<qa>  What is the cause of chronic right ventricular pacing?A number of clinical studies Danish I, Danish II, David, MOST over the past few years have shown that, in patients with intact atrioventricular AV conduction, unnecessary chronic right ventricular RV pacing can cause a variety of detrimental effects, including atrial fibrillation AF, left ventricular LV dysfunction, and congestive heart failure CHF. These effects are believed to result from the mechanical dyssynchrony and ventricular chamber dysfunction that occurs with chronic, single-site, apical ventricular stimulation. 