Summary

Cardiac resynchronization therapy (CRT) improves heart failure (HF) symptoms, ventricular performance, and myocardial efficiency. Researchers have studied the effect of CRT on cardiac remodeling in HF using a canine model of HF with 3 to 4 weeks of 240 bpm right ventricular pacing and left-ventricular diastolic end pressure of 30 to 45 mm Hg. Electrical changes included prolonged action potential duration, a hallmark of HF, and increased difference between the longest and shortest action potentials at slower rates.