[Changes in thyroid function induced by amiodarone].
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Adult↗
Biomedical subjects
M Chiozza
Publications and source records attributed to M Chiozza.
Predictive value of changes in R-wave amplitude after exercise in coronary heart disease.
To assess the predictive value of coronary events reflected by changes in R-wave amplitude after exercise, 146 patients with angiographically documented coronary heart disease were studied. All patients were followed up for 6 years, during which time myocardial infarction and death of cardiovascular origin were considered endpoints. The incidence of events in patients in whom R-wave amplitude decreased (normal response) and in those in whom R-wave amplitude did not change or increase (abnormal response) were compared. The incidence of coronary events in patients with a normal response was 23% and in those with an abnormal response, 45.8% (p less than 0.01). Correlating the results with several noninvasive and angiographic variables, an abnormal R-wave response showed a significantly higher rate of events in the subsets of patients with prior myocardial infarction, absence of cardiomegaly, maximal functional capacity lower than 4 METs, maximal heart rate higher than 140 beats/min and abnormal left ventricular function. Thus, the changes in R-wave amplitude after exercise is a variable that should be taken into account when assessing the risk of future events in patients with coronary heart disease.
Adult↗
Effects of nitrates on R-wave variations after exercise in coronary heart disease: differences in patients with and without angina pectoris.
With the purpose of investigating the pathophysiology of changes in the R wave after exercise and its relationship with left ventricular function, we studied 44 patients with coronary heart disease. They were classified into the following three groups: group A, 11 patients with angina pectoris and no prior myocardial infarction; group B, 18 patients with angina pectoris and prior myocardial infarction; and group C, 15 patients with prior myocardial infarction but no angina. All patients performed two exercise tests; one was a control test, and the other was performed after the sublingual administration of 5 mg of isosorbide dinitrate. In group A, variations in the R-wave voltage in control test and in the test after isosorbide dinitrate were 1.5 +/- 0.8 mm and -1.2 +/- 0.9 mm (P less than 0.05), respectively. In group B, results were 1.2 +/- 0.7 mm on the control test and -0.7 +/- 0.6 mm after isosorbide dinitrate (P less than 0.002), and in group C were -1.6 +/- 1.2 mm on the control test and -0.7 +/- 0.7 mm after isosorbide dinitrate (not significant). Thus, the two groups of patients with angina showed an increase of the R-wave after exercise in the control test but a decrease after the administration of nitrates, whereas the patients without angina showed a reduced R-wave after exercise both before and after the administration of nitrates (like normal subjects). This study suggests that ischemic ventricular dysfunction with exercise results in an increase in the R-wave, while exercise after nitrates results in a decrease in the R-wave consistent with less or no ventricular dysfunction due to nitrate therapy.
Administration, Topical↗