Transthoracic Cardiac Ultrasonic Stimulation Induces a Negative Chronotropic Effect

Author(s)

Buiochi, Elaine Belassiano ^[1] ; Miller, Rita J. ^[2] ; Hartman, Emily ^[3] ; Buiochi, Flavio ^[4] ; Bassani, Rosana A. ^[5] ; Costa, Eduardo T. ^{[1, 5]} ; O'Brien, Jr., William D. ^[2]

Affiliation

^[1] Univ Estadual Campinas, Dept Biomed Engn, Sch Elect & Comp Engn FEEC, Campinas - Brazil

^[2] Univ Illinois, Dept Elect & Comp Engn, Urbana, IL - USA

^[3] Univ Illinois, Biomed Imaging Ctr, Beckman Inst, Urbana, IL - USA

^[4] Univ Sao Paulo, Dept Mechatron Engn, Sao Paulo - Brazil

^[5] Univ Estadual Campinas, Ctr Biomed Engn, Campinas - Brazil

• Document type: Journal article
• Source: IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL; v. 59, n. 12, p. 2655-2661, DEC 2012.
• Web of Science Citations: 7

Abstract

The objective of this study is to investigate cardiac bioeffects resulting from ultrasonic stimulation using a specific set of acoustical parameters. Ten Sprague-Dawley rats were anesthetized and exposed to 1-MHz ultrasound pulses of 3-MPa peak rarefactional pressure and approximately 1% duty factor. The pulse repetition frequency started slightly above the heart rate and was decreased by 1 Hz every 10 s, for a total exposure duration of 30 s. The control group was composed of five rats. Two-way analysis of variance for repeated measures and Bonferroni post hoc tests were used to compare heart rate and ejection fraction, which was used as an index of myocardial contractility. It was demonstrated for the first time that transthoracic ultrasound has the potential to decrease the heart rate by similar to 20%. The negative chronotropic effect lasted for at least 15 min after ultrasound exposure and there was no apparent gross damage to the cardiac tissue. (AU)