In five patients who were treated for malignant pleural mesothelioma (MPM) with pleuropneumonectomy and intraoperative photodynamic therapy (IPDT), impending myocardial damage was monitored using ECG, the classical biochemical markers (creatine kinase [CK], total activity; CKMB, mass; and myoglobin), and the new cardiac markers troponin I (cTnI) and troponin T (cTnT). In the peroperative and postoperative period all classical markers were elevated, in contrast to cTnI and cTnT, because of the concomitant skeletal muscle damage. Sequential electrocardiogram monitoring showed no signs of myocardial damage. From this study in patients with MPM treated with pleuropneumonectomy and IPDT it can be concluded that measurement of cTnI and cTnT for the detection of myocardial damage is more suitable than measurement of the classical markers.