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,⁵ atrial (A) and ventricular (V) pacing at 180 b.p.m. for 3 weeks,⁶ a pacing protocol simulating premature ventricular contractions with an average premature ventricular contraction burden of ∼50%⁷ and chronic atrial fibrillation for 6 months.⁸