Electrical management of heart failure: from pathophysiology to treatment

Abstract

Electrical disturbances, such as atrial fibrillation (AF), dyssynchrony, tachycardia, and premature ventricular contractions (PVCs), are present in most patients with heart failure (HF). While these disturbances may be the consequence of HF, increasing evidence suggests that they may also cause or aggravate HF. Animal studies show that longer-lasting left bundle branch block, tachycardia, AF, and PVCs lead to functional derangements at the organ, cellular, and molecular level. Conversely, electrical treatment may reverse or mitigate HF. Clinical studies have shown the superiority of atrial and pulmonary vein ablation for rhythm control and AV nodal ablation for rate control in AF patients when compared with medical treatment. Ablation of PVCs can also improve left ventricular function. Cardiac resynchronization therapy (CRT) is an established adjunct therapy currently undergoing several interesting innovations. The current guideline recommendations reflect the safety and efficacy of these ablation therapies and CRT, but currently, these therapies are heavily underutilized. This review focuses on the electrical treatment of HF with reduced ejection fraction (HFrEF). We believe that the team of specialists treating an HF patient should incorporate an electrophysiologist in order to achieve a more widespread use of electrical therapies in the management of HFrEF and should also include individual conditions of the patient, such as body size and gender in therapy fine-tuning.

Keywords: ablation; atrial fibrillation; heart failure; premature ventricular contractions; resynchronization therapy; tachycardia; ventricular dyssynchrony.

Graphical Abstract

Upper panel: Schematic representation of the interaction between the various arrhythmia and conduction abnormalities with four electrical abnormalities and their consequences for remodelling and developing heart failure. Red text in boxes indicates the therapeutic approaches that treat the electrical abnormalities and thereby also heart failure. CRT, cardiac resynchronization therapy. Lower panel: Flow chart of recommended checks for the eligibility of heart failure with reduced ejection fraction patients for the various electrical therapies based on the evidence presented in the upper panel and guidelines.

Figure 1

Upper panel (A): Schematic representation of the interaction between the various arrhythmia and conduction abnormalities with the four pathophysiological mechanisms / triggers and their consequences for remodelling and developing heart failure. Red text in boxes indicate the therapeutic approaches that primarily treat the electrical abnormalities, but thereby also of failure. CRT, cardiac resynchronization therapy. Lower panel (B): Relative reduction in left ventricular ejection fraction after five electrophysiological interventions in experimental studies in dogs: left bundle branch block by radiofrequency ablation and maintained normal heart rate, atrial (A) and ventricular (V) pacing at 180 b.p.m. for 3 weeks, a pacing protocol simulating premature ventricular contractions with an average premature ventricular contraction burden of ∼50% and chronic atrial fibrillation for 6 months.

Figure 2

Upper panels: Electrocardiographic selection criteria for cardiac resynchronization therapy and their relation to outcome (combined endpoint of survival free from left ventricular assist device implant, heart transplant, or death) in a study on ∼1500 patients. (A) Conventional criteria (left bundle branch block and QRS duration >150 ms), (B) area under the QRS complex (QRSarea). The presence of left bundle branch block is a determinant of cardiac resynchronization therapy outcome, in particular if QRS duration is >150 ms, but QRSarea >109 µV s is a stronger determinant of cardiac resynchronization therapy outcome than left bundle branch block. Lower panels: Schematic overview of the current options for cardiac resynchronization therapy. Positions 1 and 2 indicate the conventional right ventricular and left ventricular pacing locations. Endocardial cardiac resynchronization therapy can be achieved by introducing a conventional pacing lead through the foramen ovale and the mitral valve into the left ventricle (3) or using a wireless pacing electrode (4) that is stimulated using an ultrasound transducer. His bundle (5), left bundle branch (6), and deep left ventricular septal pacing (7) is performed using a 4 Fr lead introduced transvenously and screwed in the septum. Small studies also investigated the combination of His bundle pacing (HOT-CRT) or left bundle branch pacing with left ventricular pacing (LOT-CRT).

Figure 3

Schematic representation of judgement that is recommended for optimal treatment of heart failure patients, based on the evidence presented in this article.