[Work capacity evaluation of patients with sick sinus syndrome].
Thirty-four normal subjects, 30 patients with sinoatrial node weakness (SANW), and 129 patients with coronary heart disease (CHD) without the signs of sinoatrial node involvement were examined. The work fitness was studied with the aid of indirect estimates (PWC 170, maximal oxygen consumption per kg bw, double product), spiroergometry (oxygen pulse, rest quotient) and central hemodynamic data (cardiac and stroke indices). The work fitness in SANW patients was low, depending on the disease etiology and chronotropic reserves of the heart. PWC 170, maximal oxygen consumption per kg bw, oxygen pulse were found to overestimate the genuine level of the SANW patients' physical status. In view of this fact these estimates cannot be used for its evaluation. It is inferred that the power of the threshold loading, the rest quotient, the cardiac index, and double product adequately reflect the work fitness of SANW patients.