[Non-invasive evaluation of hemodynamics during mild upright exercise using the CO2 rebreathing method]

Non-invasive evaluation of systemic hemodynamics during exercise in ischemic heart disease (IHD) was attempted by simultaneous measurement of cardiac output by the CO2 rebreathing method and indirect blood pressure in 44 males and 7 females with suspected IHD who underwent left ventriculography and coronary angiography. Thirty-nine of the 51 patients had abnormalities in the regional left ventricular systolic function (asynergy) and/or 75% or more stenosis of the major coronary arteries (IHD group). The other 12 patients were free of these findings, and injection of acetylcholine into the coronary arteries did not induce spasm. These patients were used as the control group. There were no differences in cardiac index (CI), mean blood pressure (MBP), or total peripheral resistance index (TPRI) at rest between the 2 groups. The IHD group had significantly lower CI (p < 0.01) and significantly higher TPRI (p < 0.05) during 25 and 50W exercise than the control group. There were no differences in MBP. A discriminant function using the change in CI (delta CI: l/min/m2) and the percent change in TPRI (% delta TPRI: %) during 25W exercise could predict IHD or control patients with probabilities of 82 and 83%, respectively. D = 3.66-1.39 x (delta CI)-6.67 x 10(-3) x (% delta TPRI), where D > or = 0.3 indicates IHD, and D < 0.3 indicates control. These results suggest that IHD patients have abnormal systemic hemodynamics during mild upright ergometer exercise, even though the resting hemodynamics are nearly normal.(ABSTRACT TRUNCATED AT 250 WORDS)