Outcome of tailored therapy in rheumatic heart disease with persistent atrial fibrillation (RHD-AF).

INTRODUCTION: Rheumatic heart disease with persistent atrial fibrillation (RHD-AF) is associated with increased morbidity. However, there is no standardized approach for the maintenance of sinus rhythm (SR) in them. We aimed to determine the utility of a stepwise approach to achieve SR in RHD-AF. METHODS: Consecutive patients with RHD-AF from July 2021 to August 2023 formed the study cohort. The stepwise approach included pharmacological rhythm control and/or electrical cardioversion (Central illustration). In patients with recurrence, additional options included AF ablation or pace and ablate strategy with conduction system pacing or biventricular pacing. Clinical improvement, NT-proBNP, 6-Minute Walk Test (6MWT), heart failure (HF) hospitalizations, and thromboembolic complications were documented during follow-up. RESULTS: Eighty-three patients with RHD-AF (mean age 56.13 ± 9.51 years, women 72.28%) were included. Utilizing this approach, 43 (51.81%) achieved and maintained SR during the study period of 11.04 ± 7.14 months. These patients had improved functional class, lower NT-proBNP, better distance covered for 6MWT, and reduced HF hospitalizations. The duration of AF was shorter in patients who achieved SR, compared to those who remained in AF (3.15 ± 1.29 vs 6.93 ± 5.23, p = 0.041). Thirty-five percent (29) maintained SR after a single cardioversion over the study period. Only one underwent AF ablation. Of the 24 who underwent pace and ablate strategy, atrial lead was implanted in 22 (hybrid approach), and 50% of these achieved and maintained SR. Among these 24, none had HF hospitalizations, but patients who maintained SR had further improvement in clinical and functional parameters. CONCLUSIONS: RHD-AF patients who could achieve SR with a stepwise approach, had better clinical outcomes and lower HF hospitalizations.

Radiofrequency catheter ablation of ventricular arrhythmias in patients with hypertrophic cardiomyopathy.

BACKGROUND: Compared to other non-ischemic substrates, there is limited data on the role and outcome of catheter ablation in HCM. The objective of this study is to assess the safety and efficacy of catheter ablation for the treatment of VT in patients with HCM. METHODS: Fourteen patients with HCM and drug refractory VT who underwent catheter ablation at a single center were included in this study. The data was evaluated retrospectively. Acute success, procedure-related complications, and long-term outcomes were documented during follow up. RESULTS: Among the 14 patients (mean age 48.2 ± 8.2 years, 85.7% males, mean LVEF 42.6 ± 6.5%), 4 had an apical aneurysm. Eleven patients had evidence of scar-related VT and three patients had a bundle-branch re-entry VT. The most common sites for scar-related VT were the border-zones of the apical aneurysms, basal septum, and LV lateral wall. Patient either underwent an endocardial ablation or a combined endocardial and epicardial ablation. Acute success was achieved in all patients. In 6 patients VT was terminated during ablation. In two patients, non-clinical VTs were inducible at the end of the procedure. No major or minor complications were observed during and after the procedure in all patients. During long-term follow up, elimination of VTs reached 78%. CONCLUSION: Catheter ablation of VT in patients with HCM is safe and successful in eliminating VT. Combining endocardial and epicardial ablation techniques can potentially lead to better outcomes in these patients. Bundle branch re-entry should be considered as a potential mechanism of VT in patients with HCM.

Feasibility of a using chest strap and dry electrode system for longer term cardiac arrhythmia monitoring: Results from a pilot observational study.

BACKGROUND AND AIM: Cardiac arrhythmia diagnostic yield improves with increased duration of monitoring. We investigated patient comfort, diagnostic quality of ECG, and arrhythmia diagnostic yield using a single lead longer term external cardiac monitor (ECM). METHODS: The observational ECM feasibility study enrolled patients with increased risk of cardiac arrhythmia. The ECM investigational prototype was designed using a chest strap with dry electrodes connected to module capable of triggered loop recording of ECG, and automatic detection of arrhythmia. In group-A of study (24-h inpatient), patients wore ECM and Holter that recorded ECG from the ECM and adhesive electrodes. In group-B of study (12-weeks ambulatory), at monthly follow-ups patients filled out a comfort survey and device stored arrhythmia episodes were reviewed. RESULTS: The study enrolled 34 patients (38 % females, average age 57.5 years, 65 % had palpitations, 12 % had syncope). Diagnostic quality ECG was recorded on 76.5 % of the monitoring duration in 12 of 20 patients with reviewable data in group-A, with motion artifacts causing loss in ECG signal for 18.7 % of the time. In 14 patients in group-B, 94.9 % of the survey responses indicated that ECM was comfortable to wear. Cardiac arrhythmia was observed in 4 of 17 patients (24 %) in group-A and 9 of 14 patients (64 %) in group-B in device recorded episodes. All ECM detected pause and tachycardia were inappropriate detections due to motion artifacts and temporary device removal. CONCLUSION: The chest strap-based ECM device was mostly comfortable to wear and recorded diagnostic quality ECG in three-fourth of monitoring period. Cardiac arrhythmia was observed in 64 % of patients over 3-month monitoring along with large number of motion artifact induced inappropriate detections.

High rate episodes in a dual chamber pacemaker: What is the mechanism?

Detection of high rate episodes can potentially result from oversensing of physiological or nonphysiological signals. Assessment of lead integrity, lead connection and analysis of noise characteristics on electrograms are decisive steps in the evaluation of oversensing. We report a case of high atrial and ventricular rate episodes due to minute ventilation oversensing in the presence of lead connector issues.

His-bundle pacing versus cardiac resynchronisation therapy: Effect on ECG parameters of repolarization.

INTRODUCTION: Cardiac resynchronization therapy (CRT) by biventricular pacing (BiV) may worsen indices of ventricular repolarization. The impact of His bundle pacing (HBP) on repolarization is not well studied in patients with left ventricular systolic dysfunction. The aim of the study is to compare the repolarization parameters in ECG between these two pacing modalities. METHODS: Baseline and post implant parameters of 20 patients who had undergone HBP were compared with 18 patients who underwent CRT (BiV) implantation. Repolarization parameters were monitored before implantation, within 24  hours and after 6 weeks of implantation. Patients were followed up till 6 months with clinical and echocardiographic parameters. RESULT: Baseline clinical, electrocardiographic and echocardiographic parameters were similar in both groups. Significant differences were noted in QTc, Tp-e and Tp-e/QTc between HBP and CRT groups both on immediate post implant and after 6 weeks of implantation. Compared to pre-implantation,significant shortening of Tp-e and Tp-e/QTc was observed immediately (90.54 ± 24.35 vs 69.62 ± 12.92, p < 0.05 and 0.20 ± 0.05 vs 0.15 ± 0.03, p < 0.05) and after 6 weeks (90.54 ± 24.35 vs 66.08 ± 14.95, p < 0.05 and 0.20 ± 0.05 vs 0.15 ± 0.02, p < 0.05) in HBP implant (group A). However, these changes were not present in CRT cohort (group B). During a follow up of 6 months, NYHA class and LV function between two groups remain comparable. CONCLUSION: HBP is associated with significant reduction of Tp-e and Tp-e/QTc compared to CRT. Further evaluation is needed to determine whether this improvement in indices of repolarization is associated with reduction in clinical arrhythmic events or not.

A case of cardiac sarcoidosis mimicking Brugada syndrome.

A 17-year-old boy was admitted for management of ventricular fibrillation (VF) with intermittent Brugada pattern on ECG. On evaluation, cardiac MRI revealed myocardial scar and mediastinal lymphadenopathy. 18-Fluorodeoxyglucose positron emission tomography scan showed inflammation in the heart, lungs, and lymph nodes. He was diagnosed as a case of cardiac sarcoidosis (CS) and treated with steroids. However, there was a reactivation of cardiac inflammation and the development of a second VF storm. Following catheter ablation, the patient's arrhythmia improved. This report highlights the inflammation due to CS mimicking channelopathic features.

PVCs with multiple exits and single site of origin in the outflow tract: What is the mechanism?

A 40 year old man with frequent PVCs with two different morphologies was referred for catheter ablation. Although initial mapping in the RVOT revealed fragmented potentials 20ms earlier than PVC2 onset with a good pace map score, ablation at this site was unsuccessful. Subsequent mapping in the LCC/NCC junction revealed that local ventricular activation preceded QRS onset by 30 and 28 ms for PVC1 and PVC2, respectively. Altering the pacing output at this site produced QRS morphologies similar to PVC1(low output,6mA) and PVC2(high output,15mA) with better pace map scores compared to RVOT. During high-output pacing, there was an increase in stim-QRS latency with decremental conduction. Ablation at this site was successful and suppressed both PVCs.

Inappropriate defibrillator shock due to oversensing. What is the mechanism?

Implantable cardioverter defibrillator (ICD) is often advised for secondary prevention of sudden cardiac death. Inappropriate shocks from ICD is uncommon but can seriously affect the quality of life. One of the reasons for inappropriate ICD shock is loose set screw, which may remain undetected by device interrogation and/or fluoroscopy. A 55-year lady presented with multiple inappropriate shocks few hours after an ICD implantation. The discrepancy between near field (NF, tip to ring) and far field (FF, Can to RV coil) signals helped us to suspect noise related to loose set screw, as the underlying problem. Re-exploration of the pocket had to be performed as the last resort to confirm the diagnosis and rectify the problem.

Prevalence, clinical profile, and stroke risk of atrial fibrillation in rural Andhra Pradesh, India (The AP-AF study) - Rationale and design.

INTRODUCTION: The epidemiology of atrial fibrillation (AF) in India has not been studied systematically in large scale population based surveys. Stroke is one of the leading causes of death and disability in India. As AF is a major contributor of stroke, it is important to know the burden of AF and stroke risk in the population. The Andhra Pradesh Atrial Fibrillation (AP-AF) study aims to assess the prevalence, etiology, risk factors and stroke risk among the rural population in Andhra Pradesh, India. METHODS: This is a cross-sectional survey done using a two-stage sampling process. Adults (≥18years) from villages in East and West Godavari districts were sampled. Field investigators used a structured questionnaire to collect information on basic demographics, cardiovascular risk factors and medical history. Anthropometric measurements were performed, blood pressure measured and fasting capillary blood glucose was assessed. Electrocardiogram was done using a hand-held mobile ECG device-KardioMobile. ECGs were interpreted by study cardiologists. Participants diagnosed to have AF were invited to participate in a camp conducted by cardiologists where echocardiogram was done and also a focused history related to AF was collected. Along with age and sex stratified prevalence of AF, descriptive statistics will be used to present demographics, clinical profile, and cardiovascular risk factors. Stroke risk will be calculated using CHA 2 DS 2 -Vasc score. CONCLUSION: The AP-AF study is expected to provide important information on AF epidemiology in rural India. The information may help improve health care policies in preventing stroke and other complications of AF.

Underdiagnosis of VT due to cycle length variation among cardiac sarcoidosis patients having ICD: Problem with stability discriminator.

BACKGROUND: Implantable cardioverter defibrillator (ICD) is recommended for patients with ventricular tachycardia (VT) due to cardiac sarcoidosis (CS). Programming supraventricular tachycardia (SVT) discriminators (onset, stability, and morphology/template match) is generally recommended to minimize inappropriate therapies. However, VT in patients with CS is known to show cycle length variability (CLV) and pleomorphism. OBJECTIVE: To determine whether the stability criterion, designed to prevent inappropriate therapy during atrial fibrillation with rapid ventricular rates, could potentially lead to incorrect classification of VT as SVT and inappropriately delay or inhibit ICD therapy. METHODS: Cases of biopsy-proven CS with VT were analyzed. For patients with implanted devices, all recorded electrograms of tachycardia episodes and ICD therapies were analyzed at last follow up. RESULTS: A total of 142 patients were included (mean age 38 years, 87 males). One hundred and three of 142 patients had implanted devices (ICD or CRT-D). Thirty eight of 103 (36.9%) patients received appropriate ICD therapies over 3 ± 2.2 years follow up. Four of 38 (10.5%) of patients experienced delayed-detection or underdetection of VT related to CLV, resulting in VT counters being repeatedly "reset" (classified as "unstable" rhythms). Retrospective analysis of other VT episodes in 70 of 103 (68%) patients revealed that 25 of 80 (31.3%) episodes had > 50 ms cycle length oscillations. CONCLUSION: Among CS patients with VT, CLV is a common occurrence seen in two-thirds of VT episodes. Routine programming of the stability criterion may result in underdetection of VT in a subset of such patients. We recommend that the stability criterion should be programmed "OFF" for patients with CS, unless the patient has documented atrial fibrillation.

Mitral valve tuberculoma: Role of sequential multimodality imaging of an unusual intracardiac mass.

We present an unusual intracardiac mass posing a diagnostic dilemma. A middle-aged male patient was referred for workup of a symptomatic cardiac mass involving the mitral valve. Multimodality imaging consisting of cardiac magnetic resonance (CMR) imaging and 18F-fluorodeoxyglucose positron emission computerized tomography (18FDG-PET) scan was utilized to further characterize the mass after initial echocardiographic identification. CMR imaging identified extent of valvular mass into the interatrial septum and basal portion of the interventricular septum. On 18FDG-PET scan, the intracardiac mass was found to be metabolically active. It also revealed the presence of FDG avid lymph nodes in the abdomen. Histology of the lymph node revealed active granulomatous inflammation suggestive of tuberculosis. Treatment with antitubercular therapy resulted in resolution of the mass and mitral regurgitation, avoiding surgery.

Severe left ventricular systolic dysfunction after permanent pacemaker implantation: Should we pause before upgrading to biventricular pacing?

Left ventricular (LV) systolic dysfunction leading to heart failure (HF) is known to occur after permanent pacemaker implantation (PPI) in a subset of patients. They are often treated by upgradation of the pacemaker to cardiac resynchronisation therapy (CRT). We report a case of progressive LV dysfunction and HF after PPI. Cardiac 18FDG-PET-CT scan revealed abnormal myocardial FDG uptake suggestive of cardiac sarcoidosis (CS). Biopsy from FDG avid lymph node demonstrated non-caseating granuloma. Therapy with steroids resulted in resolution of HF symptoms accompanied by a significant improvement in LV function.

Catheter ablation of recurrent polymorphic tachycardia: Use of sodium channel blockade to organize the tachycardia: A case report.

A 55 year old male presented with recurrent implantable cardioverter defibrillator (ICD) shocks due to polymorphic ventricular tachycardia (PMVT). He had undergone prior catheter ablation for VT three years ago. During the prior attempt he underwent voltage guided substrate ablation. With programmed ventricular extrastimulation (PVES), PMVT was repeatedly induced requiring DC shock. Intravenous procainamide was administered and PVES was repeated which induced sustained monomorphic ventricular tachycardia (MMVT). This VT had pseudo delta waves with maximum deflection index of 0.68, suggestive of epicardial origin. Activation mapping was performed epicardially. Presystolic potentials were recorded in mid anterolateral wall of left ventricular epicardial region. Radiofrequency (RF) ablation at this site terminated the VT. Post ablation there was no inducible tachycardia and patient is free of arrhythmias during 2 years of follow-up.

Catheter ablation of ventricular tachycardia: strategies to improve outcomes.

Catheter ablation of ventricular arrhythmias has evolved considerably since it was first described more than 3 decades ago. Advancements in understanding the underlying substrate, utilizing pre-procedural imaging, and evolving ablation techniques have improved the outcomes of catheter ablation. Ensuring safety and efficacy during catheter ablation requires adequate planning, including analysis of the 12 lead ECG and appropriate pre-procedural imaging. Defining the underlying arrhythmogenic substrate and disease eitology allow for the developed of tailored ablation strategies, especially for patients with non-ischemic cardiomyopathies. During ablation, the type of anesthesia can affect VT induction, the quality of the electro-anatomic map, and the stability of the catheter during ablation. For high risk patients, appropriate selection of hemodynamic support can increase the success of VT ablation. For patients in whom VT is hemodynamically unstable or difficult to induce, substrate modification strategies can aid in safe and successful ablation. Recently, there has been an several advancements in substrate mapping strategies that can be used to identify and differentiate local late potentials. The incorporation of high-definition mapping and contact-sense technologies have both had incremental benefits on the success of ablation procedures. It is crucial to harness newer technology and ablation strategies with the highest level of peri-procedural safety to achieve optimal long-term outcomes in patients undergoing VT ablation.

Efficacy of SGLT2 Inhibitors in Patients With Diabetes and Nonobstructive Hypertrophic Cardiomyopathy.

The objective of this study was to evaluate the effects of sodium glucose co-transporter 2 inhibitors (SGLT2i) on functional capacity and diastolic function in patients with diabetes with nonobstructive hypertrophic cardiomyopathy (nHCM) and preserved left ventricular (LV) function. From January 2019 to October 2020, a prospective open-label study was performed on patients with type 2 diabetes mellitus and nHCM with New York Heart Association class II-III symptoms. Patients with a LV ejection fraction <50% were excluded. Patients were recruited from January 2019 to November 2019 to the SGLT2i arm and from November 2019 to October 2020 to the control arm. The primary composite end point was defined as achieving an improvement of at least 1.5 in E/e' and a reduction of ≥1 New York Heart Association functional class after 6 months of therapy. At baseline, there were no significant differences between the SGLT2i (n = 24) and control arms (n = 24). More patients in the SGLT2i arm achieved the primary end point than the patients in the control arm (70.8% vs 4.2%, p <0.001). After 6 months of therapy, patients in the SGLT2i arm showed a significant improvement in all diastolic function parameters (E/e' 16.3 ± 1.9 vs 13.3 ± 1.6, p <0.001; E/A 2.8 ± 0.1 vs 2.4 ± 0.1, p <0.001; left atrial volume 45.6 ± 5.2 vs 40.8 ± 4.9 ml/m2, p = 0.003). There was also an improvement in the 6-minute walk distance (295.1 ± 31.5 vs 343.0 ± 31.1 m, p <0.001) and N-terminal pro-B-type natriuretic peptide (481.4 ± 52.6 vs 440.9 ± 43.9 pg/ml, p <0.001) in patients who received SGLT2i. There was no significant change in the LV mass in the SGLT2i or control arm (-0.1 ± 0.3 vs 0.1 ± 0.5 g/m2, p = 0.319) after 6 months of therapy. A patient in the SGLT2i arm discontinued therapy because of a urinary tract infection. In conclusion, the use of SGLT2i improved diastolic function and functional capacity in patients with diabetes with nHCM and a preserved LV function.

Best Practices for the Catheter Ablation of Ventricular Arrhythmias.

Techniques for catheter ablation have evolved to effectively treat a range of ventricular arrhythmias. Pre-operative electrocardiographic and cardiac imaging data are very useful in understanding the arrhythmogenic substrate and can guide mapping and ablation. In this review, we focus on best practices for catheter ablation, with emphasis on tailoring ablation strategies, based on the presence or absence of structural heart disease, underlying clinical status, and hemodynamic stability of the ventricular arrhythmia. We discuss steps to make ablation safe and prevent complications, and techniques to improve the efficacy of ablation, including optimal use of electroanatomical mapping algorithms, energy delivery, intracardiac echocardiography, and selective use of mechanical circulatory support.

Catheter Ablation for Ventricular Arrhythmias in Hypertrophic Cardiomyopathy.

Implantable cardioverter-defibrillators are the mainstay of therapy for prevention of sudden cardiac death in high-risk patients with hypertrophic cardiomyopathy (HCM). Catheter ablation is a useful option for patients with recurrent, drug refractory monomorphic ventricular tachycardia (VT), and device therapy. Compared with other nonischemic substrates, there are limited data on the role and outcomes of catheter ablation in HCM. The challenges of VT ablation in HCM patients include deep intramural and epicardial substrates, suboptimal power delivery, and higher recurrence due to progression of disease. Patient selection, using cardiac MRI scar localization, and optimizing ablation techniques can improve outcomes in these patients.

Ventricular Tachycardia in Granulomatous Myocarditis: Role of Catheter Ablation.

Granulomatous myocarditis is an inflammatory disease of the myocardium, characterized by lymphocytic infiltration with characteristic granuloma formation. Although a host of disease processes can elicit myocardial granulomas, two common entities are cardiac sarcoidosis and cardiac tuberculosis. Cardiac arrhythmias in this condition are frequent and management of ventricular arrhythmias can be challenging, especially in those with drug-refractory ventricular tachycardia and electrical storm. In this review, we highlight the role of catheter ablation for ventricular tachycardia and optimal patient selection for catheter ablation, based on cardiac imaging.