Independent regulation of atrial coronary blood flow by atrial contraction rate in conscious dogs.

The effects of separate increases in atrial and ventricular contraction rates on the distribution of coronary flow within the heart were determined in conscious dogs with chronic heart block. Atrial tachycardia increased atrial blood flow and did not change ventricular blood flow. Ventricular tachycardia increased ventricular blood flow but not atrial blood flow. The results are consistent with the concept of local regulation of coronary perfusion by local myocardial energy turnover. The results also call attention to a potential adverse impact of atrial tachyarrhythmia in patients with underlying coronary ischemia.