The mortality angle in hemodialysis
Sudden cardiac death is the leading single cause of mortality for patients on hemodialysis.
But is an independent association found between measures of electrophysiological substrate and mortality? Until now, this question has not been answered, says a team of US-American and Canadian scientists (Tereshchenko LG et al, Electrophysiologic Substrate and Risk of Mortality in Incident Hemodialysis; J Am Soc Nephrol 2016;27:3413-3420). In the current study, they found a significant association between spatial QRS-T angle and cardiovascular mortality as well as sudden cardiac death – independent of other, typical risk factors observed in patients initiating hemodialysis.
The authors examined measures of electrophysiological substrate in 571 patients on incident hemodialysis. 358 participants completed both baseline 5-minute and 12-lead electrocardiogram recordings on a non-dialysis day. During a follow-up period totaling 864.6 person-years, 77 patients died. Of these, 35 died from cardiovascular causes; 15 of these were sudden cardiac deaths.
After adjusting for demographic, cardiovascular and dialysis factors, Cox regression analysis showed that a QRS-T angle ≥75° was significantly associated with an almost threefold increased risk of cardiovascular mortality (hazard ratio, 2.99;) and with an almost fivefold increased risk of sudden cardiac death (hazard ratio, 4.52). By contrast, abnormal signal-averaged electrocardiogram measures demonstrated no association with mortality.
The authors conclude that there is a significant association between spatial QRS-T angle and cardiovascular mortality in patients starting hemodialysis.