Table 2.
Comparison of participants in NYHA class I and II at baseline
| NYHA class I (N=198) | NYHA class II (N=14) | P Value | |
|---|---|---|---|
| Age, years | 21.3 (9.1) | 34.7 (10.0) | <0.001 |
| Female gender (%) | 83 (42) | 3 (21) | 0.13 |
| Race (%) | 1.000 | ||
| White | 189 (95) | 14 (100) | |
| Black | 3 (1) | 0 (0) | |
| Other | 6 (3) | 0 (0) | |
| Sarcomeric Gene (%) | 0.02 | ||
| ACTC | 3 (1.5) | 0 (0) | |
| MYBPC3* | 106 (53.5) | 2 (14.3) | |
| MYH7 | 64 (32.3) | 10 (71.4) | |
| MYL2 | 1 (0.5) | 1 (7.1) | |
| MYL3 | 5 (2.5) | 0 (0) | |
| TNNI3 | 7 (3.5) | 0 (0) | |
| TNNT2 | 7 (3.5) | 1 (7.1) | |
| TPM1 | 5 (2.5) | 0 (0) | |
| Echocardiographic findings | |||
| Average e’, cm/s | 12 (3) | 7 (3) | <0.001 |
| E/e’ average | 7 (2) | 11 (4) | 0.004 |
| Peak left ventricular outflow tract gradient at rest, mmHg | 7 (3) | 9 (3) | 0.472 |
| Peak left ventricular outflow tract gradient during Valsalva maneuver, mmHg | 7 (4) | 10 (6) | 0.126 |
| Cardiopulmonary exercise test | |||
| Peak VO2, ml/kg/min | 33 (9) | 26 (6) | 0.022 |
| % predicted maximal VO2 | 82 (20) | 73 (19) | 0.308 |
| CMR findings | |||
| LGE Present (%) | 23 (13) | 6 (55) | <0.001 |
| LGE mass, g | 15 (12) | 40 (30) | 0.004 |
| LGE mass, % of LV | 10 (8) | 26 (21) | 0.009 |
| LV mass, g | 114 (41) | 159 (46) | <0.001 |
| LV mass indexed to BSA, g/m2 | 62 (17) | 77 (19) | 0.005 |
| Max LV wall thickness, mm** | 11 (3) | 16 (4) | <0.001 |
| LA volume diastolic, ml | 28 (19) | 44 (19) | 0.010 |
Results are presented as % or as mean (SD). CMR indicates, cardiac magnetic resonance imaging; E, peak early mitral inflow velocity; e’, peak early mitral annular relaxation velocity; LA, left atrial; LGE, late gadolinium enhancement; LV, left ventricular; NYHA, New York Heart Association Class; VO2, peak oxygen uptake; ACTC, Alpha cardiac actin gene; MYBPC3, Cardiac myosin binding protein C gene; MYH7, Cardiac β-myosin heavy chain gene; MYL2, Myosin light chain 2 gene; MYL3, Myosin light chain 3 gene; TNNI3, Cardiac troponin I gene; TNNT2, Cardiac troponin T gene; TPM1, Tropomyosin 1 gene. Difference between groups assessed by Chi-Square or Fisher’s exact test or two-sample t test depending on number and type of variable.
5 Class I patients with MYBPC3 mutation also have MYH7 (n=4) or TNNT2 (n=1).
The maximum LV wall thickness from CMR is the maximum value across the 16 American Heart Association segments. Between group differences were assessed using ANOVA, Chi-square test or Fisher’s exact test depending on type of variable and expected frequency.