Ashish Nabar

Radiofrequency ablation of “class IC atrial flutter” in patients with resistant atrial fibrillation

In some patients with atrial fibrillation, atrial flutter develops after administration of class IC antiarrhythmic drugs, the so-called class IC atrial flutter. Radiofrequency ablation of the right atrial isthmus results in clinical improvement in 85% of patients and provides an alternative management strategy for a subset of patients with therapy-resistant atrial fibrillation.

Isoproterenol to Evaluate Resumption of Conduction After Right Atrial Isthmus Ablation in Type I Atrial Flutter

BACKGROUND After radiofrequency (RF) ablation of atrial flutter (AFL), the demonstration of bidirectional isthmus conduction (BIC) block is considered the hallmark of a successful procedure. The purpose of our study was to test the persistence of BIC block after isoproterenol administration and to evaluate the importance of this finding with regard to AFL recurrences. METHODS AND RESULTS RF ablation of AFL was performed in 44 consecutive patients with type I AFL by linear ablation of the posterior isthmus (n=29 patients), septal isthmus (n=4 patients), or both right atrial (RA) isthmi (n=11 patients). The procedural end point was complete BIC block and noninducibility of AFL. In case of noninducibility and apparent BIC block, the pacing protocol was repeated under isoproterenol infusion (1 to 3 microgram/min). Reversal of apparent BIC block occurred in 7 (15.9%) of 44 patients. Six patients had bidirectional and 1 had unidirectional resumption of isthmus conduction. Counterclockwise AFL could be reinduced in 4 of these patients. Two to 24 (median, 4) additional RF applications were required to achieve permanent BIC block. At a mean follow-up of 7.3+/-7.6 months (range, 2 to 31 months), 2 (4.5%) of 44 patients had AFL recurrences. CONCLUSIONS Partial linear RF ablation could possibly aggravate preexisting nonuniform anisotropic conduction in the RA isthmus, resulting in profound conduction slowing and apparent BIC block. Isoproterenol can unmask apparent BIC block, thus providing an opportunity to assess the possibility of reversal of BIC block and completeness of isthmus ablation during the same procedure. The low incidence (4.5%) of AFL recurrences at follow-up suggests that noninducibility and BIC block under isoproterenol infusion may be a better end point for successful AFL ablation.

Comparison of results of an 8-mm split-tip versus a 4-mm tip ablation catheter to perform radiofrequency ablation of type I atrial flutter.

Thirty consecutive patients with type I atrial flutter were randomized to undergo radiofrequency ablation using an 8-mm split-tip versus a 4-mm tip catheter. Procedural success was high in both groups (100% vs 93%). However, requirement of a fewer number of radiofrequency pulses and fluoroscopy time suggests superiority of the 8-mm split-tip over the 4-mm tip ablation catheter.

Use of a saline-irrigated tip catheter for ablation of ventricular tachycardia resistant to conventional radiofrequency ablation : Early experience

Irrigated Tip Catheter for Ablation of Resistant VT. Introduction: Radiofrequency (RF) catheter ablation of ventricular tachycardia (VT) may fail if the critical isthmus is located intramyocardially or epicardially. The design of a saline‐irrigated tip (SIT) catheter (Thermo‐Cool™, Cordis‐Webster) involves active cooling of the tip electrode, which allows creation of larger ablation lesions.

Echocardiographic predictors of survival in patients undergoing radiofrequency ablation of postinfarct clinical ventricular tachycardia

Predictors of Survival in Postinfarct VT. Introduction: The aim of this study was to determine the predictive value of echocardiographic parameters of systolic left ventricular (LV) dysfunction for survival in a group of patients with “mappable” ventricular tachycardia (VT) after myocardial infarction who underwent radiofrequency ablation (RFA) of their clinical VT(s).

Use of Sedation During Cardioversion With the Implantable Atrial Defibrillator

BACKGROUND The low shock energy used during internal atrial defibrillation may decrease the need for sedation during defibrillation with an implantable atrial defibrillator. METHODS AND RESULTS The atrial defibrillator (Metrix Atrioverter) was implanted in 12 patients. During the in-hospital treatment of atrial fibrillation (AF) episodes, intravenous sedation was given only on patient request. The Atrioverter was programmed for ambulatory therapy in 4 patients. Efficacy, number of shocks delivered, and sedation requirements were recorded. A total of 393 shocks (1.8+/-1. 6 shocks/AF episode) were delivered to treat 213 AF episodes; 85 of 213 AF episodes (40%) were treated away from the hospital. Sinus rhythm was restored in 195 AF episodes (92%). Five patients never requested sedation. No sedation was needed for ambulatory-treated AF episodes. During the treatment of 26 of 213 AF episodes (12%), 75 shocks were delivered after patients received sedation. The number of shocks required to treat an AF episode determined the need for sedation (4.3+/-2.1 shocks for AF episodes requiring sedation versus 2+/-1 shocks for AF episodes requiring no sedation; P<0.001). These additional shocks were needed to treat immediate reinitiation of AF (14 episodes) or initial failure to cardiovert (4 episodes). For 8 AF episodes, sedation was requested before the first shock. CONCLUSIONS This study suggests that, in a selected group of patients, AF can be treated with Atrioverter therapy without sedation. Successful ambulatory treatment of AF episodes with the Atrioverter, programmed to deliver </=2 shocks, did not require sedation. When multiple shocks were required to treat an AF episode, the need for sedation increased and included patients initially not requesting sedation.

Transcatheter closure of patent ductus arteriosus in children weighing <10 kg with Gianturco coils using the balloon occlusion technique

We evaluated the immediate and intermediate follow-up results of transcatheter closure (TCC) of patent ductus arteriosus (PDA) using Gianturco coils in children weighing < 10 kg. The results of PDA < or = 2.5 mm (group I, n = 18) and > 2.5 mm (group II, n = 16) were compared. Coils were deployed sequentially by transarterial route using a temporary balloon occlusion technique. The immediate clinical success rate in both groups was comparable. There was no significant difference in the number of coils required per patient and in the embolization rate between the two groups. Both groups had comparable occlusion rates at intermediate-term follow-up. At intermediate follow-up, one patient had developed left pulmonary artery stenosis while obstruction of the descending aorta was not seen in any; in 4 children the PDA had recanalized. Spontaneous reocclusion was observed in 3 of the latter at the last follow-up. We conclude that TCC of PDA is feasible and safe in children weighing < 10 kg with gratifying intermediate-term results.

A survey of cardiac implantable electronic device implantation in India: By Indian Society of Electrocardiology and Indian Heart Rhythm Society

Background There is limited data regarding the demographics and type of cardiac implantable electronic device (CIED) in India. Aim The aim of this survey was to define trends in CIED implants, which included permanent pacemakers (PM), intracardiac defibrillators (ICD), and cardiac resynchronization therapy pacemakers and defibrillators (CRT-P/D) devices in India. Methods The survey was the initiative of the Indian Society of Electrocardiology and the Indian Heart Rhythm Society. The type of CIED used, their indications, demographic characteristics, clinical status and co-morbidities were collected using a survey form over a period of 1 year. Results 2117 forms were analysed from 136 centers. PM for bradyarrhythmic indication constituted 80% of the devices implanted with ICDs and CRT-P/D forming approximately 10% each. The most common indication for PM implantation was complete atrio-ventricular block (76%). Single chamber (VVI) pacemakers formed 54% of implants, majority in males (64%). The indication for ICD implantation was almost equal for primary and secondary prevention. A single chamber ICD was most commonly implanted (65%). Coronary artery disease was the etiology in 58.5% of patients with ICD implants. CRT pacemakers were implanted mostly in patients with NYHA III/IV (82%), left ventricular ejection fraction <0.35 (88%) with CRT-P being most commonly used (57%). Conclusion A large proportion of CIED implants in India are PM for bradyarrhythmic indications, predominantly AV block. ICDs are implanted almost equally for primary and secondary prophylaxis. Most CRT devices are implanted for NYHA Class III. There is a male predominance for implantation of CIED.

Unruptured aneurysm of the sinus of valsalva presenting with right ventricular outflow tract obstruction, complete heart block, and protrusion into left ventricular outflow tract: a rare combination.

![Figure][1] [![Graphic][3] ][3][![Graphic][4] ][4][![Graphic][5] ][5][![Graphic][6] ][6] A 20-year-old male presented with exertional dyspnoea and exertional presyncope of 7 months duration, 1 episode of syncope 6 months ago with worsening dyspnea since 1 week.

Percutaneous tricuspid valvotomy for pacemaker lead-induced tricuspid stenosis

Permanent pacemaker lead-induced tricuspid regurgitation is extremely uncommon. We report a patient with severe tricuspid stenosis detected 10 years after permanent single chamber pacemaker implantation in surgically corrected congenital heart disease. The loop at the level of the tricuspid valve may have caused endothelial injury and eventually led to stenosis. Percutaneous balloon valvotomy for such stenosis has not been reported from India.