Non-sudden Death Research Articles

Sudden Death After Hospitalization for Heart Failure With Reduced Ejection Fraction (from the EVEREST Trial)

Patients with chronic heart failure with reduced ejection fraction (HFrEF) benefit from medical and device therapies targeting sudden cardiac death (SCD). Contemporary estimates of SCD risk after hospitalization for heart failure are limited. We describe the incidence, timing, and clinical predictors of SCD after hospitalization for HFrEF (≤40%) in the EVEREST (Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study with Tolvaptan) trial. Multiple logistic regression analyses tested >30 baseline covariates (including treatment randomization, demographics, comorbid conditions, natriuretic peptides, ejection fraction, and medical and device therapies) to identify predictors of 1-year SCD. Of the 4,024 trial patients discharged alive (97%), there were 268 who experienced SCD (7%) and 703 who experienced non-SCD (17%) during median follow-up of 9.9 months. Implantable cardioverter defibrillator use at baseline was 14.5%. Estimates of SCD at 1, 3, 6, and 12 months were 0.8%, 2.3%, 4.1%, and 7.4%, respectively. Most patients were readmitted before SCD (n = 147, 55%). Male gender, black race, diabetes mellitus, and angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker use were potential predictors of 1-year SCD after hospitalization for HFrEF (all p <0.10); however, this final model demonstrated poor discrimination (C-statistic 0.57). In conclusion, in the EVEREST trial, patients hospitalized for HFrEF faced risks of 1-year postdischarge SCD of 7%, which accrued gradually over time, and were balanced with high competing risks of nonsudden death (17%). Traditional clinical characteristics fail to adequately predict SCD risk. Further data are needed to identify patients at greatest relative risk for SCD (compared with non-SCD) after hospitalization for HFrEF.

Abstract P018: Poincare Plot Asymmetry is Associated With Sudden Cardiac Death in the Community: The Atherosclerosis Risk in Community Study

Introduction: Poincare plot asymmetry has been associated with sustained ventricular tachyarrhythmias, implicating involvement of the autonomic nervous system. An association between sudden cardiac death (SCD) and Poincare plot asymmetry has not previously been studied in a general population cohort. Porta index measures time asymmetry in heart rate variability (HRV), corresponding to disproportionate relative tachycardic predominance. Hypothesis: We hypothesized that increasing tachycardic asymmetry as measured by Porta Index is associated with SCD. Methods: We analyzed 10-second ECG in 14,247 participants across 5 visits in the Atherosclerosis Risk in Communities (ARIC) cohort (mean age 54.1±5.87y; 6,380 [45%] men; 10,569 [74%] white, 1,582 [11%] with prevalent cardiovascular disease (CVD)). Participants with atrial fibrillation, premature contractions, sinoatrial (SA) or atrioventricular (AV) blocks II-III were excluded. Only normal sinus beats were included in the semi-automated analysis. Accuracy of automated R-peak detection was manually validated. SCD, non-SCD, and non-cardiac death served as competing outcomes in a Fine and Gray competing risk model. Results: Overall, there was larger variability in Porta index within the same participant from visit to visit (50.0±12.1) than between different participants (50.0±8.4). Over median follow-up of 24.4 years, there were 497 SCDs (incidence 1.66 [95% CI 1.52-1.82], 742 non-SCD (incidence 2.48 [95%CI 2.31-2.67], and 3,753 non-cardiac deaths (incidence 12.6 [95% CI 12.1-13.0]) per 1,000 person-years. In time-updated analysis, Porta index was independently associated with increased risk of SCD (HR 1.13 [1.04-1.23]). Neither non-sudden cardiac death nor non-cardiac death are associated with Porta ndex. Conclusion: Time-updated Poincare Plot asymmetry as measured by Porta index, reflecting tachycardic runs longer than bradycardic runs, is independently associated with SCD in the community. Poincare plot asymmetry requires further study.

Abstract P027: Time-updated Premature Ventricular Contractions on 12-lead ECG Are Associated With the Risk of Sudden Cardiac Death: Atherosclerosis Risk in Communities Study and Cardiovascular Health Study

Introduction: The association between premature ventricular contractions (PVCs) and Sudden Cardiac Death (SCD) remains controversial. Hypothesis: We hypothesized that PVCs are associated with SCD. Methods: Presence of PVCs was detected on 12-lead ECG recorded at baseline or any of 4 follow-up visits in 15,667 participants (pts) (mean age: 54.2 + 5.8 Yrs; 55% female; 73% Whites) of the Atherosclerosis Risk in Communities (ARIC) study. For validation cohort, we included baseline and 9 follow-up visits ECG data in 5,846 pts (mean age: 72.8+ 5.6 yrs; 57.7% female, 84.2% whites) from Cardiovascular Health Study (CHS). Competing risk analyses models were constructed to test the association between time-updated PVCs and SCD risk. Model 1 was adjusted for age, sex, race and study center. Model 2 in addition was adjusted for time-updated coronary heart disease, heart failure, atrial fibrillation, stroke, and hypertension. Results: In ARIC pts, across all study visits, PVCs were observed in 2.6% of the ECGs; 99.7% of pts were PVC-free at least once; 8.8% of pts had PVC at least once. 97.7% of pts without PVCs remained PVC-free at the next visit; 19.1% of pts with detected PVC had PVC at the next visit; 2.4% of pts who were PVC-free on previous ECG, transitioned to having PVC on subsequent visit ECG. In CHS, across all 10 yearly study visits, on average, PVC was observed on 4.85% of ECG recordings; 99.4% of participants were PVC-free at least once; 21.9% of pts had PVC at least once. 96.4% of PVC-free pts remained free from PVC at the next visit. 30.6% of pts with detected PVC on a given ECG had PVC at the next visit. 3.6% of pts who did not have PVC on previous ECG, transitioned to having PVC at the next visit. 69.4% of pts with PVC on a given ECG transitioned to being PVC-free next year. In adjusted competing risk analysis PVC was associated with SCD, but not with non-sudden cardiac death or non-cardiac death (Table). Conclusions: Time-updated presence of PVC on a short 10-sec resting 12-lead ECG is associated with SCD.

Prognostic value of T-wave morphology parameters in coronary artery disease in current treatment era.

The prognostic value of T-wave morphology parameters in coronary artery disease in the current treatment era is not well established. The Innovation to reduce Cardiovascular Complications of Diabetes at the Intersection (ARTEMIS) study included 1,946 patients with angiographically verified coronary artery disease (CAD). The study patients underwent thorough examinations including 12-lead digital electrocardiogram (ECG) at baseline. During a follow-up period of 73±22months, a total of 201 (10.3%) patients died. Of the study patients, 95 (4.9%) experienced cardiac death (CD) consisting of 44 (2.3%) sudden cardiac deaths (SCD) and 51 (2.6%) nonsudden cardiac deaths (NSCD), and 106 (5.4%) patients experienced noncardiac death (NCD). T-wave morphology dispersion (TMD), T-wave area dispersion (TWAD), and total cosine R-to-T (TCRT) had a significant association with CD even after adjustment with relevant clinical risk markers in the Cox regression analysis (multivariate HRs: 1.015, 95% CI 1.007-1.023, p=.0003; 0.474, 95% CI 0.305-0.737, p=.0009; 0.598, 95% CI 0.412-0.866, p=.006, respectively). When including these parameters to the clinical risk model for CD, the C-index increased from 0.810 to 0.823 improving the discrimination significantly (integrated discrimination index [IDI]=0.0118, 95% CI 0.0028-0.0208, p=.01). These parameters were more closely associated with NSCD (multivariate p-values from .016 to .001) than with SCD (univariate/multivariate p-values for TMD .015/.197 and for TCRT .012/.43). T-wave morphology parameters describing repolarization heterogeneity improve the predictive power of the clinical risk model for CD in patients with CAD in the current treatment era.

Analysis and strategy of related factors in patients with sudden cardiac death in Department of Cardiology

The clinical data of 196 cases of sudden death in hospital were randomly selected, which were divided into two groups: patients with sudden cardiac death (SCD) (n = 138) and non-sudden cardiac death (NSCD) (n = 58), of which 123 were male and 73 females; and according to their age, they were divided into three groups: age 60 group. The general situation, previous medical history (coronary heart disease, hypertension, diabetes mellitus), sudden death precipitating factors, aura and the results of laboratory-assisted examination of patients with SCD and SNCD were analyzed retrospectively to select the related risk factors of SCD.

Heart rate variability: implications for perioperative anesthesia care.

Heart rate variability (HRV) is a measure of the balance between both the parasympathetic and sympathetic nervous system and may provide useful information for anesthesia care providers. HRV may offer predictive information about critically ill and operative patients. Further, HRV collection provides real-time information of patient autonomic nervous system status and may allow tailoring of the analgesia for patients in the ICU and operating room. Reduced and abnormal resting HRV predict sudden and nonsudden cardiac death. Recent evidence shows that decreased HRV correlates with worsened outcomes in both trauma patients and patients with sepsis, as well as the risk of developing hypotension after induction of general anesthesia and placement of intrathecal local anesthesia. In addition, HRV appears to provide an accurate assessment of the nociception-analgesia balance in deeply sedated ICU patients and those under general anesthesia. No study has assessed the prognostic value of preoperative HRV in patients presenting for surgery. Use of HRV for patient risk stratification and intraoperative analgesia management may allow tailored perioperative care and improved outcomes. If intraoperative HRV data leads to decreased perioperative opioid use, opioid-related adverse events, a serious perioperative issue, may be decreased. Not applicable.

Ventricular Tachycardia Ablation in the Elderly

Successful ventricular tachycardia (VT) ablation is associated with improved survival in patients with heart failure. However, the safety and efficacy of VT ablation in the elderly, a population with higher competing nonsudden death risk and comorbidities, have not been well defined. The International Ventricular Tachycardia Center Collaborative Study Group registry of 2061 patients who underwent VT ablation at 12 international centers was analyzed. Kaplan-Meier analysis was used to estimate survival of patients ≥70 years with and without VT recurrence. Of the 2049 patients who met inclusion criteria, 681 (33%) patients were ≥70 years of age (mean age, 75±4 years). Among these, 92% were men, 71% had ischemic VT, and 42% had VT storm at presentation. Mean (±SD) left ventricular ejection fraction was 30±11%. Compared with patients <70 years, patients ≥70 years had higher in-hospital (4.4% versus 2.3%; P=0.01) and 1-year mortality (15% versus 11%; P=0.002) but a similar incidence of VT recurrence at 1 year (26% versus 25%; P=0.74) and time to VT recurrence (280 versus 289 days; P=0.20). Absence of VT recurrence during follow-up was strongly associated with improved survival in patients ≥70 years. VT ablation in the elderly is feasible and reasonably safe with a modestly higher in-hospital and 1-year mortality, with similar rates of VT recurrence at 1 year compared with younger patients. Successful VT ablation, that is, lack of VT recurrence, is strongly associated with improved survival even in this elderly subgroup.

Predictors of sudden cardiac death in atrial fibrillation: The Atherosclerosis Risk in Communities (ARIC) study.

We previously reported that incident atrial fibrillation (AF) is associated with an increased risk of sudden cardiac death (SCD) in the general population. We now aimed to identify predictors of SCD in persons with AF from the Atherosclerosis Risk in Communities (ARIC) study, a community-based cohort study. We included all participants who attended visit 1 (1987–89) and had no prior AF (n = 14,836). Incident AF was identified from study electrocardiograms and hospitalization discharge codes through 2012. SCD was physician-adjudicated. We used cause-specific Cox proportional hazards models, followed by stepwise selection (backwards elimination, removing all variables with p>0.10) to identify predictors of SCD in participants with AF. AF occurred in 2321 (15.6%) participants (age 45–64 years, 58% male, 18% black). Over a median of 3.3 years, SCD occurred in 110 of those with AF (4.7%). Predictors of SCD in AF included higher age, body mass index (BMI), coronary heart disease, hypertension, diabetes, current smoker, left ventricular hypertrophy, increased heart rate, and decreased albumin. Predictors associated only with SCD and not other cardiovascular (CV) death included increased BMI (HR per 5-unit increase, 1.15, 95% CI, 0.97–1.36, p = 0.10), increased heart rate (HR per SD increase, 1.18, 95% CI 0.99–1.41, p = 0.07), and low albumin (HR per SD decrease 1.23, 95% CI 1.02–1.48, p = 0.03). In the ARIC study, predictors of SCD in AF that are not associated with non-sudden CV death included increased BMI, increased heart rate, and low albumin. Further research to confirm these findings in larger community-based cohorts and to elucidate the underlying mechanisms to facilitate prevention is warranted.

Highlights From the Circulation Family of Journals.

Highlights From the Circulation Family of Journals.

Denervated Myocardium Is Preferentially Associated With Sudden Cardiac Arrest in Ischemic Cardiomyopathy: A Pilot Competing Risks Analysis of Cause-Specific Mortality.

Previous studies have identified multiple risk factors that are associated with total cardiac mortality. Nevertheless, identifying specific factors that distinguish patients at risk of arrhythmic death versus heart failure could better target patients likely to benefit from implantable cardiac defibrillators, which have no impact on nonsudden cardiac death. We performed a pilot competing risks analysis of the National Institutes of Health-sponsored PAREPET trial (Prediction of Arrhythmic Events with Positron Emission Tomography). Death from cardiac causes was ascertained in subjects with ischemic cardiomyopathy (n=204) eligible for an implantable cardiac defibrillator for the primary prevention of sudden cardiac arrest after baseline clinical evaluation and imaging at enrollment (positron emission tomography and 2-dimensional echo). Mean age was 67±11 years with an ejection fraction of 27±9%, and 90% were men. During 4.1 years of follow-up, there were 33 sudden cardiac arrests (arrhythmic death or implantable cardiac defibrillator discharge for ventricular fibrillation or ventricular tachycardia >240 bpm) and 36 nonsudden cardiac deaths. Sudden cardiac arrest was correlated with a greater volume of denervated myocardium (defect of the positron emission tomography norepinephrine analog 11C-hydroxyephedrine), lack of angiotensin inhibition therapy, elevated B-type natriuretic peptide, and larger left ventricular end-diastolic volume index. In contrast, nonsudden cardiac death was associated with a higher resting heart rate, older age, elevated creatinine, larger left atrial volume index, and larger left ventricular end-diastolic volume index. Distinct clinical, laboratory, and imaging variables are associated with cause-specific cardiac mortality in primary-prevention candidates with ischemic cardiomyopathy. If prospectively validated, these multivariable associations may help target specific therapies to those at the greatest risk of sudden and nonsudden cardiac death. URL: https://clinicaltrials.gov. Unique identifier: NCT01400334.

New York Heart Association class and the survival benefit from primary prevention implantable cardioverter defibrillators: A pooled analysis of 4 randomized controlled trials

Primary prevention implantable cardioverter defibrillator (ICD) reduce all-cause mortality by reducing sudden cardiac death. There are conflicting data regarding whether patients with more advanced heart failure derive ICD benefit owing to the competing risk of nonsudden death. We performed a patient-level meta-analysis of New York Heart Association (NYHA) class II/III heart failure patients (left ventricular ejection fraction ≤35%) from 4 primary prevention ICD trials (MADIT-I, MADIT-II, DEFINITE, SCD-HeFT). Bayesian-Weibull survival regression models were used to assess the impact of NYHA class on the relationship between ICD use and mortality. Of the 2,763 patients who met study criteria, 68% (n=1,867) were NYHA II and 52% (n=1,435) were randomized to an ICD. In a multivariable model including all study patients, the ICD reduced mortality (hazard ratio [HR] 0.65, 95% posterior credibility interval [PCI]) 0.40-0.99). The interaction between NYHA class and the ICD on mortality was significant (posterior probability of no interaction=.036). In models including an interaction term for the NYHA class and ICD, the ICD reduced mortality among NYHA class II patients (HR 0.55, PCI 0.35-0.85), and the point estimate suggested reduced mortality in NYHA class III patients (HR 0.76, PCI 0.48-1.24), although this was not statistically significant. Primary prevention ICDs reduce mortality in NYHA class II patients and trend toward reducing mortality in the heterogeneous group of NYHA class III patients. Improved risk stratification tools are required to guide patient selection and shared decision making among NYHA class III primary prevention ICD candidates.

Long-term Non-Invasive ECG-based Risk Stratification of Sudden Cardiac Death: Extended 5-year Results

&lt;p&gt;Objectives: To evaluate predictive value of heart rate turbulence (HRT), deceleration capacity (DC) and microvolt T-wave alternans (mTWA) for risk stratification for sudden cardiac death (SCD) in patients after myocardial infarction (MI) during 60 months of follow-up.&lt;/p&gt;&lt;p&gt;Methods: We studied 111 patients after MI occurred &amp;gt; 60 days (27 [9; 84] months) before enrollment (84 men; mean age 64.1±10.5 years). All subjects had 24-hour ambulatory ECG monitoring with HRT, DC and mTWA evaluation. Follow-up period was 60 months; primary endpoint was SCD, secondary endpoint included all non-sudden cardiovascular deaths.&lt;/p&gt;&lt;p&gt;Results: During follow-up, we registered 19 cases of SCD and 11 cases of non-sudden cardiovascular deaths (including 7 fatal MI and 3 fatal strokes). DC had high negative predictive value (97.4% for all-cause mortality and 93.7% for SCD). DC values below 4.15 for all-cause mortality and 2.0 for SCD significantly increased risk of all-cause mortality (OR 8.5, 95% CI 2.9 to 24.6, р&amp;lt;0.001) и SCD (OR 9.6, 95% CI 3.2 to 28.5, р&amp;lt;0.001). Combined risk assessment at 12 months revealed that the most significant combination was HRT2 and mTWA100 &amp;gt; 53 mcV, which increased risk both of all-cause mortality (30.7-fold) and SCD (63.3-fold); however, at 60 months this predictive value for SCD decreased (OR = 20.8 (95% CI 2.8 to 114.0), p &amp;lt;0.001).&lt;/p&gt;Conclusion: Evaluation of HRT, DC and mTWA during 24-hour ECG monitoring may define the high risk of cardiovascular mortality and SCD in post-MI patients especially during the first 12 months after the baseline examination.

52 Suitability for subcutaneous implantable cardioverter-defibrillator therapy – the impact of different selection policies

BackgroundWith subcutaneous ICDs (S-ICD) not offering the same range of pacing therapies as transvenous systems (T-ICD), it is unclear how many ICD recipients may be suitable for a S-ICD. In...

Association Between Midwall Late Gadolinium Enhancement and Sudden Cardiac Death in Patients With Dilated Cardiomyopathy and Mild and Moderate Left Ventricular Systolic Dysfunction.

Current guidelines only recommend the use of an implantable cardioverter defibrillator in patients with dilated cardiomyopathy for the primary prevention of sudden cardiac death (SCD) in those with a left ventricular ejection fraction (LVEF) <35%. However, registries of out-of-hospital cardiac arrests demonstrate that 70% to 80% of such patients have an LVEF >35%. Patients with an LVEF >35% also have low competing risks of death from nonsudden causes. Therefore, those at high risk of SCD may gain longevity from successful implantable cardioverter defibrillator therapy. We investigated whether late gadolinium enhancement (LGE) cardiovascular magnetic resonance identified patients with dilated cardiomyopathy without severe LV systolic dysfunction at high risk of SCD. We prospectively investigated the association between midwall LGE and the prespecified primary composite outcome of SCD or aborted SCD among consecutive referrals with dilated cardiomyopathy and an LVEF ≥40% to our center between January 2000 and December 2011 who did not have a preexisting indication for implantable cardioverter defibrillator implantation. Of 399 patients (145 women, median age 50 years, median LVEF 50%, 25.3% with LGE) followed for a median of 4.6 years, 18 of 101 (17.8%) patients with LGE reached the prespecified end point, compared with 7 of 298 (2.3%) without (hazard ratio [HR], 9.2; 95% confidence interval [CI], 3.9-21.8; P<0.0001). Nine patients (8.9%) with LGE compared with 6 (2.0%) without (HR, 4.9; 95% CI, 1.8-13.5; P=0.002) died suddenly, whereas 10 patients (9.9%) with LGE compared with 1 patient (0.3%) without (HR, 34.8; 95% CI, 4.6-266.6; P<0.001) had aborted SCD. After adjustment, LGE predicted the composite end point (HR, 9.3; 95% CI, 3.9-22.3; P<0.0001), SCD (HR, 4.8; 95% CI, 1.7-13.8; P=0.003), and aborted SCD (HR, 35.9; 95% CI, 4.8-271.4; P<0.001). Estimated HRs for the primary end point for patients with an LGE extent of 0% to 2.5%, 2.5% to 5%, and >5% compared with those without LGE were 10.6 (95% CI, 3.9-29.4), 4.9 (95% CI, 1.3-18.9), and 11.8 (95% CI, 4.3-32.3), respectively. Midwall LGE identifies a group of patients with dilated cardiomyopathy and an LVEF ≥40% at increased risk of SCD and low risk of nonsudden death who may benefit from implantable cardioverter defibrillator implantation. URL: http://clinicaltrials.gov. Unique identifier: NCT00930735.

Prediction of sudden and non-sudden cardiac death in post-infarction patients with reduced left ventricular ejection fraction by periodic repolarization dynamics: MADIT-II substudy.

AimsTo test the value of Periodic Repolarization Dynamics (PRD), a recently validated electrocardiographic marker of sympathetic activity, as a novel approach to predict sudden cardiac death (SCD) and non-sudden cardiac death (N-SCD) and to improve identification of patients that profit from ICD-implantation.Methods and resultsWe included 856 post-infarction patients with left-ventricular ejection fraction (LVEF) ≤30% of the MADIT-II trial in sinus rhythm. Of these, 507 and 348 patients were randomized to ICD or conventional treatment. PRD was assessed from multipolar 10-min baseline ECGs. Primary and secondary endpoints were total mortality, SCD and N-SCD. Multivariable analyses included treatment group, QRS-duration, New York Heart Association classification, blood-urea nitrogen, diabetes mellitus, beta-blocker therapy and LVEF. During follow-up of 20.4 months, 119 patients died (53 SCD and 36 N-SCD). On multivariable analyses, increased PRD was a significant predictor of mortality (standardized coefficient 1.37[1.19–1.59]; P < 0.001) and SCD (1.40 [1.13–1.75]; P = 0.003) but also predicted N-SCD (1.41[1.10–1.81]; P = 0.006). While increased PRD predicted SCD in conventionally treated patients (1.61[1.23–2.11]; P < 0.001), it was predictive of N-SCD (1.63[1.28–2.09]; P < 0.001) and adequate ICD-therapies (1.20[1.03–1.39]; P = 0.017) in ICD-treated patients. ICD-treatment substantially reduced mortality in the lowest three PRD-quartiles by 53% (P = 0.001). However, there was no effect in the highest PRD-quartile (mortality increase by 29%; P = 0.412; P < 0.001 for difference) as the reduction of SCD was compensated by an increase of N-SCD.ConclusionIn post-infarction patients with impaired LVEF, PRD is a significant predictor of SCD and N-SCD. Assessment of PRD is a promising tool to identify post-MI patients with reduced LVEF who might benefit from intensified treatment.

Identifying patients with less potential to benefit from implantable cardioverter-defibrillator therapy: comparison of the performance of four risk scoring systems

PurposePatients at high non-sudden cardiac death risk may gain no significant benefit from implantable cardioverter-defibrillator (ICD) therapy. A number of approaches have been proposed to identify these patients, including single clinical markers and more complex scoring systems. The aims of this study were to use the proposed scoring systems to (1) establish how many current ICD recipients may be too high risk to derive significant benefit from ICD therapy and (2) evaluate how well the scoring systems predict short-term mortality in an unselected ICD cohort.MethodsWe performed a single-centre retrospective observational study of all new ICD implants over 5 years (2009–2013). We used four published scoring systems (Bilchick, Goldenberg, Kramer and Parkash) and serum urea to identify new ICD recipients whose short-term predicted mortality risk was high. We evaluated how well the scoring systems predicted death.ResultsOver 5 years, there were 406 new implants (79% male, mean age 70 (60–76), 58% primary prevention). During a follow-up of 936 ± 560 days, 96 patients died. Using the scoring systems, the proportion of ICD recipients predicted to be at high short-term mortality risk were 5.9% (Bilchick), 34.7% (Goldenberg), 7.4% (Kramer), 21.4% (Parkash) and 25% (urea, cut-off of >9.28 mM). All four risk scores predicted mortality (P < 0.0001); however, none outperformed urea for the prediction of 1- or 3-year mortality.ConclusionsUsing published scoring systems, a significant proportion of current ICD recipients are at high short-term mortality risk. Although all four scoring systems predicted mortality during follow-up, none significantly outperformed serum urea.

Abstract MP083: Autonomic Imbalance at the Level of Atrioventricular Node, but Not at the Level of Sinus Node, is Associated With Sudden Cardiac Death: The Atherosclerosis Risk in Community Study

Introduction: Autonomic imbalance, quantified by decreased heart rate variability (HRV), is associated with increased cardiovascular mortality. It is unknown if autonomic influences on sinus and atrioventricular (AV) nodes are equally important for the risk of sudden cardiac death (SCD). Hypothesis: Autonomic influences on sinus and AV node are equally strongly associated with increased SCD, non-sudden cardiac death (non-SCD), and non-cardiac death. Methods: Baseline visit 10-second ECGs (n=14,250) of the Atherosclerosis Risk in Communities (ARIC) cohort were analyzed. Normalized variance of P-onset to P-onset intervals (PPVN) and QRS-onset to QRS-onset intervals (QQVN) was calculated to assess autonomic influence on sinus and AV node respectively. Normalized variance of Rpeak - Rpeak intervals was determined as HRV measure. Values were log-transformed to normalize distribution. SCD served as primary outcome. Secondary outcomes were non-SCD and non-cardiac death. Three Cox regression models were constructed for dichotomized at 20 th percentile predictor variables. Results: Over median follow-up of 24.4 years, there were 497 SCDs (incidence 1.66 [95%CI 1.52-1.82], 742 non-SCDs (incidence 2.48 [95%CI 2.31-2.67], and 3,753 non-cardiac deaths (incidence 12.6 [95%CI 12.1-13.0]) per 1,000 person-years. In paired analysis, LogPPVN was significantly larger than LogQQVN (-7.28±1.06 vs. -7.72±1.24; P&lt;0.0001). There was no difference between LogQQVN and Log RRVN (-7.72±1.24 vs -7.72±1.23; P=0.364). After full adjustment, LogRRVN and LogQQVN were significantly associated with non-SCD and SCD. Association with non-SCD was stronger. LogPPVN was independently associated with non-SCD but not SCD. No value was associated with non-cardiac death. Conclusion: Autonomic imbalance at the AV node, with likely summary effect at the bundle of His, is associated with SCD and non-SCD. Autonomic imbalance at the SA node is associated with non-SCD only. Autonomic input to SA and AV node should be further studied.

Abstract MP081: Short-long-short Sequence of RR Intervals is Associated With Increased Risk of Sudden Cardiac Death: the Atherosclerosis Risk in Community Study

Introduction: A Short-long-short sequence of RR’ intervals frequently precedes ventricular tachyarrhythmia. However, an association of RR’ alternans with sudden cardiac death (SCD) in the general population has not been previously studied. Hypothesis: We hypothesized that RR’ alternans is associated with SCD. Methods: We analyzed baseline visit 10-second ECG in 14,250 participants of the Atherosclerosis Risk in Communities (ARIC) cohort (mean age 54.1±5.87y; 45% men; 74% white). Only normal sinus beats were included in the semi-automated analysis. Digital 12-lead ECG was transformed into orthogonal ECG, from which respiratory signal was derived. Joint symbolic analysis was used to assess increase or decrease in successive RR’ intervals and R-instant respiratory phases calculated using the Hilbert transform. Short-long-short or long-short-long RR’ sequence was defined as RR’ alternans. RR’ alternans occurring during respiratory phase transitions were not considered. SCD, non-SCD, and non-cardiac death served as competing outcomes. Three competing risks models were constructed. Model 1 was adjusted for age, sex, race, and study center. Model 2 was in addition adjusted for prevalent CVD. Model 3 was further adjusted for subclinical CVD, its risk factors, including traditional ECG predictors, and medications affecting SA or AV nodes. Results: Over median follow-up of 24.4 years, there were 497 SCDs (incidence 1.66 [95%CI 1.52-1.82], 742 non-sudden cardiac deaths (incidence 2.48 [95%CI 2.31-2.67], and 3,753 non-cardiac deaths (incidence 12.6 [95%CI 12.1-13.0]) per 1,000 person-years. RR alternans was present in 1,679(11.8%) participants. In competing risks analysis (Table) the presence of RR’ alternans, excluding those occurring due to respiratory phase changes, was independently associated with increased risk of SCD. Conclusion: In competing risks analysis the presence of RR’ alternans that are not due to respiratory phase transition is associated with SCD. Further study of RR’ alternans is warranted.

Long-term prognosis associated with early repolarisation pattern in Chinese population with atherosclerotic risk factors

BackgroundRecent evidence has linked early repolarisation pattern (ERP) to sudden cardiac death (SCD) in patients without structural heart disease. However, no studies have clarified the prognostic value of ERP in...

Distinguishing between those dying suddenly or not suddenly from coronary heart disease: long-term prospective results from the Northwick Park Heart Study

AimTo establish whether ECG findings are associated with subsequent risk of sudden death from coronary heart disease (CHD).Methods and resultsPotential risk factors for CHD were measured at entry to the...