Table 4.
Studies of QRS-T angle reporting on associations with cardiovascular parameters and dialysis procedure.
| Study | Participants | Age (years) | IHD | Calculation of QRS-T angle | Findings |
|---|---|---|---|---|---|
| de Bie et al., 2013a | 101 prevalent Male 76% 66% HD, 44% Peritoneal Dialysis |
56.3 ± 17 | 30% | Inverse Dower matrix from standard 12 lead snapshot ECG. Measured as angle between mean QRS and T vectors. |
QRS-T angle associated with left ventricular ejection fraction, QRS duration and left ventricular systolic dyssynchrony. |
| Tereshchenko et al., 2016 | 358 incident HD Male 59% Black 73% |
55 ± 13 | 37% | Calculated from continuous unfiltered averaged xyz ECG signal. Measured as angle between spatial mean QRS vector and spatial peak T vector. |
QRS-T angle >75° associated with wider QRS and echocardiographic left ventricular hypertrophy defined as left ventricular mass index >51 g/m2.7 in men and >47 g/m2.7 in women. |
| Skampardoni et al., 2018a | 178 prevalent HD Male 72% Caucasian 80% South Asian 17% Black 3% |
67 ± 14 | 23.5% | Singular value decomposition to standard snapshot 12 lead ECG. Measured as total cosine R to T. |
QRS-T angle by TCRT correlated with left ventricular mass indexed for height in univariate and Global Longitudinal Strain in multivariate analysis. |
| Jaroszynski et al., 2009 | 57 prevalent Peritoneal Dialysis patients 49% male Caucasians |
47.7 ± 7.1 | Excluded | Inverse Dower matrix from standard 12 lead snapshot ECG. Measured as angular difference between maximum spatial QRS and T vectors. |
QRS-T angle associated with increased coronary artery calcium burden, atherosclerosis and troponin T elevation. |
| Jaroszynski et al., 2010 | 73 prevalent HD 52% male Caucasians |
51.5 ± 4.5 | Not reported | Inverse Dower matrix from standard 12 lead snapshot ECG. Measured as angular difference between maximum spatial QRS and T vectors. |
QRS-T angle associated with Troponin T. HD session resulted in increased QRS-T in 59 patients, decreased in 12 patients, and unchanged in 2 patients. |
| Poulikakos et al., 2013 | 72 (prevalent HD) Males 70% |
61 ± 15 | 21% | Singular value decomposition to overlapping 10 s segment 12 lead ECGs during continuous monitoring repeated 5 times every 2 weeks. Measured as total cosine R to T. |
Intra-subject reproducibility confirmed using analysis of variance. Variable effect of HD to TCRT Intradialytic QRS-T change correlated with PTH levels. |
ECG, electrocardiogram; HD, hemodialysis; IHD, Ischemic heart disease; TCRT, total Cosine R to T.