Prevalence and Prognostic Significance of Negative U-waves in a 12-lead Electrocardiogram in the General Population

Negative U-waves are a relatively rare finding in an electrocardiogram (ECG), but are often associated with cardiac disease. The prognostic significance of negative U-waves in the general population is unknown. We evaluated 12-lead ECGs of 6,518 adults (45% male, mean age 50.9 +/- 13.8 years) for the presence of U-waves, and followed the subjects for 24.5 +/- 10.3 years. Primary end points were all-cause mortality, cardiac mortality, and sudden cardiac death; secondary end point was hospitalization due to cardiac causes. Negative U-waves (amplitude >= 0.05 mV) were present in 231 subjects (3.5%), minor negative (amplitude 0.30). In conclusion, negative U-waves are associated with adverse events in the general population. In men, this association is independent of cardiovascular risk factors. (C) 2018 Elsevier Inc. All rights reserved.Peer reviewe

Prognostic significance of flat T-waves in the lateral leads in general population

Publisher Copyright: © 2021 Elsevier Inc.Background: Negative T-waves are associated with sudden cardiac death (SCD) risk in the general population. Whether flat T-waves also predict SCD is not known. The aim of the study was to examine the clinical characteristics and risk of SCD in general population subjects with flat T-waves. Methods: We examined the electrocardiograms of 6750 Finnish general population adults aged ≥30 years and classified the subjects into 3 groups: 1) negative T-waves with an amplitude ≥0.1 mV in ≥2 of the leads I, II, aVL, V4–V6, 2) negative or positive low amplitude T-waves with an amplitude <0.1 mV and the ratio of T-wave and R-wave <10% in ≥2 of the leads I, II, aVL, V4–V6, and 3) normal positive T-waves (not meeting the aforesaid criteria). The association between T-wave classification and SCD was assessed during a 10-year follow-up. Results: A total of 215 (3.2%) subjects had negative T-waves, 856 (12.7%) flat T-waves, and 5679 (84.1%) normal T-waves. Flat T-wave subjects were older and had more often cardiovascular morbidities compared to normal T-wave subjects, while negative T-wave subjects were the oldest and had most often cardiovascular morbidities. After adjusting for multiple factors, both flat T-waves (hazard ratio [HR] 1.81; 95% confidence interval [CI] 1.13–2.91) and negative T-waves (HR 3.27; 95% CI 1.85–5.78) associated with SCD. Conclusions: Cardiovascular risk factors and disease are common among subjects with flat T-waves, but these minor T-wave abnormalities are also independently associated with increased SCD risk.Peer reviewe

Impact of age and sex on the long-term prognosis associated with early repolarization in the general population

BACKGROUND Early repolarization (ER) has been linked to the risk of sudden cardiac death (SCD) in the general population, although controversy remains regarding risks across various subgroups. OBJECTIVE The purpose of this study was to investigate whether age and sex influence the prognostic significance of ER. METHODS We evaluated the 12-lead electrocardiograms of 6631 Finnish general population subjects age >= 30 years (mean age 50.1 +/- 13.9 years; 44.5% men) for the presence of ER (J-point elevation >= 0.1 mV in >= 2 inferior/lateral leads) and followed them for 24.4 +/- 10.3 years. We analyzed the association between ER and the risk of SCD, cardiac death, and ad-cause mortality in subgroups according to age (= 50 years) and sex. RESULTS ER was present in 367 of the 3305 subjects age = 50 years. ER was not associated with any of the endpoints in the entire study population. After adjusting for clinical factors, ER was associated with SCD (hazard ratio [HR] 1.88; 95% confidence interval [CI] 1.16-3.07) in subjects CONCLUSION ER is associated with SCD in subjects younger than 50 years, particularly in women, but not in subjects 50 years and older.Peer reviewe

Electrocardiographic Risk Markers of Cardiac Death : Gender Differences in the General Population

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 110 ms (p = 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.Peer reviewe

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

Publisher Copyright: © 2022 Heart Rhythm SocietyBackground: 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). Conclusion: PRWP was associated with adverse prognosis in the general population and with SCD in subjects with CAD.Peer reviewe

Risk Factors Associated With Atrioventricular Block

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 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.Peer reviewe

Gender differences in prevalence and prognostic value of fragmented QRS complex

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. (C) 2020 The Authors. Published by Elsevier Inc.Peer reviewe

Risk of sudden cardiac death associated with QRS, QTc, and JTc intervals in the general population

BACKGROUND QRS duration and corrected QT (QTc) interval have been associated with sudden cardiac death (SCD), but no data are available on the significance of repolarization component (JTc interval) of the QTc interval as an independent risk marker in the general population. OBJECTIVE In this study, we sought to quantify the risk of SCD associated with QRS, QTc, and JTc intervals. METHODS This study was conducted using data from 3 population cohorts from different eras, comprising a total of 20,058 individuals. The follow-up period was limited to 10 years and age at baseline to 30-61 years. QRS duration and QT interval (Bazett's) were measured from standard 12-lead electrocardiograms at baseline. JTc interval was defined as QTc interval - QRS duration. Cox proportional hazards models that controlled for confounding clinical factors identified at baseline were used to estimate the relative risk of SCD. RESULTS During a mean period of 9.7 years, 207 SCDs occurred (1.1 per 1000 person-years). QRS duration was associated with a significantly increased risk of SCD in each cohort (pooled hazard ratio [HR] 1.030 per 1-ms increase; 95% confidence interval [CI] 1.017-1.043). The QTc interval had borderline to significant associations with SCD and varied among cohorts (pooled HR 1.007; 95% CI 1.001-1.012). JTc interval as a continuous variable was not associated with SCD (pooled HR 1.001; 95% CI 0.996-1.007). CONCLUSION Prolonged QRS durations and QTc intervals are associated with an increased risk of SCD. However, when the QTc interval is deconstructed into QRS and JTc intervals, the repolarization component (JTc) appears to have no independent prognostic value.Peer reviewe

Risk of sudden cardiac death associated with QRS, QTc, and JTc intervals in the general population

BackgroundQRS duration and corrected QT (QTc) interval have been associated with sudden cardiac death (SCD), but no data are available on the significance of repolarization component (JTc interval) of the QTc interval as an independent risk marker in the general population.ObjectiveIn this study, we sought to quantify the risk of SCD associated with QRS, QTc, and JTc intervals.MethodsThis study was conducted using data from 3 population cohorts from different eras, comprising a total of 20,058 individuals. The follow-up period was limited to 10 years and age at baseline to 30–61 years. QRS duration and QT interval (Bazett’s) were measured from standard 12-lead electrocardiograms at baseline. JTc interval was defined as QTc interval – QRS duration. Cox proportional hazards models that controlled for confounding clinical factors identified at baseline were used to estimate the relative risk of SCD.ResultsDuring a mean period of 9.7 years, 207 SCDs occurred (1.1 per 1000 person-years). QRS duration was associated with a significantly increased risk of SCD in each cohort (pooled hazard ratio [HR] 1.030 per 1-ms increase; 95% confidence interval [CI] 1.017–1.043). The QTc interval had borderline to significant associations with SCD and varied among cohorts (pooled HR 1.007; 95% CI 1.001–1.012). JTc interval as a continuous variable was not associated with SCD (pooled HR 1.001; 95% CI 0.996–1.007).ConclusionProlonged QRS durations and QTc intervals are associated with an increased risk of SCD. However, when the QTc interval is deconstructed into QRS and JTc intervals, the repolarization component (JTc) appears to have no independent prognostic value.</p

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

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. (C) 2017 Elsevier Inc. All rights reserved.Peer reviewe