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Updated: Apr 6, 2026

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Comparison of Outcomes in Patients With Nonobstructive, Labile-Obstructive, and Chronically Obstructive Hypertrophic

Iraklis Pozios1, Celia Corona-Villalobos2, Lars L Sorensen1

  • 1Johns Hopkins HCM Center of Excellence, Baltimore, Maryland.

The American Journal of Cardiology
|August 5, 2015
PubMed

Insights

Patients with nonobstructive hypertrophic cardiomyopathy (HC) face higher risks of ventricular arrhythmias than previously thought. This study reveals nonobstructive HC is linked to more fibrosis and ischemia, predicting sudden cardiac events.

Area of Science:

  • Cardiology
  • Cardiovascular Imaging
  • Electrophysiology

Background:

  • Nonobstructive hypertrophic cardiomyopathy (HC) is often considered low-risk.
  • Traditionally, nonobstructive and labile-obstructive HC have been grouped, potentially masking distinct risk profiles.

Purpose of the Study:

  • To compare cardiovascular outcomes between nonobstructive, labile-obstructive, and obstructive HC subgroups.
  • To determine if nonobstructive hemodynamics predict adverse cardiovascular events.

Main Methods:

  • Compared cardiovascular outcomes in 293 HC patients (nonobstructive, labile-obstructive, obstructive) using exercise echocardiography and MRI.
  • Assessed fibrosis with late gadolinium enhancement (LGE) and ischemia with positron emission tomography (PET) in a subgroup.
  • Followed patients for a mean of 3.3 years, recording major adverse events.

Main Results:

  • Nonobstructive HC patients showed significantly higher LGE (≥20% myocardial mass) and regional PET perfusion abnormalities.
  • Nonobstructive HC was an independent predictor of ventricular tachycardia/ventricular fibrillation (VT/VF).
  • Appropriate defibrillator discharges were more frequent in nonobstructive patients (18%) compared to labile-obstructive (0%).

Conclusions:

  • Nonobstructive hemodynamics in HC are associated with greater myocardial fibrosis and ischemia.
  • Nonobstructive HC is an independent predictor of VT/VF, challenging the low-risk classification.
  • Risk stratification for HC should differentiate between nonobstructive and labile-obstructive phenotypes.

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