Responses of peak ear-pulse derivative to changing left ventricular function

The ear densitograph displacement pulse derivative (dD/dtear) is the analog of the arterial pressure derivative (dP/dt) and behaves comparably under a variety of cardiocirculatory challenges. Technical reliability and uniform application of the transducer are advantages that make it ideal for intrasubject monitoring. With atrial fibrillation as a model of functional variability in eight subjects, peak dD/dtear (P) tracked echocardiographic stroke volume, ejection fraction, ejection rate, and velocity of circumferential fiber shortening quite closely with the exception of some values in three subjects, two of whom had mitral regurgitation and one paradoxic septal movement. In all subjects, P showed good to excellent correlations with cycle length, preejection period (PEP), LVET (left ventricular ejection time), and PEP/LVET. The method appears to be ideally suited to intrasubject monitoring for changing ventricular function.