title: Cardiopulmonary Exercise Testing and Prognosis in Hypertrophic Cardiomyopathy.
abstract: BACKGROUND
  Exercise testing is performed in patients with hypertrophic cardiomyopathy to evaluate blood pressure response, a risk factor for sudden cardiac death. The prognostic role of exercise gas exchange variables is unknown.
  
  
  RESULTS
  Between 1998 and 2010, 1898 patients (age 47±15 years, range 16-86 years; 67% male) with hypertrophic cardiomyopathy underwent cardiopulmonary exercise testing. A total of 178 (9.4%) patients reached the primary end point of all-cause mortality or heart transplant (death/transplant) during a median follow-up of 5.6 years (interquartile range 2.6-8.9), giving an annual event rate of 1.6% per person year. Peak oxygen consumption (adjusted hazard ratio [HR] 0.82, 95% confidence interval [CI] 0.77-0.88, P<0.001), ventilatory efficiency (adjusted HR 1.10, 95% CI 1.00-1.22, P=0.049), and ventilatory anaerobic threshold (adjusted HR 0.82, 95% CI 0.70-0.96, P=0.016) were predictors of the primary outcome after correction for age, sex, left atrial size, nonsustained ventricular tachycardia, and ejection fraction. The overall adjusted death/transplant estimates for patients in the lowest quartile with peak oxygen consumption ≤15.3 mL/kg/min were 14% at 5 years and 31% at 10 years. Peak oxygen consumption (HR 0.81, 95% CI 0.77-0.86, P<0.01) and ventilation to carbon dioxide production (HR 1.10, 95% CI 1.08-1.13, P<0.001) were predictors of death because of heart failure or transplantation but not sudden cardiac death or implantable cardioverter defibrillator shocks.
  
  
  CONCLUSIONS
  Cardiopulmonary exercise testing provides prognostic information in patients with hypertrophic cardiomyopathy. Submaximal exercise parameters, such as ventilatory efficiency and anaerobic threshold, measured alone or in combination with peak oxygen consumption, predict death from heart failure.
authors.affiliation: From the Institute of Cardiovascular Science (C.J.C., B.M., W.J.M., P.M.E.), and Institute of Neurology (K.R.), University College London, London, United Kingdom; Royal Free Hospital NHS Trust, London, United Kingdom (A.B.); and University College London Hospitals NHS Trust, London, United Kingdom (A.P.). c.coats@ucl.ac.uk.
authors.forename: Caroline J
authors.initials: CJ
authors.lastname: Coats
authors.affiliation: From the Institute of Cardiovascular Science (C.J.C., B.M., W.J.M., P.M.E.), and Institute of Neurology (K.R.), University College London, London, United Kingdom; Royal Free Hospital NHS Trust, London, United Kingdom (A.B.); and University College London Hospitals NHS Trust, London, United Kingdom (A.P.).
authors.forename: Khadija
authors.initials: K
authors.lastname: Rantell
authors.affiliation: From the Institute of Cardiovascular Science (C.J.C., B.M., W.J.M., P.M.E.), and Institute of Neurology (K.R.), University College London, London, United Kingdom; Royal Free Hospital NHS Trust, London, United Kingdom (A.B.); and University College London Hospitals NHS Trust, London, United Kingdom (A.P.).
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Bartnik
authors.affiliation: From the Institute of Cardiovascular Science (C.J.C., B.M., W.J.M., P.M.E.), and Institute of Neurology (K.R.), University College London, London, United Kingdom; Royal Free Hospital NHS Trust, London, United Kingdom (A.B.); and University College London Hospitals NHS Trust, London, United Kingdom (A.P.).
authors.forename: Amour
authors.initials: A
authors.lastname: Patel
authors.affiliation: From the Institute of Cardiovascular Science (C.J.C., B.M., W.J.M., P.M.E.), and Institute of Neurology (K.R.), University College London, London, United Kingdom; Royal Free Hospital NHS Trust, London, United Kingdom (A.B.); and University College London Hospitals NHS Trust, London, United Kingdom (A.P.).
authors.forename: Bryan
authors.initials: B
authors.lastname: Mist
authors.affiliation: From the Institute of Cardiovascular Science (C.J.C., B.M., W.J.M., P.M.E.), and Institute of Neurology (K.R.), University College London, London, United Kingdom; Royal Free Hospital NHS Trust, London, United Kingdom (A.B.); and University College London Hospitals NHS Trust, London, United Kingdom (A.P.).
authors.forename: William J
authors.initials: WJ
authors.lastname: McKenna
authors.affiliation: From the Institute of Cardiovascular Science (C.J.C., B.M., W.J.M., P.M.E.), and Institute of Neurology (K.R.), University College London, London, United Kingdom; Royal Free Hospital NHS Trust, London, United Kingdom (A.B.); and University College London Hospitals NHS Trust, London, United Kingdom (A.P.).
authors.forename: Perry M
authors.initials: PM
authors.lastname: Elliott
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015308:Anaerobic Threshold / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D002312:Cardiomyopathy, Hypertrophic / Q000175:diagnosis / Q000401:mortality* / Q000503:physiopathology*; D015331:Cohort Studies; D005080:Exercise Test; D005260:Female; D016027:Heart Transplantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D011237:Predictive Value of Tests; D011379:Prognosis; D016019:Survival Analysis; D055815:Young Adult
keywords: exercise testing; heart failure; hypertrophic cardiomyopathy; prognosis; sudden cardiac death