Toward Sex-Specific Guidelines for Cardiac Resynchronization Therapy?

An important treatment for patients with heart failure is cardiac resynchronization therapy (CRT). Even though only 20 % of women were included in clinical trials for CRT, a benefit has been shown in recent studies for subgroups of women compared to their male counterparts. Given this low inclusion rate of women in clinical studies, professional society guideline-based CRT recommendations, such as those by the American College of Cardiology Foundation (ACCF)/American Heart Association (AHA)/Heart Rhythm Society (HRS), may not truly represent the best treatment for women, especially since most of the reports that showed this greater benefit in women were published after the latest guidelines. Despite having research and multiple publications regarding sex-specific heart failure outcomes and response to CRT, the ACCF/AHA/HRS guidelines have not yet been updated to account for the recent information regarding the differences in benefit for women and men with similar patient characteristics. This review discusses the physiology behind CRT, sex-specific characteristics of heart failure, and cardiac electrophysiology and summarizes the current sex-specific literature to encourage consideration of CRT guidelines for women and men separately.     

Should We Optimize Cardiac Resynchronization Therapy During Exercise?

Should We Optimize CRT During Exercise? Cardiac resynchronization therapy aims at diminishing cardiac dyssynchrony in patients with heart failure. The effect of cardiac resynchronization therapy can be improved by optimization of the atrioventricular (AV) and interventricular (VV) delays. Currently, optimization of these pacing settings is mainly performed during resting conditions. This paper aims to objectively review the current literature about a rate‐adaptive AV and VV delay in cardiac resynchronization therapy. The current evidence for a rate‐adaptive AV and VV delay comprises only small nonrandomized studies on acute effects. The effect of exercise on the optimal AV delay was heterogeneous between studies. The optimal VV delay was influenced by exercise conditions in some, but not all patients. Possible explanations lie in the heterogeneous electrical and mechanical responses to exercise in patients with a complex disease such as heart failure with asynchronous contraction. Current evidence is insufficient to show the superiority of a rate‐adaptive AV or VV delay in all CRT patients. Individualized exercise programming may be warranted in selected patients. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1307‐1316, November 2010)     

Cardiac Resynchronization Therapy: Do Women Benefit More Than Men?

Gender and Resynchronization Therapy. Introduction: Women are underrepresented in cardiac resynchronization therapy (CRT) trials. Whether there is a gender difference in the benefit derived from CRT has not been well studied. Methods: This study included 728 consecutive CRT recipients at our institution who met guidelines for placement of a CRT device. Clinical characteristics and echocardiographic parameters were collected at baseline and after CRT; Kaplan–Meier survival analysis was performed using a national death and location database. The effects and outcome of CRT were compared between women and men. Results: Of 728 patients, 166 were female (22.8%). Female patients were younger than male patients (66.0 ± 11.9 years vs 69.4 ± 10.9 years; P < 0.001) and more often had nonischemic cardiomyopathy (68% vs 36%; P < 0.001). Both female and male patients had significantly improved clinical and echocardiographic parameters after CRT. The magnitude of improvement was similar in women and men, except that improvement in New York Heart Association (NYHA) class was greater in women than in men (–0.79 ± 0.78 vs –0.56 ± 0.85; P = 0.009). Although women were at lower risk of death than men after CRT (hazard ratio, 0.51; 95% confidence interval, 0.35–0.75; P < 0.001, unadjusted), multivariate analysis indicated gender was not, but age at CRT placement, cardiomyopathy cause, NYHA class, and lead location were independent predictors of survival. Conclusion: Female CRT recipients seem to achieve greater survival benefit than male recipients. However, this benefit is majorly driven by nonischemic cardiomyopathy and other clinical factors. (J Cardiovasc Electrophysiol, Vol. 23, pp. 172‐178, February 2012)     

The Emerging Role of Cardiac Resynchronization Therapy in Milder Heart Failure: Are We Implanting Too Late for Response?

The role of cardiac resynchronization therapy in mild heart failure has become a focus of attention with the publication of recent clinical trials. We present a review of the data supporting implantation of cardiac resynchronization devices in early stage heart failure. In addition, we present evidence that may suggest patients are often implanted too late for clinical benefit, potentially contributing to the relatively high nonresponder rate seen in randomized trials and clinical practice.     

Is Cardiac Resynchronization Therapy an Antiarrhythmic Therapy for Atrial Fibrillation? A Systematic Review and Meta-Analysis

The impact of cardiac resynchronization therapy (CRT) on atrial fibrillation (AF) burden is poorly characterized. To assess the influence of CRT on AF, we performed a systematic literature search in MEDLINE using the MeSH headings “cardiac resynchronization therapy” or “cardiac pacing, artificial” and “atrial fibrillation.” Selected studies were peer-reviewed and written in English. Most studies enrolled patients meeting traditional CRT criteria. Ten observational studies and two secondary analyses of clinical trials were identified. Although ten studies suggest that CRT favorably impacts AF, one secondary analysis of a clinical trial showed no effect of CRT on new-onset AF. In a meta-analysis of three studies examining the effect of CRT on persistent or permanent AF, the combined rate of conversion from persistent or permanent AF to sinus rhythm was 0.107 (95 % confidence interval 0.069-0.163). Prospective studies, particularly among patients not meeting traditional CRT criteria, are needed.     

Controversies in Cardiac Resynchronization Therapy: Do Sex Differences in Response Exist?

Cardiac resynchronization therapy (CRT) is well established in the treatment of patients with heart failure, but lacks data addressing sex differences in response. Women with heart failure outnumber men, but have additional comorbidities and typically are older. Women continue to be underrepresented in clinical trials, but examining their response to a therapy across multiple studies could provide significant insight into the treatment effect. The major clinical trials did have a significant percentage of female patients, but present minimal in subgroup analysis. A few small studies comparing the effect of CRT between men and women indicate a more positive effect in women. This early data suggests CRT is at least as effective in women as it is in men, and may have additional benefit in this population.     

Cardiac Resynchronization Therapy Remote Monitoring – COVID-19 Pandemic Experiences and Future Perspectives

Cardiac resynchronization therapy (CRT) is a well-established form of the treatment for heart failure (HF) in patients with left ventricle contraction dyssynchrony. Apart from typical in-office management, remote monitoring enables constant surveillance on both the patient's and the device's condition. This way, in case of any problems, clinical decisions could be made earlier leading to better outcome of CRT patients. COVID-19 pandemic with following lockdowns in many countries resulted in getting more attention on remote monitoring systems. The aim of this paper was to gather and summarize worldwide experiences from CRT remote monitoring during COVID-19 pandemic and point out future possibilities for HF patients treated with CRT. Already published experiences from remote monitoring of CRT devices during COVID-19 restrictions confirmed previous advantages of telemedical approach, however, more publications in this area would be helpful.     

Cardiac Resynchronization Therapy for Chronic Heart Failure: Why Does It Not Always Work?

Since coronary angiography and ventriculography are performed in all of these patients with LV dysfunction and symptoms of heart failure, it seems silly to waste the opportunity to study this technique and its value in identifying patients who will respond to CRT, at least in the immediate post-CRT state. The critical factors that may result in a successful long-term positive result of CRT in patients with optimal device programming and optimized medical therapy for heart failure are these: (1) Venous anatomy suitable for electrical stimulation of the LV free wall. (2) Viable myocardium in the septum and the LV free wall. (3) Adequate perfusion of the microcirculation in the distribution where the leads are being placed.     

Cardiac Drug Therapy—Considerations in the Elderly

Elderly individuals constitute a majority of patients encountered in current cardiovascular clinical practice. Management of these patients is a clinical challenge owing to a multitude of factors. Although medications such as statins have been shown to reduce cardiovascular mortality in the general population, evidence supporting the use of these drugs in patients greater than 75 years of age is sparse. Furthermore, aging associated changes in organ function and associated comorbidities influence the pharmacokinetics of multiple medications and can potentiate drug toxicity. In this article, we review the evidence behind the use of common cardiovascular medications in elderly patients and discuss pertinent clinical challenges.