Clinical characteristics of unexplained sudden cardiac death in Korea

Unique clinical features and long term follow up of survivors of sudden cardiac death in an Asian multicenter study

There has been no long-term clinical follow-up data of survivors or victims of sudden cardiac death (SCD). The Taiwan multi-center sudden arrhythmia death syndrome follow-up and clinical study (TFS-SADS) is a collaborative multi-center study with median follow-up time 43 months. In this cohort, the clinical characteristics of these SADS patients were compared with those with ischemic heart disease (IHD). In this SCD cohort, around half (42%) were patients with IHD, which was different from Caucasian SCD cohorts. Among those with normal heart, most had Brugada syndrome (BrS). Compared to those with SADS, patients with IHD were older, more males and more comorbidities, more arrhythmic death, and lower left ventricular ejection fraction. In the long-term follow-up, patients with SADS had a better survival than those with IHD (p < 0.001). In the Cox regression analysis to identify the independent predictors of mortality, older age, lower LVEF, prior myocardial infarction and history of out-of-hospital cardiac arrest were associated with higher mortality and beta blocker use and idiopathic ventricular fibrillation or tachycardia (IVF/IVT) with a better survival during follow-up. History of prior MI was associated with more arrhythmic death. Several distinct features of SCD were found in the Asia-Pacific region, such as higher proportion of SADS, poorer prognosis of LQTS and better prognosis of IVF/IVT. Patients with SADS had a better survival than those with IHD. For those with SADS, patients with channelopathy had a better survival than those with cardiomyopathy.

Circadian Rhythms in Sudden Cardiac Arrest: A Review

BACKGROUND

Sudden cardiac arrest (SCA) is a serious public health issue caused by the cessation of cardiac electrical and mechanical activity. Despite advances in pedestrian lifesaving technologies like defibrillators, the SCA mortality rate remains high, and survivors are at risk of suffering ischemic injury to various organs. Understanding the contributing factors for SCA is essential for improving morbidity and mortality. One factor capable of influencing SCA incidence and survival is the time of day at which SCA occurs.

OBJECTIVES

This review focused on the effect of time of day on SCA incidence, survival rate, and survival to discharge over the past 30 years and the role of age, sex, and SCA location in modulating the timing of SCA.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews criteria guided this review. Four databases (PubMed, Cochrane Libraries, Scopus, and Cumulative Index to Nursing and Allied Health Literature) were queried for research reports or articles addressing time of day and cardiac arrest, which were subsequently screened by the authors for inclusion in this analysis.

RESULTS

A total of 48 articles were included in the final analysis. This analysis showed a bimodal SCA distribution with a primary peak in the morning and a secondary peak in the afternoon; these peaks were dependent on age (older persons), sex (more frequent in males), and the location of occurrence (out-of-hospital cardiac arrest vs. in-hospital cardiac rest). Survival following SCA was lowest between midnight and 06:00 a.m.

DISCUSSION

The circadian rhythm likely plays an important role in the time-of-day-dependent pattern that is evident in both the incidence of and survival following SCA. There is a renewed call for nursing research to examine or address circadian rhythm as an element in studies involving older adults and activities affecting cardiovascular or respiratory parameters.

Incidence and etiology of sudden cardiac arrest in Koreans: A cohort from the national health insurance service database

The incidence of sudden cardiac arrest (SCA) in Asians is lower than that seen in Western populations, but there are few available data on the incidence and associated cardiac etiology of SCA in Asians. From 2002 to 2013, patients with SCA were analyzed using a cohort from the South Korean National Health Insurance Service (NHIS) coded database. Sudden unexplained death syndrome (SUDS) was defined as cryptogenic arrest, excluding that of non-cardiac origin, coronary artery disease (CAD), cardiomyopathy (CM), and valvular heart disease. During the 12-year study period, 5,973 patients (0.53%) from the total cohort of 1,125,691 had a cardiac arrest code. The overall incidence of arrest was 48.7 per 100,000 person-years (95% CI 16.6-18.0). The incidence of primary SCA excluding those of non-cardiac origin was 16.1 per 100,000 person-years (95% CI 15.4-16.8). It was higher in males than in females (18.1 vs. 14.1 per 100,000 person-years). CAD was the most common cause of SCA (59.4%), and followed by CM (13.9%). SUDS accounted for 14.7% of SCA events. The risk of SCA had increased gradually from over 25 years old. Heart failure, atrial fibrillation and hypertension are major factors associated with SCA incidence. Our findings outline epidemiologic data for SCA and the proportion of associated cardiac etiology leads SCA in a large population.

Temporal variation of out-of-hospital cardiac arrests in an equatorial climate

OBJECTIVE

We aimed to determine whether there is a seasonal variation of out-of-hospital cardiac arrests (OHCA) in an equatorial climate, which does not experience seasonal environmental change.

METHODS

We conducted an observational prospective study looking at the occurrence of OHCA in Singapore. Included were all patients with OHCA presented to Emergency Departments across the country. We examined the monthly, daily, and hourly number of cases over a three-year period. Data was analyzed using analysis of variance (ANOVA).

RESULTS

From October, 1st 2001 to October, 14th 2004, 2428 patients were enrolled in the study. Mean age for cardiac arrests was 60.6 years with 68.0% male. Ethnic distribution was 69.5% Chinese, 15.0% Malay, 11.0% Indian, and 4.4% Others. There was no significant seasonal variation (spring/summer/fall/winter) of events (ANOVA P = 0.71), monthly variation (P = 0.88) or yearly variation (P = 0.26). We did find weekly peaks on Mondays and a circadian pattern with daily peaks from 9-10 am.

CONCLUSIONS

We did not find any discernable seasonal pattern of cardiac arrests. This contrasts with findings from temperate countries and suggests a climatic influence on cardiac arrest occurrence. We also found that sudden cardiac arrests follow a circadian pattern.

Causes of sudden death related to sexual activity: results of a medicolegal postmortem study from 2001 to 2005

Sexual activity (SA), combined with organic heart disease, may cause sudden death (SD). However, the causes of SD related to SA are not known well. The aim of this study was to assess the causes of SD related to SA. From August 2001 to November 2005, all autopsies (n=1,379) performed at Kyungpook National University were prospectively searched for SD cases related to SA. Fourteen cases (46+/-11 yr old, 9 males) of SD related to SA were found. All were heterosexual. The toxicologic study was negative in all. Ten cases were witnessed; during SA in 4 cases, just after SA in another 4 cases, 2 and 5 hr after in 1 each case. In 4 unwitnessed cases the victims were found dead less than 12 hr from the end of their SA. The partners were steady extramarital partners (n=8), prostitutes (n=2), marital partner (n=1) and unknown (n=3). The causes of the SD were as follows; coronary artery disease in 6, subarachnoid hemorrhage with ruptured berry aneurysm in 4, fibromuscular dysplasia of the atrioventricular nodal artery in 2, and unknown in 2. Coronary artery disease and subarachnoid hemorrhage with ruptured berry aneurysm were important as causes of SD related to SA.

A Latin American registry of implantable cardioverter defibrillators: the ICD-LABOR study

OBJECTIVE

Despite the progress that has been reached in emergency medical systems and resuscitation, sudden cardiac death (SCD) continues to be the major cause of the death, and remains a significant public health problem. In this publication we are reporting our Latin American experience in the secondary prevention of SCD, by means of an ongoing registry involving seven Latin American countries and 770 patients.

METHODS

Every individual within the present registry to date has presented with antecedents of aborted sudden death or cardiac arrest due to ventricular tachycardia or ventricular fibrillation. Patients included have fulfilled the Class I indication for implantable cardioverter defibrillator (ICD) and they were implanted with a Biotronik ICD (all models). The study was not sponsored by Biotronik, nor did they have access to the data. A specific protocol was designed for implantation and follow-up of patients. The database was completely registered through the Internet and a personal password was assigned to each group of investigators. The primary end point was death from all causes. Secondary end points were SCD and death due to congestive heart failure (CHF).

RESULTS

The etiology of cardiac disease was found to be predominantly coronary artery disease (CAD) 39.7% (306 patients), followed by Chagas disease (ChD), 26.1% (201 patients), and idiopathic dilated cardiomyopathy (DCM), 17% (131 patients). Any remaining pathologies were included as miscellaneous 13.2% (101 patients). In 31 patients (4%) the etiology was unknown. The age did not differ within the principal pathologies, but was significantly older than the miscellaneous group (62.0 +/- 11.3 years vs 48.2 +/- 18.9 years, P < 0.0001). The follow-up period was 27 +/- 25 months (1-113 months) for the whole group. The mortality in functional classes I-II was significantly lower than mortality for functional classes III-IV (relative risk 1.46, CI 95%, P < 0.0001). Mean left ventricular ejection fraction (LVEF) for the whole group was 37.7 +/- 14.3%. Male LVEF was 36.1 +/- 14.1% and female LVEF was 42.2 +/- 13.8% P < 0.0001. During the follow-up period, 130 deaths were reported (global mortality 16.9 +/- 9.7%), out of which 84 (64.6%) were attributed to cardiac causes (10.9 +/- 5.1% of the total population). The annual adjusted cardiac mortality was 5.2 +/- 1.72% (range 3.5-7.0%). Among cardiac deaths the most common cause was progressive heart failure, 48 patients (57%) including 3 patients with pulmonary embolism. The second main cause of cardiac death was SCD, 36 patients (43%), including 4 patients with electrical storm and 3 patients with electromechanical dissociation after multiple shock therapy treatments.

CONCLUSIONS

Despite the differences in terms of pathologies between the ICD-LABOR (Latin American bioelectronic ongoing registry) and randomized ICD trials, a parallel evolution in all cause mortality and cardiac mortality was observed. Independent risk factors for mortality included age >70 years, male gender, NYHA III/IV, and ejection fraction <0.30. The etiology of heart disease (Chagas vs Coronary Disease) was not found to be a risk factor.

Distinct Clinical Features in the Recipients of the Implantable Cardioverter Defibrillator in Taiwan:. A Multicenter Registry Study

Little information about the ICD is available from the Asian Pacific region. The purpose of this study was to characterize the clinical features in ICD patients in Taiwan and to compare these features with those in patients in the Western populations, mainly the Canadian Implantable Defibrillator Study (CIDS), the Antiarrhythmics versus Implantable Defibrillator (AVID) trial, and the Cardiac Arrest Study Hamburg (CASH) trial. From February 1995 to October 2001, 101 ICDs were implanted in 92 patients (78 [84%] men) in 12 hospitals. Clinical presentations included sudden cardiac death due to VF/VT in 35 (38%) patients, syncopal VT in 25 (27%), drug refractory nonsyncopal VT in 27 (29%), and unexplained syncope with inducible sustained VT/VF in 5 (6%). The mean age was significantly younger than that in CIDS or AVID (59 +/- 16 vs 63 +/- 9 years in CIDS, P = 0.02; vs 65 +/- 11 years in AVID, P < 0.001), but was comparable to that in CASH (59 +/- 16 vs 58 +/- 11 years in CASH, P = 0.75). The mean LVEF was significantly higher than that in CIDS or AVID (48 +/- 19% vs 34 +/- 15% in CIDS, P < 0.001; vs 32 +/- 13% in AVID, P < 0.001), but was comparable to that in CASH (48 +/- 19 vs 46 +/- 19% in CIDS, P = 0.83). The ICD patients in the current study also showed a higher incidence of normal heart (23 vs 4% in CIDS, P < 0.001; vs 3% in AVID, P < 0.001; vs 9% in CASH, P < 0.001) and cardiomyopathy (41% vs 10% in CIDS, P < 0.001; vs 15% in AVID, P < 0.001; vs 11% in CASH, P < 0.001), but a lower incidence of coronary artery disease (29% vs 83% in CIDS, P < 0.001; vs 82% in AVID, P < 0.001; vs 73% in CASH, P < 0.001). During a mean follow-up of 28 +/- 24 months, 13 (14%) patients died. Older age was the only factor associated with poorer survival after ICD implantation. Forty-seven (51%) patients received appropriate ICD discharges during follow-up. History of prior myocardial infarction was the only factor associated with an earlier first appropriate ICD discharge and LVEF < 0.35 the only factor associated with subsequent poorer survival after the first ICD discharge. In conclusion, this study demonstrated many distinct clinical features in our ICD population that were different from those in the Western populations.

Arrhythmogenic Right Ventricular Cardiomyopathy and Sudden Cardiac Death in Young Koreans

The aim of this study was to assess the frequency and clinical characteristics of arrhythmogenic right ventricular cardiomyopathy (ARVC) in young victims of sudden cardiac death (SCD). From January 1999 to December 2000, postmortem studies were conducted in 38 cases of SCD (age < or =35 (27+/-7) years old, 26 male) from the Taegu-Kyungpook region of southeastern Korea. Cases of sudden infant death syndrome were excluded. The causes of SCD were ARVC in 42%, acute myocardial infarction in 11%, myocarditis in 11%, pulmonary embolism in 8%, hypertrophic cardiomyopathy in 5%, aortic rupture in 3%, aortic stenosis in 3%, and unknown in 18%. The mean age of the 16 ARVC victims was 27+/-5 years and 10 were male. None were competitive athletes, or had been suspected of having cardiovascular disease before death. SCD was not related to vigorous physical or competitive activity and occurred during sleep in 7 cases, during work in 4, during bathing in 2, while driving, praying and eating in 1 case each. ARVC is an important cause of SCD in young people in this area of Korea.