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.

Diastolic mitral regurgitation after dual chamber pacemaker.

First-degree Atrioventricular (AV) block can lead to symptoms of heart failure, due to AV dyssynchrony. We report a case of 40-year-old male with symptomatic 2:1 AV block with intermittent first-degree AV block who was implanted with dual chamber pacemaker with conduction system pacing (CSP). With conventional programming of managed ventricular pacing (MVP) and long AV delays, patient developed dyspnea due to diastolic mitral regurgitation because of AV dyssynchrony. Hence, AV delay optimization was done, and the patient became asymptomatic with atrial sensing and 100 % ventricular pacing. This report emphasizes the importance of AV delay optimization in CSP for symptomatic benefit.

Silent cerebral lesions following catheter ablation for atrial fibrillation: a state-of-the-art review.

Atrial fibrillation is associated with neurocognitive comorbidities such as stroke and dementia. Evidence suggests that rhythm control-especially if implemented early-may reduce the risk of cognitive decline. Catheter ablation is highly efficacious for restoring sinus rhythm in the setting of atrial fibrillation; however, ablation within the left atrium has been shown to result in MRI-detected silent cerebral lesions. In this state-of-the-art review article, we discuss the balance of risk between left atrial ablation and rhythm control. We highlight suggestions to lower the risk, as well as the evidence behind newer forms of ablation such as very high power short duration radiofrequency ablation and pulsed field ablation.

External irrigation of a non-irrigated ablation catheter for effective AV node ablation during conduction system pacing.

Ablation using non-irrigated catheter can lead to rapid rise in temperature of electrode tissue interface from tissue desiccation, steam and coagulum formation and this may limit power delivery and lesion size. We present a novel technique of external irrigation through the long sheath while using a non-irrigated ablation catheter during AV Node ablation and conduction system pacing. By bringing the long sheath closer to the tip of non-irrigated catheter and injecting cold normal saline allows cooling of electrode tissue interface leading to increase in power delivery resulting in a deeper lesion.

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.

CT-guided percutaneous epicardial access for ventricular tachycardia ablation: A proof-of-concept study.

INTRODUCTION: The objective of this study was to evaluate the safety and efficacy of preprocedural computed tomography (CT) to guide percutaneous epicardial puncture for catheter ablation of ventricular tachycardia. METHODS AND RESULTS: A preprocedural CT was used to plan the site, angle, and depth of needle insertion during epicardial access in 10 consecutive patients undergoing ventricular tachycardia (VT) ablation. Adjacent structures (right ventricle, diaphragm, liver, colon, internal mammary artery) were visualized and the course of the needle was planned avoiding these structures. During epicardial access, a protractor was used to guide the angle of needle entry into the subxiphoid space. Postprocedural CT was performed to calculate the deviation between the planned and executed access and to assess for any collateral damage. Percutaneous epicardial access was obtained successfully in all the patients using anterior (n = 4) and inferior (n = 6) approaches. The planned site and angle of puncture was more caudal (2.9 ± 0.9 vs. 3.7 ± 0.7 cm, p = .021) and acute (61.7 ± 5.8 vs. 49.0 ± 5.4°, p = .011) for an anterior approach compared to an inferior approach, respectively. Postprocedure CT revealed minimal deviation of the puncture site (5.4 ± 1.0 mm), angle (5.4 ± 1.2°), and length of needle insertion (0.5 ± 0.2 cm). With regard to the site of entry in the pericardial space, there was a deviation of 5.9 ± 1.1, 6.1 ± 1.1, and 5.8 ± 1.4 mm in the x, y, and z dimensions, respectively. In eight patients with minimal deviation between planned and executed access, there was no collateral injury to adjacent viscera or vessels. In two patients with increased deviation of angle and length of needle insertion, there was entry through the diaphragm during inferior access. CONCLUSIONS: Utilizing pre-procedural CT planning may aid in the success and safety of percutaneous epicardial access during VT ablation.

Refractory heart failure with LBBB - Pause before CRT.

In this report, we describe complete disappearance of LBBB with normalization of LV function in two patients with cardiac sarcoidosis (CS) after immunosuppressive therapy. Both of these patients were ideal Class IA candidates for CRT (Complete LBBB, QRS ≥ 150 ms, EF < 30%). If CS is identified early, immunosuppressive treatment can lead to not only improvement of left ventricular function but also disappearance of the left bundle branch block. Timely diagnosis and management of CS obviated the need of CRT in these patients. It may be reasonable to evaluate all non-ischemic cardiomyopathies for underlying reversible causes prior to CRT implantation.

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.

Impact of the inflammation on the outcomes of catheter ablation of drug-refractory ventricular tachycardia in cardiac sarcoidosis.

INTRODUCTION: Catheter ablation (CA) of ventricular tachycardia (VT) in cardiac sarcoidosis (CS) has been reported with varying success. However, there is a scarcity of data on the outcomes of CA based on ongoing inflammation. OBJECTIVE: We hypothesized that the response to VT ablation depends upon the stage of the disease. METHODS: Between July 2004 and December 2018, 24 patients of CS presented with drug-refractory VT at CARE Hospital (Hyderabad) and the University of Minnesota (Minneapolis, MN). Patients were classified into two groups based on cardiac magnetic resonance imaging and positron emission tomography: (a) inflammatory phase, (b) scar phase. All patients underwent 3D electro-anatomic mapping guided CA. RESULTS: The clinical VT was ablated in all but one patient. In 16 patients (66.6%), both the clinical and nonclinical VTs were ablated (complete success), while in seven patients (29.1%) nonclinical VTs was still inducible. In patients with inflammation (group A), complete success for VT ablation was achieved in 10 out of 17 (58.8%). In patients without inflammation (group B), complete success was achieved in six out of seven patients (85.7%). Eleven patients (45.8%) had a recurrence of VT. Among patients in the inflammatory phase (group A): 10 out of 17 patients had a recurrence of VT, while only one out of seven patients in the scar phase (group B) had VT recurrence over a mean follow-up of 5.7 ± 3.9 years. Epicardial ablation was performed in 10 (41.6%) patients. CONCLUSION: CA of drug-refractory VT in CS is effective, often requiring the epicardial approach. Incomplete success and recurrence of VT were higher in the inflammatory phase of the disease.

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.

Impact of interventricular delay on repolarization parameters in patients with biventricular pacing.

A 48-year-old man who was previously a responder to cardiac resynchronization therapy (CRT) presented with worsening of heart failure and reduction in the percentage biventricular (BiV) pacing. Device interrogation revealed T-wave oversensing that was eliminated by optimizing the interventricular (VV) delay. Compared to simultaneous BiV pacing, both sequential left ventricle-right ventricle (LV-RV) and univentricular LV pacing shortened the QTc, T peak-end intervals and reduced the T wave amplitude. Modification of VV delays can result in changes in wavefront of activation and thereby affect ventricular repolarization patterns.

Outflow-tract ventricular tachycardia: Can 12 lead ECG during sinus rhythm identify underlying cardiac sarcoidosis?

BACKGROUND: Patients with outflow tract ventricular tachycardia (OTVT) with normal echocardiogram are labeled as idiopathic VT (IVT). However, a subset of these patients is subsequently diagnosed with underlying cardiac sarcoidosis (CS). OBJECTIVE: Whether electrocardiogram (ECG) abnormalities in sinus rhythm (SR) can differentiate underlying CS from IVT. METHODS: We retrospectively analyzed the SR-ECGs of 42 patients with OTVT/premature ventricular complexes (PVC) and normal echocardiography. All underwent advanced imaging with cardiac magnetic resonance (CMR)/18FDG PET-CT for screening of CS. Twenty-two patients had significant abnormalities in cardiac imaging and subsequently had biopsy-proven CS (Cases). Twenty patients had normal imaging and were categorized as IVT (Controls). SR-ECGs of all patients were analyzed by 2 independent, blinded observers. RESULTS: Baseline characteristics were comparable. Among the ECG features analyzed - fascicular (FB) or bundle branch block (BBB) was seen in 9/22 Cases vs. 1/20 controls (p = 0.01). Among patients without FB or BBB, fragmented QRS (fQRS) was present in 9/13 cases but in none of the controls (p < 0.001). Low voltage QRS was more often seen among cases as compared to controls (10/22 vs. 3/20 p = 0.03). A stepwise algorithm based on these 3 sets of ECG findings helped to diagnose CS among patients presenting with OTVT/PVC with sensitivity of 91%, specificity of 75%, a PPV of 80%, and a NPV of 88%. CONCLUSIONS: In patients presenting with OTVT/PVC: FB/BBB, fQRS, and low QRS voltage on the baseline ECG were more often observed among patients with underlying CS as compared to true IVT. These findings may help to distinguish underlying CS among Cases presenting with OTVT/PVC.

Heart Failure With Preserved Ejection Fraction in the Young.

BACKGROUND: Heart failure with preserved ejection fraction (HFpEF), traditionally considered a disease of the elderly, may also affect younger patients. However, little is known about HFpEF in the young. METHODS: We prospectively enrolled 1203 patients with HFpEF (left ventricular ejection fraction ≥50%) from 11 Asian regions. We grouped HFpEF patients into very young (<55 years of age; n=157), young (55-64 years of age; n=284), older (65-74 years of age; n=355), and elderly (≥75 years of age; n=407) and compared clinical and echocardiographic characteristics, quality of life, and outcomes across age groups and between very young individuals with HFpEF and age- and sex-matched control subjects without heart failure. RESULTS: Thirty-seven percent of our HFpEF population was <65 years of age. Younger age was associated with male preponderance and a higher prevalence of obesity (body mass index ≥30 kg/m2; 36% in very young HFpEF versus 16% in elderly) together with less renal impairment, atrial fibrillation, and hypertension (all P<0.001). Left ventricular filling pressures and prevalence of left ventricular hypertrophy were similar in very young and elderly HFpEF. Quality of life was better and death and heart failure hospitalization at 1 year occurred less frequently ( P<0.001) in the very young (7%) compared with elderly (21%) HFpEF. Compared with control subjects, very young HFpEF had a 3-fold higher death rate and twice the prevalence of hypertrophy. CONCLUSIONS: Young and very young patients with HFpEF display similar adverse cardiac remodeling compared with their older counterparts and very poor outcomes compared with control subjects without heart failure. Obesity may be a major driver of HFpEF in a high proportion of HFpEF in the young and very young.

A Leadless Intracardiac Transcatheter Pacing System.

BACKGROUND: A leadless intracardiac transcatheter pacing system has been designed to avoid the need for a pacemaker pocket and transvenous lead. METHODS: In a prospective multicenter study without controls, a transcatheter pacemaker was implanted in patients who had guideline-based indications for ventricular pacing. The analysis of the primary end points began when 300 patients reached 6 months of follow-up. The primary safety end point was freedom from system-related or procedure-related major complications. The primary efficacy end point was the percentage of patients with low and stable pacing capture thresholds at 6 months (≤2.0 V at a pulse width of 0.24 msec and an increase of ≤1.5 V from the time of implantation). The safety and efficacy end points were evaluated against performance goals (based on historical data) of 83% and 80%, respectively. We also performed a post hoc analysis in which the rates of major complications were compared with those in a control cohort of 2667 patients with transvenous pacemakers from six previously published studies. RESULTS: The device was successfully implanted in 719 of 725 patients (99.2%). The Kaplan-Meier estimate of the rate of the primary safety end point was 96.0% (95% confidence interval [CI], 93.9 to 97.3; P<0.001 for the comparison with the safety performance goal of 83%); there were 28 major complications in 25 of 725 patients, and no dislodgements. The rate of the primary efficacy end point was 98.3% (95% CI, 96.1 to 99.5; P<0.001 for the comparison with the efficacy performance goal of 80%) among 292 of 297 patients with paired 6-month data. Although there were 28 major complications in 25 patients, patients with transcatheter pacemakers had significantly fewer major complications than did the control patients (hazard ratio, 0.49; 95% CI, 0.33 to 0.75; P=0.001). CONCLUSIONS: In this historical comparison study, the transcatheter pacemaker met the prespecified safety and efficacy goals; it had a safety profile similar to that of a transvenous system while providing low and stable pacing thresholds. (Funded by Medtronic; Micra Transcatheter Pacing Study ClinicalTrials.gov number, NCT02004873.).

Patient selection, pacing indications, and subsequent outcomes with de novo leadless single-chamber VVI pacing.

AIMS: Patient selection is a key component of securing optimal patient outcomes with leadless pacing. We sought to describe and compare patient characteristics and outcomes of Micra patients with and without a primary pacing indication associated with atrial fibrillation (AF) in the Micra IDE trial. METHODS AND RESULTS: The primary outcome (risk of cardiac failure, pacemaker syndrome, or syncope related to the Micra system or procedure) was compared between successfully implanted patients from the Micra IDE trial with a primary pacing indication associated with AF or history of AF (AF group) and those without (non-AF group). Among 720 patients successfully implanted with Micra, 228 (31.7%) were in the non-AF group. Reasons for selecting VVI pacing in non-AF patients included an expectation for infrequent pacing (66.2%) and advanced age (27.2%). More patients in the non-AF group had a condition that precluded the use of a transvenous pacemaker (9.6% vs. 4.7%, P = 0.013). Atrial fibrillation patients programmed to VVI received significantly more ventricular pacing compared to non-AF patients (median 67.8% vs. 12.6%; P < 0.001). The overall occurrence of the composite outcome at 24 months was 1.8% with no difference between the AF and non-AF groups (hazard ratio 1.36, 95% confidence interval 0.45-4.2; P = 0.59). CONCLUSION: Nearly one-third of patients selected to receive Micra VVI therapy were for indications not associated with AF. Non-AF VVI patients required less frequent pacing compared to patients with AF. Risks associated with VVI therapy were low and did not differ in those with and without AF.

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.

A Complete Absence of Missense Mutation in Myosin Regulatory and Essential Light Chain Genes of South Indian Hypertrophic and Dilated Cardiomyopathies.

BACKGROUND: Myosin is a hexameric contractile protein composed of 2 heavy chains associated with 4 light chains of 2 distinct classes - 2 regulatory light chains (MYL2) and 2 essential light chains (MYL3). The myosin light chains stabilize the long alpha helical neck of the myosin head and regulate the myosin ATPase activities. OBJECTIVES: Mutations in MYL2 and MYL3 are reported to be associated with cardiomyopathies. However, there is no study available on these genes in Indian cardiomyopathies, and therefore we planned to study them. METHOD: For the first time we sequenced MYL2 and MYL3 genes in a total of 248 clinically well-characterized cardiomyopathies consisting of 101 hypertrophic and 147 dilated cases along with 207 healthy controls from south India. RESULTS: Our study revealed a total of 10 variations - 7 in MYL2 and 3 in MYL3, of which 3 are novel variations observed exclusively in cases. However, the 15 causative missense mutations previously reported are totally absent in our study, which showed that the sequences of MYL2 and MYL3 are highly conserved in Indian cases/controls. CONCLUSIONS: MYL2 and MYL3 mutations are rare and the least cause of cardiomyopathies in Indians.