Table 1.
Baseline Clinical Features
| Thin Filament (n = 80) | Thick Filament (n = 150) | p Value | |
|---|---|---|---|
| Clinical/demographic features | |||
| Female | 36 (45) | 66 (44) | 0.488 |
| Age at enrollment, yrs | 44 ± 16 | 42 ± 17 | 0.387 |
| Age at final evaluation, yrs | 49 ± 16 | 47 ± 17 | 0.388 |
| Family history of HCM | 35 (44) | 67 (44) | 0.497 |
| Family history of sudden cardiac death | 29 (36) | 28 (18) | 0.004 |
| NYHA functional class | |||
| I | 53 (66) | 92 (61) | 0.227 |
| II | 21 (26) | 43 (29) | 0.375 |
| III/IV | 6 (8) | 16 (10) | 0.613 |
| Angina pectoris | 16 (20) | 30 (20) | 0.512 |
| Syncope | 14 (18) | 21 (14) | 0.545 |
| Symptomatic | 43 (54) | 75 (50) | 0.588 |
| Atrial fibrillation | 25 (31) | 49 (30) | 0.827 |
| Abnormal BP response to exercise | 19 (24) | 19 (13) | 0.037 |
| Nonsustained ventricular tachycardia | 24 (30) | 26 (17) | 0.032 |
| Sustained ventricular tachycardia | 6 (8) | 8 (5) | 0.395 |
| ECG | |||
| T-wave inversion | 54 (67) | 66 (44) | 0.002 |
| Increased voltage (LV hypertrophy) | 48 (60) | 97 (65) | 0.514 |
| Inferolateral Q waves | 30 (37) | 14 (9) | <0.001 |
| LV strain/repolarization abnormalities | 37 (46) | 51 (34) | 0.087 |
| Echocardiography | |||
| Left atrial diameter, mm | 44 ± 8 | 43 ± 8 | 0.367 |
| Maximum LV wall thickness, mm | 18 ± 5 | 24 ± 6 | <0.001 |
| With LV wall thickness >30 mm | 6 (7) | 26 (17) | 0.028 |
| Maximal thickness site | |||
| Septum | 55 (69) | 141 (94) | <0.001 |
| Apex | 16 (20) | 7 (5) | <0.001 |
| Concentric | 9 (11) | 2 (1) | <0.001 |
| LV end-diastolic diameter, mm | 44 ± 7 | 45 ± 7 | 0.303 |
| LV end-systolic diameter, mm | 28 ± 7 | 27 ± 8 | 0.347 |
| LV ejection fraction, % | 65 ± 10 | 68 ± 12 | 0.057 |
| With LV ejection fraction <50% | 4 (5) | 8 (5) | 0.420 |
| LVOT gradient, mm Hg | 15 ± 24 | 24 ± 24 | 0.007 |
| LVOT obstruction | 15 (19) | 51 (34) | 0.015 |
| Moderate-to-severe mitral regurgitation | 5 (6) | 13 (9) | 0.309 |
| LV filling pattern | |||
| Normal | 24 (32) | 44 (35) | 0.459 |
| Impaired relaxation | 26 (35) | 43 (25) | 0.176 |
| Pseudonormalized | 18 (25) | 35 (28) | 0.380 |
| Restrictive | 6 (8) | 3 (2) | 0.064 |
| Triphasic LV filling | 21 (26) | 14 (11) | 0.002 |
| Lateral E′, cm/s | 8.1 ± 3.3 | 10.6 ± 3.6 | <0.001 |
| Cardiac magnetic resonance | |||
| Study performed | 47 (59) | 76 (51) | 0.268 |
| LV ejection fraction, % | 65 ± 11 | 71 ± 11 | 0.004 |
| LV mass index, g/m2 | 87 ± 27 | 99 ± 38 | 0.013 |
| LGE present | 40 (85) | 61 (80) | 0.630 |
| LGE extent, % of LV mass | 20 ± 11 | 16 ± 8 | 0.002 |
| LGE >30% of LV mass | 12 (27) | 8 (11) | 0.042 |
Values are n (%) or mean ± SD.
BP = blood pressure; ECG = electrocardiograph; HCM = hypertrophic cardiomyopathy; LGE = late gadolinium enhancement; LV = left ventricular; LVOT= left ventricular outflow tract; NYHA = New York Heart Association.