Appearance of electrocardiographic initial U-wave inversion dependent on pressure-induced early diastolic impairment in patients with hypertension.

Background: ECG U-wave inversion can be classified as initial and terminal U inversion according to the phasic relationship to positive U-wave deflection. Initial U inversion is occasionally observed in hypertensive patients while terminal U inversion frequently appears during severe myocardial ischemia.

Hypothesis: The genesis of initial U inversion may be related to pressure-induced diastolic dysfunction.

Methods: In order to clarify the genesis of initial U-wave inversion we studied 11 consecutive hypertensive patients with both initial U inversion and impaired left ventricular early relaxation who were evaluated using Doppler echocardiography.

Results: The U inversion disappeared during acute pressure lowering by sublingual administration of nitroglycerin. The U inversion also disappeared and relaxation improved significantly after chronic blood pressure lowering. Initial U inversion reappeared during a cold pressor test.

Conclusion: The appearance of initial U inversion was dependent on the pressure-induced impaired left ventricular early relaxation in hypertensive patients.