Table 1.
Demographic and clinical characteristics of the study cohort
| Frequency (percentage) or mean±SD (range) or median (IQR) | |
|---|---|
| Demographics | |
| Age at initial evaluation (years) | 49.6±15.4 (6–87) |
| Male | 590/874 (67.8%) |
| Ethnicity | |
| Caucasian | 622 (71.2%) |
| Indian and other Asian | 68 (7.8%) |
| African/Caribbean | 39 (4.5%) |
| Chinese | 6 (0.7%) |
| Other | 20 (2.3%) |
| Not reported | 119 (13.6%) |
| Presentation | |
| Family history of HCM | 226/853 (26.5%) |
| Family history of SCD | 182/872 (20.9%) |
| NYHA class III or IV | 100/850 (11.8%) |
| Syncope | 140/856 (16.4%) |
| Chest pain | 205/854 (24.0%) |
| Initial ECG | |
| Atrial fibrillation | 43/874 (4.9%) |
| PR interval (ms) | 174.8±32.4 (108–320) |
| QRS duration (ms) | 101.0±25.5 (64–238) |
| Initial CPEX | |
| SBP rest (mm Hg) | 128.8±21.0 (80–210) |
| SBP response to exercise (mmHg) | 48.5±24.2 (-5–150) |
| Abnormal SBP response to exercise | 92/662 (13.9%) |
| Initial echocardiography | |
| Maximal LV wall thickness (mm) | 18.5±4.4 (9–38) |
| Severe LVH (≥30 mm) | 17/601 (2.8%) |
| Right ventricular hypertrophy (>5 mm) | 184/864 (21.3%) |
| Asymmetric septal hypertrophy pattern | 643/850 (75.6%) |
| Left atrial diameter (mm) | 44.0±7.5 (18–90) |
| LV end-diastolic diameter (mm) | 45.9±5.9 (29–65) |
| LV dilatation (>55 mm) | 38/851 (4.5%) |
| LV end-systolic diameter (mm) | 28.5±5.6 (9–50) |
| Fractional shortening (%) | 38.3±8.2 (16–70) |
| Systolic dysfunction (≤25% FS) | 29/829 (3.5%) |
| E wave deceleration time (ms) | 221.0 (184–268) |
| Mitral regurgitation—moderate/severe | 163/851 (19.2%) |
| Peak LVOT gradient (mm Hg) | 12.0 (4.0–60.0) |
| LVOT gradient >30 mm Hg | 328/812 (40.4%) |
| NSVT—Holter | 127/566 (22.4%) |
| Follow-up | |
| New-onset atrial fibrillation | 216/874 (24.7%) |
| Implantable cardioverter-defibrillator | 177/874 (20.3%) |
| Myectomy | 130/874 (14.9%) |
| Alcohol septal ablation | 46/874 (5.3%) |
| Myectomy and/or alcohol septal ablation and/or pacemaker implantation for LVOT gradient reduction | 182/874 (20.8%) |
| Cardiovascular death | 25/874 (2.9%) |
| SCD | 16/874 (1.8%) |
Total N=874.
CPEX, cardiopulmonary exercise test; FS, fractional shortening; HCM, hypertrophic cardiomyopathy; LVH, LV hypertrophy; LVOT, LV outflow tract; NSVT, non-sustained ventricular tachycardia; NYHA, New York Heart Association; SBP, systolic blood pressure; SCD, sudden cardiac death.