Ellen Moffatt

Sudden Death in Patients With Cardiac Implantable Electronic Devices

IMPORTANCE Interrogations and autopsies of sudden deaths with cardiac implantable electronic devices (CIEDs) are rarely performed. Therefore, causes of sudden deaths with these devices and the incidence of device failure are unknown. OBJECTIVE To determine causes of death in individuals with CIEDs in a prospective autopsy study of all sudden deaths over 35 months as part of the San Francisco, California, Postmortem Systematic Investigation of Sudden Cardiac Death (POST SCD) study. DESIGN, SETTING, AND PARTICIPANTS Full autopsy, toxicology, histology, and device interrogation were performed on incident sudden cardiac deaths with pacemakers or implantable cardioverter defibrillators (ICDs). The setting was the Office of the Chief Medical Examiner, City and County of San Francisco. Participants included all sudden deaths captured through active surveillance of all deaths reported to the medical examiner and San Francisco residents with an ICD (January 1, 2011, to November 30, 2013). MAIN OUTCOMES AND MEASURES Identification of a device concern in sudden deaths with CIEDs, including hardware failures, device algorithm issues, device programming issues, and improper device selection. For the ICD population, outcomes were the cumulative incidence of death and sudden cardiac death and the proportion of deaths with an ICD concern. RESULTS Twenty-two of 517 sudden deaths (4.3%) had CIEDs, and autopsy revealed a noncardiac cause of death in 6. Six of 14 pacemaker sudden deaths and 7 of 8 ICD sudden deaths died of ventricular tachycardia or ventricular fibrillation. Device concerns were identified in half (4 pacemakers and 7 ICDs), including 3 hardware failures contributing directly to death (1 rapid battery depletion with a sudden drop in pacing output and 2 lead fractures), 5 ICDs with ventricular fibrillation undersensing, 1 ICD with ventricular tachycardia missed due to programming, 1 improper device selection, and a pacemaker-dependent patient with pneumonia and concern about lead fracture. Of 712 San Francisco residents with an ICD during the study period, 109 died (15.3% cumulative 35-month incidence of death), and the 7 ICD concerns represent 6.4% of all ICD deaths. CONCLUSIONS AND RELEVANCE Systematic interrogation and autopsy of sudden deaths in one city identified concerns about CIED function that might otherwise not have been observed. Current passive surveillance efforts may underestimate device malfunction. These methods can provide unbiased data regarding causes of sudden death in individuals with CIEDs and improve surveillance for CIED problems.

Characteristics of Sudden Arrhythmic Death in a Diverse, Urban Community

BACKGROUND Sudden cardiac death (SCD) remains a major public health problem; however, its true burden remains unknown with widely variable estimates of its incidence. We aimed to examine the contemporary epidemiology and autopsy characteristics of SCD in an ethnically diverse community. METHODS Three physicians reviewed all deaths of individuals aged ≥20 years reported to the San Francisco medical examiner in 2007 for presentations fitting World Health Organization (WHO) SCD criteria-within 1 hour of symptom onset (witnessed) or within 24 hours of being observed alive and symptom free (unwitnessed). After comprehensive review of medical examiner investigation, WHO SCDs were classified as sudden arrhythmic death (SAD) or nonarrhythmic death. Coronary artery disease (CAD) and cardiac mass were evaluated in all SADs undergoing autopsy and compared with demographically similar accidental trauma control deaths. RESULTS We identified 252 WHO SCDs; 145 were SADs. Men had a 2.2-fold higher SAD rate (P < .0005). Blacks had a 3.15-fold higher SAD rate compared with whites (P = .003). Significant CAD was present in 38.9% of SADs and associated with higher SAD risk compared with control deaths (OR 2.58, 95% CI 1.12-5.97, P = .026). Mean cardiac mass was linearly associated with risk for SAD in cases without significant CAD (OR 2.06 per 100 g, 95% CI 1.43-2.98, P < .0005). CONCLUSIONS In a diverse, urban population, SAD incidence varied substantially by gender and race. Significant CAD accounted for far fewer SADs than previous studies but remained associated with a 2.6-fold higher risk as compared with control deaths. These findings may reflect the evolving contemporary epidemiology of SCD.

Underestimation of sudden deaths among patients with seizures and epilepsy

Objective: To determine the definite and potential frequency of seizures and epilepsy as a cause of death (COD) and how often this goes unrecognized. Methods: Prospective determination of seizures or epilepsy and final COD for individuals aged 18–90 years with out-of-hospital sudden cardiac deaths (SCDs) from the population-based San Francisco POST SCD Study. We compared prospective seizure or epilepsy diagnosis and final COD as adjudicated by a multidisciplinary committee (pathologists, electrophysiologists, and a vascular neurologist) vs retrospective adjudication by 2 epileptologists with expertise in seizure-related mortality. Results: Of 541 SCDs identified during the 37-month study period (mean age 62.8 years, 69% men), 525 (97%) were autopsied; 39/525 (7.4%) had seizures or epilepsy (mean age: 58 years, range: 27–92; 67% men), comprising 17% of 231 nonarrhythmic sudden deaths. The multidisciplinary team identified 15 cases of epilepsy, 6 sudden unexpected deaths in epilepsy (SUDEPs), and no deaths related to acute symptomatic seizures. The epileptologists identified 25 cases of epilepsy and 8 definite SUDEPs, 10 possible SUDEPs, and 5 potential cases of acute symptomatic seizures as a COD. Conclusions: Among the 25 patients identified with epilepsy by the epileptologists, they found definite or possible SUDEP in 72% (18/25) vs 24% (6/25) by the multidisciplinary group (6/15 cases they identified with epilepsy). The epileptologists identified acute symptomatic seizures as a potential COD in 5/14 patients with alcohol-related seizures. Epilepsy is underdiagnosed among decedents. Among patients with seizures and epilepsy who die suddenly, seizures and SUDEP often go unrecognized as a potential or definite COD.

Sudden neurologic death masquerading as out-of-hospital sudden cardiac death

Objective: To characterize the frequency of and risk factors for out-of-hospital sudden neurologic deaths. Methods: During the initial 25 months (February 1, 2011–March 1, 2013) of the San Francisco Postmortem Systematic Investigation of Sudden Cardiac Death Study, we captured incident WHO criteria sudden cardiac deaths (SCDs) through active surveillance of consecutive out-of-hospital deaths, which must be reported to the medical examiner by law. All cases were referred for full autopsy with detailed examination of the heart and cranial vault, toxicology, and histology. A multidisciplinary committee adjudicated a final cause of death. Results: Of 352 incident SCDs, 335 (95%) underwent systematic evaluation including full autopsy. Of these 335 cases, 18 (5.4%) were sudden neurologic deaths (mean age 60.6 years [SD 17.6, range 27–87]; 67.7% female), which accounted for 14.9% of the 121 noncardiac sudden deaths. The risk of sudden neurologic death compared to non-neurologic SCD was lower in male and white participants (p < 0.01). Neurologic causes included intracranial hemorrhage (8), sudden unexpected death in epilepsy (6, including 2 with juvenile myoclonic epilepsy), aneurysmal subarachnoid hemorrhage (2), acute ischemic stroke (1), and aspiration from Huntington disease (1). Most deaths were unwitnessed (16; 89%) with asystole at presentation (17; 94%). Prior stroke/TIA was not associated with risk of stroke (odds ratio [OR] 1.4 [95% confidence interval (CI) 0.18–11.8], p = 0.73), but antithrombotic medication use was (OR 3.9 [95% 1.01–15.5], p = 0.05). Conclusions: Sudden neurologic death is an important cause of out-of-hospital apparent SCDs. Low prevailing autopsy rates may result in systematic misclassification of apparent SCDs and underestimation of the incidence of sudden neurologic death.

Prospective Countywide Surveillance and Autopsy Characterization of Sudden Cardiac Death: POST SCD Study

Background: Studies of out-of-hospital cardiac arrest and sudden cardiac death (SCD) use emergency medical services records, death certificates, or definitions that infer cause of death; thus, the true incidence of SCD is unknown. Over 90% of SCDs occur out-of-hospital; nonforensic autopsies are rarely performed, and therefore causes of death are presumed. We conducted a medical examiner–based investigation to determine the precise incidence and autopsy-defined causes of all SCDs in an entire metropolitan area. We hypothesized that postmortem investigation would identify actual sudden arrhythmic deaths among presumed SCDs. Methods: Between February 1, 2011, and March 1, 2014, we prospectively identified all incident deaths attributed to out-of-hospital cardiac arrest (emergency medical services primary impression, cardiac arrest) between 18 to 90 years of age in San Francisco County for autopsy, toxicology, and histology via medical examiner surveillance of consecutive out-of-hospital deaths, all reported by law. We obtained comprehensive records to determine whether out-of-hospital cardiac arrest deaths met World Health Organization (WHO) criteria for SCD. We reviewed death certificates filed quarterly for missed SCDs. Autopsy-defined sudden arrhythmic deaths had no extracardiac cause of death or acute heart failure. A multidisciplinary committee adjudicated final cause. Results: All 20 440 deaths were reviewed; 12 671 were unattended and reported to the medical examiner. From these, we identified 912 out-of-hospital cardiac arrest deaths; 541 (59%) met WHO SCD criteria (mean 62.8 years, 69% male) and 525 (97%) were autopsied. Eighty-nine additional WHO-defined SCDs occurred within 3 weeks of active medical care with the death certificate signed by the attending physician, ineligible for autopsy but included in the countywide WHO-defined SCD incidence of 29.6/100 000 person-years, highest in black men (P<0.0001). Of 525 WHO-defined SCDs, 301 (57%) had no cardiac history. Leading causes of death were coronary disease (32%), occult overdose (13.5%), cardiomyopathy (10%), cardiac hypertrophy (8%), and neurological (5.5%). Autopsy-defined sudden arrhythmic deaths were 55.8% (293/525) of overall, 65% (78/120) of witnessed, and 53% (215/405) of unwitnessed WHO-defined SCDs (P=0.024); 286 of 293 (98%) had structural cardiac disease. Conclusions: Forty percent of deaths attributed to stated cardiac arrest were not sudden or unexpected, and nearly half of presumed SCDs were not arrhythmic. These findings have implications for the accuracy of SCDs as defined by WHO criteria or emergency medical services records in aggregate mortality data, clinical trials, and cohort studies.

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.