Exercise testing and thallium-201 myocardial perfusion scintigraphy in the clinical evaluation of patients with Wolff Parkinson White syndrome.

In 58 patients with Wolff Parkinson White syndrome (WPW), we performed exercise stress testing in order to investigate the incidence of normalization of the auriculo-ventricular conduction and the ST-segment changes. For a more accurate evaluation of the latter, exercise and redistribution radionuclide images with Thallium-201 were obtained in 18 cases. Forty-nine had type A and nine had type B of WPW.

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.

Pre-excitation syndrome and hypertrophic cardiomyopathy.

Among one hundred and five consecutive patients with pre-excitation (PE) syndrome studied during a 10-year period, eight had an associated hypertrophic cardiomyopathy (HC) (7.62 per cent), eight had a coronary heart disease (7.62 per cent) and nine had a hypertensive heart disease (8.

Reassessment of electrovectorcardiographic signs of left atrial enlargement.

Echocardiographic left atrial size was correlated with 27 electrovectorcardiographic parameters in 93 subjects. In 20 of them hemodynamic studies, including calculation of the left atrial volume, were performed. Subjects were divided into four groups as follows: Group I, 21 healthy subjects; group II, 45 patients with heart disease but no left atrial enlargement; group III, 15 patients with heart disease and left atrial size from 4.

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.

Effects of isoproterenol on bradycardia-dependent intra-His and left bundle branch blocks.

The electrophysiologic study of a patient with a history of fainting showed first- and second-degree Mobitz type I intraatrial and intra-His (IH) bundle blocks. Tachycardia and bradycardia-dependent IH block and bradycardia-dependent left bundle branch block were also present. Bradycardia-dependent block was probably caused by slight hypopolarization plus a slow rising slope of phase 4 depolarization and a shift of the threshold potential toward zero.