Sudden Cardiac Death in Women

BACKGROUND

Despite recent progress in profiling of risk for sudden cardiac death (SCD) and prevention and intervention of cardiac diseases, SCD remains a major cause of death. Among women, the incidence of SCD is significant, but lower than in men, particularly in the premenopausal and early postmenopausal years. Possibly, as a consequence of the difference in population burden, the mechanisms and risk markers of SCD are not as well defined for women. The aim of this study was to determine the autopsy findings and causes of death among women in a large SCD population. Additionally, we sought to classify prior ECG characteristics in male and female subjects with SCD.

METHODS

The Fingesture study has systematically collected clinical and autopsy data from subjects with SCD in Northern Finland between 1998 and 2017. The cohort consists of 5869 subjects with SCD. Previously recorded ECGs were available and analyzed in 1101 subjects (18.8% of total population; and in 25.3% of women).

RESULTS

Female subjects with SCD were significantly older than men: 70.1±13.1 years versus 63.5±11.8 years (mean ± standard deviation, P<0.001). The most frequently identified cause of death was ischemic heart disease in both sexes: 71.7% among women versus 75.7% among men, P=0.005. In contrast, women were more likely to have nonischemic cause of SCD than men (28.3% versus 24.3%, P=0.005). The prevalence of primary myocardial fibrosis was higher among women (5.2%, n=64) than in men (2.6%, n=120; P<0.001). Female subjects with SCD were more likely to have normal prior ECG tracings (22.2% versus 15.3% in men, P<0.001). A normal ECG was even more common among nonischemic female subjects with SCD (27.8% versus 16.2% in men, P=0.009). However, ECG markers of left ventricular hypertrophy, with or without repolarization abnormalities, were more common among women (8.2%; 17.9%) than in men (4.9%; 10.6%, P=0.036; P<0.001, respectively).

CONCLUSIONS

Women were considerably older at the time of SCD and more commonly had nonischemic causes. Women were also more likely to have a prior normal ECG than men, but an increased marker for SCD risk based on ECG criteria for left ventricular hypertrophy with repolarization abnormalities was more commonly observed in women.

HIV Infection Is Associated With Variability in Ventricular Repolarization: The Multicenter AIDS Cohort Study (MACS)

BACKGROUND

People living with human immunodeficiency virus (HIV+) have greater risk for sudden arrhythmic death than HIV-uninfected (HIV-) individuals. HIV-associated abnormal cardiac repolarization may contribute to this risk. We investigated whether HIV serostatus is associated with ventricular repolarization lability by using the QT variability index (QTVI), defined as a log measure of QT-interval variance indexed to heart rate variance.

METHODS

We studied 1123 men (589 HIV+ and 534 HIV-) from MACS (Multicenter AIDS Cohort Study), using the ZioXT ambulatory electrocardiography patch. Beat-to-beat analysis of up to 4 full days of electrocardiographic data per participant was performed using an automated algorithm (median analyzed duration [quartile 1-quartile 3]: 78.3 [66.3-83.0] hours/person). QTVI was modeled using linear mixed-effects models adjusted for demographics, cardiac risk factors, and HIV-related and inflammatory biomarkers.

RESULTS

Mean (SD) age was 60.1 (11.9) years among HIV- and 54.2 (11.2) years among HIV+ participants (P<0.001), 83% of whom had undetectable (<20 copies/mL) HIV-1 viral load (VL). In comparison with HIV- men, HIV+ men had higher QTVI (adjusted difference of +0.077 [95% CI, +0.032 to +0.123]). The magnitude of this association depended on the degree of viremia, such that in HIV+ men with undetectable VL, adjusted QTVI was +0.064 (95% CI, +0.017 to +0.111) higher than in HIV- men, whereas, in HIV+ men with detectable VL, adjusted QTVI was higher by +0.150 (95% CI, 0.072-0.228) than in HIV- referents. Analysis of QTVI subcomponents showed that HIV+ men had: (1) lower heart rate variability irrespective of VL status, and (2) higher QT variability if they had detectable, but not with undetectable, VL, in comparison with HIV- men. Higher levels of C-reactive protein, interleukin-6, intercellular adhesion molecule-1, soluble tumor necrosis factor receptor 2, and soluble cluster of differentiation-163 (borderline), were associated with higher QTVI and partially attenuated the association with HIV serostatus.

CONCLUSIONS

HIV+ men have greater beat-to-beat variability in QT interval (QTVI) than HIV- men, especially in the setting of HIV viremia and heightened inflammation. Among HIV+ men, higher QTVI suggests ventricular repolarization lability, which can increase susceptibility to arrhythmias, whereas lower heart rate variability signals a component of autonomic dysfunction.

Preoperative Noncoronary Cardiovascular Assessment and Management of Kidney Transplant Candidates

The pretransplant risk assessment for patients with ESKD who are undergoing evaluation for kidney transplant is complex and multifaceted. When considering cardiovascular disease in particular, many factors should be considered. Given the increasing incidence of kidney transplantation and the growing body of evidence addressing ESKD-specific cardiovascular risk profiles, there is an important need for a consolidated, evidence-based model that considers the unique cardiovascular challenges that these patients face. Cardiovascular physiology is altered in these patients by abrupt shifts in volume status, altered calcium-phosphate metabolism, high-output states (in the setting of arteriovenous fistulization), and adverse geometric and electrical remodeling, to name a few. Here, we present a contemporary review by addressing cardiomyopathy/heart failure, pulmonary hypertension, valvular dysfunction, and arrhythmia/sudden cardiac death within the ESKD population.

Cardiac Arrest and Cardiopulmonary Resuscitation Outcome Reports: Update of the Utstein Resuscitation Registry Template for In-Hospital Cardiac Arrest: A Consensus Report From a Task Force of the International Liaison Committee on Resuscitation (American Heart Association, European Resuscitation Council, Australian and New Zealand Council on Resuscitation, Heart and Stroke Foundation of Canada, InterAmerican Heart Foundation, Resuscitation Council of Southern Africa, Resuscitation Council of Asia)

Utstein-style reporting templates provide a structured framework with which to compare systems of care for cardiac arrest. The 2004 Utstein reporting template encompassed both out-of-hospital and in-hospital cardiac arrest. A 2015 update of the Utstein template focused on out-of-hospital cardiac arrest, which makes this update of the in-hospital template timely. Representatives of the International Liaison Committee on Resuscitation developed an updated in-hospital Utstein reporting template iteratively by meeting face-to-face, by teleconference, and by online surveys between 2013 and 2018. Data elements were grouped by hospital factors, patient variables, pre-event factors, cardiac arrest and postresuscitation processes, and outcomes. Elements were classified as core or supplemental by use of a modified Delphi process. Variables were described as core if they were considered essential. Core variables should enable reasonable comparisons between systems and are considered essential for quality improvement programs. Together with core variables, supplementary variables are considered useful for research.

Cardiac Arrest and Cardiopulmonary Resuscitation Outcome Reports: Update of the Utstein Resuscitation Registry Template for In-Hospital Cardiac Arrest: A Consensus Report From a Task Force of the International Liaison Committee on Resuscitation (American Heart Association, European Resuscitation Council, Australian and New Zealand Council on Resuscitation, Heart and Stroke Foundation of Canada, InterAmerican Heart Foundation, Resuscitation Council of Southern Africa, Resuscitation Council of Asia)

Utstein-style reporting templates provide a structured framework with which to compare systems of care for cardiac arrest. The 2004 Utstein reporting template encompassed both out-of-hospital and in-hospital cardiac arrest. A 2015 update of the Utstein template focused on out-of-hospital cardiac arrest, which makes this update of the in-hospital template timely. Representatives of the International Liaison Committee on Resuscitation developed an updated in-hospital Utstein reporting template iteratively by meeting face-to-face, by teleconference, and by online surveys between 2013 and 2018. Data elements were grouped by hospital factors, patient variables, pre-event factors, cardiac arrest and postresuscitation processes, and outcomes. Elements were classified as core or supplemental by use of a modified Delphi process. Variables were described as core if they were considered essential. Core variables should enable reasonable comparisons between systems and are considered essential for quality improvement programs. Together with core variables, supplementary variables are considered useful for research.

Invasive Management of Out of Hospital Cardiac Arrest

Out of hospital cardiac arrest (OHCA) is a major cause of morbidity and mortality worldwide. Clinical decision making is extremely difficult in this understudied patient population with high prevalence of neurological injury and inexorable shock states. As such, there are uncertain benefits from therapies available in the cardiac catheterization laboratory. Fear of futility and public reporting often affects decision making and can result in risk aversion. This review focuses on invasive management in OHCA care, with particular focus on coronary angiography, coronary revascularization, and mechanical support. Guidelines recommend emergency coronary angiography in patients with ST-segment elevations on ECG after OHCA, while the role of coronary angiography in patients without ST-segment elevations is less clear. Similar uncertainty remains in the appropriate revascularization strategy in these patients. As in other areas of cardiology, there is a growing interest in the role of mechanical circulatory support after OHCA, though the available literature shows mixed results. The many uncertainties associated with treating the patient with OHCA highlight the importance of clinical decision support tools and treatment algorithms in the care of this population. This review focuses on invasive management in OHCA care, with particular focus on coronary angiography, coronary revascularization, and mechanical support.

Duration of Heart Failure and Effect of Defibrillator Implantation in Patients With Nonischemic Systolic Heart Failure

BACKGROUND

Patients with nonischemic systolic heart failure (HF) have increased risk of sudden cardiac death (SCD) and death from progressive pump failure. Whether the risk of SCD changes over time is unknown. We seek here to investigate the relation between duration of HF, mode of death, and effect of implantable cardioverter-defibrillator implantation.

METHODS AND RESULTS

We examined the risk of all-cause death and SCD according to the duration of HF among patients with nonischemic systolic HF enrolled in the DANISH (Danish Study to Assess the Efficacy of ICDs in Patients with Non-ischemic Systolic Heart Failure on Mortality). In all, 1116 patients were included. Patients were divided according to quartiles of HF duration (≤8, 9≤18, 19≤65, and ≥66 months). Patients with the longest duration of HF were older, more often men, had more comorbidity, and more often received a cardiac resynchronization therapy device. Doubling of HF duration was an independent predictor of both all-cause mortality (hazard ratio [HR], 1.27; 95% CI, 1.17-1.38; P<0.0001), and SCD (HR, 1.29; 95% CI, 1.11-1.50; P=0.0007). The proportion of deaths caused by SCD was not different between HF quartiles (P=0.91), and the effect of implantable cardioverter-defibrillator implantation on all-cause mortality was not modified by the duration of HF (P=0.59).

CONCLUSIONS

Duration of HF predicted both all-cause mortality and risk of SCD independently of other risk indicators. However, the proportion of death caused by SCD did not change with longer duration of HF, and the effect of implantable cardioverter-defibrillator was not modified by the duration of HF.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT00542945.

Nationwide Study of Sudden Cardiac Death in People With Congenital Heart Defects Aged 0 to 35 Years

BACKGROUND

Congenital heart defects (CHD) are among the leading causes of sudden cardiac death (SCD) in the young. Nationwide incidence of SCD in people with CHD (SCD-CHD) has not been established in the young general population. The aims of this study were to investigate incidence of SCD-CHD and whether incidence of SCD-CHD in infants declined after implementation of nationwide fetal ultrasound screening in Denmark.

METHODS

All deaths (n=11 451) among people aged 0 to 35 years in Denmark in 2000 to 2009 (24.4 million person-years) were included. Danish death certificates, autopsy reports, records from hospitals and general practitioners, and data from nationwide Danish registries were used to identify SCD-CHD cases.

RESULTS

We identified 90 (11%) cases of SCD-CHD from 809 SCD. The incidence rate of SCD-CHD was 0.4 per 100 000 person-years among people aged 0 to 35 years. In total, 53 (59%) were diagnosed with CHD before death. Incidence of SCD was 9.6× higher among patients with CHD compared with people without CHD (P<0.01). Annual incidence of physical activity-related SCD-CHD among patients aged 2 to 35 years diagnosed with CHD was 0.9 per 100 000. The annual incidence rate of SCD-CHD in infants declined after implementation of nationwide fetal ultrasound screening (incidence rate ratio, 3.8; P<0.01).

CONCLUSIONS

The proportion of SCD-CHD in the young was 11%, which is higher than previously reported. Physical activity-related SCD-CHD was a rare event among patients with CHD. We observed an ≈4-fold lower incidence of SCD-CHD among infants born after implementation of nationwide screening.

Cardiac Implantable Electronic Device Interrogation at Forensic Autopsy: An Underestimated Resource?

BACKGROUND

Postmortem interrogations of cardiac implantable electronic devices (CIEDs), recommended at autopsy in suspected cases of sudden cardiac death, are rarely performed, and data on systematic postmortem CIED analysis in the forensic pathology are missing. The aim of the study was to determine whether nonselective postmortem CIED interrogations and data analysis are useful to the forensic pathologist to determine the cause, mechanism, and time of death and to detect potential CIED-related safety issues.

METHODS

From February 2012 to April 2017, all autopsy subjects in the department of forensic medicine at the University Hospital Charité who had a CIED underwent device removal and interrogation. Over the study period, 5368 autopsies were performed. One hundred fifty subjects had in total 151 CIEDs, including 109 pacemakers, 35 defibrillators, and 7 implantable loop recorders.

RESULTS

In 40 cases (26.7%) time of death and in 51 cases (34.0%) cause of death could not be determined by forensic autopsy. Of these, CIED interrogation facilitated the determination of time of death in 70.0% of the cases and clarified the cause of death in 60.8%. Device concerns were identified in 9 cases (6.0%), including 3 hardware, 4 programming, and 2 algorithm issues. One CIED was submitted to the manufacturer for a detailed technical analysis.

CONCLUSIONS

Our data demonstrate the necessity of systematic postmortem CIED interrogation in forensic medicine to determine the cause and timing of death more accurately. In addition, CIED analysis is an important tool to detect potential CIED-related safety issues.

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.

Mortality and Sudden Cardiac Death Risk Stratification Using the Noninvasive Combination of Wide QRS Duration and Late Gadolinium Enhancement in Idiopathic Dilated Cardiomyopathy

BACKGROUND

The aim of this study was to investigate whether the combination of QRS duration ≥120 ms (wide QRS duration [wQRS]) and late gadolinium enhancement (LGE) is a precise prognostic indicator for dilated cardiomyopathy.

METHODS AND RESULTS

We investigated the association between the combination of LGE plus wQRS and the primary end point (all-cause death) and a composite of sudden cardiac death (SCD) or aborted SCD in 531 patients with dilated cardiomyopathy. We also analyzed the association between the combination of LGE and wQRS and these end points among patients with a class I indication for implantable cardioverter defibrillator implantation. We divided study patients into 3 groups according to LGE status and QRS duration: 2 negative indices (LGE negative and narrow QRS), 1 positive index (LGE positive or wQRS), or 2 positive indices (LGE positive and wQRS), and followed them for 3.8 years. Multivariable Cox regression analysis identified 2 positive indices as a significant predictor of all-cause death (hazard ratio, 4.29 [1.19-15.47]; P=0.026). Among 317 patients with a class I indication for implantable cardioverter defibrillator, the 5-year event rate of SCD or aborted SCD was the lowest in the 2 negative indices group (1.4%). With propensity score-matching cohorts, the 2 negative indices group had a significantly lower event rate of SCD or aborted SCD than the other 2 groups (hazard ratio, 0.12 [0.01-0.97]; P=0.046).

CONCLUSIONS

The combination of LGE and wQRS provides additional prognostic stratification compared with LGE status alone and might improve the appropriate use of implantable cardioverter defibrillator therapy in patients with dilated cardiomyopathy.

Exercise-Induced Cardiac Troponin I Increase and Incident Mortality and Cardiovascular Events

BACKGROUND

Blood concentrations of cardiac troponin above the 99^th percentile are a key criterion for the diagnosis of acute myocardial injury and infarction. Troponin concentrations, even below the 99^th percentile, predict adverse outcomes in patients and the general population. Elevated troponin concentrations are commonly observed after endurance exercise, but the clinical significance of this increase is unknown. We examined the association between postexercise troponin I concentrations and clinical outcomes in long-distance walkers.

METHODS

We measured cardiac troponin I concentrations in 725 participants (61 [54-69] yrs) before and immediately after 30 to 55 km of walking. We tested for an association between postexercise troponin I concentrations above the 99^th percentile (>0.040 µg/L) and a composite end point of all-cause mortality and major adverse cardiovascular events (myocardial infarction, stroke, heart failure, revascularization, or sudden cardiac arrest). Continuous variables were reported as mean ± standard deviation when normally distributed or median [interquartile range] when not normally distributed.

RESULTS

Participants walked 8.3 [7.3-9.3] hours at 68±10% of their maximum heart rate. Baseline troponin I concentrations were >0.040 µg/L in 9 participants (1%). Troponin I concentrations increased after walking (P<.001), with 63 participants (9%) demonstrating a postexercise troponin concentration >0.040 µg/L. During 43 [23-77] months of follow-up, 62 participants (9%) experienced an end point; 29 died and 33 had major adverse cardiovascular events. Compared with 7% with postexercise troponin I ≤0.040 µg/L (log-rank P<.001), 27% of participants with postexercise troponin I concentrations >0.040 µg/L experienced an end point. The hazard ratio was 2.48 (95% CI, 1.29-4.78) after adjusting for age, sex, cardiovascular risk factors (hypertension, hypercholesterolemia or diabetes mellitus), cardiovascular diseases (myocardial infarction, stroke, or heart failure), and baseline troponin I concentrations.

CONCLUSIONS

Exercise-induced troponin I elevations above the 99^th percentile after 30 to 55 km of walking independently predicted higher mortality and cardiovascular events in a cohort of older long-distance walkers. Exercise-induced increases in troponin may not be a benign physiological response to exercise, but an early marker of future mortality and cardiovascular events.

Empagliflozin Reduced Mortality and Hospitalization for Heart Failure Across the Spectrum of Cardiovascular Risk in the EMPA-REG OUTCOME Trial

BACKGROUND

In the EMPA-REG OUTCOME trial (BI 10773 [Empagliflozin] Cardiovascular Outcome Event Trial in Type 2 Diabetes Mellitus Patients) in patients with type 2 diabetes mellitus and atherosclerotic cardiovascular disease, in comparison with placebo, empagliflozin reduced the risks of 3-point major adverse cardiovascular events (3-point MACE), cardiovascular and all-cause death, and hospitalization for heart failure. We investigated whether these effects varied across the spectrum of baseline cardiovascular risk.

METHODS

Cardiovascular death, all-cause mortality, 3-point MACE, and hospitalization for heart failure in the pooled empagliflozin and placebo groups were analyzed in subgroups by prior myocardial infarction and stroke at baseline, and by estimated baseline cardiovascular risk based on the 10-point TIMI (Thrombolysis In Myocardial Infarction) Risk Score for Secondary Prevention.

RESULTS

Of 7020 patients who received the study drug, 65% had a prior myocardial infarction or stroke, and 12%, 40%, 30%, and 18% were at low, intermediate, high, and highest estimated cardiovascular risk according to TIMI Risk Score for Secondary Prevention (≤2, 3, 4, and ≥5 points, respectively). In the placebo group, 3-point MACE occurred during the trial in 7.3%, 9.4%, 12.6%, and 20.6% of patients at low, intermediate, high, and highest estimated baseline risk, respectively. Relative reductions in risk of cardiovascular death, all-cause mortality, 3-point MACE and hospitalization for heart failure with empagliflozin versus placebo were consistent in patients with and without prior myocardial infarction and/or stroke and across subgroups by TIMI Risk Score for Secondary Prevention at baseline ( P>0.05 for randomized group-by-subgroup interactions).

CONCLUSIONS

Despite all patients having atherosclerotic cardiovascular disease, patients in EMPA-REG OUTCOME demonstrated a broad risk spectrum for cardiovascular events. Reductions in key cardiovascular outcomes and mortality with empagliflozin versus placebo were consistent across the range of cardiovascular risk.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov . Unique identifier: NCT01131676.