Extract

This commentary refers to ‘Biventricular pacing is superior to right ventricular pacing in bradycardia patients with preserved systolic function: 2-year results of the PACE trial’, by J.Y.-S. Chan et al., on page 2533

In medicine, it is encouraging when research yields results consistent with our understanding of the operative mechanisms, especially when there is a direct potential impact on clinical practice. Chan et al. have provided us with such a result and a clear message.1 The 2-year follow-up in the Pacing to Avoid Cardiac Enlargement (PACE) trial confirms that chronic right ventricular (RV) pacing in patients with bradycardia and preserved left ventricular (LV) function leads to sustained and progressive deterioration of LV ejection fraction (EF) and increases in LV volumes. This adverse remodelling process was prevented by pacing with cardiac resynchronization therapy (CRT).

Adverse LV remodelling is a complex maladaptive process involving structural, haemodynamic, histopathological, and genetic changes.2 The process may be multifactorial and is frequently encountered in patients after loss of myocardium (myocardial infarction), volume overload (valvular insufficiency), or pressure overload (hypertension). It involves both LV hypertrophy and dilatation, and is initially an adaptive response that serves to maintain stroke volume. If persistent and progressive, the process becomes maladaptive and leads to further deterioration of LV function, LV dilatation, and eventually the typical symptoms of heart failure (HF).

You do not currently have access to this article.