Identifying high risk patients post myocardial infarction with reduced left ventricular function using loop recorders INSPIRE-ELR clinical study.

AIMS: Sudden cardiac death (SCD) continues to be a devastating complication amongst survivors of myocardial infarction (MI). Mortality is high in the initial months after MI. The aims of the INSPIRE-ELR study were to assess the proportion of patients with significant arrhythmias early after MI and the association with mortality during 12 months of follow-up. METHODS: The study included 249 patients within 14 days after MI with left ventricular ejection fraction (LVEF) ≤35% at discharge in 11 hospitals in India. Patients received a wearable external loop recorder (ELR) 5 ± 3 days after MI to monitor arrhythmias for 7 days. RESULTS: Patients were predominantly male (86%) with a mean age of 56 ± 12 years. In 82%, reperfusion had been done and all received standard of care cardiovascular medications at discharge. LVEF was 32.2 ± 3.9%, measured 5.1 ± 3.0 days after MI. Of the 233 patients who completed monitoring (7.1 ± 1.5 days), 81 (35%) experienced significant arrhythmias, including Ventricular Tachycardia/Fibrillation (VT/VF): 10 (4.3%); frequent Premature Ventricular Contractions (PVCs): 65 (28%); Atrial Fibrillation (AF): 8 (3.4%); chronic atrial flutter: 4 (1.7%); 2nd or 3rd degree Atrioventricular (AV) block: 4 (1.7%); and symptomatic bradycardia: 8 (3.4%). In total, 26 patients died. Mortality was higher in patients with clinically significant arrhythmia (at 12 months: 23.6% vs 4.8% with 19 vs 7 deaths, hazard ratio (HR) = 5.5, 95% confidence interval (CI) 2.3 to 13.0, p < 0.0001). Excluding 7 deaths during ELR monitoring, HR = 4.5, p < 0.001. CONCLUSION: ELR applied in patients with acute MI and LV dysfunction at the time of discharge identifies patients with high mortality risk.

Incessant fascicular ventricular tachycardia in an infant with heart failure.

We report an eight month old infant who presented with incessant Fascicular tachycardia and heart failure which was refractory to drugs and cardioversion. Sinus rhythm was restored by radio frequency ablation and this resulted in improvement in clinical status and cardiac function. Role of catheter ablation in this situation is discussed.

Ventricular Tachycardia Ablation in the Presence of Left Ventricular Thrombus: Safety and Efficacy.

INTRODUCTION: The safety of ventricular tachycardia (VT) ablation in patients with laminated left ventricular (LV) thrombus has not been examined. METHODS: Patients with laminated LV thrombus on transthoracic echocardiogram who underwent scar-mediated VT ablation at two centers from 2010 to 2013 were retrospectively analyzed. All patients had failed medical therapy. Acute procedural outcomes, complications, and clinical outcomes at 1 year were assessed. RESULTS: Eight patients (four ischemic, four nonischemic cardiomyopathy) underwent VT ablation in the presence of laminated intracavitary thrombus. Six out of eight (75%) had electrical storm (ES). The mapping and ablation approach was LV endocardial-only in three patients, epicardial-only in two, combined epicardial-RV endocardial in two, and combined epicardial-LV endocardial in one. Major complication (ischemic stroke) occurred in one patient 9 days post-procedure. There was no procedural mortality. Complete acute procedural success (noninducibility of any VT after ablation) was achieved in five (63%), and partial success (ablation of only clinical VT) in an additional three (37%). At 1 year, freedom from VT and survival were achieved in six (75%) and seven (88%) patients, respectively. CONCLUSION: Initial data suggest that ablation of VT in the presence of intracavitary thrombus is feasible, is associated with a similar success rate to historical studies in patients without thrombus, and has an acceptable risk of complications given the high-risk nature of patients with ES. Further data are needed; however, the presence of a laminated thrombus should not necessarily preclude ablation in patients who have failed medical therapy for VT in whom ablation is otherwise indicated.

Sudden cardiac death after acute ST elevation myocardial infarction: insight from a developing country.

BACKGROUND: There is no data concerning sudden cardiac death (SCD) following acute ST elevation myocardial infarction (STEMI) in India. We assessed the incidence and factors influencing SCD following STEMI. METHODS: Patients with STEMI admitted in our hospital from 2006 to 2009 were prospectively entered into a database. In the period 2010-2011, patients or their kin were periodically contacted and administered a questionnaire to ascertain their survival, and mode of death if applicable. RESULTS: Study population comprised of 929 patients with STEMI (mean age 55±17 years) having a mean follow-up of 41±16 months. The total number of deaths was 159, of which 78 were SCD (mean age 62.2±10 years). The cumulative incidence of total deaths and SCD at 1 month, 1, 2, 3 years and at conclusion of the study was 10.1%, 13.2%, 14.6%, 15.8%, 17.3% and 4.9%, 6.5%, 8.0%, 8.9% and 9.7%, respectively. The temporal distribution of SCD was 53.9% at first month, 19.2% at 1 month to 1 year, 15.4% in 1-2 years, 7.6% in 2-3 years and 3.8% beyond 3 years. Comparison between SCD and survivor cohorts by multivariate analysis showed five variables were found to be associated with SCD (age p=0.0163, female gender p=0.0042, severe LV dysfunction p=0.0292, absence of both reperfusion and revascularisation p=0.0373 and lack of compliance with medications p <0.0001). CONCLUSIONS: SCD following STEMI accounts for about half of the total deaths. It involves younger population and most of these occur within the first month. This data has relevance in prioritising healthcare strategies in India.

Ventricular dyssynchrony patterns in left bundle branch block, with and without heart failure.

BACKGROUND: Assessment of ventricular dyssynchrony in patients with heart failure is used for selecting candidates for cardiac resynchronization therapy (CRT). The patterns of regional distribution of dyssynchrony in a population with LBBB with and without heart failure have not been well delineated. This aspect forms the object of the study. METHODS: Tissue Doppler Imaging (TDI) data of consecutive patients with heart failure and LBBB (Group A) was compared with those with LBBB and normal LV function (Group B). All patients had standard 2D-echocardigraphic examination and TDI. Tissue velocity curves obtained by placing sample volumes in opposing basal and mid segments of septal, lateral, inferior, anterior and posterior walls were analyzed. Inter ventricular dyssynchrony (IVD) was assessed by the difference between aortic and pulmonary pre ejection intervals. LV dyssynchrony (LVD) was assessed by the difference in times to peak velocity. A delay of >/= 40 msec was considered significant for presence of IVD and LVD. RESULTS: There were 103 patients in Group A and 25 in Group B. The mean QRS duration and PR intervals respectively were 146 +/- 25 vs. 152+/-20 msec and 182+/- 47 vs. 165+/-36 msec. (p=NS) LVEF in the 2 groups were (32 +/- 6 % vs. 61+/- 11%; p< 0.01). Prevalence of dyssynchrony in the HF group compared to Group B was 72% vs. 16%, (P< 0.01). Lateral wall dyssynchrony in the 2 groups was 37% vs. 0% (p< 0.01) while septal dyssynchrony was 16% vs. 16% (p- NS). CONCLUSIONS: 72% of heart failure patients with LBBB have documented dyssynchrony on TDI, which has a heterogeneous regional distribution. Dyssynchrony may be seen in LBBB and normal hearts but it is does not involve the lateral wall. Septal dyssynchrony in heart failure patients may not have the same significance as lateral wall delay.

Hemodynamic benefit of multiple programmable pacing configurations in patients with biventricular pacemakers.

INTRODUCTION: Cardiac resynchronization therapy (CRT) is an established treatment for patients with heart failure. However, one-third of the patients fail to improve with this therapy. Stimulation with different left ventricular stimulation (LVS) configurations has been used to prevent diaphragmatic capture and to decrease the capture thresholds. We evaluated the hemodynamic effects of different LVS configurations using echocardiography. METHODS: Recipients of CRT systems capable of multiple LVS configurations were studied. Biventricular capture was confirmed for each polarity and echocardiographic measurements were made. The atrioventricular and interventricular delays were optimized and kept constant during the study. The cardiac output (CO), myocardial performance index (MPI), and severity of mitral regurgitation (MR) were recorded for all LVS configurations and compared for the best and the worst configurations, determined by CO. RESULTS: We studied 10 men and four women, 55 +/- 13 years of age on average. The CO and MPI changed significantly by changing the LVS configurations. The difference in CO ranged from 0.3 to 1.5 L, and seven patients (50%) showed > or =20% difference in CO between best and worst LVS configurations. Severity of MR decreased by > or =1 grade in nine patients, while in two patients MR worsened despite improvement in CO. CONCLUSIONS: Changing the LVS configuration changes hemodynamic function in some CRT system recipients.

Catheter ablation of fascicular ventricular tachycardia.

Fascicular ventricular tachycardia (VT) is an idiopathic VT with right bundle branch block morphology and left-axis deviation occuring predominantly in young males. Fascicular tachycardia has been classified into three subtypes namely, left posterior fascicular VT, left anterior fascicular VT and upper septal fascicular VT. The mechanism of this tachycardia is believed to be localized reentry close to the fascicle of the left bundle branch. The reentrant circuit is composed of a verapamil sensitive zone, activated antegradely during tachycardia and the fast conduction Purkinje fibers activated retrogradely during tachycardia recorded as the pre Purkinje and the Purkinje potentials respectively. Catheter ablation is the preferred choice of therapy in patients with fascicular VT. Ablation is carried out during tachycardia, using conventional mapping techniques in majority of the patients, while three dimensional mapping and sinus rhythm ablation is reserved for patients with nonmappable tachycardia.

Ablation of incessant orthodromic reciprocating tachycardia in a child with congenitally corrected transposition of great arteries and ebsteinoid malformation of left atrioventricular valve.

We report about a patient with congenitally corrected transposition of the great arteries and ebsteinoid malformation of left atrioventricular (AV) valve who presented with incessant orthodromic atrioventricular reciprocating tachycardia due to a left posteroseptal accessory pathway. Radiofrequency catheter ablation using trans-septal approach successfully eliminated the posteroseptal pathway across the morphologic tricuspid valve. This report highlights the importance of delineating the anatomy of the interatrial septum in complex congenital heart diseases for performing safe trans-septal puncture during ablation of accessory pathways.

Catheter ablation of bundle branch reentrant ventricular tachycardia.

Bundle branch reentrant ventricular tachycardia (BBR-VT) is a form of macroreentrant tachycardia involving the bundle of His, both bundle branches, and the ventricular myocardium in the circuit. It generally occurs in the background of dilated cardiomyopathy, prior valve surgery, or other cardiac disease with an underlying His-Purkinje system (HPS) disease. Clinically, BBR-VT usually results in marked hemodynamic compromise and often presents with syncope, presyncope, or sudden cardiac arrest. When a ventricular tachycardia is induced, the presence of His deflections preceding every ventricular deflection should alert one to the possibility of this entity. It is important to show that oscillations in the H-H cycle length results in variations in V-V cycle length. Entrainment of the tachycardia from atrium and right ventricular apex and characteristics of postpacing intervals can be used to differentiate this arrhythmia from intramyocardial reentry and supraventricular tachycardia with aberrancy. Right bundle branch ablation usually cures the tachycardia, and recurrence is uncommon. The underlying cardiac disease and ventricular dysfunction dictate the prognosis and choice of device therapy in these patients.

Successful ablation of aortic cusp tachycardia from right ventricle outflow tract using a superior approach.

We report a case of successful radiofrequency catheter ablation of idiopathic aortic cusp tachycardia arising close to right coronary artery ostium performed safely from the right ventricular outflow tract (RVOT) by unconventional superior approach. As both activation mapping and pace mapping of the tachycardia were suboptimal from transfemoral RV endocardial approach, retrograde aortic mapping was performed. This revealed that the site of ventricular tachycardia (VT) origin to be on the right coronary sinus. Due to close proximity of VT site of origin and the right coronary ostium, an alternate approach to ablation was considered. We approached this area easily and successfully ablated the VT with an ablation catheter introduced from a right-sided superior approach (jugular vein). The patient has remained free from recurrences over an 18 month follow-up period.

Brugada syndrome unmasked by sodium channel blockade.

We report the case of a 29-year-old male suffering from recurrent syncope and palpitations. He had a structurally normal heart and his baseline electrocardiogram was normal. His electrophysiologic study revealed an inducible, nonsustained polymorphic ventricular tachycardia on programmed electrical stimulation. With the administration of intravenous Flecainide, there was typical ST-segment elevation in leads V2 and V3, indicative of the Brugada syndrome. He underwent an implantable cardioverter defibrillator implantation. The cardioverter defibrillator delivered an appropriate shock when the patient suffered ventricular fibrillation during follow-up one year later. This report illustrates the role of pharmacologic challenge in the diagnosis of the Brugada syndrome.

Intra-cardiac echocardiography guided cardioversion to help interventional procedures (ICE-CHIP) study: study design and methods.

The ICE CHIP study is a sequential Phase I and Phase II pilot study comparing the cardiac imaging capabilities of intracardiac echocardiography (ICE) with with transesophageal echocardiography (TEE) followed by a randomized comparison of ICE guided cardioversion with a conventional cardioversion strategy in patients with atrial fibrillation. It is a prospective open label randomized multi-center investigation performed in two phases designed to initially compare two distinct imaging modalities (Phase 1) and subsequently two different strategies (ICE guided Cardioversion and Conventional) in the management of AF in patients undergoing invasive cardiac procedures in whom electrical cardioversion is indicated (Phase 2). This study will examines two hypotheses in AF patients undergoing invasive cardiac procedures: (1) ICE has comparable efficacy to TEE in visualization of left atrial pathology including thrombi or interatrial septal defects. This will be evaluated during the Phase I component of the study. (2) ICE can identify low risk patients in whom immediate cardioversion during the procedure is safe and comparably effective to electrical cardioversion performed based on a conventional strategy of a minimum of 3 weeks of preceding anticoagulation therapy. Phase 1 will enroll 100 patients at 12 centers, who will undergo a clinically indicated TEE procedure and cardiac catheterization procedure. Each patient will be imaged by TEE & ICE and a core echo laboratory will perform a blinded comparison of the two imaging modalities. In Phase 2, a total of 300 patients (3:2 randomization) will be enrolled in the study at up to 15 investigational sites in USA and Europe. The composite incidence rate of major cardiac and bleeding complications (stroke, TIA, peripheral embolism, major hemorrhagic event) will be compared between the two treatment groups over the duration of the study.

Implantable defibrillators configured for hybrid therapy of persistent and permanent atrial fibrillation: initial clinical experience with a novel lead system.

AIM: Hybrid therapy strategies have combined antiarrhythmic drugs (AAD) with pacemakers, atrio-ventricular defibrillators (AV ICD) or atrial ablation individually. The feasibility combining AAD with dual site RA pacing (DAP) in an AV ICD has not been examined. METHODS: We used an AV ICD with a novel lead configuration permitting DAP, antitachycardia pacing (ATP) or atrial shocks (ADF) in patients (pts) with refractory persistent or permanent AF. Hybrid therapy included linear RA ablation and/or focal ablation. Continuous DAP and automatic ATP with patient or physician activated ADF. RESULTS: 24 pts, mean age 66 +/- 10 yrs, with cardiac disease (22 pts), underwent insertion of an AVICD with dual RA leads. 20 patients had concomitant ablative procedures (RA only = 19, RA + LA = 1) and all pts continued previously ineffective AAD. During a follow-up of 2-36 months (mean 17 +/- 8 mos), rhythm control was restored in all pts & maintained long-term in 19 (83%) pts. 8 pts used AF termination therapies successfully. Device datalogs showed no episodes of AF in 6 pts, asymptomatic brief arrhythmias in 4 pts, infrequent paroxysmal AF in 9 pts & persistent AF recurred in 5 pts. AV ICD detection algorithms reliably detected AF or AT in the DAP mode in all pts. Intermittent brief P wave double counting occurred during AT in selected pts. No pt received inappropriate ADF therapy. CONCLUSIONS: 1. DAP can be safely incorporated in an AVICD devices for use in an hybrid therapy strategy for AF pts. 2. These devices can be effective for both AF prevention & termination. 3. Long term rhythm control can be achieved and documented by device datalogs in persistent and permanent AF.

Biatrial and three-dimensional mapping of spontaneous atrial arrhythmias in patients with refractory atrial fibrillation.

INTRODUCTION: While atrial fibrillation (AF) initiation in the pulmonary veins has been well-studied, simultaneous biatrial and three-dimensional noncontact mapping (NCM) has not been performed. We hypothesized that these two techniques would provide novel information on triggers, initiation, and evolution of spontaneous AF and permit study of different AF populations. METHODS AND RESULTS: The origin of atrial premature beats (APBs), onset of spontaneous AF and its evolution were analyzed in 50 patients with AF in the presence or absence of structural heart disease (SHD) and in different AF presentations (group A: Persistent, group B: Paroxysmal). In 45 patients, spontaneous APBs in the right atrium (RA; n = 60) and left atrium (LA; n = 25) with similar regional distributions regardless of heart disease status were demonstrated. In total, 22 patients (44%) had > or =2 disparate regional origins. Biatrial regional foci were seen with equal frequency in patients with SHD (31%), without SHD (40%), in group A (32%), and in group B (36%). Biatrial mapping and NCM showed organized monomorphic atrial tachyarrhythmias arising in the RA (17), septum (17), or LA (21) and were classified as atrial flutter (RA = 34, LA = 8), macro-reentrant atrial tachycardia (RA = 1, LA = 3) or focal atrial tachycardia (RA = 2, LA = 7). Their regional distribution was more extensive in patients with SHD and persistent AF compared with patients without SHD or paroxysmal AF. Simultaneous biatrial tachycardias were observed only in group A patients and those with SHD. CONCLUSIONS: Simultaneous biatrial and NCM permits successful AF mapping in different AF populations and demonstrates a biatrial spectrum of spontaneous triggers and tachycardias. Organized monomorphic tachycardias with multiple unilateral or biatrial locations are commonly observed in human AF. Patients with heart disease or persistent AF have a more extensive distribution as well as simultaneous coexistence of multiple tachycardias during AF.