Left atrial remodeling postseptal myectomy for severe obstructive hypertrophic cardiomyopathy: Analysis by two‐dimensional speckle‐tracking echocardiography

Abstract

Background: Septal myectomy relieves left ventricular outflow obstruction (LVOTO) and is associated with excellent long-term outcomes. LVOTO is associated with diastolic dysfunction and increased left atrial (LA) size. We sought to investigate the changes in LA volumes and function post myectomy and the association between these changes with clinical outcomes post myectomy.Methods: Sixty-six hypertrophic cardiomyopathy patients undergoing myectomy were retrospectively studied. Pre procedural and 6-to 18-month post myectomy follow-up transthoracic echocardiographic images were obtained. LA volumes and strain were assessed by two-dimensional speckle-tracking echocardiography.Results: Left atrial volumes, that is, indexed maximal, minimal, and pre-A volumes reduced post myectomy, yet remained increased compared to controls (105.6 ± 34.5 mL vs 84.9 ± 26.7 mL, 45.2 ± 25.7 mL vs 35.4 ± 22.6 mL, 70.1 ± 31.4 mL vs 35.4 ± 22.6 mL, respectively, P < 0.05). The total emptying index did not improve post myectomy and remained lower than controls (58.6 ± 12.4 vs 59.9 ± 12.8, P = NS) whereas atrial contraction improved, yet did not normalize (active emptying index 36.1 ± 14.9 vs 41.1 ± 16.2, P < 0.05).The conduit volume remained reduced post myectomy (18.6 ± 13.3 mL vs 16.6 ± 15.1 mL, P = NS). LA strain also did not improve post myectomy (26.8 ± 7.3 vs 28.5 ± 8.8, P = NS). A multivariable logistic regression identified pre procedural E/e′ ratio and indexed maximal LA volume, as independent predictors for LA volume reduction ≥20% post myectomy. During a mean follow-up of 4.9 ± 2.3 years post myectomy, 24.2% of the patients developed atrial fibrillation and <5% of patients were severely symptomatic. We found no associations between LA volumes/function and atrial fibrillation or symptoms post myectomy. Conclusion:Postmyectomy LA volumes decreased, and the contractile function improved. There was no association between LA volumes/function and clinical outcomes post myectomy. Notably, the LA remained enlarged (though to a lesser degree) with reduced strain and emptying fraction, suggesting possible atrial myopathy. K E Y W O R D Shypertrophic obstructive cardiomyopathy, left atrial function, left atrial volume, myectomy, two-dimensional speckle-tracking echocardiography | 277 WEISSLER-SNIR Et aL.

Reverse remodeling of left atrium assessed by cardiovascular magnetic resonance feature tracking in hypertrophic obstructive cardiomyopathy after septal myectomy

“…Thus, the improvement in LV longitudinal strain in patients with HOCM after septal myectomy contributed to the increased LA reservoir function [ 23 , 24 ]. In contrast to our results, an echocardiographic investigation reported a reduction in reservoir strain after myectomy [ 25 ]. Compared to this study, their cohort differed substantially in the percentages of patients with hypertension (36%), coronary heart disease (11%), and a history of AF (26%).…”

Evolving Contemporary Management of Atrial Fibrillation in Hypertrophic Cardiomyopathy

“…41 Both myectomy and alcohol ablation are associated with modest reduction in left atrial size over long-term follow-up. [42][43][44][45] Furthermore, in patients who develop advanced heart failure symptoms in the setting of end-stage nonobstructive HCM LA size is typically increased and ~50% of these patients have AF. [46][47][48] Increases in LA pressure and stretch are responsible for atrial dilation and fibrosis that in turn leads to shortening of the effective atrial refractory period and increased dispersion of depolarization.…”

“…41 Both myectomy and alcohol ablation are associated with modest reduction in left atrial size over long-term follow-up. 42–45 Furthermore, in patients who develop advanced heart failure symptoms in the setting of end-stage nonobstructive HCM LA size is typically increased and ~50% of these patients have AF. 46–48…”

Commentary: Left heart remodeling with septal myectomy: Fibrosis is a relative but not absolute concern

“…Their results corroborate previously published data: decreased left ventricular outflow tract gradient, left atrial diameter, left ventricular ejection fraction, and wall thickness after SM. [1][2][3] Postoperative cardiac magnetic resonance imaging, performed in 57 of 507 patients (8.9%), provides further insights. In particular, it showed that the degree of left ventricular late gadolinium enhancement (LGE) increased from 15.2% AE 9.6% to 18.6% (9.6%-31.2%) after SM (P ¼ .009).…”