CARDIOPULMONARY EXERCISE CAPACITY IN PATI ENTS WITH CORONARY HEART-DISEASE

Cardiopulmonary exercise testing (CPX) allows a non-invasive control o f the cardiopulmonary exercise capacity. In this study, we wanted to i nvestigate if the CPX can be securely, practicably, and accurately per formed in patients with invasively documented coronary heart disease ( CHD). Furthermore, we wanted to find out the clinical value of CPX in CHD diagnosis. The CPX measurements (symptom-limited; ramp program wit h 20 Watts increase/min; semi-supine position; continuous registration of the cardio-circulatory parameters (HR, RR, ECG), of the gas exchan ge parameters (O-2, CO2) and of the ventilation) in 101 patients have shown that CPX is secure, accurate, and practicable. The day-to-day re producibility is high (r > 0.8). The respiratory anaerobic threshold c an be manually evaluated by means of the PET O-2 criterion in 95% of t he cases. The CCS-classification of angina pectoris could not accurate ly describe the cardiopulmonary exercise capacity as compared to the W eber-classification. The disadvantage of the Weber-classification is t hat it does not respect the age-, sex- and weight-dependent difference s of the normal values. Our own data and results from the literature d emonstrate that the anaerobic threshold, the maximum VO2 and the maxim um O-2-pulse are the more reduced the more coronary arteries are invol ved, the more reduced the left ventricular function is. But, neverthel ess, the range of values shows large overlaps so that an exact differe ntiation, based upon these parameters, is not possible. Patients with similar functional results or degree of reduced exercise capacity have different morphological alterations. Most patients demonstrated typic al ischemic cascade with anaerobic threshold, ST-segment alterations, angina pectoris and, finally, reduced max. VO2. In conclusion, CPX doe s not replace the traditional methods of non-invasive and invasive isc hemia detection, but enables secure, practicable, and accurate measure ments of the individual cardiopulmonary exercise capacity and the inte raction between muscles, heart, circulation, and lungs. Possibly, CPX can be used in the near future for identifying CHD patients with low, medium or high risk.