Table 4.
Characteristics of the four HCM phenotypes from combined QRS and T wave clustering.
| Group 1A (n = 20) | Group 1B (n = 24) | Group 2 (n = 19) | Group 3 (n = 22) | p-value (group comparison) | |
|---|---|---|---|---|---|
| Age, years | 47 ± 12 | 48 ± 18 | 44 ± 12 | 43 ± 13 | 0.53 |
| Male | 15 (76) | 15 (63) | 12 (63) | 16 (73) | 0.78 |
| Body mass index, kg/m2 | 28 ± 6 | 26 ± 4 | 25 ± 4 | 25 ± 4 | 0.06 |
| HCM Risk-SCD score, % | 4.0 (2–11)a,b,c | 1.8 (1–4) | 2.1 (1–6) | 2.5 (1–9) | 0.0001 |
| CONVENTIONAL RISK FACTORS | |||||
| NSVT | 11 (55)* | 3 (13) | 4 (21) | 5 (23) | 0.016 |
| Syncope | 2 (10) | 4 (17) | 2 (10) | 2 (9) | 0.88 |
| Family History SCD | 5 (254) | 2 (8) | 5 (26) | 5 (23) | 0.36 |
| Abnormal exercise BPR | 2 (10) | 3 (12) | 0 | 2 (9) | 0.51 |
| Massive LVH ≥30mm | 0 | 0 | 0 | 1 (5) | - |
| Appropriate ICD shock | 1 | 0 | 0 | 0 | - |
| HYPERTROPHY | |||||
| LV mass index, g/m2 | 90 ± 27a,b | 62 ± 23 | 63 ± 17 | 73 ± 26 | 0.0003 |
| Max LV wall, mm | 22 ± 4a | 16 ± 5 | 19 ± 5 | 21 ± 6 | 0.002 |
| Hypertrophy morphology | 1 × 10−7 | ||||
| No LVH (G+LVH-) | 0 | 8 (33)* | 1 (5) | 0 | |
| Septal LVH | 7 (35)* | 15 (63) | 16 (85) | 20 (90) | |
| Apical LVH | 2 (10) | 0 | 1 (5) | 1 (5) | |
| Mixed septal & apical LVH | 11 (52)* | 1 (4) | 1 (5) | 1 (5) | |
| OTHER CLINICAL FEATURES | |||||
| LV EDV, ml | 150 ± 26 | 154 ± 31 | 155 ± 33 | 156 ± 41 | 0.94 |
| LV ESV, ml | 35 ± 10 | 43 ± 15 | 43 ± 14 | 41 ± 21 | 0.26 |
| LV ejection fraction, % | 76 ± 7 | 72 ± 8 | 72 ± 8 | 74 ± 7 | 0.28 |
| Left atrial diameter, mm | 41 ± 5 | 39 ± 8 | 37 ± 6 | 38 ± 8 | 0.25 |
| LVOT gradient, mmHg | 6.5 (5–110) | 7.2 (4–111) | 6.7 (2–110) | 6.8 (3–92) | 0.81 |
| GENOTYPE | |||||
| Gene positive | 9 (45) | 19 (79) | 13 (68) | 17 (77) | 0.08 |
| ECG FEATURES | |||||
| Heart rate, bpm | 58 ± 10 | 58 ± 8 | 59 ± 13 | 58 ± 10 | 0.66 |
| QRS axis, ° | 14 ± 30c | 44 ± 29e | 29 ± 34f | −37 ± 28 | 8 × 10−13 |
| QRS duration, ms | 94 ± 8 | 100 ± 21 | 96 ± 16 | 102 ± 13 | 0.23 |
| QRS amplitude, mV | 2006 ± 780 | 1762 ± 621 | 1807 ± 588 | 1737 ± 613 | 0.70 |
| QRS ascending slope | 93 ± 36 | 95 ± 33 | 92 ± 34 | 76 ± 23 | 0.19 |
| QRS descending slope | −160 ± 60 | −139 ± 56 | −155 ± 60 | −149 ± 56 | 0.47 |
| Pathological Q waves | 3 (14) | 0† | 8 (38) | 9 (43) | 0.0003 |
| T wave axis, ° | 156 ± 45a,b,c | 42 ± 27 | 49 ± 47 | 68 ± 41 | 2 × 10−11 |
| Abnormal T axis | 17 (81)† | 0† | 6 (33) | 5 (25) | 7 × 10−8 |
| T amplitude, mV | −135 ± 202a,b,c | 308 ± 144 | 219 ± 209 | 257 ± 214 | 9 × 10−8 |
| T wave inversion | 21 (100)† | 0 | 4 (21) | 1 (5) | 8 × 10−17 |
| Giant T wave inversion | 5 (24)† | 0 | 1 (5) | 0 | 0.003 |
| T peak to T end, ms | 91 ± 17 | 80 ± 20 | 86 ± 16 | 84 ± 19 | 0.19 |
| ST segment displacement*, mV | −13 ± 51a,b,c | 32 ± 33 | 38 ± 51 | 48 ± 38 | 0.0001 |
| QTc interval, ms | 452 ± 22 | 435 ± 26 | 429 ± 26 | 443 ± 29 | 0.05 |
| JTc interval, ms | 359 ± 47 | 349 ± 87 | 342 ± 97 | 366 ± 145 | 0.42 |
Mean ± standard deviation, median (range) or number of patients (%). HCM, hypertrophic cardiomyopathy; SCD, sudden cardiac death; NSVT, non-sustained ventricular tachycardia; BPR, blood pressure response; LVH, left ventricular hypertrophy; LV, left ventricular; G+LVH-, genotype positive HCM with normal wall thickness; EDV, end-diastolic volume; ESV, end-systolic volume; LVOT, left ventricular outflow tract.
Group 1A vs. 1B,
1A vs. 2,
1A vs. 3,
1B vs. 2,
1B vs. 3,
2 vs. 3, p < 0.05 on post-hoc pairwise comparisons (p-values multiplied by 6 for Bonferroni adjustment of 6 tests).
p < 0.05 on post-hoc contingency table analysis (p-values multiplied by 16 and 8 for Bonferroni adjustment of 4 × 4 and 4 × 2 combinations, respectively). Bold values mean p-value significant (p < 0.05).