The response of normal and failing heart to externally applied vibration in the canine open chest preparation.

We examined the left ventricular functional response to externally applied vibration using four canine open chest preparations. A sinusoidal 30 Hz vibration (2.7 mm in amplitude) was applied to the ventricular epicardium at each level of propranolol-induced myocardial depression. External vibration in control conditions induced no significant change either in peak left ventricular pressure (LVP) or in stroke volume (SV). With propranolol, 0.1 and 0.3 mg/kg, peak LVP and SV were depressed by the application of external vibration, even though there was no significant change of these values in the nonvibrating condition compared to control. We conclude that the ventricular response to vibration depends on the underlying myocardial viability.