Side of brain infarction and long-term risk of sudden death in patients with symptomatic carotid disease.

BACKGROUND AND PURPOSE Current publications suggest increased risk of sudden death in experimental animals with acute right insular lesions and in patients with recent right-sided brain infarction, particularly if the insula is involved. METHODS Using 3 different time definitions, we related long-term risk of sudden death to presence and side of brain infarction on the baseline brain scan and handedness in 2885 patients with symptomatic carotid disease. RESULTS In 1295 patients without brain infarction, 5-year risk of sudden death was 5.3% (24-hour definition); in those with left-sided infarction (n=471), 8.8%; in those with right-sided infarction (n=477), 6.0%; and in those with bilateral infarction (n=535), 9.7%. After accounting for differences of other risk factors (eg, previous myocardial infarction) in Cox regression, adjusted hazard ratios (HRs) compared with no infarction were as follows: left-sided HR, 1.45 (95% confidence interval [CI], 1.00 to 2.10); right-sided HR, 0.96 (95% CI, 0.62 to 1.47); and bilateral HR, 1.40 (95% CI, 0.98 to 2.00). Insular infarction occurred in 41 patients; none died suddenly. Left-handed or ambidextrous patients (n=183) had a lower risk of sudden death than right-handers; the adjusted HR for left-handed or ambidextrous patients was 0.24 (95% Cl, 0.07 to 0.70). These results were essentially the same for the 10- and 60-minute definitions of sudden death. CONCLUSIONS In the long-term, left-sided, not right-sided, brain infarction is associated with increased risk of sudden death. Left-handed or ambidextrous patients have a lower risk of sudden death than right-handed patients, suggesting a role for the brain.