Role of Implantable Cardioverter Defibrillator in Heart Failure With Contemporary Medical Therapy

Feasibility, safety, and short-term follow-up of defibrillator lead at left bundle branch area pacing location: A pilot study

BACKGROUND

Left bundle branch area pacing (LBBAP) has been increasingly adopted as an alternative modality to cardiac resynchronization therapy (CRT). The feasibility and safety of using an LBBAP lead to provide sensing of ventricular arrhythmia in patients receiving an implantable cardioverter-defibrillator (ICD) with CRT has been demonstrated recently.

OBJECTIVES

The purpose of our study was to analyze the feasibility, safety, and short-term follow-up of a traditional defibrillator lead at the LBBAP location.

METHODS

Patients who underwent successful LBBAP defibrillator using DF-1/DF-4 lead and delivery catheter were included in the study. Defibrillation threshold (DFT) testing was performed after implantation to assess the ability of the LBBAP defibrillator lead to sense and provide appropriate therapy for ventricular arrhythmia.

RESULTS

Although the ICD lead could be successfully deployed in the left bundle branch area in 7 of 8 patients, it was repositioned to the right ventricular (RV) apex because of atrial oversensing in 1 patient and cheesy septum in another patient. Acute procedural success was 62.5% (5/8 patients). Mean patient age was 62.6 ± 21.6 years. Mean procedural duration was 115.6 ± 38.1 minutes, with LBBAP defibrillator lead fluoroscopy duration of 10.6 ± 3.5 minutes. Mean capture threshold was 0.58 ± 0.23V/0.4 ms, sensed R-wave amplitude 9.6 ± 2.2 mV, pacing impedance 560 ± 145 Ω, and shock impedance 65.4 ± 5.5 Ω. Defibrillation testing was successful in inducing ventricular fibrillation and could be sensed and reverted promptly by the shock delivered through the lead. During mean follow-up of 3.8 ± 2.2 months, pacing parameters remained stable. No episodes of inappropriate arrhythmia detection or therapy delivery occurred during follow-up.

CONCLUSION

LBBAP defibrillator is feasible, safe, and effective during short-term follow-up. DFT testing at the time of implantation will help to ensure appropriate sensing and treatment of ventricular arrhythmias.

The recent advance and prospect of natural source compounds for the treatment of heart failure

Heart failure is a continuously developing syndrome of cardiac insufficiency caused by diseases, which becomes a major disease endangering human health as well as one of the main causes of death in patients with cardiovascular diseases. The occurrence of heart failure is related to hemodynamic abnormalities, neuroendocrine hormones, myocardial damage, myocardial remodeling etc, lead to the clinical manifestations including dyspnea, fatigue and fluid retention with complex pathophysiological mechanisms. Currently available drugs such as cardiac glycoside, diuretic, angiotensin-converting enzyme inhibitor, vasodilator and β receptor blocker etc are widely used for the treatment of heart failure. In particular, natural products and related active ingredients have the characteristics of mild efficacy, low toxicity, multi-target comprehensive efficacy, and have obvious advantages in restoring cardiac function, reducing energy disorder and improving quality of life. In this review, we mainly focus on the recent advance including mechanisms and active ingredients of natural products for the treatment of heart failure, which will provide the inspiration for the development of more potent clinical drugs against heart failure.

Frailty and heart failure: State-of-the-art review

At least half of all patients with heart failure (HF) are affected by frailty, a syndrome that limits an individual ability to recover from acute stressors. While frailty affects up to 90% of patients with HF with preserved ejection fraction, it is also seen in ~30-60% of patients with HF with reduced ejection fraction, with ~26% higher prevalence in women compared with men. The relationship between frailty and HF is bidirectional, with both conditions exacerbating the other. Frailty is further complicated by a higher prevalence of sarcopenia (by ~20%) in HF patients compared with patients without HF, which negatively affects outcomes. Several frailty assessment methods have been employed historically including the Fried frailty phenotype and Rockwood Clinical Frailty Scale to classify HF patients based on the severity of frailty; however, a validated HF-specific frailty assessment tool does not currently exist. Frailty in HF is associated with a poor prognosis with a 1.5-fold to 2-fold higher risk of all-cause death and hospitalizations compared to non-frail patients. Frailty is also highly prevalent in patients with worsening HF, affecting >50% of patients hospitalized for HF. Such patients with multiple readmissions for decompensated HF have markedly poor outcomes compared to younger, non-frail cohorts, and it is hypothesized that it may be due to major physical and functional limitations that limit recovery from an acute episode of worsening HF, a care aspect that has not been addressed in HF guidelines. Frail patients are thought to confer less benefit from therapeutic interventions due to an increased risk of perceived harm, resulting in lower adherence to HF interventions, which may worsen outcomes. Multiple studies report that <40% of frail patients are on guideline-directed medical therapy for HF, of which most are on suboptimal doses of these medications. There is a lack of evidence generated from randomized trials in this incredibly vulnerable population, and most current practice is governed by post hoc analyses of trials, observational registry-based data and providers' clinical judgement. The current body of evidence suggests that the treatment effect of most guideline-based interventions, including medications, cardiac rehabilitation and device therapy, is consistent across all age groups and frailty subgroups and, in some cases, may be amplified in the older, more frail population. In this review, we discuss the characteristics, assessment tools, impact on prognosis and impact on therapeutic interventions of frailty in patients with HF.

The Relevance of Preventive Implantable Cardioverter-Defibrillators (ICDs) in Non-Ischemic Cardiomyopathy in the Presence of Effective Quadruple Therapy for Heart Failure: A Review of Contemporary Medical Literature

Cardiomyopathy is a disease of the cardiomyocytes that affects their structural function, leading to heart failure (HF). Non-ischemic cardiomyopathy (NICM) includes a subtype of dilated cardiomyopathy (DCM), restrictive cardiomyopathy (RCM), and hypertrophic cardiomyopathy (HCM). These types of cardiomyopathies have no coronary artery vessel involvement. The most common cause of NICM is DCM. In the ischemic cardiomyopathy (ICM) subtype, the utilization of implantable cardioverter-defibrillators (ICDs) has been effective in the prevention of sudden cardiac death (SCD). However, the relevance of ICDs in patients with NICM having an ejection fraction (EF) ≤35%, who are also receiving effective quadruple therapy (i.e., angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARB), beta-blockers, mineralocorticoid receptor antagonists, and sodium-glucose cotransporter-2 (SGLT2) inhibitors) for HF has been a topic of debate. The purpose of this review is to analyze the benefits of preventive ICDs in NICM patients on adequate quadruple therapy for HF. The current guidelines recommend ICD implantation in patients with NICM who have a left ventricular ejection fraction of ≤35%, come under the New York Heart Association (NYHA) class II or III, and are in sinus rhythm with optimal medical therapy. The evidence supporting this recommendation is limited. Numerous clinical studies and meta-analyses have been conducted to look into this issue. While some have discovered a substantial decrease in mortality with the implantation of an ICD in patients with NICM, others have not found significant changes. Thereby, further investigations are required to define the function of ICDs in this population.