Adverse Consequences of Right Ventricular Apical Pacing and Novel Strategies to Optimize Left Ventricular Systolic and Diastolic Function

Dual-chamber pacing confers better myocardial performance and improves clinical outcomes compared to single-chamber pacing

The deleterious effects of long term right ventricular pacing are increasingly being recognized today. Current clinical practice favors the implantation of dual-chamber permanent pacemaker which maintains atrioventricular synchrony and is associated with better quality of life. However, despite the popular belief and common sense surrounding the superiority of dual-chamber pacing over single chamber pacing, the same has never been conclusively verified in clinical trials. Some observational evidence however, does exists which supports the improved cardiac hemodynamics, lower the rate of atrial fibrillation, heart failure and stroke in dual-chamber pacing compared to single-chamber pacing. In the index study by Haque et al, right ventricular pacing, particularly in ventricular paced, ventricular sensed, inhibited response and rate responsive pacemaker adversely impacted the left ventricular functions over 9-months compared to dual pacing, dual sensing, dual responsive and rate responsive pacemaker. Although there are key limitations of this study, these findings does support a growing body of evidence reinstating the superiority of dual chamber pacing compared to single chamber pacing.

Cardiac Remodeling and Ventricular Pacing: From Genes to Mechanics

Cardiac remodeling and ventricular pacing represent intertwined phenomena with profound implications for cardiovascular health and therapeutic interventions. This review explores the intricate relationship between cardiac remodeling and ventricular pacing, spanning from the molecular underpinnings to biomechanical alterations. Beginning with an examination of genetic predispositions and cellular signaling pathways, we delve into the mechanisms driving myocardial structural changes and electrical remodeling in response to pacing stimuli. Insights into the dynamic interplay between pacing strategies and adaptive or maladaptive remodeling processes are synthesized, shedding light on the clinical implications for patients with various cardiovascular pathologies. By bridging the gap between basic science discoveries and clinical translation, this review aims to provide a comprehensive understanding of cardiac remodeling in the context of ventricular pacing, paving the way for future advancements in cardiovascular care.

Conduction system pacing and atrioventricular node ablation in heart failure: The PACE-FIB study design

AIMS

Atrial fibrillation (AF) worsens the prognosis of patients with heart failure (HF). Successful treatments are still very scarce for those with permanent AF and preserved (HFpEF) or mildly reduced (HFmrEF) ejection fraction. In this study, the long-term benefits and safety profile of heart rate regularization through left-bundle branch pacing (LBBP) and atrioventricular node ablation (AVNA) will be explored in comparison with pharmacological rate-control strategy.

METHODS AND RESULTS

The PACE-FIB trial is a multicentre, prospective, open-label, randomized (1:1) clinical study that will take place between March 2022 and February 2027. A total of 334 patients with HFpEF/HFmrEF and permanent AF will receive either LBBP followed by AVNA (intervention arm) or optimal pharmacological treatment for heart rate control according to European guideline recommendations (control arm). All patients will be followed up for a minimum of 36 months. The primary outcome measure will be the composite of all-cause mortality, HF hospitalization, and worsening HF at 36 months. Other secondary efficacy and safety outcome measures such as echocardiographic parameters, functional status, and treatment-related adverse events, among others, will be analysed too.

CONCLUSION

LBBP is a promising stimulation mode that may foster the clinical benefit of heart rate regularization through AV node ablation compared with pharmacological rate control. This is the first randomized trial specifically addressing the long-term efficacy and safety of this pace-and-ablate strategy in patients with HFpEF/HFmrEF and permanent AF.

Pacemaker-induced cardiomyopathy

ABSTRACT

Chronic right ventricular (RV) pacing is an often-unrecognized cause of cardiomyopathy, despite research that has revealed that chronic RV pacing can cause significant cardiomyopathy and heart failure, leading causes of hospitalization in the United States. Studies have found that chronic RV apical pacing results in ventricular dyssynchrony, reduced cardiac function, and heart failure. This article describes the deleterious effects of permanent cardiac pacemakers and their association with cardiomyopathy and heart failure. More research is needed to investigate other forms of pacing and treatment to prevent ventricular dyssynchrony and myocardial remodeling.

Long-term outcomes after radiofrequency catheter ablation of the atrioventricular node: The experience of a Portuguese tertiary center

INTRODUCTION

In patients with supraventricular arrhythmias and high ventricular rate, unresponsive to rate and rhythm control therapy or catheter ablation, atrioventricular (AV) node ablation may be performed.

OBJECTIVES

To assess long-term outcomes after AV node ablation and to analyze predictors of adverse events.

METHODS

We performed a detailed retrospective analysis of all patients who underwent AV node ablation between February 1997 and February 2019, in a single Portuguese tertiary center.

RESULTS

A total of 123 patients, mean age 69±9 years and 52% male, underwent AV node ablation. Most of them presented atrial fibrillation at baseline (65%). During a median follow-up of 8.5 years (interquartile range 3.8-11.8), patients improved heart failure (HF) functional class (NYHA class III-IV 46% versus 13%, p=0.001), and there were reductions in hospitalizations due to HF (0.98±1.3 versus 0.28±0.8, p=0.001) and emergency department (ED) visits (1.1±1 versus 0.17±0.7, p=0.0001). There were no device-related complications. Despite permanent pacemaker stimulation, left ventricular ejection fraction did not worsen (47±13% vs. 47%±12, p=0.63). Twenty-eight patients died (23%). The number of ED visits due to HF before AV node ablation was an independent predictor of the composite adverse outcome (OR 1.8, 95% CI 1.24-2.61, p=0.002).

CONCLUSIONS

Despite pacemaker dependency, the clinical benefit of AV node ablation persisted at long-term follow-up. The number of ED visits due to HF before AV node ablation was an independent predictor of the composite adverse outcome. AV node ablation should probably be considered earlier in the treatment of patients with supraventricular arrhythmias and HF, especially in cases that are unsuitable for selective ablation of the specific arrhythmia.