Dyssynchronization reduces dynamic obstruction without affecting systolic function in patients with hypertrophic...

Area of Science:

• Cardiology
• Cardiac Electrophysiology
• Cardiovascular Imaging

Background:

• Hypertrophic obstructive cardiomyopathy (HOCM) is characterized by dynamic left ventricular outflow tract (LVOT) obstruction.
• Biventricular pacing (BiV) is explored for its potential to mitigate LVOT obstruction.
• The impact of BiV on left ventricular (LV) systolic function in HOCM remains unclear.

Purpose of the Study:

• To evaluate the effects of BiV on LV systolic function in patients with HOCM.
• To assess the efficacy of BiV in reducing LVOT obstruction in HOCM.
• To investigate the relationship between BiV-induced changes and LV systolic performance.

Main Methods:

• A cohort of 13 HOCM patients received BiV implantation.
• 2D transthoracic echocardiography was performed pre-implantation and at 12-month follow-up.
• Speckle-tracking software analyzed global longitudinal and radial strain, and segmental displacement curves to assess LV function and dyssynchrony.

Main Results:

• BiV significantly reduced the peak LVOT gradient from 80 mmHg to 30 mmHg (p=0.005).
• LV global radial and longitudinal strain were preserved post-BiV implantation (p=NS).
• Inverted wall motion timing, indicative of dyssynchrony, correlated with reduced LVOT gradient.

Conclusions:

• BiV effectively reduces LVOT obstruction in HOCM patients.
• Achieving LV dyssynchronization and inverted wall activation timing is crucial for BiV efficacy.
• Mid-term follow-up indicates that BiV does not worsen LV systolic function in HOCM.