Table 3.
Characteristics of patients with hypertrophic cardiomyopathy according to electrocardiographic changes in response to vasodilator stress
| Characteristic | Vasodilator-induced ST-segment deviation groups (n=53) |
p Value | |||
|---|---|---|---|---|---|
| <0.1 mm (n=12) | 0.1 – 0.4 mm (n=14) | 0.5 – 0.9 mm (n=13) | ≥ 1.0 mm (n=14) | ||
| Echocardiography | |||||
| Maximal myocardial wall thickness (cm) | 2.28 ± 0.44 | 2.09 ± 0.56 | 1.97 ± 0.36 | 2.15 ± 0.57 | 0.5 |
| Left ventricular posterior wall (cm) | 1.18 ± 0.25 | 1.16 ± 0.28 | 1.17 ± .21 | 1.18 ± .22 | 0.9 |
| Resting outflow tract gradient (mm Hg) | 11 ± 9 | 21 ± 26 | 23 ± 18 | 38 ± 32 | 0.04 |
| Provoked outflow tract gradient (mm Hg) | 52 ± 50 | 43 ± 42 | 44 ± 27 | 88 ± 67 | 0.06 |
| Nonobstructive outflow tract gradients | 6 (50%) | 8 (57%) | 5 (38.5%) | 5 (36%) | |
| Obstructive outflow tract gradients | 1 (8%) | 3 (21.5%) | 3 (23%) | 7 (50%) | 0.2 |
| Latent outflow tract obstruction | 5 (42%) | 3 (21.5%) | 5 (38.5%) | 2 (14%) | |
| Baseline Electrocardiography | |||||
| Strain pattern and/or T wave inversion | 3 (25%) | 7 (50%) | 11 (85%) | 11 (79%) | 0.007 |
| Early-repolarization changes | 3 (25%) | 3 (21%) | 1 (8%) | 1 (7%) | 0.5 |
| Any ST-T abnormality | 6 (50%) | 10 (71%) | 12 (92%) | 12 (86%) | 0.07 |
| Left ventricular hypertrophy | 3 (25%) | 7 (50%) | 7 (54%) | 8 (57%) | 0.4 |
| Hemodynamics | |||||
| Resting heart rate (beat/minute) | 58 ± 10 | 66 ± 11 | 61 ± 8 | 67 ± 8 | 0.053 |
| Resting systolic blood pressure (mm Hg) | 139 ± 25 | 130 ± 18 | 133 ± 18 | 136 ± 19 | 0.7 |
| Rate pressure product (bpm*mm Hg) | 8106 ± 2368 | 8666 ± 1907 | 8123 ± 1507 | 9045 ± 1741 | 0.5 |
| Peak heart rate (beat/minute) | 84 ± 12 | 90 ± 9 | 85 ± 11 | 101 ± 16 | 0.002 |
| Heart rate difference (beat/minute) | 26 ± 10 | 24 ± 11 | 24 ± 7 | 35 ± 13 | 0.03 |
| Regadenoson as vasodilator stress agent | 9 (75%) | 6 (43%) | 5 (38.5%) | 7 (50%) | 0.3 |
| Vasodilator-induced chest pain | 0 | 1 (7%) | 0 | 4 (29%) | 0.03 |
| Stress Electrocardiography | |||||
| Mean II-III-aVF ST segment shift (mm) | −0.00 ± 0.03 | −0.18 ± 0.13 | −0.59 ± 0.20 | −1.05 ± 0.66 | <0.0001 |
| Mean V3–V5 ST segment shift (mm) | −0.00 ± 0.02 | −0.15 ± 0.15 | −0.63 ± 0.20 | −1.58 ± 0.63 | <0.0001 |
| Maximum ST segment shift (mm) | −0.01 ± 0.01 | −0.21 ± 0.12 | −0.68 ± 0.16 | −1.60 ± 0.62 | <0.0001 |
| Positron Emission Tomography | |||||
| Summed difference score (unitless) | 3.4 ± 3.2 | 7.6 ± 9.4 | 5.0 ± 3.1 | 7.4 ± 6.1 | 0.3 |
| Abnormal regional myocardial perfusion | 8 (67%) | 9 (64%) | 12 (92%) | 13 (93%) | 0.1 |
| Rest left ventricular ejection fraction (%) | 53 ± 8 | 59 ± 9 | 61 ± 8 | 62 ± 7 | 0.04 |
| Stress ejection fraction (%) | 48 ± 12 | 51 ± 13 | 44 ± 11 | 43 ± 11 | 0.3 |
| Ejection fraction reserve (%) | −5 ± 12 | −8 ± 11 | −17 ± 12 | −19 ± 13 | 0.01 |
| Negative LVEF reserve | 7 (58%) | 10 (71%) | 11 (85%) | 14 (100%) | 0.055 |
| Stress-induced wall motion abnormalities | 3 (25%) | 8 (57%) | 10 (77%) | 12 (86%) | 0.008 |
| Rest myocardial blood flow (ml/min/g) | 0.75 ± 0.14 | 0.95 ± 0.22 | 0.98 ± 0.24 | 0.95 ± 0.22 | 0.04 |
| Stress myocardial blood flow (ml/min/g) | 1.75 ± 0.41 | 1.81 ± 0.56 | 1.92 ± 0.44 | 1.88 ± 0.42 | 0.8 |
| Coronary flow reserve (unitless) | 2.37 ± 0.49 | 1.97 ± 0.60 | 2.04 ± 0.60 | 2.02 ± 0.44 | 0.2 |
| Corrected rest myocardial flow (ml/min/g) | 0.83 ± 0.22 | 0.96 ± 0.27 | 1.05 ± 0.28 | 0.91 ± 0.20 | 0.2 |
| Corrected coronary flow reserve | 2.22 ± 0.66 | 1.99 ± 0.75 | 1.95 ± 0.65 | 2.15 ± 0.60 | 0.7 |
Data are expressed as mean ± SD or as number (percentage)