Causes and characteristics of unexpected sudden cardiac death in octogenarians/nonagenarians

Abstract Introduction: The risk for sudden cardiac death (SCD) increases with ageing. Methods: We evaluated causes and characteristics of unexpected SCD in SCD victims aged ≥ 80 years in a consecutive series of 5,869 SCD victims in Northern Finland. All the victims underwent medico-legal autopsy as medico-legal autopsy is mandatory in cases of unexpected sudden death in Finland. All the non-cardiac deaths such as pulmonary embolism and cerebral hemorrhage were excluded from the study, as were unnatural deaths such as intoxications. Results: Among SCD victims ≥ 80 years, 91.0% of SCDs were due to ischemic heart disease (IHD) determined in autopsy and 9.0% due to non-ischemic heart disease (NIHD), whereas among those < 80 years, only 72.6% of SCDs were due to IHD and 27.4% due to NIHD (P < .001). Severe fibrosis in myocardium was more common whereas heart weight and liver weight, body mass index and abdominal fat thickness, were lower among SCD victims aged ≥ 80 years than among victims aged < 80 years. In those with IHD as etiology of SCD, at least 75% stenosis in one or more major coronary vessels was more common in SCD victims aged ≥ 80 years than among victims aged < 80 years (P = .001). SCD victims 80 years or older were less likely to die during physical activity than those under 80 years old (5.6% vs. 15.9%, P < .001). Dying in sauna was more common among those ≥ 80 years than among those < 80 years (5.5% vs. 2.6%, P < .001). Conclusion: In victims of unexpected SCD aged ≥ 80 years, the autopsy-based etiology of SCD was more commonly IHD than in those aged < 80 years. In SCD victims aged ≥ 80 years, severe fibrosis in myocardium, representing arrhythmic substrate, was more common than in the younger ones

Risk factors associated with atrioventricular block

Abstract Importance: Pacemaker implantations as a treatment for atrioventricular (AV) block are increasing worldwide. Prevention strategies for AV block are lacking because modifiable risk factors have not yet been identified. Objective: To identify risk factors for AV block in community-dwelling individuals. Design, Setting, and Participants: In this population-based cohort study, data from the Mini-Finland Health Survey, conducted from January 1, 1978, to December 31, 1980, were used to examine demographics, comorbidities, habits, and laboratory and electrocardiographic (ECG) measurements as potential risk factors for incident AV block. Data were ascertained during follow-up from January 1, 1987, through December 31, 2011, using a nationwide registry. A total of 6146 community-dwelling individuals were included in the analysis performed from January 15 through April 3, 2018. Main Outcomes and Measures: Incidence of AV block (hospitalization for second- or third-degree AV block). Results: Among the 6146 participants (3449 [56.1%] women; mean [SD] age, 49.2 [12.9] years), 529 (8.6%) had ECG evidence of conduction disease and 58 (0.9%) experienced a hospitalization with AV block. Older age (hazard ratio [HR] per 5-year increment, 1.34; 95% CI, 1.16–1.54; P < 0.001), male sex (HR, 2.04; 95% CI, 1.19–3.45; P = 0.01), a history of myocardial infarction (HR, 3.54; 95% CI, 1.33–9.42; P = 0.01), and a history of congestive heart failure (HR, 3.33; 95% CI, 1.10–10.09; P = 0.03) were each independently associated with AV block. Two modifiable risk factors were also independently associated with AV block. Every 10–mm Hg increase in systolic blood pressure was associated with a 22% higher risk (HR, 1.22; 95% CI, 1.10–1.34; P = 0.005), and every 20-mg/dL increase in fasting glucose level was associated with a 22% higher risk (HR, 1.22; 95% CI, 1.08–1.35; P = 0.001). Both risk factors remained statistically significant (HR for systolic blood pressure, 1.26 [95% CI, 1.06–1.49; P = 0.007]; HR for glucose level, 1.22 [95% CI, 1.04–1.43; P = 0.01]) after adjustment for major adverse coronary events during the follow-up period. In population-attributable risk assessment, an estimated 47% (95% CI, 8%–67%) of AV blocks may have been avoided if all participants exhibited ideal blood pressure and 11% (95% CI, 2%–21%) may have been avoided if all had a normal fasting glucose level. Conclusions and Relevance: In this analysis of data from a population-based cohort study, suboptimal blood pressure and fasting glucose level were associated with AV block. These results suggest that a large proportion of AV blocks are assocated with these risk factors, even after adjusting for other major adverse coronary events

Electrocardiographic risk markers for heart failure in women versus men

Abstract Heart failure (HF) is one of the leading causes of hospitalization in the Western world. Women have a lower HF hospitalization rate and mortality compared with men. The role of electrocardiography as a risk marker of future HF in women is not well known. We studied association of electrocardiographic (ECG) risk factors for HF hospitalization in women from a large middle-aged general population with a long-term follow-up and compared the risk profile to men. Standard 12-lead ECG markers were analyzed from 10,864 subjects (49% women), and their predictive value for HF hospitalization was analyzed. During the follow-up (30 ± 11 years), a total of 1,743 subjects had HF hospitalization; of these, 861 were women (49%). Several baseline characteristics, such as age, body mass index, blood pressure, and history of previous cardiac disease predicted the occurrence of HF both in women and men (p <0.001 for all). After adjusting for baseline variables, ECG sign of left ventricular hypertrophy (LVH) (p <0.001), and atrial fibrillation (p <0.001) were the only baseline ECG variables that predicted future HF in women. In men, HF was predicted by fast heart rate (p = 0.008), T wave inversions (p <0.001), abnormal Q-waves (p = 0.002), and atrial fibrillation (p <0.001). Statistically significant gender interactions in prediction of HF were observed in ECG sign of LVH, inferolateral T wave inversions, and heart rate. In conclusion, ECG sign of LVH predicts future HF in middle-aged women, and T wave inversions and elevated heart rate are associated with HF hospitalization in men

Experiences in digitizing and digitally measuring a paper-based ECG archive

Abstract Background: No established method for digitizing and digital measuring of paper electrocardiograms (ECG) exists. We describe a paper ECG digitizing and digital measuring process, and report comparability to manual measurements. Methods: A paper ECG was recorded from 7203 health survey participants in 1978–1980. With specific software, the ECGs were digitized (ECG Trace Tool), and measured digitally (EASE). A sub-sample of 100 ECGs was selected for manual measurements. Results: The measurement methods showed good agreement. The mean global (EASE)-(manual) differences were 1.4 ms (95% CI 0.5–2.2) for PR interval, −1.0 ms (95% CI −1.5–[−0.5]) for QRS duration, and 11.6 ms (95% CI 10.5–12.7) for QT interval. The mean inter-method amplitude differences of RampV5, RampV6, SampV1, TampII and TampV5 ranged from −0.03 mV to 0.01 mV. Conclusions: The presented paper-to-digital conversion and digital measurement process is an accurate and reliable method, enabling efficient storing and analysis of paper ECGs

Electrocardiographic risk markers of cardiac death:gender differences in the general population

Abstract Background: Cardiac death is one of the leading causes of death and sudden cardiac death (SCD) is estimated to cause approximately 50% of cardiac deaths. Men have a higher cardiac mortality than women. Consequently, the mechanisms and risk markers of cardiac mortality are not as well defined in women as they are in men. Aim: The aim of the study was to assess the prognostic value and possible gender differences of SCD risk markers of standard 12-lead electrocardiogram in three large general population samples. Methods: The standard 12-lead electrocardiographic (ECG) markers were analyzed from three different Finnish general population samples including total of 20,310 subjects (49.9% women, mean age 44.8 ± 8.7 years). The primary endpoint was cardiac death, and SCD and all-cause mortality were secondary endpoints. The interaction effect between women and men was assessed for each ECG variable. Results: During the follow-up (7.7 ± 1.2 years), a total of 883 deaths occurred (24.5% women, p < 0.001). There were 296 cardiac deaths (13.9% women, p < 0.001) and 149 SCDs (14.8% women, p < 0.001). Among those who had died due to cardiac cause, women had more often a normal electrocardiogram compared to men (39.0 vs. 27.5%, p = 0.132). After adjustments with common cardiovascular risk factors and the population sample, the following ECG variables predicted the primary endpoint in men: left ventricular hypertrophy (LVH) with strain pattern (p < 0.001), QRS duration > 110 ms (p < 0.001), inferior or lateral T-wave inversion (p < 0.001) and inferolateral early repolarization (p = 0.033). In women none of the variables remained significant predictors of cardiac death in multivariable analysis, but LVH, QTc ≥ 490 ms and T-wave inversions predicted SCD (p < 0.047 and 0.033, respectively). In the interaction analysis, LVH (HR: 2.4; 95% CI: 1.2–4.9; p = 0.014) was stronger predictor of primary endpoint in women than in men. Conclusion: Several standard ECG variables provide independent information on the risk of cardiac mortality in men but not in women. LVH and T-wave inversions predict SCD also in women

Poor R-wave progression as a predictor of sudden cardiac death in the general population and subjects with coronary artery disease

Abstract Background: Poor R-wave progression (PRWP) is a common clinical finding on the standard 12-lead electrocardiogram (ECG), but its prognostic significance is unclear. Objective: The purpose of this study was to examine the prognosis associated with PRWP in terms of sudden cardiac death (SCD), cardiac death, and all-cause mortality in general population subjects with and without coronary artery disease (CAD). Methods: Data and 12-lead ECGs were collected from a Finnish general population health examination survey conducted during 1978–1980 with follow-up until 2011. The study population consisted of 6854 subjects. Main end points were SCD, cardiac death, and all-cause mortality. PRWP was defined as R-wave amplitude ≤ 0.3 mV in lead V₃ and R-wave amplitude in lead V₂ ≤ R-wave amplitude in lead V₃. Results: PRWP occurred in 213 subjects (3.1%). During the follow-up period of 24.3 ± 10.4 years, 3723 subjects (54.3%) died. PRWP was associated with older age, higher prevalence of heart failure and CAD, and β-blocker medication. In multivariate analyses, PRWP was associated with SCD (hazard ratio [HR] 2.13; 95% confidence interval [CI] 1.34–3.39), cardiac death (HR 1.75; 95% CI 1.35–2.15), and all-cause mortality (HR 1.29; 95% CI 1.08–1.54). In the subgroup with CAD, PRWP had a stronger association with cardiac mortality (HR 1.71; 95% CI 1.19–2.46) than in the subgroup without CAD, while the association with SCD was significant only in the subgroup with CAD (HR 2.62; 95% CI 1.38–4.98). Conclusions: PRWP was associated with adverse prognosis in the general population and with SCD in subjects with CAD

Increased beat-to-beat variability of T-wave heterogeneity measured from standard 12-lead electrocardiogram Is associated with sudden cardiac death:a case–control study

Abstract Introduction: The prognostic significance of beat-to-beat variability of spatial heterogeneity of repolarization measured from standard 12-lead ECG is not well-understood. Methods: We measured the short-term variability of repolarization parameters, such as T-wave heterogeneity in leads V4–V6 (TWH) and QT interval (QT), from five consecutive beats of previously recorded standard 12-lead ECG in 200 victims of unexpected sudden cardiac death (SCD) confirmed to be due to complicated atherosclerotic coronary artery disease (CAD) in medico-legal autopsy and 200 age- and sex-matched controls with angiographically confirmed CAD. The short-term variability of repolarization heterogeneity was defined as the standard deviation (SD) of the measured repolarization parameters. All ECGs were in sinus rhythm, and no premature ventricular contractions were included in the measured segment. Results: TWH-SD and QT-SD were significantly higher in SCD victims than in subjects with CAD (6.9 ± 5.6 μV vs. 3.8 ± 2.6 μV, p = 1.8E-11; 8.3 ± 13.1 ms vs. 3.8 ± 7.1 ms, p = 0.00003, respectively). After adjusting in the multivariate clinical model with factors, such as diabetes, RR interval, and beta blocker medication, TWH-SD and QT-SD retained their significant power in discriminating between the victims of SCD and the patients with CAD (p = 0.00003, p = 0.006, respectively). TWH-SD outperformed QT-SD in identifying the SCD victims among the study subjects (area under the curve in the receiver operating characteristics curve 0.730 vs. 0.679, respectively). Conclusion: Increased short-term variability of repolarization heterogeneity measured from standard 12-lead ECG is associated with SCD

Gender differences in prevalence and prognostic value of fragmented QRS complex

Abstract Background: Fragmented QRS (fQRS) on 12-lead electrocardiogram (ECG) is associated with scarred myocardium and adverse outcome. However, the data on gender differences in terms of its prevalence and prognostic value is sparse. The aim of this study was to evaluate whether gender differences in fQRS exist among subjects drawn from populations with different risk profiles. Methods: We analyzed fQRS from 12-lead ECG in 953 autopsy-confirmed victims of sudden cardiac death (SCD) (78% men; 67.0 ± 11.4 yrs), 1900 coronary artery disease (CAD) patients with angiographically confirmed stenosis of ≥50% (70% men; 66.6 ± 9.0 yrs, 43% with previous myocardial infarction [MI]), and in 10,904 adults drawn from the Finnish adult general population (52% men; 44.0 ± 8.5 yrs). Results: Prevalence of fQRS was associated with older age, male sex and the history and severity of prior cardiac disease of subjects. Among the general population fQRS was more commonly found among men in comparison to women (20.5% vs. 14.8%, p < 0.001). The prevalence of fQRS rose gradually along with the severity of prior cardiac disease in both genders, yet remained significantly higher in the male population: subjects with suspected or known cardiac disease (25.4% vs. 15.8% p < 0.001), CAD patients without prior MI (39.9% vs. 26.4%, p < 0.001), CAD patients with prior MI (42.9% vs. 31.2%, p < 0.001), and victims of SCD (56.4% vs. 44.4%, p < 0.001). Conclusions: The prevalence of QRS fragmentation varies in different populations. The fragmentation is clearly related to the underlying cardiac disease in both genders, however women seem to have significantly lower prevalence of fQRS in each patient population in comparison to men