Tachycardia-Induced Diastolic Dysfunction and Resting Tone in Myocardium From Patients With a Normal Ejection Fraction

Study Questions:

Does tachycardia result in myocardial relaxation abnormalities in patients with left ventricular (LV) hypertrophy and a normal LV ejection fraction (LVEF)?

Methods:

LV biopsies were performed at the time of open heart surgery in 17 patients with a normal LVEF on a preoperative echocardiogram. Experiments were performed on the myocardial strip preparations to determine the relaxation properties of the tissue and the effects of tachycardia.

Results:

Seven of the 14 muscle preparations demonstrated incomplete relaxation. The incomplete relaxation was associated with LV hypertrophy and left atrial enlargement. As the rate of stimulation of the muscle preparation progressively increased, incomplete relaxation first was noted at a rate of approximately 105 bpm in muscle strips from patients with LV hypertrophy, compared to approximately 165 bpm in muscle strips from patients without hypertrophy.

Conclusions:

The authors concluded that relaxation abnormalities are accentuated by tachycardia, especially in the setting of LV hypertrophy.

Perspective:

The results of this study shed light on the deleterious effects of atrial fibrillation/flutter with a rapid ventricular rate. Aside from tachycardia-induced systolic dysfunction, the rapid rate may result in diastolic heart failure, particularly in patients with LV hypertrophy.

Clinical Topics: Arrhythmias and Clinical EP, Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Cardiac Surgery and Arrhythmias, Cardiac Surgery and Heart Failure, Acute Heart Failure, Chronic Heart Failure, Interventions and Imaging, Echocardiography/Ultrasound

Keywords: Hypertrophy, Left Ventricular, Heart Failure, Diastolic, Biopsy, Atrial Fibrillation, Myocardium, Cardiac Surgical Procedures, Echocardiography, Tachycardia


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