Effect of heart rate on tissue Doppler measures of diastolic function.

BACKGROUND: Our aim was to study the independent effect of heart rate (HR) on parameters of diastolic function, particularly mitral annular velocities measured by tissue Doppler imaging (TDI), an effect which is not well understood. METHODS: Sixteen patients with dual chamber pacemakers attending for routine pacemaker review underwent detailed echocardiographic assessment during atrial pacing with intact atrioventricular conduction at baseline and accelerated HRs. Mitral inflow and annular tissue Doppler velocities and systolic strain parameters were compared. RESULTS: Parameters of systolic function were unaffected by increased HR. When these parameters were compared at baseline (mean 67 bpm) and accelerated HR (mean 80 bpm), the following was observed: a significant decrease in early mitral inflow (E) wave (70.5 +/- 5.5 cm/s vs 63.5 +/- 4.9 cm/s, P < 0.02) and early mitral annular (E') velocities (7.0 +/- 0.5 cm/s vs 6.3 +/- 0.6 cm/s, P < 0.003) and a significant increase in mitral inflow A wave (70.3 +/- 4.5 cm/s vs 77.3 +/- 4.4 cm/s, P < 0.05) and late mitral annular (A') velocities (9.3 +/- 0.6 cm/s vs 10.8 +/- 0.5, P < 0.00004). CONCLUSION: Changes in HR have previously unrecognized significant effects on tissue Doppler parameters of diastolic function. Further study is required to determine if tissue Doppler derived annular velocities should be corrected for HR.