Electrophysiologic Substrate and Risk of Mortality in Incident Hemodialysis

Abstract

The single leading cause of mortality on hemodialysis is sudden cardiac death. Whether measures of electrophysiologic substrate independently associate with mortality is unknown. We examined measures of electrophysiologic substrate in a prospective cohort of 571 patients on incident hemodialysis enrolled in the Predictors of Arrhythmic and Cardiovascular Risk in End Stage Renal Disease Study. A total of 358 participants completed both baseline 5-minute and 12-lead electrocardiogram recordings on a nondialysis day. Measures of electrophysiologic substrate included ventricular late potentials by the signal-averaged electrocardiogram and spatial mean QRS-T angle measured on the averaged beat recorded within a median of 106 days (interquartile range, 78-151 days) from dialysis initiation. The cohort was 59% men, and 73% were black, with a mean±SD age of 55±13 years. Transthoracic echocardiography revealed a mean±SD ejection fraction of 65.5%±12.0% and a mean±SD left ventricular mass index of 66.6±22.3 g/m During 864.6 person-years of follow-up, 77 patients died; 35 died from cardiovascular causes, of which 15 were sudden cardiac deaths. By Cox regression analysis, QRS-T angle ≥75° significantly associated with increased risk of cardiovascular mortality (hazard ratio, 2.99; 95% confidence interval, 1.31 to 6.82) and sudden cardiac death (hazard ratio, 4.52; 95% confidence interval, 1.17 to 17.40) after multivariable adjustment for demographic, cardiovascular, and dialysis factors. Abnormal signal-averaged electrocardiogram measures did not associate with mortality. In conclusion, spatial QRS-T angle but not abnormal signal-averaged electrocardiogram significantly associates with cardiovascular mortality and sudden cardiac death independent of traditional risk factors in patients starting hemodialysis.

Global electrical heterogeneity: A review of the spatial ventricular gradient

“…Unlike the SVG, QRS-T angle (also reflected in a parameter known as the total cosine of the R-to-T), has been evaluated in numerous risk stratification studies. Increased QRS-T angle has been associated with total mortality and arrhythmic events in patients after myocardial infarction [34], total mortality, cardiovascular mortality, and sudden cardiac death in patients with end-stage renal disease on dialysis [35,36], more frequent appropriate implantable cardioverter-defibrillator therapies [37], and sudden cardiac death in the general population [29,38,39]. …”

Electrocardiographic predictors of mortality and sudden cardiac death in patients with end stage renal disease on hemodialysis

“…Recently, the spatial QRS-T angle was assessed in a prospsective cohort of 358 hemodialysis patients (mean age 55 years, 59% male, 37% with CAD, 75% with LVH, and mean LVEF 66%), and after multivariable adjustment, spatial QRS-T angle ≥75° was associated with all-cause mortality (HR 2.38, p=0.001), cardiovascular mortality (HR 2.99, p=0.01), and SCD (HR 4.52, p=0.03) [22]. The optimal abnormal cut-off value of spatial QRS-T angle for use in the ESRD population will require further study, but this ECG parameter, which integrates abnormalities of both depolarization and repolarization, shows promise as a non-invasive SCD risk stratification tool.…”

“…Between 8–25% of hemodialysis patients will have an abnormal SAECG [22,26,27], and various small studies have found that a hemodialysis session can worsen or improve the SAECG [27,28]. Increases in filtered QRS duration after hemodialysis have been associated with decreases in serum potassium [27].…”

“…Dynamic changes in the presence of late potentials might also be related to changes in QRS complex amplitude and duration associated with hemodialysis and fluid removal [30,31]. Despite the high frequency of abnormal SAECGs in hemodialysis patients, there are no currently available data supporting an association between SAECG abnormalities and total mortality, cardiovascular mortality, or SCD in this population [22,26]. …”

Genome‐Wide Associations of Global Electrical Heterogeneity ECG Phenotype: The ARIC (Atherosclerosis Risk in Communities) Study and CHS (Cardiovascular Health Study)

“…SVG is a vector sum of spatial QRS and T vectors, reflecting implication of the spatial QRS‐T angle 9. Spatial QRS‐T angle is a well‐known marker9 of the risk of ventricular tachyarrhythmias10 and sudden cardiac death (SCD)11, 12 in the general population, heart failure (HF) patients, and other populations 13, 14…”