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Electrical and mechanical response in biventricular mechanical alternans
Archives Internationales De Physiologie Et De Biochimie
|February 1, 1979
Summary
Mechanical alternans, a difference in heartbeats, can vary between ventricles. This study investigated why, finding differences linked to the timing of electrical stimuli and mechanical responses in the heart.
Area of Science:
- Cardiology
- Cardiac Electrophysiology
- Heart Mechanics
Background:
- Mechanical alternans, characterized by varying degrees of contractile force between heartbeats, can occur under various physiological and pathological conditions.
- Previous research indicates that the two ventricles may exhibit distinct patterns of mechanical alternans.
- The underlying mechanisms responsible for differential ventricular mechanical alternans remain incompletely understood.
Purpose of the Study:
- To elucidate the mechanisms driving differential mechanical alternans between the two ventricles.
- To investigate the relationship between electrical stimulation timing and mechanical response in inducing alternans.
- To explore how variations in premature beat coupling influence ventricular mechanical alternans.
Main Methods:
- Simultaneous recording of myocardial tension from both ventricles using strain gauges.
- Utilizing a miniature strain gauge to measure electrograms and myocardial tension in localized areas.
- Employing controlled electrical stimulation to drive heart rate and introduce premature beats at specific coupling intervals.
Main Results:
- Significant differences in the degree of mechanical alternans were observed between measurement sites in the two ventricles.
- The magnitude of mechanical alternans was found to be dependent on the timing of premature electrical stimulation.
- A correlation was established between the time interval from electrical stimulus to mechanical response and the observed alternans.
Conclusions:
- The timing of electrical stimuli relative to mechanical response plays a crucial role in the development of differential ventricular mechanical alternans.
- Variations in electro-mechanical coupling dynamics contribute to the observed differences in alternans between the ventricles.
- This study provides insights into the electrophysiological basis of mechanical alternans and its ventricular heterogeneity.