Stimulus-response relationship in dog ventricle in vivo

¹ Department of Clinical Therapeutics, University of Athens, and Cardiovascular Laboratory, Alexandra Hospital, Athens, Greece

Electrical pulses of short duration were applied to the ventricular myocardium of 50 dogs. Several phenomena were observed in left ventricular pressure tracings and electrograms. Synchronization and desynchronization points between the heart and the stimulator (determined for stimuli of different frequency and strength) formed a curve which may be considered a "frequency-response" curve of the heart, thus indicating its "natural frequency." Transient phenomena appearing at the time of synchronization and desynchronization and during periodic synchronization may also indicate a similarity between the heart-stimulator system and a pair of coupled oscillators.

Key Words: frequency response of ventricle • natural frequency of ventricle • synchronization between ventricle and electrical stimuli • oscillator system in ventricle

Submitted on February 5, 1964

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