Four-Chamber Deformation Remodeling and Atrial Fibrillation After Septal Myectomy for Obstructive Hypertrophic Cardiomyopathy.

INTRODUCTION

Septal myectomy treats hypertrophic obstructive cardiomyopathy (HOCM), but its effect on myocardial deformation across cardiac chambers is incompletely defined. We evaluated chamber-specific strain remodeling 1 year after septal myectomy and examined whether atrial strain was associated with atrial fibrillation (AF) during follow-up.

METHODS

We retrospectively studied 187 consecutive patients undergoing surgical septal myectomy for HOCM. Conventional echocardiography and speckle-tracking strain analysis were used to assess left ventricular (LV), right ventricular (RV), left atrial (LA), and right atrial (RA) deformation preoperatively and at 1-year follow-up. Paired analyses compared preoperative and postoperative strain values. Multivariable logistic regression evaluated associations between baseline strain measures, AF, and all-cause mortality.

RESULTS

Among 187 patients, 85 had analyzable 1-year strain studies. At 1 year, LA contractile strain (CS) improved from 10.4±5.9% to 13.6±7.1% (p = 0.005), whereas LA reservoir strain (RS) did not significantly change. In contrast, RA-RS decreased from 36.0±10.6% to 28.0±11.6% (p = 0.001), RV free-wall strain worsened from -26.3±7.0% to -21.1±6.8% (p = 0.001), and RV global longitudinal strain (GLS) worsened from -21.3±5.1% to -17.3±5.5% (p = 0.001). LV-GLS was unchanged. Higher LA-CS was associated with lower odds of AF after adjustment (aOR 0.92, 95% CI 0.85-0.99; p = 0.018), as was higher LA-RS (aOR 0.95, 95% CI 0.91-0.99; p = 0.035). LA-RS was associated with mortality in unadjusted analysis but not after multivariable adjustment.

CONCLUSIONS

Septal myectomy is followed by nonuniform, chamber-specific deformation remodeling. LA-CS improves, LA-RS and CS identify patients at higher AF risk, LV-GLS remains unchanged, and right-sided longitudinal deformation worsens at 1 year. Four-chamber strain analysis may augment post-myectomy surveillance.