Home  About us  Contact
 

QRS Morphology (qr + morphology)

Distribution by Scientific Domains
Medical Sciences100%

Selected Abstracts

Different Narrow QRS Morphologies in the Surface ECG: What is the Mechanism?

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 8 2009
LUCIO CAPULZINI M.D.
No abstract is available for this article. [source]

A Sudden Change in QRS Morphology

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 6 2002
ATA KIRILMAZ
No abstract is available for this article. [source]

Left Bundle Branch Block with Changing QRS Morphology

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 4 2000
ANIL RANGINANI
No abstract is available for this article. [source]

Radiofrequency Catheter Ablation of Idiopathic Ventricular Tachycardia Originating in the Main Stem of the Pulmonary Artery

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2002
CARL TIMMERMANS M.D.
Idiopathic Pulmonary Artery Ventricular Tachycardia. We report the case of a patient in whom successful radiofrequency catheter ablation of an idiopathic ventricular tachycardia (VT) originating in the main stem of the pulmonary artery was performed. After successful ablation of the index arrhythmia, which was an idiopathic right ventricular outflow tract VT, a second VT with a different QRS morphology was reproducibly induced. Mapping of the second VT revealed the presence of myocardium approximately 2 cm above the pulmonary valve. Application of radiofrequency energy at this site resulted in termination and noninducibility of this VT. After 6-month follow-up, the patient remained free from VT recurrences. [source]

Right Ventricular Septal Pacing: A Comparative Study of Outflow Tract and Mid Ventricular Sites

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 10 2010
RAPHAEL 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 Morphologies

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 5 2010
JOHN 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 Laboratory

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 4 2009
AMIR 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]

Electrocardiogram-Based Algorithm to Predict the Left Ventricular Lead Position in Recipients of Cardiac Resynchronization Systems

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2009
SYLVAIN PLOUX M.D.
Introduction: Biventricular pacing is associated with various electrocardiographic patterns depending on the position of the left ventricular (LV) lead. We aimed to develop an electrocardiogram-based algorithm to predict the position of the LV lead. Methods: The algorithm was developed in 100 consecutive recipients of cardiac resynchronization therapy (CRT) systems. QRS axis, morphology, and polarity were analyzed with a view to define the specific electrocardiographic characteristics associated with the various LV lead positions. The algorithm was prospectively validated in 50 consecutive CRT device recipients. Results: The first analysis of the algorithm was the QRS morphology in V1. A positive R wave in V1 suggested LV lateral or posterior wall stimulation. A QS pattern was specific of anterior LV leads. In the presence of an R wave in V1, V6 was analyzed to distinguish between an inferior and anterior LV lead. Inferior leads were never associated with a positive V6. To differentiate between lateral and posterior positions, we analyzed the pattern in V2. Lateral leads were associated with an R morphology in V1 and a negative V2. Posterior leads were associated with an R morphology in V1 and V2. The algorithm allowed a reliable distinction between an inferior or anterior and a lateral or posterior lead position in 90% of patients. Inferior, anterior, lateral, and posterior positions were reliably distinguished in 80% of patients. Conclusion: This algorithm predicted the position of the LV lead with a high sensitivity and predictive value. [source]

Nontransmural Scar Detected by Magnetic Resonance Imaging and Origin of Ventricular Tachycardia in Structural Heart Disease

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2009
MIKI YOKOKAWA M.D.
Background: Contrast-enhanced magnetic resonance imaging (CMR) identifies scar tissue as an area of delayed enhancement (DE). The scar region might be the substrate for ventricular tachycardia (VT). However, the relationship between the occurrence of VT and the characteristics of scar tissue has not been fully studied. Methods: CMR was performed in 34 patients with monomorphic, sustained VT and dilated cardiomyopathy (DCM, n = 18), ischemic cardiomyopathy (ICM, n = 10), or idiopathic VT (IVT, n = 6). The VT exit site was assessed by a detailed analysis of the QRS morphology, including bundle branch block type, limb lead polarity, and precordial R-wave transition. On CMR imaging, the transmural score of each of the 17 segments was assigned, using a computer-assisted, semiautomatic technique, to measure the DE areas. Segmental scars were classified as nontransmural when DE was 1,75% and transmural when DE was 76,100% of the left ventricular mass in each segment. Results: A scar was detected in all patients with DCM or ICM. Nontransmural scar tissue was often found at the VT exit site, in patients with DCM or ICM. In contrast, no scar was found in patients with IVT. Conclusions: CMR clarified the characteristics and distribution of scar tissue in patients with structural heart disease, and the presence and location of scar tissue might predict the VT exit site in these patients. [source]

Activation Sequence Modification During Cardiac Resynchronization by Manipulation of Left Ventricular Epicardial Pacing Stimulus Strength

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1 2007
USHA B. TEDROW M.D.
Background: Success of cardiac resynchronization therapy (CRT) depends on altering electrical ventricular activation (VA) to achieve mechanical benefit. That increases in stimulus strength (SS) can affect VA has been demonstrated previously in cardiomyopathy patients undergoing ablation. Objective: To determine whether increasing SS can alter VA during CRT. Methods: In 71 patients with CRT devices, left ventricle (LV) pacing was performed at escalating SS. Timing from pacing stimulus to right ventricular (RV) electrogram, ECG morphology, and maximal QRS duration on 12 lead ECG were recorded. Results: Demographics: Baseline QRS duration 153 ± 25 ms, ischemic cardiomyopathy 48%, ejection fraction 24%± 7%. With increased SS, conduction time from LV to right ventricle (RV) decreased from 125 ± 56 ms to 111 ± 59 ms (P = 0.006). QRS duration decreased from 212 ± 46 ms to 194 ± 42 ms (P = 0.0002). A marked change in QRS morphology occurred in 11/71 patients (15%). The RV ring was the anode in 6, while the RV coil was the anode in 5. Sites with change in QRS morphology showed decrease in conduction time from LV to RV from 110 ± 60 ms to 64 ± 68 ms (P = 0.04). Twelve patients (16%) had diaphragmatic stimulation with increased SS. Conclusions: Increasing LV SS reduces QRS duration and conduction time from LV to RV. Recognition of significant QRS morphology change is likely clinically important during LV threshold programming to avoid unintended VA change. [source]

Electrophysiologic Characteristics of Wide QRS Complexes during Pharmacologic Termination of Sustained Supraventricular Tachycardias with Verapamil and Adenosine: Observations from Electrophysiologic Study

ANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 4 2009
Cengizhan Türko, lu M.D.
Background: In this study we evaluate wide QRS complexes observed during pharmacologic termination of supraventricular tachycardias. Methods: Patients with supraventricular tachycardia, undergoing electrophysiologic study were enrolled. 12 mg of adenosine or 10 mg of verapamil were administered during tachycardia, under continuous monitoring of intaracardiac and surface electrocardiograms. Electrocardiographic features of ventricular ectopy were noted. Results: Seventy-four patients were enrolled. 48 patients were randomized to adenosine and 26 to verapamil. Five different appearance patterns of ventricular ectopy were observed during termination of tachycardias. All wide QRS complexes were of ventricular origin and all of them were observed during the termination of tachycardia. Adenosine more frequently resulted in appearance of ventricular beats (15.4% vs 41.7%, P = 0.003), and this was more frequently observed in patients with atrioventricular nodal reentrant tachycardia. Patients with ventricular beats were younger than those without, in both, verapamil (47.5 ± 15.6 vs 65.0 ± 8.8 years, P = 0.04) and adenosine (40.9 ± 13.8 vs 49.7 ± 16.8, P = 0.03) groups. Left bundle branch block (LBBB)/superior axis morphology was most frequent morphology in adenosine group (55%). Two of 4 patients in verapamil group displayed LBBB/inferior axis QRS morphology and another 2 patients displayed LBBB/superior axis morphology. Conclusions: Noncatheter induced, five different appearance patterns and four distinct morphologies of ventricular origin were observed. Most of them do not directly terminate tachycardia, but are associated with its termination and are not observed in ongoing tachycardia. [source]