Table 3.
Electrocardiogram characteristics in the hypertrophic cardiomyopathy and control groups
| Patients with HCM (n = 773) | Controls (n = 3867) | Total (n = 4640) | P-value | |
|---|---|---|---|---|
| Normal ECG | 83 (10.7%) | 2203 (57%) | 2286 (49.3%) | <0.001 |
| Atrial fibrillation/flutter/tachycardia | 58 (7.5%) | 263 (6.8%) | 321 (6.9%) | 0.48 |
| Ventricular pacing | 6 (0.8%) | 104 (2.7%) | 110 (2.4%) | <0.001 |
| LBBB | 17 (2.2%) | 106 (2.7%) | 123 (2.7%) | 0.46 |
| RBBB | 41 (5.3%) | 128 (3.3%) | 169 (3.6%) | 0.011 |
| LVH criteria | 279 (36.1%) | 170 (4.4%) | 449 (9.7%) | <0.001 |
| T-wave inversions | 410 (53.0%) | 179 (4.6%) | 589 (12.7%) | <0.001 |
| Pathologic Q waves | 73 (9.4%) | 56 (1.4%) | 129 (2.8%) | <0.001 |
| Tracing artefact | 32 (4.1%) | 146 (3.8%) | 178 (3.8%) | 0.61 |
P-values result from a Wilcoxon rank-sum test (continuous variables) or Fisher’s exact test (categorical variables).
AF, atrial fibrillation; LBBB, left bundle branch block; RBBB, right bundle branch block; LVH, left ventricular hypertrophy.
Normal ECG: sinus rhythm, 50–110 b.p.m., normal intervals, sinus arrhythmia acceptable; bundle branch blocks: complete (QRS >120 ms); LVH per Sokolow–Lyon criteria: S-wave depth in V1 + tallest R-wave height in V5––V6 (whichever is larger) >35 mm; TWIs: inferior or lateral ≥0.1 mV in ≥2 contiguous leads (in those without BBB); pathologic Q waves: ≥1/3 of R-wave or ≥0.3 mV in ≥2 contiguous inferior or lateral leads; artefact: tracing distortion that could interfere with ECG interpretation in the reviewer’s opinion [high-frequency noise, baseline wander, disconnected lead(s), combinations].