Publications by authors named "Narasimhan Calambur"

Causes of paradoxical response include Pure His capture and inadvertent intermittent direct atrial capture. In the index case , we postulate that the likely mechanism of paradoxical prolongation could be due to decrement in the AV node due to the shortening of HH interval which happened as a result of a narrower H + Vc beat .

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Background: A lack of standard Bachmann bundle (BB) capture criteria has affected the clinical impact of Bachmann bundle area pacing (BBAP) in patients with interatrial block (IAB).

Objective: The purpose of this study was to evaluate the feasibility and safety of electrogram-guided Bachmann bundle pacing (BBP) using sheath assisted, stylet-driven atrial lead implantation.

Methods: Patients with baseline IAB undergoing dual-chamber pacemaker or implantable cardioverter-defibrillator implantation were enrolled in a single-center prospective study.

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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.

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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.

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Background: Bilateral cardiac sympathetic denervation (BCSD) for refractory life-threatening ventricular arrhythmias is a neuromodulatory intervention targeting sympathetically driven focal or re-entrant ventricular arrhythmias.

Objectives: This study sought to provide a more complete and successful option for intervention in patients in whom premature ventricular contraction (PVC) ablation is not feasible or has been unsuccessful.

Methods: A total of 43 patients with >5% PVC burden and concomitant nonischemic cardiomyopathy (NICM) who previously failed medical and ablation therapies were referred for BCSD.

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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.

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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.

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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.

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Article Synopsis
  • A study evaluated the association of various cardiac sarcoidosis (CS) diagnostic criteria from different years (1993, 2006, 2014, and 2017) with negative health outcomes in patients.
  • Research involved analyzing data from a global cardiac sarcoidosis registry and identified adverse events like mortality and surgeries in 587 patients.
  • Results showed patients meeting the 1993 and 2006 criteria had significantly higher chances of experiencing adverse outcomes compared to those who didn't, while the 2014 and 2017 criteria did not show a significant correlation with these events.
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Background: Treatment options for symptomatic patients with nonobstructive hypertrophic cardiomyopathy (nHCM) are limited.

Objective: The purpose of this study was to determine the effect of sequential atrioventricular (AV) pacing, from different right ventricular (RV) sites with varying AV delays, on the diastolic function and functional capacity of patients with nHCM.

Methods: Twenty-one patients with symptomatic nHCM and normal left ventricular (LV) systolic function were prospectively enrolled.

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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.

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Transthyretin cardiac amyloidosis (ATTR-CM) is a rare and under-recognized disorder characterized by the aggregation of transthyretin-derived insoluble amyloid fibrils in the myocardium. Heterogeneity of symptoms at presentation, makes its diagnosis often delayed. An expert panel gathered on a virtual platform across India to conduct a meeting for developing a guiding tool for ATTR-CM diagnosis.

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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.

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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.

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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.

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Aims: IMPROVE Brady assessed whether a process improvement intervention could increase adoption of guideline-based therapy in sinus node dysfunction (SND) patients.

Methods: /Results: IMPROVE Brady was a sequential, prospective, quality improvement initiative conducted in India and Bangladesh. Patients with symptomatic bradycardia were enrolled.

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