Thirty suspected AHCM patients were identified, who showed TWI ≥ 0.05 mV on precordial ECG and 4 of them had GNT. The patients with typical AHCM all had TWI and 34% had GNT. None of the healthy and hypertensive control groups had TWI or GNT. None of the suspected AHCM patients had diameter stenosis ≥ 50% in coronary arteries by coronary angiography or computed tomography angiography. The maximal apical wall thickness of this group was 13.3 ± 1.2 mm, which was significantly higher than in normal controls (6.0 ± 0.6 mm, p < 0.001), but none of them exceed 15 mm. Nine suspected AHCM patients were symptomatic at the first presentation with mild symptoms of palpitations, dyspnea, dizziness, syncope, but without sustained symptomatic or ECG improvement to seek alternative diagnosis. The remaining 12 asymptomatic patients were present for further echocardiographic assessment because of incidental abnormal findings by ECG or routine echocardiography. Table 2 summarizes the general characteristics of the groups of the subjects in this study. Overall, there was no significant difference between patients with suspected AHCM and normal controls, except suspected AHCM patients had mildly reduced heart rate (63 ± 6 vs. 67 ± 9, p = 0.042) and significantly higher systolic pressure (134 ± 20 vs. 122 ± 11 mmHg, p = 0.004) which still lower than patients with essential hypertension (145 ± 20 vs. 134 ± 20 mmHg, p = 0.042). There was no significant difference in blood pressure between the suspected and typical AHCM patients.
Table 2
Baseline characteristics of patients and control subjects (suspected patients versus the other groups)
| Suspected patients (n = 30) | AHCM (n = 32) | P | Hypertension (n = 44) | P | Normal control (n = 43) | P |
Age | 59 ± 11 | 57 ± 14 | 0.687 | 59 ± 11 | 0.993 | 57 ± 7 | 0.553 |
Male n(%) | 17(80.9%) | 23(71.9%) | 0.671 | 39(88.6%) | 0.649 | 35(81.4%) | 1.000 |
Height(cm) | 166.5 ± 8.4 | 166.7 ± 7.7 | 0.952 | 167.0 ± 5.5 | 0.796 | 169.0 ± 5.0 | 0.206 |
Weight(kg) | 65.0 ± 10.0 | 69.3 ± 11.9 | 0.171 | 65.9 ± 9.7 | 0.730 | 63.6 ± 9.1 | 0.602 |
BSA(m2) | 1.8 ± 0.2 | 1.8 ± 0.2 | 0.293 | 1.8 ± 0.1 | 0.688 | 1.8 ± 0.1 | 0.990 |
SBP(mmHg) | 134 ± 20 | 138 ± 19 | 0.460 | 145 ± 20 | 0.042 | 122 ± 11 | 0.004 |
DBP(mmHg) | 75 ± 11 | 79 ± 12 | 0.267 | 80 ± 18 | 0.191 | 76 ± 9 | 0.745 |
HR(bpm) | 63 ± 6 | 68 ± 10 | 0.036 | 69 ± 9 | 0.002 | 67 ± 9 | 0.042 |
TWI n(%) | 30(100%) | 32(100%) | 0.111 | 0 | < 0.001 | 0 | < 0.001 |
GNT n(%) | 4(19%) | 11(34%) | < 0.001 | 0 | < 0.001 | 0 | < 0.001 |
AHCM: apical hypertrophic cardiomyopathy; BSA: body surface area; DBP: diastolic blood pressure; FR: heart rate; SBP: systolic blood pressure; TWI: T wave inversion; GNT: giant negative T wave |
Comparisons of conventional echocardiography between suspected AHCM patients and typical AHCM patients and normal/hypertensive controls (Table 3)
Table 3
Parameters of conventional echocardiography (suspected patients versus the other groups)
| Suspected patients (n = 30) | AHCM (n = 32) | P | Hypertension (n = 44) | P | Normal control (n = 43) | P |
IVST (mm) | 10.8 ± 2.4 | 12.2 ± 2.7 | 0.052 | 12.3 ± 1.8 | 0.014 | 7.8 ± 1.0 | < 0.001 |
LVPWT (mm) | 10.0 ± 1.7 | 10.1 ± 1.8 | 0.729 | 11.3 ± 1.8 | 0.004 | 8.1 ± 1.0 | < 0.001 |
LVEDV(ml) | 92.5 ± 21.5 | 87.0 ± 24.8 | 0.416 | 91.5 ± 22.2 | 0.862 | 102.8 ± 18.6 | 0.057 |
LVESV(ml) | 30.4 ± 11.7 | 33.9 ± 8.9 | 0.264 | 32.0 ± 9.0 | 0.570 | 40.3 ± 11.0 | 0.002 |
SV(ml) | 62.1 ± 16.9 | 55.9 ± 13.2 | 0.149 | 59.5 ± 15.4 | 0.551 | 62.5 ± 10.4 | 0.922 |
LVEF(%) | 67 ± 9 | 62 ± 6 | 0.024 | 65 ± 5 | 0.249 | 61 ± 5 | 0.002 |
LAV(ml) | 66.9 ± 25.5 | 76.9 ± 15.8 | 0.121 | 47.9 ± 14.0 | 0.004 | 43.4 ± 14.2 | 0.001 |
LAVI(ml/cm2) | 37.4 ± 14.3 | 43.6 ± 9.8 | 0.071 | 26.0 ± 7.3 | 0.002 | 23.71 ± 7.49 | < 0.001 |
A(m/s) | 0.69 ± 0.15 | 0.68 ± 0.16 | 0.935 | 0.83 ± 0.21 | 0.008 | 0.68 ± 0.13 | 0.839 |
E(m/s) | 0.73 ± 0.18 | 0.68 ± 0.19 | 0.391 | 0.69 ± 0.20 | 0.441 | 0.70 ± 0.16 | 0.496 |
E/A ratio | 1.06 ± 0.26 | 1.08 ± 0.56 | 0.896 | 0.87 ± 0.29 | 0.015 | 0.98 ± 0.35 | 0.401 |
e1 (lateral) (m/s) | 0.09 ± 0.03 | 0.08 ± 0.03 | 0.208 | 0.09 ± 0.03 | 0.914 | 0.11 ± 0.03 | 0.012 |
e2 (septal) (m/s) | 0.06 ± 0.02 | 0.05 ± 0.01 | 0.065 | 0.06 ± 0.02 | 0.130 | 0.08 ± 0.02 | < 0.001 |
E/e’ ratio | 11.0 ± 5.0 | 11.3 ± 3.7 | 0.109 | 9.6 ± 3.7 | 0.221 | 7.7 ± 2.0 | 0.007 |
e’: average of e1 and e2; e1(lateral): tissue Doppler early diastolic wave at basal ventricular septum; e2(septal): tissue Doppler early diastolic wave at basal LV lateral wall; IVST: interventricular septum thickness; LAV: left atrial volume; LAVI: left atrial volume index; LVDd: left ventricular end-diastolic dimension; LVDs: left ventricular end-systolic dimension; LVEDV: left ventricular end-diastolic volume; LVEF: left ventricular ejection fraction; LVESV: left ventricular end-systolic volume; LVPWT: left ventricular posterior wall thickness; A: pulse Doppler mitral valve A wave; E: pulse Doppler mitral valve E wave; SV: stroke volume |
The myocardium at LV basal was thicker in suspected AHCM patients than in normal controls. Compared to normal controls, suspected AHCM patients had normal LV size with significantly increased LVEF, E/e’ ratio and LA volume index.
In patients with typical AHCM, there was a similar LV basal wall thickness as suspected AHCM patients. There was no significant difference in LV diastolic performance between the two groups of AHCM patients. Compared to the suspected AHCM patients, hypertensive patients had significantly, thicker LV basal wall, comparable LVEF, and smaller LAVI.
Comparisons of apical morphological and dynamic characteristics between suspected AHCM patients and typical AHCM patients and normal/hypertensive controls (Table 4)
Table 4
The apical morphological and dynamic parameters measured by echocardiography (suspected patients versus the other groups)
| Suspected patients (n = 30) | AHCM (n = 32) | P | Hypertension (n = 44) | P | Normal control (n = 43) | P |
APWTmax | 13.3 ± 1.2 | 18.2 ± 1.7 | < 0.001 | 8.4 ± 1.3 | < 0.001 | 6.0 ± 0.6 | < 0.001 |
ABR | 1.37 ± 0.23 | 1.85 ± 0.42 | < 0.001 | 0.75 ± 0.11 | < 0.001 | 0.75 ± 0.08 | < 0.001 |
apA-d (°) | 85.9 ± 22.6 | 79.0 ± 12.2 | 0.107 | 96.7 ± 11.0 | 0.047 | 103.3 ± 6.2 | 0.002 |
apA-s (°) | 23.7 ± 21.3 | 16.9 ± 28.6 | 0.367 | 69.5 ± 14.1 | < 0.001 | 86.9 ± 9.0 | < 0.001 |
ΔapA (%) | 74 ± 23 | 80 ± 33 | 0.490 | 28 ± 13 | < 0.001 | 16 ± 8 | < 0.001 |
Cavity obliteration n(%) | 6(28.6%) | 21(65.6%) | < 0.001 | 0 | < 0.001 | 0 | < 0.001 |
Vap(m/s) | 0.49 ± 0.25 | 0.88 ± 0.50 | 0.001 | 0.32 ± 0.11 | 0.006 | 0.24 ± 0.06 | < 0.001 |
VLVOT(m/s) | 1.07 ± 0.22 | 1.17 ± 0.24 | 0.155 | 1.04 ± 0.16 | 0.502 | 0.91 ± 0.15 | 0.004 |
Vap/VLVOT ratio | 0.5 ± 0.3 | 0.8 ± 0.5 | 0.009 | 0.3 ± 0.1 | 0.017 | 0.3 ± 0.1 | 0.003 |
ABR: apical basal wall thickness ratio; apA-d: apical angle at end-diastole; apA-s: apical angle at end-systole; APWTmax: maximal apical wall thickness; TWI: T wave inversion; Vap: pulsed Doppler velocity at apex; VLVOT: pulsed Doppler velocity at left ventricular outflow tract |
Compared to normal controls, suspected AHCM patients had significantly higher ABR, lower apical angles and higher percentage change of the apical angle. The Doppler velocity at LV apex and velocity ratio were significantly higher in suspected AHCM compared to normal controls. There was no significant difference in apical angles or its percentage change during the cardiac cycle between patients with typical AHCM and patients with suspected AHCM. ABR was significantly higher in typical AHCM patients than in suspected AHCM patients. The Doppler velocity at LV apex and velocity ratio in patients with AHCM was significantly higher than in patients with suspected AHCM. Compared to patients with suspected AHCM, hypertensive patients had significantly wider apical angles, less dynamic change of the apical angle during cardiac cycle, and lower ABR and velocity ratio.
There was no significant difference between hypertension and healthy controls in the mean ABR (0.75 ± 0.11 vs 0.75 ± 0.08, P༞0.05) while the mean basal wall thickness was greater in hypertension than healthy control group (12.3 ± 1.8 mm vs 7.8 ± 1.0 mm, P < 0.001).