Background:

Extended septal myectomy (ESM) has proven to be a useful strategy to improve symptoms in patients with hypertrophic obstructive cardiomyopathy (HOCM).

Objectives:

The aim of this study was to analyze the impact of ESM on short and mid-term structural and functional echocardiographic parameters in patients with HCM and left ventricular (LV) outflow tract dynamic obstruction.

Methods:

Preoperative, immediate postoperative (1 month after surgery) and late postoperative (2 to 3 years) echocardiograms of patients undergoing ESM were analyzed.

Results:

A total of 94 patients with mean age of 57.6 ± 13.8 years underwent surgery. A significant reduction was observed in maximum septal thickness in the immediate postoperative period, which was sustained in the late postoperative period, and in atrial size in the immediate postoperative period, which deepened in the late postoperative period (p < 0.001). Intraventricular gradient at rest dropped from 49.2 to 6.4 mmHg (p < 0.001) and then to 4.6 mmHg (p=0.224) in the immediate and late periods and with Valsalva maneuver from 93.9 to 8.7 mmHg (p < 0.001), and then to 7.2 mmHg (p=0.226), respectively. Preoperative diastolic function was assessed as grade II in 58.5% of patients, decreasing to 51.7% in the immediate postoperative period and to 29% in the late postoperative period. In agreement with these results, a change was evidenced in the E/e´ ratio and pulmonary artery systolic pressure, degree of mitral regurgitation and left atrial dimensions.

Conclusion:

In this cohort of patients with HOCM, ESM was associated with a significant improvement in LV diastolic function, reduction in filling and pulmonary pressures and degree of mitral regurgitation, and left atrial reverse remodeling. It is possible that this combination of effects explains the clinical benefits of the intervention.