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Exercise capacity and paroxysmal atrial fibrillation in patients with hypertrophic cardiomyopathy
  1. Farnaz Azarbal1,
  2. Maneesh Singh2,
  3. Gherardo Finocchiaro1,
  4. Vy-Van Le1,3,
  5. Ingela Schnittger1,
  6. Paul Wang1,
  7. Jonathan Myers1,3,
  8. Euan Ashley1,
  9. Marco Perez1
  1. 1Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
  2. 2Division of Gastroenterology, Department of Medicine, University of California San Francisco, San Francisco, California, USA
  3. 3Department of Cardiology, VAPAHCS, Palo Alto, California, USA
  1. Correspondence to Dr Marco V Perez, Stanford Center for Inherited Cardiovascular Disease, 300 Pasteur Drive #H2155, Stanford, CA 94305-5233, USA; mvperez{at}


Background Atrial fibrillation (AF) is the most common arrhythmia among patients with hypertrophic cardiomyopathy (HCM). The relationship between paroxysmal AF and exercise capacity in this population is incompletely understood.

Methods Patients with HCM underwent symptom-limited cardiopulmonary testing with expired gas analysis at Stanford Hospital between October 2006 and October 2012. Baseline demographics, medical histories and resting echocardiograms were obtained for all subjects. Diagnosis of AF was established by review of medical records and baseline ECG. Those with paroxysmal AF were in sinus rhythm at the time of cardiopulmonary testing with expired gas analysis. Exercise intolerance was defined as peak VO2<20 mL/kg/min. We used multivariate logistic regression to evaluate the association between exercise intolerance and paroxysmal AF.

Results Among the 265 patients recruited, 55 had AF (28 paroxysmal and 27 permanent). Compared with those without AF, subjects with paroxysmal AF were older, more likely to use antiarrhythmic and anticoagulant medications, and had larger left atria. Patients with paroxysmal AF achieved lower peak VO2 (21.9±9.2 mL/kg/min vs 26.9±10.8 mL/kg/min, p=0.02) and were more likely to have exercise intolerance (61% vs 28%, p<0.001) compared with those without AF. After adjustment for age, sex and body mass index (BMI) exercise intolerance remained significantly associated with paroxysmal AF (OR 4.65, 95% CI 1.83 to 11.83, p=0.001).

Conclusions Patients with HCM and paroxysmal AF demonstrate exercise intolerance despite being in sinus rhythm at the time of exercise testing.

  • Hypertrophic cardiomyopathy
  • atrial fibrillation
  • exercise capacity

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