynchronization Therapy Utilizing a Magnetic Navigation SystemJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2007PETER GALLAGHER M.D. Introduction: The placement of left ventricular (LV) leads during cardiac resynchronization therapy (CRT) involves many technical difficulties. These difficulties increase procedural times and decrease procedural success rates. Methods and Results: A total of 50 patients with severe cardiomyopathy (mean LV ejection fraction was 21 ± 6%) and a wide QRS underwent CRT implantation. Magnetic navigation (Stereotaxis, Inc.) was used to position a magnet-tipped 0.014, guidewire (CronusÔ guidewire) within the coronary sinus (CS) vasculature. LV leads were placed in a lateral CS branch, either using a standard CS delivery sheath or using a "bare-wire" approach without a CS delivery sheath. The mean total procedure time was 98.1 ± 29.1 minutes with a mean fluoroscopy time of 22.7 ± 15.1 minutes. The mean LV lead positioning time was 10.4 ± 7.6 minutes. The use of a delivery sheath was associated with longer procedure times 98 ± 32 minutes vs 80 ± 18 minutes (P = 0.029), fluoroscopy times 23 ± 15 minutes vs 13 ± 4 minutes (P = 0.0007) and LV lead positioning times 10 ± 6 minutes vs 4 ± 2 minutes (P = 0.015) when compared to a "bare-wire" approach. When compared with 52 nonmagnetic-assisted control CRT cases, magnetic navigation reduced total LV lead positioning times (10.4 ± 7.6 minutes vs 18.6 ± 18.9 minutes; P = 0.005). If more than one CS branch vessel was tested, magnetic navigation was associated with significantly shorter times for LV lead placement (16.2 ± 7.7 minutes vs 36.4 ± 23.4 minutes; P = 0.004). Conclusions: Magnetic navigation is a safe, feasible, and efficient tool for lateral LV lead placement during CRT. Magnetic navigation during CRT allows for control of the tip direction of the CronusÔ 0.014, guidewire using either a standard CS delivery sheath or "bare-wire" approach. Although there are some important limitations to the 0.014, CronusÔ magnetic navigation can decrease LV lead placement times compared with nonmagnetic-assisted control CRT cases, particularly if multiple CS branches are to be tested. [source] Idiopathic Ventricular Tachycardia Originating from the Posteroseptal Mitral Annulus: A Case ReportJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2006KEIICHI ASHIKAGA M.D. We describe a 71-year-old man with a ventricular tachycardia (VT) originating from the mitral annulus. A sustained VT was induced by exercise or an isoproterenol administration, but not by pacing. Frequent premature ventricular contractions (PVCs) with the same QRS as the VT were transiently suppressed by an adenosine triphosphate injection, suggesting that it was due to cyclic-AMP mediated triggered activity. The PVCs and VT were all abolished by radiofrequency catheter ablation guided by the earliest activation and a perfect pace map, which was located at the posteroseptal mitral annulus. The patient has been free from any symptoms for 2 years. [source] Successful Radiofrequency Catheter Ablation of Epicardial Left Ventricular Outflow Tract Tachycardia from the Anterior Interventricular Coronary VeinJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2005YASUHIRO HIRASAWA M.D. We report a case of idiopathic left ventricular outflow tract (LVOT) tachycardia that was eliminated by a radiofrequency application from the anterior interventricular coronary vein (AIV). The ECG exhibited QRS complexes with an inferior axis and atypical left bundle branch block pattern with an early transition of the precordial R waves at V3. Several radiofrequency applications from the coronary cusps and endocardial LVOT were not effective. Radiofrequency applications in the AIV, where the activation preceded the onset of the QRS by 30 msec, successfully eliminated the tachycardia. The AIV may be an optional site for radiofrequency ablation of idiopathic epicardial LVOT tachycardia. [source] Identification and Ablation of Three Types of Ventricular Tachycardia Involving the His-Purkinje System in Patients with Heart DiseaseJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 1 2004GUSTAVO LOPERA M.D. Introduction: Ventricular tachycardia (VT) with involvement of the His-Purkinje system (HPS) can be difficult to recognize in patients with heart disease, but it may be particularly susceptible to ablation targeting the HPS. This study defines the incidence and types of HPS involvement in VT. Methods and Results: Involvement of the HPS was sought during electrophysiologic study with catheter mapping in 234 consecutive patients referred for catheter ablation of recurrent VT associated with heart disease. HPS VT was observed in 20 (8.5%) patients (mean ejection fraction 29%± 17%); in 9 (11%) of 81 patients with nonischemic heart disease and 11 (7.1%) of 153 patients with coronary artery disease (P = NS). Three types of HPS VT were observed: 16 patients (group 1) had typical bundle branch reentry, 2 patients (group 2) had bundle branch reentry and interfascicular reentry, and 2 patients (group 3) had VT consistent with a focal origin in the distal HPS. In all three groups, the VT QRS had morphologic similarity to the sinus rhythm QRS. Ablation of HPS VT was successful in all patients in whom it was attempted but produced high-degree AV block in 6 (30%). In 12 patients (60%), other VTs due to reentry through scar also were inducible. Conclusion: Involvement of the HPS in VT associated with heart disease has three distinct clinical forms, all of which are susceptible to ablation. Ablation often is not sufficient as the sole therapy due to other induced VT's and conduction abnormalities, requiring pacemaker and/or defibrillator implantation. (J Cardiovasc Electrophysiol, Vol. 15, pp. 52-58, January 2004) [source] Endocardial Mapping of Right Ventricular Outflow Tract Tachycardia Using Noncontact Activation MappingJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 6 2003Michael Ribbing M.D. Introduction: Activation mapping and pace mapping identify successful ablation sites for catheter ablation of right ventricular outflow tract (RVOT) tachycardia. These methods are limited in patients with nonsustained tachycardia or isolated ventricular ectopic beats. We investigated the feasibility of using noncontact mapping to guide the ablation of RVOT arrhythmias. Methods and Results: Nine patients with RVOT tachycardia and three patients with ectopic beats were studied using noncontact mapping. A multielectrode array catheter was introduced into the RVOT and tachycardia was analyzed using a virtual geometry. The earliest endocardial activation estimated by virtual electrograms was displayed on an isopotential color map and measured33 ± 13 msecbefore onset of QRS. Virtual unipolar electrograms at this site demonstrated QS morphology. Guided by a locator signal, ablation was performed with a mean of6.9 ± 2.2radiofrequency deliveries. Acute success was achieved in all patients. During follow-up, one patient had a recurrence of RVOT tachycardia. Compared with patients(n = 21)who underwent catheter ablation using a conventional approach, a higher success rate was achieved by noncontact mapping. Procedure time was significantly longer in the noncontact mapping group. Fluoroscopy time was not significantly different in the two groups. Conclusion: Noncontact mapping can be used as a reliable tool to identify the site of earliest endocardial activation and to guide the ablation procedure in patients with RVOT tachycardia and in patients with ectopic beats originating from the RVOT. (J Cardiovasc Electrophysiol, Vol. 14, pp. 602-608, June 2003) [source] Noninvasive Assessment of Cardiac Resynchronization Therapy for Congestive Heart Failure Using Myocardial Strain and Left Ventricular Peak Power as Parameters of Myocardial Synchrony and FunctionJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2002Ph.D., ZORAN B. POPOVI Resynchronization Therapy for Heart Failure.Introduction: Although invasive studies have shown that cardiac resynchronization therapy by biventricular pacing improves left ventricular (LV) function in selected heart failure patients, it is impractical to apply such techniques in the clinical setting. The aim of this study was to assess the acute effects of cardiac resynchronization therapy by noninvasive techniques. Methods and Results: Twenty-two patients enrolled in the InSync trial (age 64 ± 9 years, 18 men and 4 women; all with ejection fraction <35% and QRS >130 msec) were studied 1 to 12 months after pacemaker implantation during pacing, and while ventricular pacing was inhibited. Regional myocardial strains of the interventricular septum, LV free wall, and right ventricular free wall were derived from color Doppler tissue echocardiography. Peak power index was calculated as a product of simultaneously recorded noninvasive blood pressure and pulse-wave (PW) Doppler velocity of the LV outflow tract. The Z ratio (sum of LV ejection and filling times divided by RR interval) and tei index were calculated from PW Doppler data. During pacing, overall regional strain improved (P = 0.01), while the LV strain coefficient of variation decreased from 2.7 ± 2.4 to 1.3 ± 0.7 (P = 0.009). Additionally, peak power index improved from 84 ± 24 to 94 ± 27 cm· mmHg/sec (P = 0.004). The Z ratio increased from 0.71 ± 0.08 to 0.78 ± 0.07 (P = 0.0005), while the tei index decreased from 0.86 ± 0.33 to 0.59 ± 0.16 (P = 0.0002). Conclusion: Using novel noninvasive indices, we demonstrated that cardiac resynchronization therapy improves LV performance. [source] Arrhythmogenesis of T Wave Alternans Associated with Surface QRS Complex Alternans and the Role of Ventricular Prematurity: Observations from a Canine Model of LQT3 SyndromeJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 6 2002MASAOMI CHINUSHI M.D. Intramural TWA and Its Arrhythmogenesis.Introduction: T wave alternans (TWA) is characterized by cycle-to-cycle changes in the QT interval and/or T wave morphology. It is believed to amplify the underlying dispersion of ventricular repolarization. The aim of this study was to examine the mechanisms and arrhythmogenesis of TWA accompanied by QRS complex and/or blood pressure (BP) waveform alternans, using transmural ventricular electrogram recordings in an anthopleurin-A model of long QT syndrome. Methods and Results: The cardiac cycle length was gradually shortened by interruption of vagal stimulation, and TWA was induced in six canine hearts. Transmural unipolar electrograms were recorded with plunge needle electrodes from endocardial (Endo), mid-myocardial (Mid), and epicardial (Epi) sites, along with the surface ECG and BP. The activation-recovery interval (ARI) was measured to estimate local refractoriness. During TWA, ARI alternans was greater at the Mid than the Epi/Endo sites, and it was associated with the development of marked spatial dispersion of ventricular repolarization. As TWA increased, ventricular activation of the cycles associated with shorter QT intervals displayed delayed conduction at the Mid sites as a result of a critically longer ARI of the preceding cycle and longer QT interval, while normal conduction was preserved at the Epi site. Delayed conduction at the Mid sites manifested as surface ECG QRS and BP waveform alternans, and spontaneous ventricular tachyarrhythmias developed in absence of ventricular prematurity. In other instances, in absence of delayed conduction during TWA, ventricular premature complexes infringed on a prominent spatial dispersion of ventricular repolarization of cycles with long QT intervals and initiated ventricular tachyarrhythmia. Conclusion: TWA accompanied by QRS alternans may signal a greater ventricular electrical instability, since it is associated with intramural delayed conduction, which can initiate ventricular tachyarrhythmia without ventricular premature complexes. [source] Relatively Benign Clinical Course in Asymptomatic Patients with Brugada-Type Electrocardiogram Without Family History of Sudden DeathJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 1 2001SHIHO TAKENAKA M.D. Asymptomatic Brugada-Type ECG.Introduction: The incidence of sudden death or ventricular fibrillation (VF) in asymptomatic Brugada syndrome patients with a family history of sudden death is reported to be very high. However, there are few reports on the prognosis of asymptomatic Brugada syndrome patients without a family history of sudden death. Methods and Results: Eleven patients (all male; mean age 40.5 ± 9.6 years, range 26 to 56) with asymptomatic Brugada-type ECG who had no family history of sudden death were evaluated. The degrees of ST segment elevation and conduction delay on signal-averaged ECG (SAECG) before and after pilsicainide were evaluated in all 11 patients. VF inducibility by ventricular electrical stimulation also was evaluated in 8 of 11 patients. Patients were followed for a period of 9 to 84 months (mean 42.5 ± 21.6). The J point level was increased (V1 :0.19 ± 0.09 mV to 0.36 ± 0.23 mV; V2: 0.31 ± 0.12 mV to 0.67 ± 0.35 mV) by pilsicainide. Conduction delay was increased (total QRS: 112.2 ± 6.3 msec to 131 7 ± 6.3 msec; under 40 , V: 42.0 ± 8.5 msec to 52.7 ± 12.7 msec; last 40 msec: 17.4 ± 5.9 , V to 10.4 ± 6.1 , V) on SAECG by pilsicainide. VF was induced in only 1 of 8 patients. None of the patients had syncope or sudden death during a mean follow-up of 42.5 ± 21.6 months. Conclusion: This study suggests that asymptomatic patients with Brugada-type ECG who have no family history of sudden death have a relatively benign clinical course. [source] Acute effects of escalating doses of amiodarone in isolated guinea pig heartsJOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 3 2002S. BICER Bicer, S., Patchell, J. S., Hamlin, D. M., Hamlin, R. L. Acute effects of escalating doses of amiodarone in isolated guinea pig hearts. J. vet Pharmacol. Therap.25, 221,226. Cardiac effects of escalating concentrations of amiodarone were determined on isolated perfused guinea pig hearts (Langendorff preparations). Spontaneously beating hearts were instrumented for the measurement of RR, PQ, QRS, QT and QTc durations (from a bipolar electrogram), and dP/dtmax and dP/dtmin from an isovolumetric left ventricular pressure curve. Ten hearts were exposed to escalating concentrations of amiodarone (10,7, 10,6, 10,5 and 10,4 M) in dimethyl sulfoxide (DMSO)/Krebs,Henseleit or to DMSO/Krebs,Henseleit (vehicle). Measurements were collected during the last minute of a 15-min concentration. Means of all parameters were compared by ANOVA with repeated measures design. When compared with vehicle, amiodarone prolonged QT and QTc durations at concentrations >10,6 M. The apparent lengthening of RR, PQ and QRS at concentrations >10,6 M did not achieve statistical significance. Similarly, the apparent decreases in dP/dtmax and dP/dtmin at concentrations >10,6 M did not achieve statistical significance. The putative therapeutic concentration of amiodarone is between 2 and 4 × 10,6 M. In this study, at a concentration of 10,6 M, only RR and dP/dtmin tended to change, but they were not different from vehicle. Thus, amiodarone in this preparation has little potential for cardiac toxicity at therapeutic concentrations. [source] Right Ventricular Septal Pacing: A Comparative Study of Outflow Tract and Mid Ventricular SitesPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 10 2010RAPHAEL ROSSO M.D. Background: Prolonged right ventricle (RV) apical pacing is associated with left ventricle (LV) dysfunction due to dysynchronous ventricular activation and contraction. Alternative RV pacing sites with a narrower QRS compared to RV pacing might reflect a more physiological and synchronous LV activation. The purpose of this study was to compare the QRS morphology, duration, and suitability of RV outflow tract (RVOT) septal and mid-RV septal pacing. Methods: Seventeen consecutive patients with indication for dual-chamber pacing were enrolled in the study. Two standard 58-cm active fixation leads were passed to the RV and positioned in the RVOT septum and mid-RV septum using a commercially available septal stylet (model 4140, St. Jude Medical, St. Paul, MN, USA). QRS duration, morphology, and pacing parameters were compared at the two sites. The RV lead with less-satisfactory electrical parameters was withdrawn and deployed in the right atrium. Results: Successful positioning of the pacing leads at the RVOT septum and mid-RV septum was achieved in 15 patients (88.2%). There were no significant differences in the mean stimulation threshold, R-wave sensing, and lead impedance between the two sites. The QRS duration in the RVOT septum was 151 ± 14 ms and in the mid-RV septum 145 ± 13 ms (P = 0.150). Conclusions: This prospective observational study shows that septal pacing can be reliably achieved both in the RVOT and mid-RV with active fixation leads using a specifically shaped stylet. There are no preferences in regard to acute lead performance or paced QRS duration with either position. (PACE 2010; 33:1169,1173) [source] Cardiac Resynchronization Therapy in Non-Left Bundle Branch Block MorphologiesPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 5 2010JOHN RICKARD M.D. Introduction: In select patients with systolic heart failure, cardiac resynchronization therapy (CRT) has been shown to improve quality of life, exercise capacity, ejection fraction (EF), and survival. Little is known about the response to CRT in patients with right bundle branch block (RBBB) or non-specific intraventricular conduction delay (IVCD) compared with traditionally studied patients with left bundle branch block (LBBB). Methods: We assessed 542 consecutive patients presenting for the new implantation of a CRT device. Patients were placed into one of three groups based on the preimplantation electrocardiogram morphology: LBBB, RBBB, or IVCD. Patients with a narrow QRS or paced ventricular rhythm were excluded. The primary endpoint was long-term survival. Secondary endpoints were changes in EF, left ventricular end-diastolic and systolic diameter, mitral regurgitation, and New York Heart Association (NYHA) functional class. Results: Three hundred and thirty-five patients met inclusion criteria of which 204 had LBBB, 38 RBBB, and 93 IVCD. There were 32 deaths in the LBBB group, 10 in the RBBB, and 27 in the IVCD group over a mean follow up of 3.4 ± 1.2 years. In multivariate analysis, no mortality difference amongst the three groups was noted. Patients with LBBB had greater improvements in most echocardiographic endpoints and NYHA functional class than those with IVCD and RBBB. Conclusion: There is no difference in 3-year survival in patients undergoing CRT based on baseline native QRS morphology. Patients with RBBB and IVCD derive less reverse cardiac remodeling and symptomatic benefit from CRT compared with those with a native LBBB. (PACE 2010; 590,595) [source] A Technique for the Rapid Diagnosis of Wide Complex Tachycardia with 1:1 AV Relationship in the Electrophysiology LaboratoryPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 4 2009AMIR ABDELWAHAB M.B. B.Ch., M.Sc. Background:The differential diagnosis of wide complex tachycardia (WCT) with 1:1 atrioventricular (AV) relationship is broad. Accurate identification of the tachycardia mechanism is essential for successful ablation. We suggest a simple pacing maneuver that can immediately clarify the tachycardia mechanism in the electrophysiology laboratory. Methods:Eight consecutive patients (four males, 32 ± 14 years) demonstrating stable sustained WCT with persistent 1:1 AV relationship during electrophysiologic testing were included in this study. During the tachycardia, atrial overdrive pacing was performed. The following responses were observed: (1) a change of the QRS morphology during atrial pacing and (2) the first return electrogram of the tachycardia, whether occurring in the atrium (AVA response) or in the ventricle (AVVA response). Results:Atrial overdrive pacing was successfully performed in all patients. It was associated with either a change or narrowing of the QRS in all ventricular tachycardia (VT) patients but not in supraventricular tachycardia (SVT) patients. All VT patients had an AVVA response upon cessation of atrial overdrive pacing as opposed to AVA response in SVT patients, P = 0.029. Conclusion:The response to atrial overdrive pacing during WCT with 1:1 AV relationship can rapidly diagnose or rule out VT as a mechanism of tachycardia. [source] Cardiac Resynchronization Therapy in Patients with Mildly Impaired Left Ventricular FunctionPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2009PAUL W.X. FOLEY M.R.C.P. Aims: We sought to determine the unknown effects of cardiac resynchronization therapy (CRT) in patients with a left ventricular ejection fraction (LVEF) >35%. Because of its technical limitations, echocardiography (Echo) may underestimate LVEF, compared with cardiovascular magnetic resonance (CMR). Methods: Of 157 patients undergoing CRT (New York Heart Association [NYHA] functional class III or IV, QRS , 120 ms), all of whom had a preimplant Echo-LVEF ,35%, 130 had a CMR-LVEF ,35% (Group A, 19.7 ± 7.0%[mean ± standard deviation]) and 27 had a CMR-LVEF >35% (Group B, 43.6 ± 7.7%). All patients underwent a CMR scan at baseline and a clinical evaluation, including a 6-minute walk test and a quality of life questionnaire, at baseline and after CRT. Results: Both groups derived similar improvements in NYHA functional class (A =,1.3, B =,1.2, [mean]), quality of life scores (A =,21.6, B =,33.0; all P < 0.0001 for changes from baseline), and 6-minute walking distance (A = 64.5, B = 70.1 m; P < 0.001 and P < 0.0001, respectively). Symptomatic response rates (increase by ,1 NYHA classes or 25% 6-minute walking distance) were 79% in group A and 92% in group B. Over a maximum follow-up period of 5.9 years for events, patients in group A were at a higher risk of death from any cause, hospitalization for major cardiovascular events (P = 0.0232), or cardiovascular death (P = 0.0411). There were borderline differences in the risk of death from any cause (P = 0.0664) and cardiovascular death or hospitalization for heart failure (P = 0.0526). Conclusions: This observational study suggests that the benefits of CRT extend to patients with a LVEF > 35%. [source] Validation of Criteria for Selective His Bundle and Para-Hisian Permanent PacingPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 12 2006F. CANTÙ M.D. Background: His Bundle (HB) pacing is a valid alternative to right ventricular pacing for patients with preserved His-ventricle conduction who are candidates for permanent stimulation. Permanent pacing in the HB area enables Selective HB pacing (SHBP) or para-Hisian pacing (PHP) to be achieved. The aim of our study was to draw up a set of easy criteria to differentiate and validate the two kinds of stimulations according to the pacing output and the ECG/EKG signals. Methods and Results: From February to July 2005, 17 patients eligible for a pacemaker (PM) procedure underwent implantation with the Medtronic SelectSecure® lead (Medtronic, Minneapolis, MN, USA) screwed into the HB area.SHBP was defined when the intrinsic QRS was equal, in both duration and morphology, to the paced QRS, the His-Ventricular (H-V) interval was equal to Pace-Ventricular interval (Vp-V) and, at low output, only the HB was captured, while increasing the output resulted in both the HB and right ventricular (RV) being captured (widening of QRS at high output). Conversely, PHP was defined when the intrinsic QRS differed from the paced one, either in morphology or in duration and, at high output, both the RV and HB were captured (non-SHBP), while decreasing the output resulted in losing HB capture (widening of QRS at low output). According to these criteria, SHBP was achieved in 11 patients, while in the remaining 6, PHP was obtained. No adverse events were reported. Conclusions: The above criteria enabled SHBP and PHP to be validated easily and clearly. A longer follow-up will be needed in order to ascertain whether the clinical outcome of these two approaches differs. [source] Influence of Drive Cycle Length on Initiation of Ventricular Fibrillation During Implantable Cardioverter Defibrillator Threshold TestingPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 9 2006NEIL K. SANGHVI Background: Programmed electrical stimulation of the heart as a method to induce tachyarrhythmias has been described since the 1960s. To date, no study has examined optimal drive cycle length in the induction of ventricular fibrillation (VF) during defibrillation threshold testing after implantable cardioverter-defibrillator placement. We hypothesized that longer drive cycle length, by means of the longer action potential duration, would promote intramyocardial phase 2 reentry and facilitate induction of VF. Methods: Fifty consecutive implants were randomized in a prospective crossover format for this study. The group consisted of 40 men and 10 women, with each patient receiving either a 400 or 600 ms initial drive train prior to 1.2 J internal shock on the T wave with a goal to induce ventricular fibrillation. The timing of the T wave shock was determined by measuring the interval from the beginning of the QRS to the apex of the T wave in lead II. Successful inductions were defibrillated via the cardioverter defibrillator. Patients were then crossed over and the protocol repeated. Results: Twenty of 23 (87%) patients were successfully induced into VF in the initial 400 ms drive train arm whereas 22 of 27 (81%) were successfully induced in the 600 ms arm. Thus, a total of 44 (88%) patients were successfully induced at 400 ms, 41 (82%) patients were successfully induced at 600 ms, and 2 (4%) patients were not inducible at either cycle length, but were inducible with 50 Hz ventricular stimulation. However, no significant difference was noted between the two groups. Conclusion: No investigation to date has questioned whether a relationship exists between drive cycle length and initiation of ventricular fibrillation. Our study addresses this question, though negative for difference between 400 and 600 ms drive trains. Further research into optimal strategies for inducing ventricular fibrillation will minimize patient sedation time and discomfort while undergoing defibrillator threshold testing. [source] Improvement of Congestive Heart Failure by Upgrading of Conventional to Resynchronization PacemakersPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 8 2006IBRAHIM MARAI Aims: To compare the clinical response of patients with right ventricular apical pacing (RVAP) upgraded to cardiac resynchronization therapy (CRT) to that of previously nonpaced heart failure (HF) patients who had de novo CRT implantation. Background: The role of CRT in patients with wide QRS and HF due to RVAP is less well established than in other CRT candidates. Methods: Ninety-eight consecutive patients with CRT were studied (mean age 70, mean ejection fraction 0.23). Group A: patients having RVAP prior to CRT implantation (n = 25), group B: patients without prior RVAP (n = 73). Clinical and echocardiographic parameters were recorded prior to, and 3 months after, CRT implantation. Results: Group A patients had a wider QRS at baseline compared to group B (203 ± 32 ms vs 163 ± 30 ms respectively, P < 0.001), and a shorter 6-minute walking distance (222 ± 118 m vs 362 ± 119 m, respectively, P < 0.005). Otherwise, clinical and echocardiographic parameters were not different. At follow up, group A patients had an average 0.7 ± 0.5 decrease in their NYHA functional class, compared to 0.3 ± 0.7 in group B patients (P < 0.05). Six-minute walking distance increased by 93 ± 113 m in group A, versus 36 ± 120 m in group B (P = 0.22). There was no difference in echocardiographic response to CRT between the groups. Conclusions: HF patients with prior RVAP demonstrate clinical improvement after upgrading to CRT that is comparable, and in some aspects, even better than that observed in HF patients with native conduction delay who undergo de novo CRT implantation. [source] Epicardial Ablation of Ventricular Tachycardia Associated with Isolated Ventricular NoncompactionPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 7 2006HONG EUY LIM A 52-year-old man presented with sudden onset of palpitations and dizziness. Echocardiogram confirmed the diagnosis of isolated noncompaction of ventricular myocardium with moderated systolic dysfunction, and the electrocardiogram (ECG) revealed ventricular tachycardia (VT), of which the focus seemed to match an area of prominent left ventricular noncompaction on the 12-lead surface ECG. Through the activation mapping from the endo- and epicardium, simultaneously, a discrete potential preceding the QRS during VT was observed at the anterolateral epicardial wall. He subsequently underwent radiofrequency ablation, and VT was successfully eliminated. [source] Multichannel mapping of fetal magnetocardiogram in an unshielded hospital settingPRENATAL DIAGNOSIS, Issue 5 2005Donatella Brisinda Abstract Objectives To evaluate the feasibility of unshielded in-hospital multichannel mapping of fetal magnetocardiogram (FMCG), with a 36-channel system for standard adult magnetocardiographic (MCG) recordings, and its reliability according to the recommended standards for FMCG. Methods FMCG was ambulatory mapped with a 36-channel MCG system, in six normal pregnancies at different gestational ages. MCG analysis included adaptive digital filtering of 50 Hz, signal averaging, reconstruction of magnetic field distribution (MFD) and source localization. Fixed Point Independent Component Analysis algorithm (FastICA) was used to reconstruct the FMCG, separating them from maternal contamination and noise. Results The quality of FMCG recorded after the 32nd gestational week and reconstructed with FastICA was close to FMCG obtained in shielded rooms, and good enough to measure cardiac intervals and heart rate variability parameters. In two cases, reconstruction of the MFD during the QRS allowed three-dimensional localization of ventricular sources. Conclusions A first demonstration has been given that multichannel mapping of FMCG can be performed in unshielded clinical environments, with resolution good enough for contactless assessment of fetal cardiac electrophysiology. FastICA processing on unshielded FMCG, recorded after the 32nd week, provided beat-to-beat analysis and heart rate variability assessment. Further work is needed to improve signal reconstruction in early pregnancy. Copyright © 2005 John Wiley & Sons, Ltd. [source] Psychopathology and familial stress , comparison of boys with Fragile X syndrome and Spinal Muscular AtrophyTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 7 2002A. Von Gontard Background: Chronic illness and mental retardation are both associated with an increased rate of behavioural problems in children and with considerable emotional strain in families. The aim of the study was to analyse and compare the specific effects of two exemplary conditions on familial stress and coping. Methods: Forty-nine boys with Fragile X syndrome (FXS) were compared with 46 boys with Spinal Muscular Atrophy (SMA) and 32 male controls. Intelligence was measured with the RAVEN or K-ABC tests. Psychopathology was assessed with the CBCL questionnaire and a structured psychiatric interview (Kinder-DIPS), parental stress with the QRS, coping with the F-COPES and social support with the F-SOZU questionnaires. Results: The mean age of the FXS boys was 8.6, of the SMA boys 12.7 and of the controls 11.2 years. The mean IQ was 47 for the FXS, 112 for the SMA and 103 for the control groups. According to the CBCL, 89.8% of the FXS boys, 21.7% of the SMA and 15.7% of the controls had a total score in the borderline or clinical range. The rates were 63.3%, 34.8% and 21.9% for internalising and 67.3%, 10.9% and 18.8% for externalising behaviour, respectively. 81.6% of the FXS and 10.9% of the SMA patients had a DSM-IV or ICD-10 psychiatric diagnosis. The most common were ADHD (FXS: 36) and Separation Anxiety Disorder (SMA: 4). In total, parental stress was significantly higher in the FXS than in the SMA families (and in both compared to controls). There were no major inter-group differences regarding social support and familial coping. Conclusions: Children with FXS are severely mentally retarded and have a high rate of mainly externalising disorders. Despite good coping abilities and social support, this is associated with high familial stress. The SMA boys, with an intelligence in the upper normal range, are no more deviant than their healthy controls. Parental stress is lower in the SMA families with good coping abilities. In conclusion, families with mentally retarded children are in even greater need of help than those of children with severe chronic illness/physical handicap. Abbreviations: SMA: Spinal Muscular Atrophy; FXS: Fragile X syndrome. [source] Effect of hypertonic saline on electrocardiography QRS duration in rabbit model of bupivacaine toxicity resuscitated by intravenous lipidANAESTHESIA, Issue 8 2010G. Cave Summary Intravenous lipid emulsion is established therapy for bupivacaine induced cardiotoxicity. The benefit of combined hypertonic saline and lipid treatment is unexplored. In this experiment, sedated rabbits were resuscitated from bupivacaine-induced asystole with intravenous lipid according to the Association of Anaesthetists of Great Britain and Ireland's guideline, or by identical lipid dosing with hypertonic saline: 6 mEq.kg,1 21% sodium chloride. Early electrocardiography QRS prolongation was less with lipid plus hypertonic saline (mean (SD) QRS 0.19 (0.07) s lipid only vs 0.09 (0.01) s lipid plus hypertonic saline; p = 0.003) at 9 min though not different from the lipid only group at 20 min. No difference was observed in rates of circulatory return (7/10 lipid only and 9/10 lipid plus hypertonic saline; p = 0.58) or survival (5/10 lipid only and 6/10 lipid plus hypertonic saline; p = 1.00). Some benefit to cardiac conduction may be afforded by hypertonic saline co-administered with lipid emulsion in bupivacaine-induced cardiotoxicity. [source] Dynamics and Rate-Dependence of the Spatial Angle between Ventricular Depolarization and Repolarization Wave Fronts during Exercise ECGANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 3 2010Tuomas Kenttä M.Sc. Background: QRS/T angle and the cosine of the angle between QRS and T-wave vectors (TCRT), measured from standard 12-lead electrocardiogram (ECG), have been used in risk stratification of patients. This study assessed the possible rate dependence of these variables during exercise ECG in healthy subjects. Methods: Forty healthy volunteers, 20 men and 20 women, aged 34.6 ± 3.4, underwent an exercise ECG testing. Twelve-lead ECG was recorded from each test subject and the spatial QRS/T angle and TCRT were automatically analyzed in a beat-to-beat manner with custom-made software. The individual TCRT/RR and QRST/RR patterns were fitted with seven different regression models, including a linear model and six nonlinear models. Results: TCRT and QRS/T angle showed a significant rate dependence, with decreased values at higher heart rates (HR). In individual subjects, the second-degree polynomic model was the best regression model for TCRT/RR and QRST/RR slopes. It provided the best fit for both exercise and recovery. The overall TCRT/RR and QRST/RR slopes were similar between men and women during exercise and recovery. However, women had predominantly higher TCRT and QRS/T values. With respect to time, the dynamics of TCRT differed significantly between men and women; with a steeper exercise slope in women (women, ,0.04/min vs ,0.02/min in men, P < 0.0001). In addition, evident hysteresis was observed in the TCRT/RR slopes; with higher TCRT values during exercise. Conclusions: The individual patterns of TCRT and QRS/T angle are affected by HR and gender. Delayed rate adaptation creates hysteresis in the TCRT/RR slopes. Ann Noninvasive Electrocardiol 2010;15(3):264,275 [source] Aspects of Left Ventricular Morphology Outperform Left Ventricular Mass for Prediction of QRS DurationANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 2 2010Nina Hakacova M.D., Ph.D. Background: The knowledge of the case-specific normal QRS duration in each individual is needed when determining the onset, severity and progression of the heart disease. However, large interindividual variability even of the normal QRS duration exists. The aims of the study were to develop a model for prediction of normal QRS complex duration and to test it on healthy individuals. Methods: The study population of healthy adult volunteers was divided into a sample for development of a prediction model (n = 63) and a testing sample (n = 30). Magnetic resonance imaging data were used to assess anatomical characteristics of the left ventricle: the angle between papillary muscles (PMA), the length of the left ventricle (LVL) and left ventricular mass (LVM). Twelve-lead electrocardiogram (ECG) was used for measurement of the QRS duration. Multiple linear regression analysis was used to develop a prediction model to estimate the QRS duration. The accuracy of the prediction model was assessed by comparing predicted with measured QRS duration in the test set. Results: The angle between PMA and the length of the LVL were statistically significant predictors of QRS duration. Correlation between QRS duration and PMA and LVL was r = 0.57, P = 0.0001 and r = 0.45, P = 0.0002, respectively. The final model for prediction of the QRS was: QRSPredicted= 97 + (0.35 × LVL) , (0.45 × PMA). The predicted and real QRS duration differed with median 1 ms. Conclusions: The model for prediction of QRS duration opens the ability to predict case-specific normal QRS duration. This knowledge can have clinical importance, when determining the normality on case-specific basis. Ann Noninvasive Electrocardiol 2010;15(2):124,129 [source] Fragmented QRS in Prediction of Cardiac Deaths and Heart Failure Hospitalizations after Myocardial InfarctionANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 2 2010Petri Korhonen M.D. Background: Increased QRS fragmentation in visual inspection of 12-lead ECG has shown association with cardiac events in postmyocardial infarction (MI) patients. We investigated user-independent computerized intra-QRS fragmentation analysis in prediction of cardiac deaths and heart failure (HF) hospitalizations after MI. Methods: Patients (n = 158) with recent MI and reduced left ventricular ejection fraction (LVEF) were studied. A 120-lead body surface potential mapping was performed at hospital discharge. Intra-QRS fragmentation was computed as the number of extrema (fragmentation index FI) in QRS. QRS duration (QRSd) was computed for comparison. Results: During a mean follow-up of 50 months 15 patients suffered cardiac death and 23 were hospitalized for HF. Using the mean + 1 SD as cut-point both parameters were univariate predictors of both end-points. In multivariate analysis including age, gender, LVEF, previous MI, bundle branch block, atrial fibrillation, and diabetes FI was an independent predictor for cardiac deaths (HR 8.7, CI 3.0,25.6) and HF hospitalizations (HR 3.8, CI 1.6,9.3) whereas QRSd only predicted HF hospitalizations (HR 4.6, CI 2.0,10.7). In comparison to QRSd, FI showed better positive (PPA) and equal negative (NPA) predictive accuracy for both end-points, and PPA was further improved when combined to LVEF < 40%. Limiting fragmentation analysis to 12-lead ECG or a randomly selected 8-lead set instead of all 120 leads resulted in an almost similar prediction. Conclusions: Increased QRS fragmentation in post-MI patients predicts cardiac deaths and HF progression. A computer-based fragmentation analysis is a stronger predictor than QRSd. Ann Noninvasive Electrocardiol 2010;15(2):130,137 [source] Optimization of Repolarization during Biventricular Pacing: A New Target in Patients with Biventricular Devices?ANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 1 2010Cengizhan Türko, lu M.D. Background: Evaluation of repolarization during sequentional biventricular pacing. Methods: Patients with biventricular devices, and left ventricular leads placed to the basal part of lateral left ventricular wall were enrolled. QRS, QTc, JTc, and corrected Tpeak-Tend intervals were compared during sequentional biventricular, left ventricular, and right ventricular pacing. Results: Five patients with nonischemic and five with ischemic cardiomyopathy due to anterior myocardial infarction were enrolled. No correlation was observed between values of repolarization among patients. The optimal values of repolarization were significantly different from values of echocardiographically guided hemodynamic optimization. Two patients with biventricular pacing-induced ventricular fibrillation were successfully treated by reprogramming of V-V delay according to interventricular delay resulting in shorter Tpeak-Tend interval, although delayed effect of amiodarone in one of these patients cannot be ruled out. Conclusions: Patients with biventricular devices may be prone to development of ventricular arrhythmias depending on programmed V-V interval. We suggest that optimization of repolarization may be performed in patients with biventricular pacemakers in the absence of backup ICD and those with frequent episodes of ventricular tachyarrhythmias, although this finding deserves further study. Ann Noninvasive Electrocardiol 2010;15(1):36,42 [source] Correlation of Mechanical Dyssynchrony with QRS Duration Measured by Signal-Averaged ElectrocardiographyANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 3 2009F.E.S.C., George K. Andrikopoulos M.D. Background: Preimplantation left ventricular dyssynchrony is considered a prerequisite for a beneficial response to cardiac resynchronization therapy (CRT). However, electrical dyssynchrony estimated by QRS duration (QRSd) on ECG has not been proven to be an optimal surrogate of mechanical dyssynchrony. We evaluated the correlation of mechanical dyssynchrony with QRSd as measured by signal-averaged electrocardiography (SAECG) in comparison with measurements based on conventional surface ECG and with onscreen measurements based on digital ECG. Methods: We included 49 consecutive patients with decompensated heart failure (40 men, aged 66.8 ± 9.5 years), New York Heart Association (NYHA) class II,IV, and LVEF , 40%. QRSd was calculated by manual measurement of 12-lead ECG, on-screen measurement of computer-based ECG, and calculation of total ventricular activation time on SAECG. Results: Only 60.4% of the studied patients had QRS , 120 ms based on measurements derived by SAECG compared to 69.4% by using on-screen measurement of computer-based ECG and 73.5% based on surface ECG (P = 0.041). Interventricular but not intraventricular delay was correlated with QRSd. The correlation of interventricular dyssynchrony with QRSd was stronger when measured by SAECG than by surface ECG (r = 0.45, P = 0.001 vs r = 0.35, P < 0.01). Among patients with ischemic cardiomyopathy, no significant correlation was demonstrated between mechanical dyssynchrony and QRSd. In nonischemic patients, interventricular delay was significantly correlated with QRSd measured by surface ECG (r = 0.45, P < 0.05) and SAECG (r = 0.46, P < 0.05). Conclusions: The use of SAECG results in different patient classification in wide QRS complex category as compared to surface ECG. Furthermore, QRSd measured by SAECG is correlated with interventricular but not intraventricular dyssynchrony in heart failure patients. [source] | |||||||||||||