HIGHER MYOCARDIAL OXYGEN CONSUMPTION DURING SUBMAXIMAL EXERCISE IN SUBJECTS WITH ELEVATED PULSE WAVE VELOCITY

Abstract

Objective: Blood pressure (BP) during standardized workload has prognostic value regarding future cardiovascular (cv) morbidity and mortality independent of BP at rest. Pulse wave velocity (PWV) as a marker of arterial stiffness has independent prognostic value for future cv events. This study was designed to compare BP response to exercise and myocardial oxygen consumption in subjects with elevated PWV with normal subjects. Design and method: In 103 subjects (72 males, aged 50.4 ± 13.3 years, BMI 25.3 ± 3.4 kg/m2) without antihypertensive medication, PWV was measured at rest and non-invasively by Mobil-O-Graph® (I.E.M. GmbH, GERMANY). During and after standardized exercise (50–100 watts, increments 10 watts/minute) BP was measured with the cuff method and the product of heart rate during exercise and systolic BP at 100 watts (BP100W, HR100W) was calculated as a usual measure of myocardial oxygen consumption. Results: Mean PWV at rest was 7,6 ± 1,7 m/sec and correlated significantly with systolic BP100W (176,6 ± 22,2 mmHg, p < 0.01, r = 0,51) and systolic BP 3 minutes after exercise (146,7 ± 19,7 mmHg, p < 0.01, r = 0,37). In subjects with elevated PWV, both mean HR100W and mean BP100W were higher (p < 0.01) when compared with the normal subjects. Subjects with a pathological PWV presented a 23% (p < 0.05) higher myocardial oxygen consumption than normals. Conclusions: There is a considerably stronger correlation between PWV at rest and systolic BP during submaximal exercise compared to BP measurements at rest. Subjects with elevated PWV as an early sign of hemodynamic alterations, have already a considerably higher HR and systolic BP (sBP) during submaximal exercise. Therefore, the product of both HR and sBP as a measure of myocardial oxygen consumption during submaximal exercise is considerably higher in those with the elevated PWV, thus resulting in a lower total physical capacity.