Table 2. Cardiac characteristics of patients with IIMs.
| Clinical parameters | Total (N=62) | With myocarditis (N=31) | Without myocarditis (N=31) | P value |
|---|---|---|---|---|
| Onset with cardiac symptoms, n (%) | 15 (24.2) | 15 (48.4) | 0 | <0.001 |
| Hypertension, n (%) | 11 (17.7) | 5 (16.1) | 6 (19.4) | 1.000 |
| Atherosclerosis, n (%) | 3 (3.8) | 3 (9.7) | 0 | 0.238 |
| Diabetes, n (%) | 5 (8.1) | 1 (3.2) | 4 (12.9) | 0.354 |
| BMI (mean ± SD, µg/L) | 22.2±4.2 | 20.9±3.3 | 23.3±4.7 | 0.080 |
| Hyperlipidemia, n (%) | 4 (6.5) | 3 (9.7) | 1 (3.2) | 0.612 |
| Creatine kinase-isozyme, M (QR), µg/L | 23.5 (3.5–87.3) | 33.0 (8.6–90.6) | 4.8 (1.7–58.8) | 0.053 |
| Troponin I, M (QR), ng/L | 130.0 (9.0–525.0) | 423.0 (173.5–2,581.5) | 4.0 (0–41.5) | <0.001 |
| NT-proBNP, M (QR), pg/L | 731.5 (83.5–2,749.8) | 2028.0 (1,059.5–4,518.5) | 82.0 (47.5–266.0) | <0.001 |
| Electrocardiographic and holter markers | ||||
| Heart rate (mean ± SD, bpm) | 82.9±17.8 | 82.8±20.0 | 83.0±15.5 | 0.971 |
| Duration of QRS wave (mean ± SD, ms) | 99.3±18.5 | 108.3±21.6 | 91.2±9.9 | <0.001 |
| Atrial arrhythmia1, n (%) | 16 (25.8) | 16 (53.3) | 0 | <0.001 |
| Ventricular arrhythmia2, n (%) | 24 (38.7) | 23 (76.7) | 1 (3.2) | <0.001 |
| Left axis deviation, n (%) | 35 (56.5) | 21 (67.7) | 14 (45.2) | 0.071 |
| Low-voltage of the limb leads, n (%) | 15 (24.2) | 13 (43.3) | 2 (6.5) | 0.001 |
| Poor R wave progression on V1–V6, n (%) | 22 (35.5) | 20 (64.5) | 2 (6.5) | <0.001 |
| Abnormal Q wave, n (%) | 23 (37.1) | 23 (74.2) | 0 | <0.001 |
| Conduction block on the left side, n (%) | 19 (30.6) | 19 (63.3) | 0 | <0.001 |
| Left bundle branch block, n (%) | 2 (3.2) | 2 (6.5) | 0 | 0.238 |
| LAFB, n (%) | 16 (25.8) | 16 (51.6) | 0 | <0.001 |
| Intraventricular block, n (%) | 1 (1.6) | 1 (3.3) | 0 | 0.492 |
| Echocardiographic characteristics | ||||
| LVEDD (mean ± SD, mm) | 49.2±7.4 | 52.7±8.4 | 45.6±3.8 | <0.001 |
| LVESD (mean ± SD, mm) | 34.3±10.0 | 41.1±10.1 | 27.7±3.0 | <0.001 |
| FS (mean ± SD, %) | 31.2±10.8 | 22.7±8.9 | 39.4±3.9 | <0.001 |
| LVEF (mean ± SD, %) | 56.3±17.5 | 42.8±14.8 | 69.9±4.7 | <0.001 |
| LVEF <40%, n (%) | 14 (23.3) | 14 (45.2) | 0 | <0.001 |
| LVEF 40–50%, n (%) | 9 (14.5) | 9 (29.0) | 0 | <0.001 |
| LVEF >50%, n (%) | 39 (62.9) | 8 (25.8) | 31 (100.0) | <0.001 |
| Left ventricular enlargement, n (%) | 20/29 (69.0) | 15 (48.4) | 0 | <0.001 |
| Left atrial enlargement, n (%) | 26 (41.9) | 22 (71.0) | 4 (12.9) | <0.001 |
| Segmental abnormality of LVWM, n (%) | 8 (12.9) | 8 (25.8) | 0 | <0.001 |
| Diffuse abnormality of LVWM, n (%) | 15 (24.2) | 15 (48.4) | 0 | <0.001 |
| Left ventricular diastolic dysfunction | 26 (41.9) | 15 (48.4) | 11 (35.5) | 0.306 |
| Normal, n (%) | 35 (56.5) | 15 (48.4) | 20 (64.5) | 0.199 |
| Degree 1, n (%) | 12 (19.4) | 2 (6.5) | 10 (32.3) | 0.022 |
| Degree 2, n (%) | 5 (8.1) | 4 (12.9) | 1 (3.2) | 0.354 |
| Degree 3, n (%) | 9 (14.5) | 9 (29.0) | 0 | 0.002 |
| Right ventricular enlargement, n (%) | 15 (24.2) | 15 (48.4) | 0 | <0.001 |
| Right atrial enlargement, n (%) | 18 (29.0) | 18 (58.1) | 0 | <0.001 |
| Right ventricular systolic dysfunction3, n (%) | 16 (25.8) | 16 (51.6) | 0 | <0.001 |
| Tricuspid regurgitation (mean ± SD, m/s) | 2.6±0.5 | 2.7±0.5 | 2.4±0.3 | 0.003 |
| SPAP (mean ± SD, mmHg) | 32.6±12.4 | 38.6±13.8 | 26.7±6.8 | <0.001 |
| Pericardial effusion, n (%) | 19 (30.6) | 12 (38.7) | 7 (22.6) | 0.167 |
1, including atrial tachycardia, atrial fibrillation and atrial flutter; 2, including frequent premature ventricular complexes, non-sustained ventricular tachycardia, sustained ventricular tachycardia, torsades de pointes, ventricular flutter and ventricular fibrillation; 3, defined as tricuspid annular plane systolic excursion less than 16 mini-meters. Values are compared between myocarditis related to IIMs and controls, using independent sample t-test, Mann-Whitney U or Fisher’s exact test, as appropriate. IIM, idiopathic inflammatory myopathy; BMI, body mass index; SD, standard deviation; NT-proBNP, N-terminal of prohormone brain natriuretic peptide; LAFB, left anterior fascicular block; LVEDD, left ventricular end-diastolic dimension; LVESD, left ventricular end-systolic dimension; FS, left ventricular fractional shortening; LVEF, left ventricular ejection factor; LVWM, left ventricular wall motion; SPAP, pulmonary arterial systolic pressure.