HIV Infection and the Risk of World Health Organization-Defined Sudden Cardiac Death.

Background People living with HIV have higher sudden cardiac death (SCD) rates compared with the general population. Whether HIV infection is an independent SCD risk factor is unclear. Methods and Results This study evaluated participants from the Veterans Aging Cohort Study, an observational, longitudinal cohort of veterans with and without HIV infection matched 1:2 on age, sex, race/ethnicity, and clinical site. Baseline for this study was a participant's first clinical visit on or after April 1, 2003. Participants were followed through December 31, 2014. Using Cox proportional hazards regression, we assessed whether HIV infection, CD4 cell counts, and/or HIV viral load were associated with World Health Organization (WHO)-defined SCD risk. Among 144 336 participants (30% people living with HIV), the mean (SD) baseline age was 50.0 years (10.6 years), 97% were men, and 47% were of Black race. During follow-up (median, 9.0 years), 3035 SCDs occurred. HIV infection was associated with increased SCD risk (hazard ratio [HR], 1.14; 95% CI, 1.04-1.25), adjusting for possible confounders. In analyses with time-varying CD4 and HIV viral load, people living with HIV with CD4 counts <200 cells/mm3 (HR, 1.57; 95% CI, 1.28-1.92) or viral load >500 copies/mL (HR, 1.70; 95% CI, 1.46-1.98) had increased SCD risk versus veterans without HIV. In contrast, people living with HIV who had CD4 cell counts >500 cells/mm3 (HR, 1.03; 95% CI, 0.90-1.18) or HIV viral load <500 copies/mL (HR, 0.97; 95% CI, 0.87-1.09) were not at increased SCD risk. Conclusions HIV infection is associated with increased risk of WHO-defined SCD among those with elevated HIV viral load or low CD4 cell counts.

Refining the World Health Organization Definition: Predicting Autopsy-Defined Sudden Arrhythmic Deaths Among Presumed Sudden Cardiac Deaths in the POST SCD Study.

BACKGROUND: Conventional definitions of sudden cardiac death (SCD) presume cardiac cause. We studied the World Health Organization-defined SCDs autopsied in the POST SCD study (Postmortem Systematic Investigation of SCD) to determine whether premortem characteristics could identify autopsy-defined sudden arrhythmic death (SAD) among presumed SCDs. METHODS: Between January 2, 2011, and January 4, 2016, we prospectively identified all 615 World Health Organization-defined SCDs (144 witnessed) 18 to 90 years in San Francisco County for medical record review and autopsy via medical examiner surveillance. Autopsy-defined SADs had no extracardiac or acute heart failure cause of death. We used 2 nested sets of premortem predictors-an emergency medical system set and a comprehensive set adding medical record data-to develop Least Absolute Selection and Shrinkage Operator models of SAD among witnessed and unwitnessed cohorts. RESULTS: Of 615 presumed SCDs, 348 (57%) were autopsy-defined SAD. For witnessed cases, the emergency medical system model (area under the receiver operator curve 0.75 [0.67-0.82]) included presenting rhythm of ventricular tachycardia/fibrillation and pulseless electrical activity, while the comprehensive (area under the receiver operator curve 0.78 [0.70-0.84]) added depression. If only ventricular tachycardia/fibrillation witnessed cases (n=48) were classified as SAD, sensitivity was 0.46 (0.36-0.57), and specificity was 0.90 (0.79-0.97). For unwitnessed cases, the emergency medical system model (area under the receiver operator curve 0.68 [0.64-0.73]) included black race, male sex, age, and time since last seen normal, while the comprehensive (area under the receiver operator curve 0.75 [0.71-0.79]) added use of ß-blockers, antidepressants, QT-prolonging drugs, opiates, illicit drugs, and dyslipidemia. If only unwitnessed cases <1 hour (n=59) were classified as SAD, sensitivity was 0.18 (0.13-0.22) and specificity was 0.95 (0.90-0.97). CONCLUSIONS: Our models identify premortem characteristics that can better specify autopsy-defined SAD among presumed SCDs and suggest the World Health Organization definition can be improved by restricting witnessed SCDs to ventricular tachycardia/fibrillation or nonpulseless electrical activity rhythms and unwitnessed cases to <1 hour since last normal, at the cost of sensitivity.

Incidence of cardiac fibrosis in SUDEP and control cases.

OBJECTIVE: Since cardic fibrosis was previously found more frequently in patients with sudden unexpected death in epilepsy (SUDEP) than control cases, we compared blinded and quantitative reviews of cardiac pathology in SUDEP to multiple control groups. METHODS: We adjudicated causes of death in epilepsy patients as part of consecutive out-of-hospital sudden cardiac deaths (SCDs) from the Postmortem Systematic Investigation of Sudden Cardiac Death (POSTSCD) study. Blinded cardiac gross and microscopic examinations were performed by forensic and cardiac pathologists. RESULTS: Of 541 SCDs over 37 months (mean age 62.8 years, 69% male), 525 (97%) were autopsied; 25/525 (4.8%) had epilepsy (mean age 56.4 years ± 15.4, range 27-92; 67% male). The 25 epilepsy patients died of definite SUDEP/definite SUDEP-plus (n = 8), possible SUDEP (n = 10), or other causes (n = 7). Comparison groups included autopsy-defined sudden arrhythmic death (SAD; n = 285) and trauma (n = 104) and we adjusted for age, sex, HIV, coronary artery disease, congestive heart failure, and cardiomyopathy in the analyses. Compared to SAD cases, SUDEP cases had less gross and histologic evidence of cardiac pathology; significant for cardiac mass (p < 0.0011), coronary artery disease (p < 0.0024), total cardiac fibrosis (CF) (p = 0.022), and interstitial CF (p = 0.013). Compared to trauma cases, SUDEP cases had similar cardiac pathology including CF. CONCLUSION: Among SUDEP cases, cardiac pathology was less severe than in SAD cases but similar to trauma and epilepsy controls. Our data do not support prior studies finding elevated rates of CF among SUDEP cases compared to controls. Larger studies including molecular analyses would further our understanding of cardiac changes associated with SUDEP.