Increased myocardial energy expenditure in cardiac syndrome X: More work, more pain [Kardiyak sendrom X’li hastalarda artmış miyokart enerji tüketimi: Çok iş, çok ağrı]

Objective: The aim of this study was to assess the myocardial energy expenditure (MEE) in patients with cardiac syndrome X (CSX) and to examine its association with exercise electrocardiogram (ECG) parameters. Methods: A total of 99 patients who underwent coronary an-giography and who were diagnosed as having normal coronary arteries were included. The patients were divided into 2 groups based on symptoms and exercise ECG parameters: 56 CSX patients and 43 control patients with a negative stress test. MEE was calculated using transthoracic echocardiography-derived parameters: circumferential end-systolic stress, left ventricular ejection time, and stroke volume. Results: In patients with CSX, the MEE at rest was 28% higher in than the control group (89.2±36.3 vs. 69.8±17.2 cal/ minute). Correlation analysis revealed a moderately negative correlation between MEE and the Duke treadmill score (DTS) (ß:-0.456; p<0.001). Receiver operating characteristic analysis with a cut-off value of 74.6 cal/minute for MEE had a sensitivity of 78.1% and a specificity of 75.3% for the prediction of CSX (area under the curve: 0.872; p