Table 1.
ECG Abnormalities in Those Without Risk Factors in Early Stage HD
| ECG abnormality | Age ranges separated by disease stage | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| All age ranges, n (%) | 20‐39 years, n (%) | 40‐59 years, n (%) | ≥60 years, n (%) | |||||||||
| Total (n = 590) | Stage 1 (n = 271) | Stage 2 (n = 319) | Total (n = 105) | Stage 1 (n = 53) | Stage 2 (n = 52) | Total (n = 346) | Stage 1 (n = 151) | Stage 2 (n = 195) | Total (n = 139) | Stage 1 (n = 67) | Stage 2 (n = 72) | |
| Unexplained abnormal ECGs | 231 (39.2) | 105 (38.7) | 126 (39.5) | 29 (27.6) | 11 (20.8) | 18 (34.6) | 136 (39.3) | 64 (42.4) | 72 (36.9) | 66 (47.5) | 30 (44.8) | 36 (50.0) |
| Unexplained abnormal ECGs (not including bradycardia with HR ≥50) | 139 (23.6) | 61 (22.5) | 78 (24.5) | 16 (15.2) | 5 (9.4) | 11 (21.2) | 79 (22.8) | 36 (23.8) | 43 (22.1) | 44 (31.7) | 20 (29.9) | 24 (33.3) |
| Brady‐arrhythmia: expressed as % of pool without individual risk factors a | (n = 502) | (n = 233) | (n = 269) | (n = 97) | (n = 48) | (n = 49) | (n = 303) | (n = 137) | (n = 166) | (n = 101) | (n = 48) | (n = 53) |
| Bradycardia (HR<60) | 142 (28.3) | 68 (25.1) | 74 (29.2) | 20 (20.6) | 10 (20.8) | 10 (20.4) | 84 (27.7) | 40 (29.2) | 44 (26.5) | 38 (37.6) | 18 (37.5) | 20 (37.7) |
| Marked bradycardia (HR<50) | 29 (5.8) | 16 (6.7) | 13 (4.8) | 6 (6.2) | 4 (8.3) | 2 (4.1) | 17 (5.6) | 8 (5.8) | 10 (6.0) | 6 (5.9) | 4 (8.3) | 2 (3.8) |
| Ectopy: expressed as % of pool with or without individual risk factors b | (n = 553) | (n = 254) | (n = 299) | (n = 101) | (n = 51) | (n = 50) | (n = 331) | (n = 147) | (n = 184) | (n = 121) | (n = 56) | (n = 65) |
| Ectopy (atrial and ventricular) | 22 (4.0) | 10 (3.9) | 12 (4.0) | 3 (3.0) | 0 (0) | 3 (6.0) | 8 (2.4) | 3 (3.1) | 5 (2.7) | 11 (9.1) | 7 (12.5) | 4 (6.2) |
| PVCs | 11 (2.0) | 7 (2.8) | 4 (1.3) | 1 (1.0) | 0 (0) | 1 (2.0) | 4 (1.2) | 2 (1.4) | 2 (1.1) | 6 (5.0) | 5 (8.9) | 1 (1.5) |
| Bigeminy | 1 (0.2) | 1 (0.4) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 1 (0.3) | 1 (0.7) | 0 (0) | 0 (0) | 0 (0) | 0 (0) |
| Conduction abnormalities | ||||||||||||
| AV block: expressed as % of pool without individual risk factors c | (n = 543) | (n = 250) | (n = 293) | (n = 103) | (n = 51) | (n = 52) | (n = 327) | (n = 147) | (n = 180) | (n = 113) | (n = 52) | (n = 61) |
| All AV block | 23 (4.2) | 12 (4.8) | 11 (3.8) | 0 (0) | 0 (0) | 0 (0) | 12 (3.7) | 7 (4.8) | 5 (2.8) | 11 (9.7) | 5 (9.6) | 6 (9.8) |
| 1st degree AV block | 22 (4.1) | 12 (4.8) | 10 (3.1) | 0 (0) | 0 (0) | 0 (0) | 11 (3.4) | 7 (4.8) | 4 (2.1) | 11 (9.7) | 5 (9.6) | 6 (9.8) |
| Mobitz 2 Wenckebach | 1 (0.2) | 0 (0) | 1 (0.3) | 0 (0) | 0 (0) | 0 (0) | 1 (0.3) | 0 (0) | 1 (0.6) | 0 (0) | 0 (0) | 0 (0) |
| Infra‐Hisian block: expressed as % of pool without individual risk factors d | (n = 555) | (n = 261) | (n = 294) | (n = 103) | (n = 53) | (n = 50) | (n = 330) | (n = 150) | (n = 180) | (n = 122) | (n = 58) | (n = 64) |
| Prolonged QRS (≥110ms) | 27 (4.9) | 9 (3.4) | 18 (6.1) | 1 (1.0) | 0 (0) | 1 (2.0) | 17 (5.2) | 7 (4.7) | 10 (5.6) | 9 (7.4) | 2 (3.4) | 7 (10.9) |
| IVCD | 19 (3.4) | 7 (2.7) | 12 (4.1) | 0 (0) | 0 (0) | 0 (0) | 15 (4.5) | 5 (3.3) | 10 (5.6) | 4 (3.3) | 2 (3.4) | 2 (3.1) |
| RBBB | 7 (1.3) | 2 (0.8) | 5 (1.7) | 1 (1.0) | 0 (0) | 1 (2.0) | 2 (0.6) | 2 (1.3) | 0 (0) | 4 (3.3) | 0 (0) | 4 (6.3) |
| LBBB | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) |
| Other: Wolff‐Parkinson‐White | 1 (0.2) | 0 (0) | 1 (0.3) | 1 (1.0) | 0 (0) | 1 (2.0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) |
| QT prolongation: expressed as % of pool without individual risk factors e | (n = 294) | (n = 160) | (n = 134) | (n = 57) | (n = 31) | (n = 26) | (n = 171) | (n = 90) | (n = 81) | (n = 66) | (n = 39) | (n = 27) |
| QT prolongation | 11 (3.7) | 4 (2.5) | 7 (5.2) | 2 (3.5) | 0 (0) | 2 (7.7) | 7 (4.1) | 3 (3.3) | 4 (4.9) | 2 (3.0) | 1 (2.6) | 1 (3.7) |
| Cardiac axis abnormalities and fascicular block: expressed as % of pool without individual risk factors f | (n = 541) | (n = 249) | (n = 292) | (n = 105) | (n = 52) | (n = 50) | (n = 322) | (n = 141) | (n = 181) | (n = 117) | (n = 56) | (n = 61) |
| Left axis deviation | 20 (3.7) | 8 (3.2) | 12 (4.1) | 0 (0) | 0 (0) | 0 (0) | 8 (2.5) | 3 (2.1) | 5 (2.8) | 12 (10.3) | 5 (8.9) | 7 (11.5) |
| Left anterior fascicular block | 15 (2.8) | 6 (2.4) | 9 (3.1) | 0 (0) | 0 (0) | 0 (0) | 6 (1.9) | 3 (2.1) | 3 (1.7) | 9 (7.7) | 3 (5.4) | 6 (9.8) |
| Unexplained Ischemic changes (ST, T other changes): expressed as % of pool without individual risk factors g | (n = 569) | (n = 262) | (n = 307) | (n = 104) | (n = 53) | (n = 51) | (n = 341) | (n = 151) | (n = 190) | (n = 124) | (n = 58) | (n = 66) |
| Total ischemic changes | 27 (4.7) | 14 (5.3) | 13 (4.2) | 3 (2.9) | 1 (1.9) | 2 (3.9) | 17 (5.0) | 9 (6.0) | 8 (4.2) | 7 (5.6) | 4 (6.9) | 3 (4.5) |
| Q waves | 3 (0.5) | 2 (0.8) | 1 (0.3) | 0 (0) | 0 (0) | 0 (0) | 2 (0.6) | 1 (0.7) | 1 (0.5) | 1 (0.8) | 0 (0) | 1 (1.5) |
| ST changes | 10 (1.8) | 4 (1.5) | 7 (2.3) | 2 (1.9) | 0 (0) | 2 (3.9) | 6 (1.8) | 3 (2.0) | 3 (1.6) | 2 (1.6) | 1 (1.7) | 1 (1.5) |
| T wave changes (T wave inversion) | 19 (3.5) | 11 (4.2) | 9 (2.9) | 3 (2.9) | 1 (1.9) | 2 (3.9) | 13 (3.8) | 8 (5.3) | 5 (2.6) | 4 (3.2) | 2 (3.4) | 2 (3.0) |
| Poor R wave progression | 2 (0.4) | 1 (0.4) | 1 (0.3) | 0 (0) | 0 (0) | 0 (0) | 1 (0.3) | 0 (0) | 1 (0.5) | 1 (0.8) | 1 (1.7) | 0 (0) |
| Left ventricular hypertrophy: expressed as % of pool without individual risk factors h | 465 | 212 | 253 | 94 | 45 | 49 | 287 | 126 | 161 | 84 | 41 | 43 |
| LVH | 2 (0.4) | 0 (0) | 2 (0.8) | 1 (1.1) | 0 (0) | 1 (2.0) | 1 (0.3) | 0 (0) | 1 (0.6) | 0 (0) | 0 (0) | 0 (0) |
Abbreviations: AV, atrioventricular); CAD, coronary artery disease; HR, heart rate; IVCD, intraventricular conduction delay; LVH, left ventricular hypertrophy; PVCs, premature ventricular contractions; RBBB, right bundle branch block; TdP, torsades de pointes.
aBradyarrhythmias unexplained by SA nodal blocking drugs, hypothyroidism, CAD, or hypertensive heart disease (defined as LVH/CAD/CHF).
bEctopy unexplained by CAD, hyperthyroidism or stimulants.
cAV block unexplained by CAD or AV nodal blocking drugs.
dInfra‐Hisian block unexplained by QRS prolonging drugs or CAD.
eQT prolongation unexplained by QT prolonging drugs with a known or possible risk of TdP or cardiac disease.
fCardiac axis abnormalities and fascicular block unexplained by CAD, hypertensive heart disease or obstructive sleep apnea.
gIschemic changes unexplained by CAD, digoxin therapy or hypertensive heart disease.
hLeft ventricular hypertrophy unexplained by hypertension.