Myocardial depressant effect of vibrations in the isolated rabbit heart

A working rabbit heart preparation was developed in which vibrations could be induced in the left ventricular outflow tract. The vibrations were produced by a special vibrator from which a metal pin was connected to a thin metal plate sutured onto the left ventricle. Vibrations of 0.3, 0.6 and 1.2 mm amplitude and frequencies of 50, 80 and 100 Hz were used. Increasing amplitudes or frequencies resulted in more pronounced reduction of cardiac output, aortic flow and left ventricular peak systolic pressure. The left ventricular end diastolic pressure increased at higher amplitudes or frequencies. The coronary flow was not significantly changed. It is suggested that vibrations of the ventricular wall might be a myocardial depressant factor of importance in valvular heart disease.