Genetic Variants Associated With Sudden Cardiac Death in Victims With Single Vessel Coronary Artery Disease and Left Ventricular Hypertrophy With or Without Fibrosis.

Objective: Cardiac hypertrophy with varying degrees of myocardial fibrosis is commonly associated with coronary artery disease (CAD) related sudden cardiac death (SCD), especially in young victims among whom patterns of coronary artery lesions do not entirely appear to explain the cause of SCD. Our aim was to study the genetic background of hypertrophy, with or without fibrosis, among ischemic SCD victims with single vessel CAD. Methods: The study population was derived from the Fingesture study, consisting of all autopsy-verified SCDs in Northern Finland between the years 1998 and 2017 (n = 5,869). We carried out targeted next-generation sequencing using a panel of 174 genes associated with myocardial structure and ion channel function in 95 ischemic-SCD victims (mean age 63.6 ± 10.3 years; 88.4% males) with single-vessel CAD in the absence of previously diagnosed CAD and cardiac hypertrophy with or without myocardial fibrosis at autopsy. Results: A total of 42 rare variants were detected in 43 subjects (45.3% of the study subjects). Five variants in eight subjects (8.4%) were classified as pathogenic or likely pathogenic. We observed 37 variants of uncertain significance in 39 subjects (40.6%). Variants were detected in myocardial structure protein coding genes, associated with arrhythmogenic right ventricular, dilated, hypertrophic and left ventricular non-compaction cardiomyopathies. Also, variants were detected in ryanodine receptor 2 (RYR2), a gene associated with both cardiomyopathies and catecholaminergic polymorphic ventricular tachycardias. Conclusions: Rare variants associated with cardiomyopathies, in the absence of anatomic evidence of the specific inherited cardiomyopathies, were common findings among CAD-related SCD victims with single vessel disease and myocardial hypertrophy found at autopsies, suggesting that these variants may modulate the risk for fatal arrhythmias and SCD in ischemic disease.

Association of Silent Myocardial Infarction and Sudden Cardiac Death.

Importance: Myocardial infarction in the absence of major or unrecognized symptoms are characterized as silent (SMI). The prevalence of SMI among individuals who experience sudden cardiac death (SCD), with or without concomitant electrocardiographic (ECG) changes, has not previously been described in detail from large studies to our knowledge. Objective: To determine the prevalence of SMI in individuals who experience SCD without a prior diagnosis of coronary artery disease (CAD) and to detect ECG abnormalities associated with SMI-associated SCD. Design, Setting, and Participants: This case-control study compared autopsy findings, clinical characteristics, and ECG markers associated with SMI in a consecutive cohort of individuals in the Finnish Genetic Study of Arrhythmic Events (Fingesture) study population who were verified to have had SCD. The Fingesture study consists of individuals who had autopsy-verified SCD in Northern Finland between 1998 and 2017. Individuals who had SCD with CAD and evidence of SMI were regarded as having had cases; those who had SCD with CAD without SMI were considered control participants. Analyses of ECG tests were carried out by investigators blinded to the SMI data. Data analysis was completed from October 2018 through November 2018. Main Outcomes and Measures: Silent MI was defined as a scar detected by macroscopic and microscopic evaluation of myocardium without previously diagnosed CAD. Clinical history was obtained from medical records, previously recorded ECGs, and a standardized questionnaire provided to the next of kin. The hypothesis tested was that SMI would be prevalent in the population who had had SCD with CAD, and it might be detected or suspected from findings on ECGs prior to death in many individuals. Results: A total of 5869 individuals were included (2459 males [78.8%]; mean [SD] age, 64.9 [12.4] years). The cause of SCD was CAD in 4392 individuals (74.8%), among whom 3122 had no history of previously diagnosed CAD. Two individuals were excluded owing to incomplete autopsy information. An ECG recorded prior to SCD was available in 438 individuals. Silent MI was detected in 1322 individuals (42.4%) who experienced SCD without a clinical history of CAD. The participants with SMI were older than participants without MI scarring (mean [SD] age, 66.9 [11.1] years; 65.5 [11.6] years; P < .001) and were more often men (1102 of 1322 [83.4%] vs 1357 of 1798 [75.5%]; P < .001). Heart weight was higher in participants with SMI (mean [SD] weight, 483 [109] g vs 438 [106] g; P < .001). In participants with SMI, SCD occurred more often during physical activity (241 of 1322 [18.2%] vs 223 of 1798 [12.4%]; P < .001). A prior ECG was abnormal in 125 of the 187 individuals (66.8%) who had SCD after SMI compared with 139 of 251 (55.4%) of those who had SCD without SMI (P = .02). Conclusions and Relevance: Many individuals who experienced SCD associated with CAD had a previously undetected MI at autopsy. Previous SMI was associated with myocardial hypertrophy and SCD during physical activity. Premortem ECGs in a subset with available data were abnormal in 67% of the individuals who had had a SCD after an SMI.

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

BACKGROUND: The prognostic value of T-wave morphology parameters in coronary artery disease in the current treatment era is not well established. METHODS: 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. RESULTS: During a follow-up period of 73 ± 22 months, 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). CONCLUSION: 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.

Fragmented QRS complex as a predictor of exercise-related sudden cardiac death.

INTRODUCTION: Little is known about the association between electrocardiographic abnormalities and exercise-related sudden cardiac death. Therefore, our aim was to identify possible electrocardiographic findings related to exercise-induced sudden cardiac death. METHODS AND RESULTS: The FinGesture study includes 3,989 consecutive sudden cardiac deaths in northern Finland between 1998 and 2012, out of whom a total of 647 subjects had a previously recorded electrocardiography acquired from the archives of Oulu University Hospital. In 276 of these cases the death was witnessed, and the activity at the time of death was either rest or physical exercise (PE); in 40 (14%) cases sudden cardiac death was exercise-related and in 236 (86%) cases death took place at rest. Fragmented QRS complex in at least two consecutive leads within anterior leads (V1-V3) was more common in the exercise-group compared to rest-group (17 of 40, 43% vs. 51 of 236, 22%, P  =  0.005). Pathologic Q wave in anterior leads was more common in the PE group (9 of 40, 23% vs. 26 of 236, 11%; P  =  0.044). Median QRS duration was prolonged in the exercise-group compared to the rest-group (100 milliseconds vs. 94 milliseconds, P = 0.047). QTc interval, the prevalence of inverted T-waves, or other electrocardiographic abnormalities did not differ significantly between the two groups. CONCLUSIONS: As a conclusion, fragmented QRS complex in the anterior leads is associated with an increased risk of sudden cardiac death during PE.

Inferolateral early repolarization among non-ischaemic sudden cardiac death victims.

Aim: Inferolateral early repolarization (ER) has been associated with an increased risk of sudden cardiac death (SCD). However, this association is thought to be mainly due to ischaemic SCD. The association of ER and non-ischaemic SCD has not been studied. The aim was to evaluate whether inferolateral ER is associated with non-ischaemic SCD. Methods and results: Study population consists of 275 consecutive victims of non-ischaemic SCD with 12-lead ECG and control group of general population cohort with 10 864 subjects. Sudden cardiac deaths were verified as non-ischaemic by medicolegal autopsy. Hypertensive cardiomyopathy (HTCMP) (25%), alcohol related dilated cardiomyopathy (ACMP) (24%), obesity associated cardiomyopathy (OCMP) (23%), and idiopathic myocardial fibrosis (IMF) (15%) were the most common causes of non-ischaemic SCD. A structurally normal heart was seen in only 1.5%. The prevalence of inferolateral ER was 20.7% among patients with non-ischaemic SCD compared to 5.3% in the general population (P < 0.001). The ECG pattern was accompanied with a horizontal/descending ST segment in 95% of the cases. The prevalence of inferolateral ER was slightly higher in the HTCMP group (26%) and the ACMP group (24%) than in the IMF group (20%) and the OCMP group (13%). The history of previously diagnosed cardiac diseases was not higher among subjects with ER (55%) than those without (59%, P = 0.59). Conclusion: The prevalence of inferolateral ER among non-ischaemic SCD victims is high. Almost all ER patterns are accompanied with the malignant horizontal/descending ST segment morphology suggesting that inferolateral ER is not only associated with an ischaemic SCD but also a non-ischaemic SCD.