Clinical presentation, management, and outcomes in the Indian Heart Rhythm Society-Atrial Fibrillation (IHRS-AF) registry.

AIM: A national atrial fibrillation (AF) registry was conducted under the aegis of the Indian Heart Rhythm Society (IHRS), to capture epidemiological data-type of AF, clinical presentation and comorbidities, current treatment practices, and 1-year follow-up outcomes. METHODS: A total of 1537 patients were enrolled from 24 sites in India in the IHRS-AF registry from July 2011 to August 2012. Their baseline characteristics and follow-up data were recorded in case report forms and subsequently analyzed. RESULTS: The average age of Indian AF patients was 54.7 years. There was a marginal female preponderance - 51.5% females and 48.5% males. At baseline, 20.4% had paroxysmal AF; 33% had persistent AF; 35.1% had permanent AF and 11% had first AF episode. At one-year follow-up, 45.6% patients had permanent AF. Rheumatic valvular heart disease (RHD) was present in 47.6% of patients. Hypertension, heart failure, coronary artery disease, and diabetes were seen in 31.4%, 18.7%, 16.2%, and 16.1%, respectively. Rate control was the strategy used in 75.2% patients, digoxin and beta-blockers being the most frequently prescribed rate-control drugs. Oral anticoagulation (OAC) drugs were used in 70% of patients. The annual mortality was 6.5%, hospitalization 8%, and incidence of stroke 1%. CONCLUSIONS: In India, AF patients are younger and RHD is still the most frequent etiology. Almost two-third of the patients have persistent/permanent AF. At one-year follow-up, there is a significant mortality and morbidity in AF patients in India.

Aliskiren, the first direct renin inhibitor for treatment of hypertension: the path of its development.

Standard treatments available today for treating hypertension is diuretics, ß-blockers, angiotensin converting enzyme inhibitors (ACEs), angiotensin receptor blockers (ARBs), calcium channel blockers, a-blockers, vasodilators, and centrally acting drugs. It is difficult to achieve the optimized renin angiotensin aldosterone system suppression with currently available antihypertensive agents, because ACE inhibitors, ARBs, and diuretics all activate the compensatory feedback mechanism that increases renin release and increase plasma renin activity. The first orally active direct renin inhibitors (DRIs) were developed in 1980s, including enalkiren, remikiren, and zankiren. However, poor absorption from the gastrointestinal tract, less bioavailability (<2%), short half life, and low potency hindered the development of these compounds. Aliskiren is the first DRI for the treatment of hypertension. Aliskiren is designed through a combination of molecular modeling techniques and crystal structure elucidation. Aliskiren effectively reduces the blood pressure as a mono therapy as well in combination therapy.

Radiofrequency ablation of atrial arrhythmias after previous open-heart surgery.

AIM: To report the results of ablation of atrial arrhythmias (AA) after previous open-heart surgery. METHODS: Nineteen patients [50+/-11 years, 11 women] underwent ablation of symptomatic AAs after previous open-heart surgery. In 11 patients mapping was performed using conventional multielectrode catheters. In the other eight patients CARTO electro-anatomical mapping system was used to supplement conventional mapping. RESULTS: After conventional mapping, 10/11 patients (91%) were found to have typical atrial flutter (AFL). The cavotricuspid isthmus was successfully ablated in these 10 patients. CARTO combined with conventional mapping showed that 7 of 8 patients had one macro-reentry right atrial circuit. The remaining patient had two focal atrial tachycardias. CARTO-guided ablation was successful in all eight patients (100%). After follow-up of 12+/-11 months, 2/18 patients (11%) had recurrence of either the same (n=1) or a new (n=1) AA. CONCLUSIONS: AAs after previous open-heart surgery can be ablated successfully (>90%) with a low recurrence rate (11%) at 1-year follow-up. Typical AFL was found frequently (14/19 patients, 72%). This could be ablated successfully, often, after conventional mapping alone. CARTO helps to uncover peri-scar reentry and guide the ablation by creating a line of block connecting the scar to another landmark (unconventional isthmus).

Biatrial activation in isthmus-dependent atrial flutter.

BACKGROUND: The aim of this study was to determine the biatrial activation pattern in isthmus-dependent atrial flutter (AFL) to understand the functional interatrial connections and the activation pattern of the left atrium (LA). METHODS AND RESULTS: Biatrial activation was performed, using an electroanatomic mapping system, in 10 patients undergoing right atrial isthmus ablation for counterclockwise (n=7) or clockwise (n=3) AFL. The AFL circuit was peritricuspid and propagated slowly (0.5+/-0.2 m/s) through the isthmus. LA was activated by two wave fronts, with discrete breakthroughs in the superior, mid, or inferior atrial septum. The activation of LA overlapped 50+/-16% of the AFL cycle length. In counterclockwise AFL, at least one breakthrough was located in the inferior atrial septum. LA activation began immediately after the exit of the flutter wave from the isthmus and was directed inferosuperiorly in all patients, being synchronous with the atrial septal activation. The septal breakthroughs in patients with clockwise AFL were variably located. The direction of LA activation was superoinferior in 2 and inferosuperior in 1 patient. CONCLUSIONS: The circuit of isthmus-dependent AFL was entirely in the right atrium. LA activation was a bystander and followed trans-septal conduction across the inferior coronary sinus-LA connection, Bachmann's bundle, and/or fossa ovalis.

Class IC antiarrhythmic drug induced atrial flutter: electrocardiographic and electrophysiological findings and their importance for long term outcome after right atrial isthmus ablation.

OBJECTIVE: To describe the electrocardiographic and electrophysiological findings of new atrial flutter developing in patients taking class IC antiarrhythmic drugs for recurrent atrial fibrillation, and to report the long term results of right atrial isthmus ablation in relation to the ECG pattern of spontaneous atrial flutter. DESIGN: Retrospective analysis. SETTING: Tertiary care academic hospital. PATIENTS: 24 consecutive patients with atrial fibrillation (age 54 (12) years; 5 female, 19 male) developing atrial flutter while taking propafenone (n = 12) or flecainide (n = 12). RESULTS: The ECG was classified as typical (n = 13; 54%) or atypical atrial flutter (n = 8) or coarse atrial fibrillation (n = 3). Counterclockwise atrial flutter was the predominant arrhythmia. Acute success after isthmus ablation was similar in patients with typical (12/13) and atypical (8/8) atrial flutter. After long term follow up (13 (6) months, range 6-26 months), continuation of antiarrhythmic drug treatment appeared to result in better control of recurrences of atrial fibrillation in patients with typical atrial flutter (11/13) than in those with atypical atrial flutter (4/8), but the difference was not significant. Ablation for coarse atrial fibrillation was unsuccessful. CONCLUSIONS: New atrial flutter developing in patients taking class IC antiarrhythmic drugs for recurrent atrial fibrillation has either typical or atypical flutter wave morphology on ECG. The endocardial activation pattern and the acute results of ablation suggest that the flutter circuit was located in the right atrium and that the isthmus was involved in the re-entry mechanism. There appeared to be better long term control of recurrent atrial fibrillation in patients with typical (85%) as compared with atypical atrial flutter (50%). Patients developing coarse atrial fibrillation may not be candidates for this strategy.

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

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. METHODS AND RESULTS: Eight patients (6 men, age 59 +/- 12 years) in whom the clinical target VT (cycle length 430 +/- 97 msec) could not be ablated using a conventional 4-mm tip RF ablation catheter underwent additional attempts to ablate this VT using a SIT catheter. Six patients had an old myocardial infarction, 1 patient had a dilated cardiomyopathy, and 1 patient had a structurally normal heart. Ablation of the clinical target VT using a SIT catheter was attempted from the left ventricle in 6 (septal, posterobasal, and inferior: 2 each) and from the right ventricle in 2 patients (both septal), by entrainment (n = 6), activation (n = 1), or pace mapping (n = 1). A mean of 6 +/- 5 (range 2 to 15) pulses were delivered. Target VT ablation was successful in 5 patients (63%). After successful ablation, at a mean follow-up of 6.5 +/- 4 months and while taking antiarrhythmic drugs, all 5 patients were free of VT recurrences. CONCLUSION: The clinical target VT could be ablated using a SIT catheter in 5 (63%) of the 8 patients in whom ablation using a conventional RF catheter was unsuccessful. In the 2 patients with septal VT, a biventricular approach to mapping and ablation was required.

A re-analysis of our current understanding of isthmus-dependent atrial flutter: some gaps, some hypotheses.

The macro-reentrant circuit of isthmus-dependent atrial flutter (AFL) is located in the right atrium around the tricuspid annulus. High acute success and low recurrence rate makes isthmus ablation a definitive therapy for patients with only AFL. However, a review of the literature suggests that, different aspects of this macro-reentrant circuit are still not entirely understood, while new information continues to emerge. The aim of this article is to discuss some gaps in our "complete" understanding of isthmus-dependent AFL. Few hypotheses have been stated which are open to investigation.

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.

Capture and fusion beats during atrial fibrillation and ventricular tachycardia.

Two patients were presented, and two previously unreported observations were made. Patient 1, a 50 year old man with episodic palpitations and dizziness for 10 years, exhibited initiation of idiopathic ventricular tachycardia (VT) by atrial fibrillation (AF). Patient 2, a 43 year old woman with a structurally normal heart but recurrent palpitations for one year, demonstrated fusion and capture beats during simultaneous VT and AF. An explanation is given as to why the latter phenomenon is rarely observed.

Dual morphology of idiopathic ventricular tachycardia.

INTRODUCTION: Idiopathic ventricular tachycardia (VT) typically has a single morphology originating either in the right ventricular outflow tract (RVOT) or near the posterior fascicle of the left ventricle (LV) in most instances. We present our observations in six patients with idiopathic VT in whom two morphologies were present. METHODS AND RESULTS: Of 55 patients with idiopathic VT who underwent radiofrequency (RF) ablation, 44 had LV "fascicular" tachycardia, whereas 11 had RVOT tachycardia. During RF energy delivery, there was a change in VT morphology in two patients with idiopathic LV tachycardia. This second morphology was not ablated initially, recurred at follow-up, and was reablated successfully. In two additional patients with idiopathic LV tachycardia, a second VT was inducible after ablation of the "clinical" VT. This second morphology recurred at follow-up and was ablated successfully in one patient. The site where the second VT was ablated in all the three patients was remote from that of the first VT. In two patients with RVOT tachycardia, a second VT, originating from a different area of the RVOT, was induced after RF ablation of the "clinical" VT. This second VT recurred at follow-up and was reablated successfully in one patient. CONCLUSION: Idiopathic VT is a more heterogenous entity than hitherto believed. A second VT was seen in 11% of patients during or after RF ablation of the "clinical" VT. The appearance of a second VT suggests either a different exit site of the same circuit or another site of origin.

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

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.

Effect of right atrial isthmus ablation on the occurrence of atrial fibrillation: observations in four patient groups having type I atrial flutter with or without associated atrial fibrillation.

BACKGROUND: The goal of this study was to test the hypothesis that the occurrence of atrial fibrillation (AF), in at least some patients with coexisting type I atrial flutter (AFL), is based on macro-reentry around the tricuspid valve orifice, including the right atrial (RA) isthmus, by evaluation of AF recurrences after successful ablation of AFL. METHODS AND RESULTS: Eighty-two consecutive patients with type I AFL, with or without concomitant AF, underwent radiofrequency ablation (RFA) of the RA isthmus by an anatomical approach. The results were analyzed in 4 groups of patients: group 1 (only AFL; 29 patients), group 2 (AFL >AF; 22 patients), group 3 (AF >AFL; 15 patients), and group 4 (developing AFL while receiving class IC antiarrhythmic drug therapy for AF, the "class IC atrial flutter"; 16 patients). In all groups, RFA of type I AFL was performed with a high (>/=93%) procedural success rate. In group 1, only 2 patients (8%) had AF after (18+/-14 months) AFL ablation. These figures were 38% (20+/-14 months) and 86% (13+/-8 months) in groups 2 and 3, respectively. Group 4 patients (4+/-2 months) had a 73% freedom of AF recurrences with continuation of the class IC agent. CONCLUSIONS: The low incidence of new AF during long-term follow-up after RFA of type I AFL makes it unlikely that radiofrequency lesions promote the development of AF. The impact of isthmus ablation on AF recurrences differs according to the clinically predominant atrial arrhythmia and suggests a possible role of the RA isthmus in the occurrence of AF in some patients. Ablation of class IC atrial flutter in patients with therapy-resistant AF is a novel approach to management of this patient subset. Careful classification of AF patients plays a role in the selection of the site of ablation therapy.

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.

Emergence of bidirectional accessory pathway conduction in adulthood.

A 30-year-old woman presented with tachycardiomyopathy due to atrial flutter-fibrillation and underwent radiofrequency ablation of the AV node and VVIR pacemaker implantation. There was no evidence of any accessory pathway (AP) conduction during the AV nodal ablation or during chronic ventricular pacing. One year later, she had a transient preexcited tachycardia. A year after this, her ECG showed 1:1 AV conduction with preexcitation. Electrophysiologic study revealed a left lateral AP with anterograde and retrograde refractory periods of 280 and 240 msec, respectively. Successful radiofrequency ablation of the AP was performed. This case highlights a unique emergence of an AP in adult life.

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.

Scope and efficacy of complex radiofrequency ablation.

Radiofrequency ablation is an effective treatment for various tachycardias. In some patients undergoing radiofrequency ablation, there are additional complexities. Of 254 consecutive patients (161 males, 93 females, aged 38 +/- 15 years) who underwent radiofrequency ablation, two groups were identified. Patients with structural heart disease, multiple accessory pathways, multifocal idiopathic ventricular tachycardia, parahisian accessory pathways, and multiple mechanisms of tachycardia were considered as complex radiofrequency ablation (Group I) and the remaining as non-complex radiofrequency ablation (Group II). There were 23 patients in Group I. The overall success rate was not different in the two groups: 20/23 (87%) vs 208/231 (90%) in groups I and II, respectively. The procedure and fluoroscopy time (212 +/- 91 min vs 136 +/- 45 min; p = 0.0001; and 55 +/- 31 min vs 31 +/- 21 min; p = 0.001, respectively) were significantly longer in Group I. There was a higher recurrence rate in Group I (6/20, 30% vs 20/208, 9.6%; p = 0.02); repeat radiofrequency ablation was successfully performed in four patients with recurrence in Group I. Complications were rare in both the groups. There was no mortality. Thus radiofrequency ablation in complex situations was effective, though more demanding than non-complex radiofrequency ablation and associated with higher recurrence.

Obstructive total anomalous pulmonary venous drainage.

Obstructive total anomalous pulmonary venous drainage (TAPVD) has a florid presentation in the neonatal period from the resulting pulmonary edema. A complete anatomical and functional diagnosis is usually possible by transthoracic color Doppler echocardiography, and cardiac catheterization with its attendant risks can usually be avoided in the sick neonate. Currently balloon atrial septostomy has a limited role in palliation of these neonates. Corrective surgery on urgent basis has gratifying results and prevents progression of pulmonary vascular occlusive disease. Pulmonary hypertensive crisis in the early post-operative course needs to be avoided and treated vigorously if it were to develop. Late post-operative course can be complicated by anastomotic obstruction or progressive narrowing of the individual pulmonary veins. Although the former can be dealt successfully by re-operation, surgical treatment of the latter is not satisfactory. Balloon dilatation of the obstructed pulmonary venous pathways, native and post-operative, has been reported with equivocal results. Infant heart-lung transplant is a viable option in patients with diffusely narrow pulmonary veins or complex TAPVDs.