The assessment of P-wave dispersion and myocardial repolarization parameters in patients with chronic kidney disease

P-wave durations from automated electrocardiogram analysis to predict atrial fibrillation and mortality in heart failure

BACKGROUND

P-wave indices have been used to predict incident atrial fibrillation (AF), stroke, and mortality. However, such indices derived from automated ECG measurements have not been explored for their predictive values in heart failure (HF). We investigated whether automated P-wave indices can predict adverse outcomes in HF.

METHODS

This study included consecutive Chinese patients admitted to a single tertiary centre, presenting with HF but without prior AF, and with at least one baseline ECG, between 1 January 2010 and 31 December 2016, with last follow-up of 31 December 2019.

RESULTS

A total of 2718 patients were included [median age: 77.4, interquartile range (IQR): (66.9-84.3) years; 47.9 males]. After a median follow-up of 4.8 years (IQR: 1.9-9.0 years), 1150 patients developed AF (8.8/year), 339 developed stroke (2.6/year), 563 developed cardiovascular mortality (4.3/year), and 1972 had all-cause mortality (15.1/year). Compared with 101-120 ms as a reference, maximum P-wave durations predicted new-onset AF at ≤90 ms [HR: 1.17(1.11, 1.50), P < 0.01], 131-140 ms [HR: 1.29(1.09, 1.54), P < 0.001], and ≥141 ms [HR: 1.52(1.32, 1.75), P < 0.001]. Similarly, they predicted cardiovascular mortality at ≤90 ms [HR: 1.50(1.08, 2.06), P < 0.001] or ≥141 ms [HR: 1.18(1.15, 1.45), P < 0.001], and all-cause mortality at ≤90 ms [HR: 1.26(1.04, 1.51), P < 0.001], 131-140 ms [HR: 1.15(1.01, 1.32), P < 0.01], and ≥141 ms [HR: 1.31(1.18, 1.46), P < 0.001]. These remained significant after adjusting for significant demographics, past co-morbidities, P-wave dispersion, and maximum P-wave amplitude.

CONCLUSIONS

Extreme values of maximum P-wave durations (≤90 ms and ≥141 ms) were significant predictors of new-onset AF, cardiovascular mortality, and all-cause mortality.

Electrocardiographic substrates of arrhythmias in patients with end-stage and chronic kidney diseases: a case-control study

BACKGROUND

Cardiovascular disease (CVD) is the most common cause of death in patients with renal diseases. Cardiac arrhythmia and sudden cardiac death are particularly important, and the burden is higher in patients on hemodialysis. The aim of this study is to compare specific ECG changes as markers of arrhythmias in patients with CKD and patients with end-stage renal disease (ESRD); all without clinically manifest heart disease, with normal control subjects.

RESULTS

Seventy-five ESRD patients on regular hemodialysis, 75 patients with stage 3-5 CKD and 40 healthy control subjects were included. All candidates were subjected to thorough clinical evaluation and laboratory tests including serum creatinine, glomerular filtration rate calculation, serum potassium, magnesium, calcium, phosphorus, iron, parathyroid hormone, and total iron binding capacity (TIBC). Resting twelve-lead ECG was done to calculate P wave dispersion (P-WD), corrected QT interval, QTc dispersion, Tpeak-Tend interval (Tp-e), and Tp-e/QT. Patients with ESRD had a significantly higher QTc dispersion (p < 0.001) and P-WD (p = 0.001) when compared to the other 2 groups. In the ESRD group, males had a significantly higher P-WD (p = 0.045), insignificantly higher QTc dispersion (p = 0.445), and insignificantly lower Tp-e/QT ratio (p = 0.252) as compared to females. Multivariate linear regression analysis for ESRD patients showed that serum creatinine (β = 0.279, p = 0.012) and transferrin saturation (β =  - 0.333, p = 0.003) were independent predictors of increased QTc dispersion while ejection fraction (β = 0.320, p = 0.002), hypertension (β =  - 0.319, p = 0.002), hemoglobin level (β =  - 0.345, p = 0.001), male gender (β =  - 0.274, p = 0.009) and TIBC (β =  - 0.220, p = 0.030) were independent predictors of increased P wave dispersion. In the CKD group, TIBC (β =  - 0.285, p = 0.013) was an independent predictor of QTc dispersion while serum calcium (β = 0.320, p = 0.002) and male gender (β =  - 0.274, p = 0.009) were independent predictors of Tp-e/QT ratio.

CONCLUSIONS

Patients with stage 3-5 CKD and those with ESRD on regular hemodialysis exhibit significant ECG changes that are considered substrates for ventricular as well as supraventricular arrhythmias. Those changes were more evident in patients on hemodialysis.

Effect of dialysis and transplantation on myocardial repolarization parameters and P-wave dispersion in chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) patients are at higher risk for cardiac arrhythmias. The risk of arrhythmia may change with different treatment modalities. We proposed to compare the effects of varied therapy methods on myocardial repolarization parameters (Tp-e, QT, QTc intervals, Tp-e/QT, Tp-e/QTc ratios) and P-wave dispersion (PWD) in patients with CKD.

METHODS

Three groups were formed from the patients aged between 18 and 65 years, as Group 1 consisting of CKD patients receiving hemodialysis (HD) three times a week, Group 2 consisting of predialysis CKD patients and Group 3 consisting of CKD patients who underwent successful transplantation. All patients' basic demographic data, risk factors, and echocardiographic parameters were recorded, and electrocardiographic repolarization parameters and PWD were analyzed.

RESULTS

The PR, QT, and QTc intervals were significantly shorter in the transplantation group compared to the other groups (P = .020, P < .001, P = .035; respectively). Tp-e interval, Tp-e/QT, and Tp-e/QTc ratios were significantly higher in the predialysis group compared to the other groups (P < .001, P < .001, P = .001; respectively), while there was no significant variation between the HD and transplantation groups (P > .05). PWD was significantly increased in the predialysis group compared to other two groups (P < .001), while no significant variation between the HD and transplantation groups was observed.

CONCLUSION

We found that the Tp-e interval, Tp-e/QT, Tp-e/QTc, and PWD were significantly higher in the predialysis CKD group, but the PR, QT, and QTc intervals were significantly shorter in the transplantation group compared to the other groups. The prognostic significance and prediction of these parameters in arrhythmic events in CKD patients requires further evaluation with long-time follow-up.