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Conduction Abnormalities and Long-Term Mortality Following Septal Myectomy in Patients With Obstructive Hypertrophic

Hao Cui1, Hartzell V Schaff1, Rick A Nishimura2

  • 1Department of Cardiovascular Surgery, Mayo Clinic, Rochester, Minnesota.

Journal of the American College of Cardiology
|August 3, 2019
PubMed

Insights

Septal myectomy for hypertrophic cardiomyopathy can cause conduction abnormalities. Persistent paced rhythm after surgery is linked to increased mortality, while left bundle branch block is common but not associated with worse outcomes.

Area of Science:

  • Cardiology
  • Cardiac Surgery
  • Electrophysiology

Background:

  • Conduction abnormalities, such as bundle branch block, are known complications after septal myectomy for hypertrophic cardiomyopathy.
  • The long-term impact of these conduction changes on patient mortality remains understudied.

Purpose of the Study:

  • To investigate the effect of post-myectomy conduction abnormalities on all-cause mortality in patients with obstructive hypertrophic cardiomyopathy.
  • To identify specific conduction changes that predict long-term survival after septal myectomy.

Main Methods:

  • Analysis of outcomes for 2,482 patients who underwent transaortic septal myectomy between 1961 and 2016.
  • Review of pre-operative and early post-operative electrocardiograms to assess conduction status.
  • Evaluation of all-cause mortality as the primary study endpoint over a median follow-up of 8.6 years.

Main Results:

  • Left bundle branch block developed in 38.8% of patients with normal baseline conduction post-myectomy.
  • Complete heart block (CHB) occurred in 0.6% of patients with normal baseline conduction, but in 34.8% of those with pre-existing right bundle branch block (RBBB).
  • Persistent paced rhythm post-myectomy was associated with significantly increased mortality (HR: 1.57; p=0.005), while left bundle branch block and RBBB did not show a significant impact on mortality.

Conclusions:

  • Left bundle branch block is a frequent but generally benign sequela of septal myectomy.
  • Complete heart block is rare in patients with normal baseline conduction but a significant risk for those with pre-existing RBBB.
  • Persistent paced rhythm following myectomy is an independent predictor of increased long-term mortality.
Abstract

Keywords:
complete heart blockhypertrophic cardiomyopathyleft bundle branch blockright bundle branch blockseptal myectomy

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