Monophasic transmitral flow pattern with less increase in heart rate indicates left ventricular dysfunction

When heart rate (HR) increases, mitral flow can become monophasic. Prolonge d isovolumic contraction and relaxation time (ICT and IRT), directly relate d to left ventricular (LV) function, can potentially influence the HR with monophasic mitral flow. The present study investigated the relation between HR that causes monophasic flow and LV function. During diagnostic catheter ization, KR was increased using right atrial pacing by 2 beats/min every 2 min in a stepwise manner until the development of monophasic mitral flow in 17 patients with normal sinus rhythm. ICT, IRT, end-diastolic and end-syst olic LV volumes, LV ejection fraction, LV peak + and -dP/dt, peak (+dP/dt)/ P, and the relaxation time constant (tau) were measured by Doppler echocard iography or catheterization when monophasic mitral flow developed. The mono phasic HR varied from 74 to 106 beats/min. By univariate analysis, ICT (p < 0.01, r(2) = 0.73), LV peak +dP/dt (p < 0.05, r(2) = 0.37), peak (+dP/dt)/ P (p < 0.01, r(2) = 0.71), peak -dP/dt (p < 0.05, r(2) = 0.25), and tau (p < 0.05, r(2) = 0.33) had a significant correlation with monophasic HR. By m ultivariate analysis, prolonged ICT and reduced LV peak -dP/dt independentl y contributed to monophasic mitral flow with less increase in HR. Monophasi c mitral flow with less increase in HR indicates impaired LV systolic and d iastolic function during isovolumic contraction and relaxation.