CONGENITAL HEART DISEASE, Issue 5 2008
Neil Bhogal MD
ABSTRACT A 13-month-old boy presented with acute onset of complete atrioventricular block and wide complex tachycardia but normal hemodynamics. Endomyocardial biopsy disclosed active myocarditis with eosinophils, suggesting a hypersensitivity reaction. With no treatment, the rhythm disturbance resolved within days of onset. Our patient's presentation and self-limited illness is unique. To our knowledge, this is only the second reported case of eosinophilic myocarditis in a young child or infant. [source]

Verapamil-sensitive Ventricular Tachycardia in an Infant

CONGENITAL HEART DISEASE, Issue 3 2006
Christopher Snyder MD
ABSTRACT Patients., We report on a 6-month-old patient with a right bundle, superior axis tachycardia at 197 beats per minute. The tachycardia was unresponsive to adenosine, propranolol, flecainide, or amiodarone, or synchronized cardioversion. Overdrive atrial pacing terminated the tachycardia and since initiating verapamil, no recurrences of his tachycardia have occurred. Conclusions., If an infant presents with a right bundle, superior axis ventricular tachycardia unresponsive to multiple antiarrhythmic medications and synchronized cardioversion, but responsive to overdrive atrial pacing, one must consider verapamil-sensitive ventricular tachycardia and initiate appropriate therapy. [source]

Adenosine and Caffeine-induced Paroxysmal Supraventricular Tachycardia

ACADEMIC EMERGENCY MEDICINE, Issue 5 2010
Harry C. Karydes DO
No abstract is available for this article. [source]

Amiodarone or Procainamide for the Termination of Sustained Stable Ventricular Tachycardia: An Historical Multicenter Comparison

ACADEMIC EMERGENCY MEDICINE, Issue 3 2010
Keith A. Marill MD
Abstract Objectives:, The objective was to compare the effectiveness of intravenous (IV) procainamide and amiodarone for the termination of spontaneous stable sustained ventricular tachycardia (VT). Methods:, A historical cohort study of consecutive adult patients with stable sustained VT treated with IV amiodarone or procainamide was performed at four urban hospitals. Patients were identified for enrollment by admissions for VT and treatment with the study agents in the emergency department (ED) from 1993 to 2008. The primary measured outcome was VT termination within 20 minutes of onset of study medicine infusion. A secondary effectiveness outcome was the ultimate need for electrical therapy to terminate the VT episode. Major adverse effects were tabulated, and blood pressure responses to medication infusions were compared. Results:, There were 97 infusions of amiodarone or procainamide in 90 patients with VT, but the primary outcome was unknown after 14 infusions due to administration of another antidysrhythmic during the 20-minute observation period. The rates of VT termination were 25% (13/53) and 30% (9/30) for amiodarone and procainamide, respectively. The adjusted odds of termination with procainamide compared to amiodarone was 1.2 (95% confidence interval [CI] = 0.4 to 3.9). Ultimately, 35/66 amiodarone patients (53%, 95% CI = 40 to 65%) and 13/31 procainamide patients (42%, 95% CI = 25 to 61%) required electrical therapy for VT termination. Hypotension led to cessation of medicine infusion or immediate direct current cardioversion (DCCV) in 4/66 (6%, 95% CI = 2 to 15%) and 6/31 (19%, 95% CI = 7 to 37%) patients who received amiodarone and procainamide, respectively. Conclusions:, Procainamide was not more effective than amiodarone for the termination of sustained VT, but the ability to detect a significant difference was limited by the study design and potential confounding. As used in practice, both agents were relatively ineffective and associated with clinically important proportions of patients with decreased blood pressure. ACADEMIC EMERGENCY MEDICINE 2010; 17:297,306 © 2010 by the Society for Academic Emergency Medicine [source]

Successful Catheter Ablation and Documentation of the Activation and Propagation Pattern During a Left Atrial Focal Tachycardia in a Patient with Cor Triatriatum Sinister

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2010
KOICHIRO EJIMA M.D.
Atrial Tachycardia in Cor Triatriatum. We report a case of an atrial tachycardia (AT) originating from the left atrium (LA) associated with cor triatriatum sinister. Electroanatomical mapping of the 2 subdivided chambers of the LA during the AT revealed a centrifugal activation pattern from the posterior wall of the accessory chamber near the left superior pulmonary vein. The propagation map on the CARTO system revealed that the AT wave front spread centrifugally over the "accessory chamber," turned around the edge of the membrane subdividing the LA, and then spread over the "main chamber." A single radiofrequency application successfully abolished the AT. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1050-1054, September 2010) [source]

Efficacy of Ivabradine in a Case of Inappropriate Sinus Tachycardia and Ventricular Dysfunction

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2010
ANTONELLA SETTE M.D.
Ivabradine in IST., We present a case of a 49-year-old man with inappropriate sinus tachycardia and ventricular dysfunction. The conventional treatment (ace-inhibitor and beta-blockers) was not well tolerated by the patient, so Ivabradine, a specific inhibitor of If current in the sinus node, was started. After 3 months of using this medication, we observed an improvement of ejection fraction and quality of life. (J Cardiovasc Electrophysiol, Vol. pp. 815-817, July 2010) [source]

A Long-RP Narrow QRS Complex Tachycardia With Alternating Cycle Length: What is the Mechanism?

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2010
MIGUEL A. ARIAS M.D., Ph.D.
No abstract is available for this article. [source]

Ventricular Entrainment of a Long-RP Supraventricular Tachycardia

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2010
MIGUEL A. ARIAS M.D., Ph.D.
No abstract is available for this article. [source]

Distinguishing Far-Field Appendage from Local Pulmonary Vein Signal in the Left Upper Pulmonary Vein During Atrial Tachycardia

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2010
EDWARD DUNCAN Ph.D.
First page of article [source]

Extreme Pulmonary Vein Tachycardia,Clue or Distraction?

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2010
KAH-LENG HO M.B.B.S.
No abstract is available for this article. [source]

Characteristics of Complex Fractionated Electrograms in Nonpulmonary Vein Ectopy Initiating Atrial Fibrillation/Atrial Tachycardia

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2009
LI-WEI LO M.D.
Background: Nonpulmonary vein (PV) ectopy initiating atrial fibrillation (AF)/atrial tachycardia (AT) is not uncommon in patients with AF. The relationship of complex fractionated atrial electrograms (CFAEs) and non-PV ectopy initiating AF/AT has not been assessed. We aimed to characterize the CFAEs in the non-PV ectopy initiating AF/AT. Methods: Twenty-three patients (age 53 ± 11 y/o, 19 males) who underwent a stepwise AF ablation with coexisting PV and non-PV ectopy initiating AF or AT were included. CFAE mapping was applied before and after the PV isolation in both atria by using a real-time NavX electroanatomic mapping system. A CFAE was defined as a fractionation interval (FI) of less than 120 ms over 8-second duration. A continuous CFAE (mostly, an FI < 50 ms) was defined as electrogram fractionation or repetitive rapid activity lasting for more than 8 seconds. Results: All patients (100%) with non-PV ectopy initiating AF or AT demonstrated corresponding continuous CFAEs at the firing foci. There was no significant difference in the FI among the PV ostial or non-PV atrial ectopy or other atrial CFAEs (54.1 ± 5.6, 58.3 ± 11.3, 52.8 ± 5.8 ms, P = 0.12). Ablation targeting those continuous CFAEs terminated the AF and AT and eliminated the non-PV ectopy in all patients (100%). During a follow-up of 7 months, 22% of the patients had an AF recurrence with PV reconnections. There was no recurrence of any ablated non-PV ectopy during the follow-up. Conclusion: The sites of the origin of the non-PV ectopies were at the same location as those of the atrial continuous CFAEs. Those non-PV foci were able to initiate and sustain AF/AT. By limited ablation targeting all atrial continuous CFAEs, the AF could be effectively eliminated. [source]

Patients with Scar-Related Right Ventricular Tachycardia: Determinants of Long-Term Outcome

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 10 2009
ADRIANUS P. WIJNMAALEN M.D.
Introduction: Patients with established arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) based on task force (TF) criteria and ventricular tachycardia (VT) are at risk of VT recurrence and sudden death. Data on patients with VT due to right ventricular (RV) scar not fulfilling TF criteria are lacking. The purpose of this study was to assess the long-term arrhythmia recurrence rate and outcome in patients with scar-related right VT with and without a diagnosis of ARVC/D. Methods: Sixty-four patients (age 43.5 ± 15 years, 49 males) presenting with nonischemic scar-related VT of RV origin were studied. Scar was identified by electroanatomical mapping, contrast echocardiography, and/or magnetic resonance imaging (MRI). Patients were evaluated and treated according to a standard institute protocol. Results: Twenty-nine (45%) patients were diagnosed with ARVC/D according to TF criteria (TF+) and 35 (55%) with RV scar of undetermined origin (TF,) at the end of follow-up (64 ± 42 months). Patients were treated with antiarrhythmic drugs, radiofrequency catheter ablation, and/or implantable cardioverter-defibrillator (ICD) implantation. VT recurrence-free survival for TF+ and TF, was 76% versus 74% at 1 year and 45% versus 50% at 4 years (P = ns). Patients with fast index VT (cycle length [CL], 250 ms, n = 31) were more likely to experience a fast VT during follow-up than patients with a slow index VT (CL > 250 ms, n = 33) (61% vs 3%, P < 0.001). Conclusions: Scar-related RV VTs have a high recurrence rate in TF+ and TF, patients. Patients presenting with a fast index VT are at high risk for fast VT recurrence and may benefit most from ICD therapy. [source]

Alternating Cycle Length During Supraventricular Tachycardia: What is the Mechanism?

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2009
ERIC BUCH M.D.
[source]

Mechanism of Wide Complex Tachycardia in a Structurally Normal Heart

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2009
ZIAD F. ISSA M.D.
[source]

Mode of Induction of Ventricular Tachycardia and Prognosis in Patients with Coronary Disease: The Multicenter UnSustained Tachycardia Trial (MUSTT)

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 8 2009
JONATHAN P. PICCINI M.D.
Introduction: Programmed stimulation is an important prognostic tool in the evaluation of patients with an ejection fraction ,40% after myocardial infarction. Many believe that ventricular tachycardia (VT) requiring 3 ventricular extrastimuli (VES) for induction is less likely to occur spontaneously and has less predictive value. However, it is unknown whether the mode of VT induction is associated with long-term prognosis. Methods and Results: We analyzed a cohort of 371 patients enrolled in MUSTT who had inducible monomorphic VT and who were not treated with antiarrhythmic drugs or an implantable cardioverter defibrillator during the trial. Patients in whom sustained VT was induced with 1 or 2 VES or burst pacing (single VES n = 15, double VES n = 127, burst n = 7, total n = 149) were compared with those in whom VT was induced with 3 VES (n = 222). Compared with the others, patients requiring 3 VES were closer to their most recent myocardial infarction (17 vs 51 months, P = 0.035) and showed a trend toward a lower ejection fraction (26% vs 30%, P = 0.057). VT requiring 3 VES had a shorter cycle length (240 vs 260 ms, P < 0.001). Despite these findings, there was no difference in the incidence of arrhythmic death or cardiac arrest (HR 1.02; 95% CI 0.69-1.51) or all-cause mortality (HR 1.03; 95% CI 0.76-1.39) according to the mode of induction in adjusted analyses. Conclusions: The prognostic significance of VT induced by 3 VES is similar to that of VT induced by 1 or 2 VES, or burst pacing, in patients with coronary disease and abnormal LV function. [source]

Unraveling the Mechanism of a Wide-Complex Tachycardia

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2009
IRINA HORDUNA M.D.
No abstract is available for this article. [source]

Spontaneous Onset of Ventricular Fibrillation during Atrioventricular Nodal Reentrant Tachycardia

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2009
CHRISTIAN VON BARY M.D.
No abstract is available for this article. [source]

Origin of Atrial Tachycardia: The High Right Atrium or Right Superior Pulmonary Vein?

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2009
SHINYA KOWASE M.D.
No abstract is available for this article. [source]

Maintenance of Atrial Fibrillation by Pulmonary Vein Tachycardia with Ostial Conduction Block: Evidence of an Interpulmonary Vein Electrical Connection

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 10 2008
SEIICHIRO MATSUO M.D.
We report a case of a 56-year-old man with paroxysmal atrial fibrillation who underwent segmental, ostial pulmonary vein (PV) isolation while in arrhythmia. During isolation of the left superior PV (LSPV), organized electrical activity was seen within the vein, suggestive of a PV tachycardia with a cycle length of 90 ms. Simultaneously, organized electrical activity with a cycle length of 180 ms was seen in the left inferior PV (LIPV), suggestive of 2:1 conduction between the LSPV and the LIPV. Isolation of the LIPV resulted in conversion to sinus rhythm, while confirming isolation of the LSPV by the presence of ongoing PV tachycardia in this vein. This case demonstrates a direct electrical connection between the ipsilateral left PVs, leading to maintenance of atrial fibrillation. [source]

Quantitative Analysis of the Duration of Slow Conduction in the Reentrant Circuit of Ventricular Tachycardia After Myocardial Infarction

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2008
YI-GANG LI M.D.
Background: Few data are available to define the circuits in ventricular tachycardia (VT) after myocardial infarction and the conduction time (CT) through the zone of slow conduction (SCZ). This study assessed the CT of the SCZ and identified different reentrant circuits. Methods: During VTs, concealed entrainment (CE) was attempted. The SCZ was identified by a difference between postpacing interval (PPI) and VT cycle length (VTcl) ,30 ms. Since the CT in the normally conducting part of the VT circuit is constant during VT and CE, a CE site within the reentrant circuit with (S-QRS)/PPI , 50% was classified as an inner reentry in which the entire circuit was within the scar, and a CE site with (S-QRS)/PPI < 50% as a common reentry in which part of the circuit was within the scar and part out of the scar. Results: CE was achieved in 20 VTs (12 patients). Six VTs (30%) with a (S-QRS)/PPI ,50% were classified as inner reentry and 14 VTs (70%) with a (S-QRS)/PPI <50% during CE mapping as common reentry. The EG-QRS interval (308 ± 73 ms vs 109 ± 59 ms, P < 0.0001) was significantly longer and the incidence of systolic potentials higher (4/6 vs 0/12, P < 0.001) in the inner reentry group. For the 14 VTs with a common reetry, the CT of the SCZ was 348 ± 73 ms, while the CT in the normal area was 135 ± 50 ms. Conclusion: According to the proposed classification, 30% of VTs after myocardial infarction had an entire reentrant circuit within the scar. In VTs with a common reentrant circuit, the CT of the SCZ is approximately four times longer than the CT in the normal area, accounting for more than 70% of VTcl. [source]

Anatomy and Physiology of the Right Interganglionic Nerve: Implications for the Pathophysiology of Inappropriate Sinus Tachycardia

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2008
JING ZHOU M.D.
Objective: To simulate inappropriate sinus tachycardia (IST) in experimental animals. Background: We recently found that epinephrine injected into the anterior right ganglionated plexi (ARGP) adjacent to the sinoatrial (SA) node induced an arrhythmia simulating IST. Methods: In 19 anesthetized dogs, via a right thoracotomy, the course of the interganglionic nerve (IGN) from the right stellate ganglion along the superior vena cava to the heart was delineated. High-frequency stimulation (HFS; 0.1 msec duration, 20 Hz, 4.5,9.3 V) was applied to IGN at the junction of innominate vein and SVC. Results: HFS of the IGN significantly increased the sinus rate (SR) (baseline: 156 ± 19 beats/minutes [bpm], 4.5 V: 191 ± 28 bpm*, 8.0 V: 207 ± 23 bpm*, 9.3 V: 216 ± 18 bpm*; *P < 0.01 compared to baseline) without significant changes in A-H interval or blood pressure. P-wave morphology, ice mapping, and noncontact mapping indicated that this tachycardia was sinus tachycardia. In 8 of 19 dogs, injecting hexamethonium (5 mg), a ganglionic blocker, into the ARGP attenuated the response elicited by IGN stimulation (baseline: 160 ± 21 bpm, 4.5 V: 172 ± 32 bpm, 8.0 V: 197 ± 32 bpm*, 9.3 V: 206 ± 26 bpm*; *P < 0.05 compared to baseline). In 19 of 19 animals, after formaldehyde injection into the ARGP, SR acceleration induced by IGN stimulation was markedly attenuated (baseline: 149 ± 17 bpm, 4.5 V: 151 ± 21 bpm, 8.0 V: 155 ± 23 bpm, 9.3 V: 167 ± 24 bpm*; *P < 0.05 compared to baseline). Conclusions: HFS of the IGN caused a selective and significant acceleration of the SR. A significant portion of IGN traverses the ARGP or synapses with the autonomic ganglia in the ARGP before en route to the SA node. Dysautonomia involving the IGN and/or ARGP may play an important role in IST. [source]

The Proarrhythmic Effect of Incomplete Pulmotricuspid Isthmus Ablation in a Patient with Sarcoid-Related Ventricular Tachycardia?

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 8 2008
ARASH ARYANA M.D.
Proarrhythmia is relatively common after extensive atrial ablation for atrial fibrillation, but has not been frequently documented after catheter ablation of ventricular tachycardia (VT). In theory, this phenomenon could occur if an incomplete ablation line is created between two nonconducting structures, such as dense scar or valvular annuli. This report illustrates the possible proarrhythmic effect of ablation in a patient with sarcoid-related VT and extensive right ventricular (RV) myopathy who presented with slow incessant VT one month after an ablation procedure including ablation at the pulmotricuspid isthmus (PTI). The extensive preexisting RV myopathy appeared to be an important substrate in the pathogenesis of this patient's incessant VT. This case suggests that the PTI region may serve as a critical tachycardia isthmus if sufficiently modified with an incomplete ablation line in the setting of significant myocardial scarring. [source]

Electrophysiological Characteristics and Catheter Ablation in Patients with Paroxysmal Supraventricular Tachycardia and Paroxysmal Atrial Fibrillation

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2008
SHIH-LIN CHANG M.D.
Introduction: Paroxysmal supraventricular tachycardia (PSVT) is often associated with paroxysmal atrial fibrillation (AF). However, the relationship between PSVT and AF is still unclear. The aim of this study was to investigate the clinical and electrophysiological characteristics in patients with PSVT and AF, and to demonstrate the origin of the AF before the radiofrequency (RF) ablation of AF. Methods and Results: Four hundred and two consecutive patients with paroxysmal AF (338 had a pure PV foci and 64 had a non-PV foci) that underwent RF ablation were included. Twenty-one patients (10 females; mean age 47 ± 18 years) with both PSVT and AF were divided into two groups. Group 1 consisted of 14 patients with inducible atrioventricular nodal reentrant tachycardia (AVNRT) and AF. Group 2 consisted of seven patients with Wolff-Parkinson-White (WPW) syndrome and AF. Patients with non-PV foci of AF had a higher incidence of AVNRT than those with PV foci (11% vs. 2%, P = 0.003). Patients with AF and atypical AVNRT had a higher incidence of AF ectopy from the superior vena cava (SVC) than those with AF and typical AVNRT (86% vs. 14%, P = 0.03). Group 1 patients had smaller left atrial (LA) diameter (36 ± 3 vs. 41 ± 3 mm, P = 0.004) and higher incidence of an SVC origin of AF (50% vs. 0%, P = 0.047) than did those in Group 2. Conclusion: The SVC AF has a close relationship with AVNRT. The effect of atrial vulnerability and remodeling may differ between AVNRT and WPW syndrome. [source]

Catheter Ablation of Peri-AV Nodal Atrial Tachycardia from the Noncoronary Cusp of the Aortic Valve

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2008
Ph.D, SAUMYA DAS M.D.
Introduction: Atrial tachycardias (AT) originating from the anteroseptal region of the aortic root, near the atrioventricular node can be challenging to eliminate safely by catheter ablation. In this study, we examine the characteristics of anteroseptal ATs in a cohort of patients at our centers, and demonstrate the long-term efficacy and safety of targeting the arrhythmias from within the base of the noncoronary aortic valve cusp (NCC). Methods & Results: From among a cohort of 54 patients with symptomatic focal AT undergoing invasive electrophysiological evaluation, the point of earliest right atrial (RA) activation was at the peri-AV nodal region in 10 patients, just postero-superior to the His-bundle. Before further mapping, RA lesions placed in two patients were unsuccessful in eliminating the arrhythmia. Because of its proximity to the interatrial septum, the base of the NCC was mapped using a retrograde aortic approach, and revealed a point of early activation without the presence of a His potential. The arrhythmia terminated with <10 seconds of radiofrequency or cryothermal energy delivery and was successfully eliminated in 7 of 10 patients. Transient termination or acceleration of the AT was noted in the other three patients, prompting successful ablation from a left atrial septal position or a reattempt from a para-Hisian RA position. All patients have been arrhythmia free during follow-up (41 ± 12 months). Conclusions: Catheter ablation from within the base of the NCC represents a safe and effective means to eliminate focal AT arising from the peri-AV nodal region. [source]

The Morphology Changes in Limb Leads after Ablation of Verapamil-Sensitive Idiopathic Left Ventricular Tachycardia and Their Correlation with Recurrence

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2008
SHU-YUAN YAO Ph.D
Objectives: This study was designed to explore the morphology changes in limb leads of ECGs after successful ablation of verapamil sensitive idiopathic left ventricular tachycardia (ILVT) and their correlation with tachycardia recurrence. Methods: Between January 2001 and December 2006, 116 patients who underwent successful ablation of ILVT were included in the study. Twelve-lead surface ECG recordings during sinus rhythm were obtained in all patients before and after ablation to compare morphology changes in limb leads. Results: The ECG morphology changes after ablation were divided into two categories: one with new or deepening Q wave in inferior leads and/or disappearance of Q wave in leads I and aVL, and the other without change. The changes in any Lead II, III, or aVF after ablation occurred significantly more in patients without recurrence of ventricular tachycardia (VT) (P < 0.0001, 0.002, and 0.0001, respectively). The patients with recurrence of VT tended to have no ECG changes, compared with those without recurrence of VT (P = 0.009). The sensitivity of leads II, III, and aVF changes in predicting nonrecurrence VT were 66.7%, 78.7%, and 79.6%, specificity were 100%, 75%, and 87.5%, and nonrecurrence predictive value of 100%, 97.7%, and 98.9%, respectively. When inferior leads changes were combined, they could predict all nonrecurrence patients with 100% specificity. Conclusions: Successful radiofrequency ablation of ILVT could result in morphology changes in limb leads of ECG, especially in inferior leads. The combined changes in inferior leads can be used as an effective endpoint in ablation of this ILVT. [source]

A Case of Narrow Complex Tachycardia

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2008
AMIR ABDELWAHAB M.B. B.Ch., M.Sc.
No abstract is available for this article. [source]

A Wide Complex Tachycardia: What is the Mechanism?

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2008
MICHAEL KUHNE M.D.
No abstract is available for this article. [source]

Differentiating Atrioventricular Nodal Reentrant Tachycardia from Junctional Tachycardia: Novel Application of the Delta H-A Interval

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 1 2008
KOMANDOOR SRIVATHSAN M.D.
Introduction: Junctional tachycardia (JT) and atrioventricular nodal reentrant tachycardia (AVNRT) can be difficult to differentiate. Yet, the two arrhythmias require distinct diagnostic and therapeutic approaches. We explored the utility of the delta H-A interval as a novel technique to differentiate these two tachycardias. Methods: We included 35 patients undergoing electrophysiology study who had typical AVNRT, 31 of whom also had JT during slow pathway ablation, and four of whom had spontaneous JT during isoproterenol administration. We measured the H-A interval during tachycardia (H-AT) and during ventricular pacing (H-AP) from the basal right ventricle. Interobserver and intraobserver reliability of measurements was assessed. Ventricular pacing was performed at approximately the same rate as tachycardia. The delta H-A interval was calculated as the H-AP minus the H-AT. Results: There was excellent interobserver and intraobserver agreement for measurement of the H-A interval. The average delta H-A interval was ,10 ms during AVNRT and 9 ms during JT (P < 0.00001). For the diagnosis of JT, a delta H-A interval , 0 ms had the sensitivity of 89%, specificity of 83%, positive predictive value of 84%, and negative predictive value of 88%. The delta H-A interval was longer in men than in women with JT, but no gender-based differences were seen with AVNRT. There was no difference in the H-A interval based on age , 60 years. Conclusion: The delta H-A interval is a novel and reproducibly measurable interval that aids the differentiation of JT and AVNRT during electrophysiology studies. [source]

Predictors of All-Cause Mortality for Patients with Chronic Chagas' Heart Disease Receiving Implantable Cardioverter Defibrillator Therapy

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2007
AUGUSTO CARDINALLI-NETO M.D., Ph.D.
Background: Implantable Cardioverter Defibrillators (ICD) have sporadically been used in the treatment of either Sustained Ventricular Tachycardia (VT) or Ventricular Fibrillation (VF) in Chagas' disease patients. This study aimed at determining predictors of all-cause mortality for Chagas' disease patients receiving ICD therapy. Methods and Results: Ninety consecutive patients were entered the study. Mean left ventricular ejection fraction was 47 ± 13%. Twenty-five (28%) patients had no left ventricular systolic dysfunction. After device implantation, all patients were given amiodarone (mean daily dose = 331, 1 ± 153,3 mg), whereas a B-Blocking agent was given to 37 (40%) out of 90 patients. Results: A total of 4,274 arrhythmias were observed on stored electrogram in 64 (71%) out of 90 patients during the study period; SVT was observed in 45 out of 64 (70%) patients, and VF in 19 (30%) out of 64 patients. Twenty-six (29%) out of 90 patients had no arrhythmia. Fifty-eight (64%) out of 90 patients received appropriate shock, whereas Antitachycardia Pacing was delivered to 58 (64%) out of 90 patients. There were 31 (34%) deaths during the study period. Five patients were lost to follow up. Sudden cardiac death affected 2 (7%) out of 26 patients, whereas pump failure death was detected in the remaining 24 (93%) patients. Number of shocks per patient per 30 days was the only independent predictor of mortality. Conclusion: Number of shocks per patient per 30 days predicts outcome in Chagas' disease patients treated with ICD. [source]

The VA Relationship After Differential Atrial Overdrive Pacing: A Novel Tool for the Diagnosis of Atrial Tachycardia in the Electrophysiologic Laboratory

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 11 2007
MITSUNORI MARUYAMA M.D.
Introduction: Despite recent advances in clinical electrophysiology, diagnosis of atrial tachycardia (AT) originating near Koch's triangle remains challenging. We sought a novel technique for rapid and accurate diagnosis of AT in the electrophysiologic laboratory. Methods: Sixty-two supraventricular tachycardias including 18 ATs (10 ATs arising from near Koch's triangle), 32 atrioventricular nodal reentrant tachycardias (AVNRTs), and 12 orthodromic reciprocating tachycardias (ORTs) were studied. Overdrive pacing during the tachycardia from different atrial sites was performed, and the maximal difference in the postpacing VA intervals (last captured ventricular electrogram to the earliest atrial electrogram of the initial beat after pacing) among the different pacing sites was calculated (delta-VA interval). Results: The delta-VA intervals were >14 ms in all AT patients and <14 ms in all AVNRT/ORT patients, and thus, the delta-VA interval was diagnostic for AT with the sensitivity, specificity, and positive and negative predictive values all being 100%. When the diagnostic value of the delta-VA interval and conventional maneuvers were compared for differentiating AT from atypical AVNRT, both a delta-VA interval >14 ms and "atrial-atrial-ventricular" response after overdrive ventricular pacing during the tachycardia were diagnostic. However, the "atrial-atrial-ventricular" response criterion was available in only 52% of the patients because of poor ventriculoatrial conduction. Conclusions: The delta-VA interval was useful for diagnosing AT irrespective of patient conditions such as ventriculoatrial conduction. [source]