Energy production, O2 consumption, and blood flow reserve in experimental aortic valve disease

Left ventricular energy production and its relation to myocardial O2 consumption and blood flow reserve were studied in 11 dogs with surgically produced valvular aortic stenosis (AS, 6 of 11) or combined stenosis and insufficiency (AS + AI, 5 of 11), and 7 dogs undergoing sham operation (S). Two months after operation the combined AS + AI group had the highest left ventricular mass (S, 4.85 +/- 0.53; AS, 6.38 +/- 0.90; AS + AI, 7.23 +/- 0.39 g/kg), left ventricular end-diastolic pressure (S, 2.1 +/- 1.6; AS, 6.3 +/- 1.7; AS + AI, 8.6 +/- 3.1 mmHg), left ventricular end-diastolic volume (S, 61.1 +/- 8.5; AS, 73.0 +/- 7.8; AS + AI, 95.8 +/- 20.9 ml), and stroke work. At rest, total left ventricular myocardial blood flow was increased in AS and AS + AI compared with sham (S, 89 +/- 8; AS, 135 +/- 19; AS + AI, 164 +/- 9 ml/min, P less than 0.05); and coronary resistance was lower in both AS and AS + AI groups. Peak-to-resting flow ratio determined by adenosine vasodilation was reduced in AS and AS + AI despite normal resting function (peak-to-resting flow ratio: S, 6.78 +/- 2.24; AS, 3.19 +/- 0.58, AS + AI, 3.99 +/- 0.84, P less than 0.02). Peak-to-resting flow ratio was inversely proportional to left ventricular mass. In turn the degree of hypertrophy correlated with the total power requirement of the left ventricle, regardless of the type of overload lesion.(ABSTRACT TRUNCATED AT 250 WORDS)