DOES MAXIMAL EXERCISE HEART-RATE PREDICT WORKING CAPACITY IN PACEMAKER PATIENTS

In rate-adaptive pacing a higher exercise heart rate should improve pa tients' working capacity. However, up to now there is a lack of an ana lysis of the factors which determine the working capacity in pacemaker patients in physiological exercise. Therefore we performed a 6-minute walk test in 97 pacemaker patients where patients determined their sp eed by themselves. 42 of them did a conventional bicycle ergometry add itionally. The correlation between maximal heart rate, age, underlying diseases and working capacity was statistically analysed. RESULTS In the 6-minute walk age was significantly correlated to working capacity (r = -0.53; p < 0.001). Working capacity of patients with a history o f dyspnea (NYHA III), hypertension, valvular heart disease or arthropa thy was lower (p < 0.05) than working capacity of patients without any underlying diseases. Coronary heart disease, stroke and respiratory d isorders did not influence working capacity. No significant correlatio n was found between maximal heart rate and working capacity (r = 0). W orking capacity was slightly higher in bicycle ergometry with good cor relation to the 6-minute walk (r = 0.74; p < 0.001). CONCLUSIONS Age a nd certain underlying diseases, but not maximal heart rate, are the ma jor factors determining working capacity in pacemaker patients. This h as to be considered in rate adaptive pacing. The 6-minute walk is an a dequate and physiological exercise test which can easily be performed in nearly all pacemaker patients.