Evaluation of Master's Double Two-step Test : Study of the Factors Reflecting Left Ventricular Dysfunction

An objective assay of cardiovascular response to Master's double two-step exercise test in an important tool in the diagnosis and evaluation of patients with coronary artery disease. The purpose of exercise is to increase body oxygen consumption and to augment myocardial work. The increase of cardiac oxygen demand thus may exceed the available supply in the coronary artery disease, thereby producing myocardial ischema as reflected in the electrocardiogram. To evaluate Master's exercise test, the test was performed on the 522 patients, aged 18 to 77 years, who had chest oppressive sensation. The frequency of the patients with positive response is highest in the age of 40 to 50 years and followed by 50 to 60 and 60 to 70 years. The exercize positive response appears more frequently in females as compared with males. It is characteristic finding in the patients with the exercise positive response that resting blood pressure is comparactively high and the exercise elevates conspicuously not only heart rate but systolic blood pressure, and that the rate pressure product which is indirect index of cardiac oxygen demand increases significantly after the exercise and also the delayed recovery of the increased rate pressure product is observed. These characteristics indicate that Master's exercise test positive response represents unbalance of cardiac oxygen demand and supply i.e. ischemic change of myocardium. Electrocardiographic sign of left ventricular overloading, abnormal P terminal force V_1, and prolongation of QT_c after the exercise which may estimate the coronary atherosclerotic disease, are found more frequently in the patients with the exercise positive response than in the negative. As the results, it is concluded that Master's exercise test positive response is not always the indicator of the myocardial ischemia due to coronary atherosclerosis, but shows the existence of the factor with induce unbalance of cardiac oxygen demand and supply, in particular reflect indirectly left cardiac dysfunction.