Factors influencing the decision to ICD implantation in survivors of OHCA and its influence on long term survival

Bundle branch block in cardiac arrest survivors without ischemic heart disease

Aims

Cardiac arrest (CA) survivors with left/right bundle branch block (LBBB/RBBB) and no ischemic heart disease (IHD) have not been previously characterized. The aim of this study was to describe heart failure, implantable cardioverter defibrillator (ICD) therapy and mortality in this population.

Methods

Between 2009 and 2019 we consecutively identified all CA survivors with a consistent bundle branch block (BBB) defined as a QRS ≥ 120 ms, who had a secondary prophylactic ICD implanted. Patients with congenital and ischemic heart disease (IHD) were excluded.

Results

Among 701 CA-survivors who survived to discharge and received an ICD, a total of 58 (8%) were free from IHD and had BBB; 46 (79%) had LBBB, 10 (17%) had RBBB and 2 (3%) had non-specific BBB (NSBBB). The prevalence of LBBB was 7%. Pre-arrest ECG were available in 34 (59%) patients; 20 patients (59%) had LBBB, 6 (18%) had RBBB, 2 (6%) had NSBBB, 1 had (3%) incomplete LBBB, and 4 (12%) without BBB. At discharge, patients with LBBB had a significantly lower left ventricular ejection fraction (LVEF) than patients with other types of BBB, p < 0.001. During follow-up, 7 (12%) died after a median of 3.6 years (IQR: 2.6-5.1) with no difference between BBB subtypes.

Conclusion

We identified 58 CA-survivors with BBB and no IHD. The prevalence of LBBB among all CA-survivors was high, 7%. During CA hospitalization LBBB patients presented with a significantly lower LVEF than patients with other types of BBB (P < 0.001). ICD treatment and mortality did not differ between BBB subtypes during follow-up.

The association of duration of resuscitation and long-term survival and functional outcomes after out-of-hospital cardiac arrest

AIM

Longer emergency medical system cardiopulmonary-resuscitation-to-return of-spontaneous-circulation (EMS CPR-to-ROSC) interval has been associated with worse hospital discharge outcomes after out-of-hospital cardiac arrest (OHCA). We hypothesized that this association extends post-discharge in hospital survivors. We investigated whether pre-arrest co-morbidities influence the duration of resuscitation.

METHODS

We included EMS-treated adult OHCA (January 2009 - December 2016) from British Columbia Cardiac Arrest Registry linked to provincial databases. Pre-OHCA characteristics were compared by ≤10, 10-20, and >20 min interval categories. Outcomes included survival and functional outcomes at hospital discharge and 1- and 3-year survival. We examined the relationship between CPR-to-ROSC intervals and survival using Kaplan-Meier. We examined the relationship between the CPR-to-ROSC interval (continuous variable) with all outcomes using regression models.

RESULTS

Among 10,241 OHCA, 4604 (45%) achieved ROSC, with a median CPR-to-ROSC interval of 15.5 (IQR 9.0-22.9) minutes. Diabetes, chronic kidney disease, and prior myocardial infarction were associated with longer CPR-to-ROSC intervals. 1245 (12.2%) survived to hospital discharge. Among hospital survivors, Kaplan-Meier survival at 1- and 3-years were 92% [95% CI 90-93%] and 84% [95% CI 82-86%] respectively; survival curves stratified by CPR-to-ROSC intervals were not statistically different. Longer CPR-to-ROSC interval was non-linearly associated with lower survival and functional outcomes at hospital discharge but not with post-discharge outcomes.

CONCLUSION

Longer CPR-to-ROSC interval was associated with lower survival at hospital discharge and was influenced by pre-arrest co-morbidities. However, these intervals were not associated with long-term survival or functional outcome among hospital survivors, suggesting early risk of longer CPR-to-ROSC intervals does not persist.

Long-term outcomes after out-of-hospital cardiac arrest: a systematic review and meta-analysis

AIMS

Long term outcomes after out-of-hospital cardiac arrest (OHCA) are not well understood. This study aimed to evaluate the long-term (1-year and beyond) survival outcomes, including overall survival and survival with favorable neurological status and the quality-of-life (QOL) outcomes, among patients who survived the initial OHCA event (30 days or till hospital discharge).

METHODS

Embase, Medline and PubMed were searched for primary studies (randomized controlled trials, cohort and cross-sectional studies) which reported the long-term survival outcomes of OHCA patients. Data abstraction and quality assessment was conducted, and survival at predetermined timepoints were assessed via single-arm meta-analyses of proportions, using generalized linear mixed models. Comparative meta-analyses were conducted using the Mantel-Haenszel Risk Ratio (RR) estimates, using the DerSimonian and Laird model.

RESULTS

67 studies were included, and among patients that survived to hospital discharge or 30-days, 77.3% (CI=71.2-82.4), 69.6% (CI=54.5-70.3), 62.7% (CI=54.5-70.3), 46.5% (CI=32.0-61.6), and 20.8% (CI=7.8-44.9) survived to 1-, 3-, 5-, 10- and 15-years respectively. Compared to Asia, the probability of 1-year survival was greater in Europe (RR=2.1, CI=1.8-2.3), North America (RR=2.0, CI=1.7-2.2) and Oceania (RR=1.9,CI=1.6-2.1). Males had a higher 1-year survival (RR:1.41, CI=1.25-1.59), and patients with initial shockable rhythm had improved 1-year (RR=3.07, CI=1.78-5.30) and 3-year survival (RR=1.45, CI=1.19-1.77). OHCA occurring in residential locations had worse 1-year survival (RR=0.42, CI=0.25-0.73).

CONCLUSION

Our study found that up to 20.8% of OHCA patients survived to 15-years, and survival was lower in Asia compared to the other regions. Further analysis on the differences in survival between the regions are needed to direct future long-term treatment of OHCA patients.

Long-term clinical outcomes and predictors for survivors of out-of-hospital cardiac arrest

AIMS

Improvement in resuscitation efforts has translated to an increasing number of survivors after out-of-hospital cardiac arrest (OHCA). Our objectives were to assess the long-term outcomes and predictors of mortality for patients who survived OHCA.

METHODS

We conducted a population-based cohort study linking the Toronto RescuNET cardiac arrest database with administrative databases in Ontario, Canada. We included patients with non-traumatic OHCA from December 1, 2005 to December 31, 2014. The primary outcomes were mortality at 1 year and 3 years. Cox proportional hazard models were constructed to evaluate the predictors of mortality.

RESULTS

Among the 28,611 OHCA patients who received treatment at the scene of arrest, 1591 patients survived to hospital discharge. During hospitalization, 36% received coronary revascularizations and 27% received an implantable cardioverter defibrillator. At one year after discharge, 12.6% of patients had died and 37.3% were readmitted. At 3 years, mortality rate was 20% and all-cause readmission rate was 54.1%. Older age and a history of cancer were associated with higher risk of 3-year mortality. Shockable rhythm at presentation (hazard ratio [HR] 0.62, 95% CI 0.45-0.85), use of coronary revascularization (HR 0.37, 95% CI 0.28-0.51) or implantable cardioverter defibrillator (HR 0.28, 95% CI 0.20-0.41) was associated with substantially lower 3-year mortality. Prior cardiac conditions and other arrest characteristics were not associated with long-term mortality.

CONCLUSIONS

Survivors of OHCA face significant morbidity and mortality after hospital discharge. Clinical trials are needed to evaluate the potential benefits of invasive cardiac procedures in OHCA survivors.

Implantable cardioverter defibrillator and survival after out-of-hospital cardiac arrest due to acute myocardial infarction in Denmark in the years 2001-2012, a nationwide study

AIM

The purpose of this study was to describe the implantation of implantable cardioverter defibrillator after out-of-hospital cardiac arrest caused by myocardial infarction in Denmark 2001-2012 and subsequent survival.

METHODS

The Danish Cardiac Arrest Registry was used to identify patients ⩾18 years surviving to discharge without prior implantable cardioverter defibrillator. Information on cardioverter defibrillator implantation was obtained from the National Patient Registry.

RESULTS

We identified 974 myocardial infarction-out-of-hospital cardiac arrest patients surviving to hospital discharge, 130 of these patients (13%) had a cardioverter defibrillator implanted early (⩽40 days post-out-of-hospital cardiac arrest), 58 patients (6%) had late implantable cardioverter defibrillator (41-365 days post-out-of-hospital cardiac arrest). Odds of implantable cardioverter defibrillator implantation within one year were higher in patients receiving cardiopulmonary resuscitation (odds ratio (OR)_CPR: 1.99, confidence interval (CI): 1.23-3.22, p=0.01), and Charlson Comorbidity Index level 1, (OR_CCI1: 2.10, CI:1.25-3.49, p<0.01). Odds of a late implantable cardioverter defibrillator was higher in patients undergoing percutaneous coronary intervention (PCI) (OR_PCI: 3.67, CI: 1.35-9.97, p=0. 01). An early, but not late implantable cardioverter defibrillator was associated with increased survival (event time ratio_{Early ICD}: 1.45, CI: 1.11-1.90, p=0.01). Chronic heart failure, higher age groups, Charlson Comorbidity Index levels 1 to ⩾3 and male sex were associated with lower survival. Highest income was associated with higher survival.

CONCLUSION

Cardioverter defibrillator implantation rates in patients surviving an myocardial infarction-out-of-hospital cardiac arrest increased from 14% to 19% over the period. Of the total patient population, 13% had implantation earlier than recommended by guidelines, presumably as primary prevention of sudden cardiac death. Acute PCI and arrest later in the study period (increase one year) were predictors of late cardioverter defibrillator implantation. Early cardioverter defibrillator implantation was significantly associated with a long-term survival benefit, later implantation was not.

Late gadolinium enhancement among survivors of sudden cardiac arrest

OBJECTIVES

The aim of this study was to describe the role of contrast-enhanced cardiac magnetic resonance (CMR) in the workup of patients with aborted sudden cardiac arrest (SCA) and in the prediction of long-term outcomes.

BACKGROUND

Myocardial fibrosis is a key substrate for SCA, and late gadolinium enhancement (LGE) on a CMR study is a robust technique for imaging of myocardial fibrosis.

METHODS

We performed a retrospective review of all survivors of SCA who were referred for CMR studies and performed follow-up for the subsequent occurrence of an adverse event (death and appropriate defibrillator therapy).

RESULTS

After a workup that included a clinical history, electrocardiogram, echocardiography, and coronary angiogram, 137 patients underwent CMR for workup of aborted SCA (66% male; mean age 56 ± 11 years; left ventricular ejection fraction 43 ± 12%). The presenting arrhythmias were ventricular fibrillation (n = 105 [77%]) and ventricular tachycardia (n = 32 [23%]). Overall, LGE was found in 98 patients (71%), with an average extent of 9.9 ± 5% of the left ventricular myocardium. CMR imaging provided a diagnosis or an arrhythmic substrate in 104 patients (76%), including the presence of an infarct-pattern LGE in 60 patients (44%), noninfarct LGE in 21 (15%), active myocarditis in 14 (10%), hypertrophic cardiomyopathy in 3 (2%), sarcoidosis in 3, and arrhythmogenic cardiomyopathy in 3. In a median follow-up of 29 months (range 18 to 43 months), there were 63 events. In a multivariable analysis, the strongest predictors of recurrent events were the presence of LGE (adjusted hazard ratio: 6.7; 95% CI: 2.38 to 18.85; p < 0.001) and the extent of LGE (hazard ratio: 1.15; 95% CI: 1.11 to 1.19; p < 0.001).

CONCLUSIONS

Among patients with SCA, CMR with contrast identified LGE in 71% and provided a potential arrhythmic substrate in 76%. In follow-up, both the presence and extent of LGE identified a group at markedly increased risk of future adverse events.