Positron emission tomographic evaluation of regulation of myocardial perfusion in physiological (elite athletes) and pathological (systemic hypertension) left ventricular hypertrophy.

Myocardial perfusion (MP) may differ in physiologic and pathologic left ventricular hypertrophy (LVH). We compared MP in LVH in elite athletes and patients with hypertension with healthy, age-matched subjects. We included 12 rowers with LVH, 19 patients with hypertension with LVH, and 2 age-matched groups of healthy subjects (n = 11 and n = 12). The left ventricular mass index was determined echocardiographically. MP was measured by N-13 ammonia positron emission tomography. The maximal perfusion and perfusion reserve were studied using dipyridamole, and endothelial function was assessed by a cold pressor test. The degree of LVH was similar in athletes and those with hypertension. Compared with controls, athletes had 20% lower baseline MP (p <0.05), a similar response to the cold pressor test, and a higher perfusion reserve (31%, p <0.05). The patients with hypertension had a 25% higher baseline MP (p <0.05), a reduced increase during the cold pressor test (12% vs 25% in controls, p <0.05), and a reduced perfusion reserve (27% lower, p <0.001). The peak global perfusion (MP x left ventricular mass index) was 62% higher in athletes (p <0.05) than in controls, but the peak global perfusion in patients with hypertension did not differ from that of controls. In conclusion, physiologic LVH in athletes is suited for a high peak workload at the cost of only a small increase in basal myocardial oxygen consumption. In contrast, LVH in the presence of hypertension is a good adaptation to the increased baseline workload with maintained maximal cardiac performance. Endothelial dysfunction may contribute to the reduced perfusion reserve seen in hypertensive LVH.