Section of Cardiac Electrophysiology, Division of Cardiology, Department of Medicine (Z.H.T., J.E.O.)
Section of Cardiac Electrophysiology, Division of Cardiology, Department of Medicine (Z.H.T., J.E.O.).
Circulation. 2018 Jun 19;137(25):2689-2700. doi: 10.1161/CIRCULATIONAHA.117.033427.
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.
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.
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 (<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 (=0.024); 286 of 293 (98%) had structural cardiac disease.
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.
院外心脏骤停和心源性猝死（SCD）的研究使用急救医疗服务记录、死亡证明或推断死因的定义；因此，SCD 的真实发病率尚不清楚。超过 90%的 SCD 发生在院外；很少进行非法医尸检，因此死因被假定。我们进行了一项法医调查，以确定整个大都市区所有 SCD 的准确发病率和尸检定义的原因。我们假设死后调查将在假定的 SCD 中确定实际的心律失常性死亡。
2011 年 2 月 1 日至 2014 年 3 月 1 日期间，我们通过法医对连续院外死亡的监测，前瞻性地确定了旧金山县 18 至 90 岁之间归因于院外心脏骤停（急救医疗服务初步印象，心脏骤停）的所有尸检、毒理学和组织学的所有事件死亡，所有报告均符合法律规定。我们获得了全面的记录，以确定院外心脏骤停死亡是否符合世界卫生组织（WHO）对 SCD 的标准。我们每季度审查死亡证明，以确定是否漏报 SCD。尸检定义的心律失常性死亡没有心脏外死因或急性心力衰竭。一个多学科委员会对最终死因进行裁决。
所有 20440 例死亡均进行了回顾；有 12671 例无人照管，并向法医报告。在这些病例中，我们确定了 912 例院外心脏骤停死亡；541 例（59%）符合 WHO SCD 标准（平均年龄 62.8 岁，69%为男性），525 例（97%）进行了尸检。在接受医疗护理的 3 周内，又发生了 89 例符合 WHO 定义的 SCD，死亡证明由主治医生签署，不符合尸检条件，但包括在全县范围内符合 WHO 定义的 SCD 发病率 29.6/100000 人年，黑人男性最高（<0.0001）。在 525 例符合 WHO 定义的 SCD 中，301 例（57%）无心脏病史。主要死因是冠心病（32%）、隐性药物过量（13.5%）、心肌病（10%）、心脏肥大（8%）和神经源性（5.5%）。尸检定义的心律失常性死亡占总 SCD 的 55.8%（293/525）、目击 SCD 的 65%（78/120）和未目击 SCD 的 53%（215/405）（=0.024）；293 例中的 286 例（98%）有结构性心脏病。
归因于明确心脏骤停的死亡中，有 40%不是突然或意外的，近一半的假定 SCD 不是心律失常性的。这些发现对 WHO 标准或急救医疗服务记录在总死亡率数据、临床试验和队列研究中定义 SCD 的准确性有影响。
