A pilot study in hemodialysis of an electrophysiological tool to measure sudden cardiac death risk.

BACKGROUND: The hemodialysis procedure may play a role in the elevated risk of sudden cardiac death seen in hemodialysis patients.
METHODS: Microvolt T wave alternans, a promising noninvasive electrophysiological test developed to measure sudden cardiac death risk, was used to test the hypotheses that high-risk hemodialysis patients commonly manifest cardiac electrophysiology that is associated with higher sudden death risk in nondialysis patients and that the hemodialysis procedure modifies cardiac electrophysiology in a manner predisposing to malignant ventricular arrhythmias. To test this hypothesis, microvolt T wave alternans tracings were done in 9 patients before and immediately after an early week hemodialysis session.
RESULTS: 7 of 9 individuals had non-negative (i.e. higher risk) tracings either before or after hemodialysis. 2 of 4 subjects with tracings initially negative before hemodialysis became non-negative after hemodialysis.
CONCLUSION: This pilot study provides the first objective preliminary evidence using microvolt T wave alternans that high-risk hemodialysis patients commonly exhibit abnormal cardiac repolarization and that hemodialysis treatments can acutely alter repolarization in a potentially harmful manner.