Thresholds for premature ventricular contractions in frog hearts exposed to lithotripter fields.
Piezoelectrically generated lithotripter shocks were shown to produce premature ventricular contractions of the frog heart. Anesthetized grass frogs, Rana pipiens, were studied following implantation of an aortic catheter and EKG leads. The most sensitive phase of the heart cycle for the generation of premature ventricular contractions with lithotripter shocks at 30 MPa peak pressure was found to be the T-P segment. During this phase of the heart cycle, the minimum peak-positive pressure shock wave necessary to produce a premature ventricular contraction in a frog heart was between 5 MPa and 10 MPa.
Dalecki
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D
Department of Electrical Engineering, Rochester Center for Biomedical Ultrasound, University of Rochester, NY 14627.
Keller
B B
BB
Carstensen
E L
EL
Neel
D S
DS
Palladino
J L
JL
Noordergraaf
A
A
D000818:Animals; D001011:Aorta; D001794:Blood Pressure / Q000502:physiology; D005117:Cardiac Complexes, Premature / Q000209:etiology*; D004562:Electrocardiography; D006321:Heart / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology; D008096:Lithotripsy / Q000009:adverse effects* / Q000295:instrumentation; D009200:Myocardial Contraction / Q000502:physiology; D011894:Rana pipiens; D013997:Time Factors; D014160:Transducers, Pressure; D016276:Ventricular Function / Q000502:physiology