This study was also undertaken to estimate the extent to which variations of cardiac adrenergic tone may interfere with the aspect of the repolarization in normal subjects and in patients with cardiac disorders of organic origin. Activation and inhibition of the adrenergic discharge to the heart by physiologic stimuli was considered the most suitable method for this type of investigation; such a method was elaborated and utilized in the present study. The direction and the extent of variations of the cardiac sympathetic drive were evaluated by circulatory measurements reflecting the inotropic state, and were related to the repolarization changes. Although the tests used have some practical value, we do not offer them as a tool for definitive differentiation between organic and functional ST-T wave alterations. The following conclusions can be drawn: (1) The nervous outflow to the heart may be varied from the baseline to opposite directions by different stressful stimuli. (2) ST-T alterations may be induced and abolished by adrenergic activation and inhibition respectively. (3) These effects are dissociated from or not necessarily associated with an exaggerated responsiveness of the cardiac beta receptors. (4) The adrenergic influences on the ST-T abnormalities of myocardial ischemia and hypertension are limited.
|Number of pages||14|
|Publication status||Published - 1978|
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine