title: Predictors of long-term outcomes in patients with hypertrophic cardiomyopathy undergoing cardiopulmonary stress testing and echocardiography.
abstract: BACKGROUND
  Patients with hypertrophic cardiomyopathy (HCM) have exercise intolerance due to left ventricular outflow tract (LVOT) obstruction, mitral regurgitation, and left ventricular dysfunction. We sought to study predictors of outcomes in HCM patients undergoing cardiopulmonary stress testing (CPT).
  
  
  METHODS
  We studied 1,005 HCM patients (50 ± 14 years, 64% men, 77% on β-blockers) who underwent CPT with echocardiography. Clinical, echocardiographic, and exercise variables (peak oxygen consumption [VO2] and heart rate recovery [HRR] at first minute postexercise) were recorded. End point was a composite of death, appropriate defibrillator discharges, resuscitated sudden death, stroke, and heart failure admission.
  
  
  RESULTS
  Mean left ventricular ejection fraction (LVEF), postexercise LVOT gradient, and peak VO2 were 62% ± 6%, 92 ± 51 mm Hg, and 21 ± 6 mL kg(-1) min(-1), respectively. Despite 789 patients (78%) being in New York Heart Association classes I to II, only 8% achieved >100% age-gender predicted peak VO2, whereas 77% and 15% achieved 50% to 100% and <50%, respectively. Left ventricular outflow tract gradient ≥30 mm Hg was observed in 83% patients, whereas 23% had abnormal HRR. More than 5.5 ± 4 years, there were 94 (9%) events; 511 (50%) patients underwent surgery for LVOT obstruction. Multivariable Cox proportional analysis demonstrated % age-gender predicted peak VO2 (hazard ratio [HR] 0.96 [0.93-0.98]), normal vs abnormal HRR (HR 0.48 [0.32-0.73]), higher LVEF (HR 0.96 [0.93-0.98]), surgery (0.53 [0.33-0.83]), and atrial fibrillation (HR 1.65 [1.04-2.60]) were associated with outcomes (all P < .05).
  
  
  CONCLUSIONS
  In HCM patients undergoing CPT, a higher % of achieved age-gender predicted VO2 and surgical relief of LVOT obstruction were associated with better outcomes, whereas abnormal HRR, atrial fibrillation, and lower LVEF were associated with worse outcomes.
authors.affiliation: Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Masri
authors.affiliation: Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH.
authors.forename: Lee M
authors.initials: LM
authors.lastname: Pierson
authors.affiliation: Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH.
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Smedira
authors.affiliation: Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH.
authors.forename: Shikhar
authors.initials: S
authors.lastname: Agarwal
authors.affiliation: Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH.
authors.forename: Bruce W
authors.initials: BW
authors.lastname: Lytle
authors.affiliation: Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH.
authors.forename: Peyman
authors.initials: P
authors.lastname: Naji
authors.affiliation: Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH.
authors.forename: Maran
authors.initials: M
authors.lastname: Thamilarasan
authors.affiliation: Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH.
authors.forename: Harry M
authors.initials: HM
authors.lastname: Lever
authors.affiliation: Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH.
authors.forename: Leslie S
authors.initials: LS
authors.lastname: Cho
authors.affiliation: Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH. Electronic address: desaim2@ccf.org.
authors.forename: Milind Y
authors.initials: MY
authors.lastname: Desai
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000150:complications; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D004452:Echocardiography; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D011379:Prognosis; D016016:Proportional Hazards Models; D018570:Risk Assessment; D013318:Stroke Volume; D016019:Survival Analysis; D014694:Ventricular Outflow Obstruction / Q000209:etiology / Q000503:physiopathology / Q000601:surgery