Ischaemic stroke in women with atrial fibrillation: temporal trends and clinical implications.

BACKGROUND AND AIMS: Female sex has been linked with higher risk of ischaemic stroke (IS) in atrial fibrillation (AF), but no prior study has examined temporal trends in the IS risk associated with female sex. METHODS: The registry-linkage Finnish AntiCoagulation in Atrial Fibrillation (FinACAF) study included all patients with AF in Finland from 2007 to 2018. Ischaemic stroke rates and rate ratios were computed. RESULTS: Overall, 229 565 patients with new-onset AF were identified (50.0% women; mean age 72.7 years). The crude IS incidence was higher in women than in men across the entire study period (21.1 vs. 14.9 events per 1000 patient-years, P < .001), and the incidence decreased both in men and women. In 2007-08, female sex was independently associated with a 20%-30% higher IS rate in the adjusted analyses, but this association attenuated and became statistically non-significant by the end of the observation period. Similar trends were observed when time with and without oral anticoagulant (OAC) treatment was analysed, as well as when only time without OAC use was considered. The decrease in IS rate was driven by patients with high IS risk, whereas in patients with low or moderate IS risk, female sex was not associated with a higher IS rate. CONCLUSIONS: The association between female sex and IS rate has decreased and become non-significant over the course of the study period from 2007 to 2018, suggesting that female sex could be omitted as a factor when estimating expected IS rates and the need for OAC therapy in patients with AF.

QRS-T angle: is it a specific parameter associated with sudden cardiac death in type 2 diabetes? Results from the SURDIAGENE and the Mini-Finland prospective cohorts.

AIMS/HYPOTHESIS: Type 2 diabetes is associated with a high risk of sudden cardiac death (SCD), but the risk of dying from another cause (non-SCD) is proportionally even higher. The aim of the study was to identify easily available ECG-derived features associated with SCD, while considering the competing risk of dying from non-SCD causes. METHODS: In the SURDIAGENE (Survie, Diabete de type 2 et Genetique) French prospective cohort of individuals with type 2 diabetes, 15 baseline ECG parameters were interpreted among 1362 participants (mean age 65 years; HbA1c 62±17 mmol/mol [7.8±1.5%]; 58% male). Competing risk models assessed the prognostic value of clinical and ECG parameters for SCD after adjusting for age, sex, history of myocardial infarction, N-terminal pro b-type natriuretic peptide (NT-proBNP), HbA1c and eGFR. The prospective Mini-Finland cohort study was used to externally validate our findings. RESULTS: During median follow-up of 7.4 years, 494 deaths occurred including 94 SCDs. After adjustment, frontal QRS-T angle ≥90° (sub-distribution HR [sHR] 1.68 [95% CI 1.04, 2.69], p=0.032) and NT-proBNP level (sHR 1.26 [95% CI 1.06, 1.50] per 1 log, p=0.009) were significantly associated with a higher risk of SCD. Nevertheless, frontal QRS-T angle was the only marker not to be associated with causes of death other than SCD (sHR 1.08 [95% CI 0.84, 1.39], p=0.553 ). These findings were replicated in the Mini-Finland study subset of participants with diabetes (sHR 2.22 [95% CI 1.05, 4.71], p=0.04 for SCD and no association for other causes of death). CONCLUSIONS/INTERPRETATION: QRS-T angle was specifically associated with SCD risk and not with other causes of death, opening an avenue for refining SCD risk stratification in individuals with type 2 diabetes.

Ischemic Stroke Temporally Associated With New-Onset Atrial Fibrillation: A Population-Based Registry-Linkage Study.

BACKGROUND: Limited data exist on the temporal relationship between new-onset atrial fibrillation (AF) and ischemic stroke and its impact on patients' clinical characteristics and mortality. METHODS: A population-based registry-linkage database includes all patients with new-onset AF in Finland from 2007 to 2018. Ischemic stroke temporally associated with AF (ISTAF) was defined as an ischemic stroke occurring within ±30 days from the first AF diagnosis. Clinical factors associated with ISTAF were studied with logistic regression and 90-day survival with Cox proportional hazards analysis. RESULTS: Among 229 565 patients with new-onset AF (mean age, 72.7 years; 50% female), 204 774 (89.2%) experienced no ischemic stroke, 12 209 (5.3%) had past ischemic stroke >30 days before AF, and 12 582 (5.8%) had ISTAF. The annual proportion of ISTAF among patients with AF decreased from 6.0% to 4.8% from 2007 to 2018. Factors associated positively with ISTAF were higher age, lower education level, and alcohol use disorder, whereas vascular disease, heart failure, chronic kidney disease cancer, and psychiatric disorders were less probable with ISTAF. Compared with patients without ischemic stroke and those with past ischemic stroke, ISTAF was associated with ≈3-fold and 1.5-fold risks of death (adjusted hazard ratios, 2.90 [95% CI, 2.76-3.04] and 1.47 [95% CI, 1.39-1.57], respectively). The 90-day survival probability of patients with ISTAF increased from 0.79 (95% CI, 0.76-0.81) in 2007 to 0.89 (95% CI, 0.87-0.91) in 2018. CONCLUSIONS: ISTAF depicts the prominent temporal clustering of ischemic strokes surrounding AF diagnosis. Despite having fewer comorbidities, patients with ISTAF had worse, albeit improving, survival than patients with a history of or no ischemic stroke. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04645537. URL: https://www.encepp.eu; Unique identifier: EUPAS29845.

Temporal trends of gender disparities in oral anticoagulant use in patients with atrial fibrillation.

AIMS: To investigate sex-specific temporal trends in the initiation of oral anticoagulant (OAC) therapy among patients diagnosed with atrial fibrillation (AF) in Finland between 2007 and 2018. METHODS: The registry-linkage Finnish AntiCoagulation in Atrial Fibrillation (FinACAF) Study included all patients with incident AF in Finland from 2007 to 2018. The primary outcome was the initiation of any OAC therapy. RESULTS: We identified 229,565 patients with new-onset AF (50.0% women; mean age 72.7 years). The initiation of OAC therapy increased continuously during the observation period. While women were more likely to receive OAC therapy overall, after adjusting for age, stroke risk factors and other confounding factors, female sex was associated with a marginally lower initiation of OACs (unadjusted and adjusted hazard ratios comparing women to men: 1.08 (1.07-1.10) and 0.97 (0.96-0.98), respectively). Importantly, the gender disparities in OAC use attenuated and reached parity by the end of the observation period. Furthermore, when only patients eligible for OAC therapy according to the contemporary guidelines were included in the analyses, the gender inequalities in OAC initiation appeared minimal. Implementation of direct OACs for stroke prevention was slightly slower among women. CONCLUSION: This nationwide retrospective cohort study covering all patients with incident AF in Finland from 2007 to 2018 observed that although female sex was initially associated with a lower initiation of OAC therapy, the sex-related disparities resolved over the course of the study period.

Sex- and age-specific differences in the use of antiarrhythmic therapies among atrial fibrillation patients: a nationwide cohort study.

AIMS: Atrial fibrillation (AF) patients frequently require active rhythm control therapy to maintain sinus rhythm and reduce symptom burden. Our study assessed whether antiarrhythmic therapies (AATs) are used disproportionately between men and women after new-onset AF. METHODS AND RESULTS: The nationwide Finnish anticoagulation in AF registry-based linkage study covers all patients with new-onset AF in Finland during 2007-2018. Study outcomes included initiation of AATs in the form of antiarrhythmic drugs (AADs), cardioversion, or catheter ablation. The study population constituted of 229 565 patients (50% females). Women were older than men (76.6 ± 11.8 vs. 68.9 ± 13.4 years) and had higher prevalence of hypertension or hyperthyroidism, but lower prevalence of vascular disease, diabetes, renal disease, and cardiomyopathies than men. Overall, 17.6% of women and 25.1% of men were treated with any AAT. Women were treated with AADs more often than men in all age groups [adjusted subdistribution hazard ratio (aSHR) 1.223, 95% confidence interval (CI) 1.187-1.261]. Cardioversions were also performed less often on women than on men aged <65 years (aSHR 0.722, 95% CI 0.695-0.749), more often in patients ≥ 75 years (aSHR 1.166, 95% CI 1.108-1.227), while no difference between the sexes existed in patients aged 65-74 years. Ablations were performed less often in women aged <65 years (aSHR 0.908, 95% CI 0.826-0.998) and ≥75 years (aSHR 0.521, 95% CI 0.354-0.766), whereas there was no difference in patients aged 65-74 years. CONCLUSION: Women used more AAD than men in all age groups but underwent fewer cardioversion and ablation procedures when aged <65 years.

Thromboembolic and bleeding complications after elective cardioversion of atrial fibrillation: a nationwide cohort study.

AIMS: Elective cardioversion (ECV) is routinely used in atrial fibrillation (AF) to restore sinus rhythm. However, it includes a risk of thromboembolism even during adequate oral anticoagulation treatment. The aim of this study was to evaluate the risk of thromboembolic and bleeding complications after ECV in a real-life setting utilizing data from a large AF population. METHODS AND RESULTS: This nationwide register-based study included all (n = 9625) Finnish AF patients undergoing their first-ever ECV between 2012 and 2018. The thromboembolic and bleeding complications within 30 days after ECV were analysed. The mean age of the patients was 67.7 ± 9.9 years, 61.2% were men, and the mean CHA2DS2-VASc score was 2.6 ± 1.6. Warfarin was used in 6245 (64.9%) and non-vitamin K oral anticoagulants (NOACs) in 3380 (35.1%) cardioversions. Fifty-two (0.5%) thromboembolic complications occurred, of which 62% were ischaemic strokes, 25% transient ischaemic attacks, and 13% other systemic embolisms. Thromboembolic events occurred in 14 (0.4%) NOAC-treated patients and in 38 (0.6%) warfarin-treated patients (odds ratio 0.77; confidence interval: 0.42-1.39). The median time from ECV to the thromboembolic event was 2 days, and 78% of the events occurred within 10 days. Age and alcohol abuse were significant predictors of thromboembolic events. Among warfarin users, thromboembolic complications were more common with international normalized ratio (INR) <2.5 than INR ≥2.5 (0.9% vs. 0.4%, P = 0.026). Overall, 27 (0.3%) bleeding events occurred. CONCLUSION: The rate of thromboembolic and bleeding complications related to ECV was low without significant difference between NOAC- and warfarin-treated patients. With warfarin, INR ≥2.5 at the time of cardioversion reduced the risk of thromboembolic complications.

Prognostic value of P-wave morphology in general population.

AIMS: To evaluate the prognostic significance of novel P-wave morphology descriptors in general population. METHODS AND RESULTS: Novel P-wave morphology variables were analyzed from orthogonal X-, Y-, Z-leads of the digitized electrocardiogram using a custom-made software in 6906 middle-aged subjects of the Mini-Finland Health Survey. A total of 3747 (54.3%) participants died during the follow-up period of 24.3 ± 10.4 years; 379 (5.5%) of the study population succumbed to sudden cardiac death (SCD), 928 (13.4%) to non-SCD (NSCD) and 2440 (35.3%) patients to non-cardiac death (NCD). In univariate comparisons, most of the studied P-wave morphology parameters had a significant association with all modes of death (P from <0.05 to <0.001). After relevant adjustments in the Cox multivariate hazards model, P-wave morphology dispersion (PMD) still tended to predict SCD [hazard ratio (HR): 1.006, 95% confidence interval (CI): 1.000-1.012, P = 0.05) but not NSCD (HR: 0.999, 95% CI: 0.995-1.003, P = 0.68) or NCD (HR: 0.999, 95% CI: 0.997-1.001, P = 0.44). The P-wave maximum amplitude in the lead Z (P-MaxAmp-Z) predicted SCD even after multivariate adjustments (HR: 1.010, 95% CI: 1.005-1.015, P = 0.0002) but also NSCD (HR: 1.005, 95% CI: 1.002-1.009, P = 0.0005) and NCD (HR: 1.002, 95% CI: 1.000-1.005, P = 0.03). CONCLUSION: Abnormalities of P-wave morphology are associated with the risk of all modes of death in general population. After relevant adjustments, PMD was still closely associated with the risk of SCD but not with NSCD or NCD. P-MaxAmp-Z predicted SCD even after adjustments, however, it also retained its association with NSCD and NCD.

Mental health conditions and risk of first-ever ischaemic stroke and death in patients with incident atrial fibrillation: A nationwide cohort study.

BACKGROUND: Atrial fibrillation (AF) patients with mental health conditions (MHCs) have higher incidence of ischaemic stroke (IS) than patients without MHC, but whether this results from direct impact of MHCs or relates to higher prevalence of comorbidities and differences in the use of oral anticoagulant (OAC) therapy is unclear. We assessed the hypothesis that MHCs independently increase the risk of IS in patients with incident AF. METHODS: The nationwide FinACAF cohort covered all 203,154 patients diagnosed with incident AF without previous IS or transient ischaemic attack in Finland during 2007-2018. MHCs of interest were depression, bipolar disorder, anxiety disorder, schizophrenia and any MHC. The outcomes were first-ever IS and all-cause death. RESULTS: The patients' (mean age 73.0 ± 13.5 years, 49.0% female) mean follow-up time was 4.3 (SD 3.3) years and 16,272 (8.0%) experienced first-ever IS and 63,420 (31.2%) died during follow-up. After propensity score matching and adjusting for OAC use, no MHC group was associated with increased IS risk (adjusted SHRs (95% CI): depression 0.961 (0.857-1.077), bipolar disorder 1.398 (0.947-2.006), anxiety disorder 0.878 (0.718-1.034), schizophrenia 0.803 (0.594-1.085) and any MHC 1.033 (0.985-1.085)). Lower rate of OAC use partly explained the observed higher crude IS incidence in patients with any MHC. Depression, schizophrenia and any MHC were associated with higher all-cause mortality (adjusted HRs [95% CI]: 1.208 [1.136-1.283], 1.543 [1.352-1.761] and 1.149 [1.116-1.175], respectively). CONCLUSIONS: In this nationwide retrospective cohort study, MHCs were not associated with the incidence of first-ever IS in patients with AF.

Association between electrocardiographic QRS transition zone and mortality from all causes and cardiovascular diseases: A systematic review and meta-analysis.

AIMS: To investigate whether clockwise rotation (CWR) and counterclockwise rotation (CCWR) of electrocardiographic QRS transition zone is associated with mortality from all causes and cardiovascular diseases (CVD). METHODS: Studies were identified from searching of PubMed, EMBASE and the reference lists of relevant papers. Summary multivariate-adjusted hazard ratios (HRs) and the corresponding 95% confidence intervals (CIs) and 95% prediction intervals (PIs) were computed through meta-analysis. RESULTS: A total of five observational cohort studies fulfilled the inclusion criteria, which included 47,252 participants from the general population (8.8% CWR; 44.1% CCWR). Pooling data revealed that CWR was significantly associated with the increased risk of all-cause mortality (HR, 1.18; 95% CI: 1.12-1.24; 95% PI: 1.03-1.37) and CVD mortality (HR, 1.18; 95% CI: 1.08-1.29; 95% PI: 0.98-1.42) compared to NR pattern, with low heterogeneity among studies (P = 0.29, I2 = 20%; P = 0.37; I2 = 7%; respectively). However, CCWR was inversely associated with the risk of all-cause mortality (HR, 0.92; 95% CI: 0.89-0.95; 95% PI: 0.80-1.05) with low heterogeneity (P = 0.14; I2 = 43%), while no significant association existed between CCWR and CVD mortality (HR, 0.89; 95% CI: 0.77-1.02; 95% PI: 0.53-1.48) with high heterogeneity (P < 0.01; I2 = 78%). CONCLUSION: Our meta-analysis demonstrated CWR was positively associated with higher risk of mortality from all-cause and CVD, while CCWR was negatively associated with the risk of all-cause mortality and no significant association with CVD mortality. These findings suggested that QRS transition zone carries important prognostic value, more attention should be paid in clinical practice.

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

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.

Orthogonal P-wave morphology, conventional P-wave indices, and the risk of atrial fibrillation in the general population using data from the Finnish Hospital Discharge Register.

AIMS: Identifying subjects at high and low risk of atrial fibrillation (AF) is of interest. This study aims to assess the risk of AF associated with electrocardiographic (ECG) markers linked to atrial fibrosis: P-wave prolongation, 3rd-degree interatrial block, P-terminal force in lead V1, and orthogonal P-wave morphology. METHODS AND RESULTS: P-wave parameters were assessed in a representative Finnish population sample aged ≥30 years (n = 7217, 46.0% male, mean age 51.4 years). Subjects (n = 5489) with a readable ECG including the orthogonal leads, sinus rhythm, and a predefined orthogonal P-wave morphology type [positive in leads X and Y and either negative (Type 1) or ± biphasic (Type 2) in lead Z; Type 3 defined as positive in lead X and ± biphasic in lead Y], were followed 10 years from the baseline examinations (performed 1978-80). Subjects discharged with AF diagnosis after any-cause hospitalization (n = 124) were defined as having developed AF. Third-degree interatrial block was defined as P-wave ≥120 ms and the presence of ≥2 ± biphasic P waves in the inferior leads. Hazard ratios (HRs) and confidence intervals (CIs) were assessed with Cox models. Third-degree interatrial block (n = 103, HR 3.18, 95% CI 1.66-6.13; P = 0.001) and Type 3 morphology (n = 216, HR 3.01, 95% CI 1.66-5.45; P < 0.001) were independently associated with the risk of hospitalization with AF. Subjects with P-wave <110 ms and Type 1 morphology (n = 2074) were at low risk (HR 0.46, 95% CI 0.26-0.83; P = 0.006), compared to the rest of the subjects. CONCLUSION: P-wave parameters associate with the risk of hospitalization with AF.

Real-life experience with non-vitamin K antagonist oral anticoagulants versus warfarin in patients undergoing elective cardioversion of atrial fibrillation.

BACKGROUND: Nonvitamin K antagonist oral anticoagulants (NOACs) are increasingly used in patients with atrial fibrillation (AF) undergoing elective cardioversion (ECV). The aim was to investigate the use of NOACs and warfarin in ECV in a real-life setting and to assess how the chosen regimen affected the delay to ECV and rate of complications. METHODS: Consecutive AF patients undergoing ECVs in the city hospitals of Helsinki between January 2015 and December 2016 were studied. Data on patient characteristics, delays to cardioversion, anticoagulation treatment, acute (<30 days) complications, and regimen changes within one year were evaluated. RESULTS: Nine hundred patients (59.2% men; mean age, 68.0 ± 10.0) underwent 992 ECVs, of which 596 (60.0%) were performed using NOACs and 396 (40.0%) using warfarin. The mean CHA2 DS2 -VASc score was 2.5 (±1.6). In patients without previous anticoagulation treatment, NOACs were associated with a shorter mean time to cardioversion than warfarin (51 versus. 68 days, respectively; p < .001). Six thromboembolic events (0.6%) occurred: 4 (0.7%) in NOAC-treated patients and 2 (0.5%) in warfarin-treated patients. Clinically relevant bleeding events occurred in seven patients (1.8%) receiving warfarin and three patients (0.5%) receiving NOACs. Anticoagulation treatment was altered for 99 patients (11.0%) during the study period, with the majority (88.2%) of changes from warfarin to NOACs. CONCLUSIONS: In this real-life study, the rates of thromboembolic and bleeding complications were low in AF patients undergoing ECV. Patients receiving NOAC therapy had a shorter time to cardioversion and continued their anticoagulation therapy more often than patients on warfarin.

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.

Risk Factors of Sudden Cardiac Death in the Young: Multiple-Year Community-Wide Assessment.

BACKGROUND: Prevention of sudden cardiac arrest (SCA) in the young remains a largely unsolved public health problem, and sports activity is an established trigger. Although the presence of standard cardiovascular risk factors in the young can link to future morbidity and mortality in adulthood, the potential contribution of these risk factors to SCA in the young has not been evaluated. METHODS: We prospectively ascertained subjects who experienced SCA between the ages of 5 and 34 years in the Portland, Oregon, metropolitan area (2002-2015, catchment population ≈1 million). We assessed the circumstances, resuscitation outcomes, and clinical profile of subjects who had SCA by a detailed evaluation of emergency response records, lifetime clinical records, and autopsy examinations. We specifically evaluated the association of standard cardiovascular risk factors and SCA, and sports as a trigger for SCA in the young. RESULTS: Of 3775 SCAs in all age groups, 186 (5%) occurred in the young (mean age 25.9±6.8, 67% male). In SCA in the young, overall prevalence of warning signs before SCA was low (29%), and 26 (14%) were associated with sports as a trigger. The remainder (n=160) occurred in other settings categorized as nonsports. Sports-related SCAs accounted for 39% of SCAs in patients aged ≤18, 13% of SCAs in patients aged 19 to 25, and 7% of SCAs in patients aged 25 to 34. Sports-related SCA cases were more likely to present with shockable rhythms, and survival from cardiac arrest was 2.5-fold higher in sports-related versus nonsports SCA (28% versus 11%; P=0.05). Overall, the most common SCA-related conditions were sudden arrhythmic death syndrome (31%), coronary artery disease (22%), and hypertrophic cardiomyopathy (14%). There was an unexpectedly high overall prevalence of established cardiovascular risk factors (obesity, diabetes mellitus, hypertension, hyperlipidemia, smoking) with ≥1 risk factors in 58% of SCA cases. CONCLUSIONS: Sports was a trigger of SCA in a minority of cases, and, in most patients, SCA occurred without warning symptoms. Standard cardiovascular risk factors were found in over half of patients, suggesting the potential role of public health approaches that screen for cardiovascular risk factors at earlier ages.

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.

Electrical surrogate for detection of severe left ventricular systolic dysfunction.

BACKGROUND: Early diagnosis and therapy improves outcomes in heart failure with severely reduced left ventricular ejection fraction (LVEF ≤35%), but some patients may remain undiagnosed. We hypothesized that a combination of electrocardiogram (ECG) markers may identify individuals with severely reduced LVEF. METHODS: From a community-based study in the Northwest US (the Oregon Sudden Unexpected Death Study), we evaluated the prevalence of conventional ECG markers by LVEF. We then evaluated the association of nine additional ECG markers and LVEF. We validated the correlation of these ECG markers and LVEF in a separate, large health system in Los Angeles, California. RESULTS: In the discovery population (n = 1,047), patients with LVEF ≤35% were twice as likely as those with LVEF >35% to have ≥1 conventional ECG abnormality. In the subset without conventional ECG abnormalities, ≥4 abnormal ECG markers from the expanded panel were found in 12% vs. 1% of patients with LVEF ≤35% and >35%, respectively. In the validation population (n = 9,742), 44% with LVEF ≤35% and 17% with LVEF >35% had ≥1 conventional ECG abnormality. In patients without conventional ECG abnormalities (n = 7,601), 40% with LVEF ≤35% and 5% with LVEF >35% had ≥4 abnormal ECG markers from the expanded panel. Each additional abnormal ECG marker from the expanded panel (range 0 to ≥4) more than doubled the odds of LVEF ≤35%. CONCLUSIONS: An expanded panel of easily obtained ECG markers correlated strongly with severely reduced LVEF in two separate populations. This electrical surrogate score could facilitate diagnosis of severely reduced LVEF, and warrants prospective evaluation.

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 1.4ms (95% CI 0.5-2.2) for PR interval, -1.0ms (95% CI -1.5-[-0.5]) for QRS duration, and 11.6ms (95% CI 10.5-12.7) for QT interval. The mean inter-method amplitude differences of RampV5, RampV6, SampV1, TampII and TampV5 ranged from -0.03mV to 0.01mV. 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.

Electrical risk score beyond the left ventricular ejection fraction: prediction of sudden cardiac death in the Oregon Sudden Unexpected Death Study and the Atherosclerosis Risk in Communities Study.

AIMS: There is an urgent need to extend sudden cardiac death (SCD) risk stratification beyond the left ventricular ejection fraction (LVEF). We evaluated whether a cumulative electrocardiogram (ECG) risk score would improve identification of individuals at high risk of SCD. METHODS AND RESULTS: In the community-based Oregon Sudden Unexpected Death Study (catchment population ∼1 million), 522 SCD cases with archived 12-lead ECG available (65.3 ± 14.5 years, 66% male) were compared with 736 geographical controls to assess the incremental value of multiple ECG parameters in SCD prediction. Heart rate, LV hypertrophy, QRS transition zone, QRS-T angle, QTc, and Tpeak-to-Tend interval remained significant in the final model, which was externally validated in the Atherosclerosis Risk in Communities (ARIC) Study. Sixteen percent of cases and 3% of controls had ≥4 abnormal ECG markers. After adjusting for clinical factors and LVEF, increasing ECG risk score was associated with progressively greater odds of SCD. Overall, subjects with ≥4 ECG abnormalities had an odds ratio (OR) of 21.2 for SCD [95% confidence interval (CI) 9.4-47.7; P < 0.001]. In the LVEF >35% subgroup, the OR was 26.1 (95% CI 9.9-68.5; P < 0.001). The ECG risk score increased the C-statistic from 0.625 to 0.753 (P < 0.001), with net reclassification improvement of 0.319 (P < 0.001). In the ARIC cohort validation, risk of SCD associated with ≥4 ECG abnormalities remained significant after multivariable adjustment (hazard ratio 4.84; 95% CI 2.34-9.99; P < 0.001; C-statistic improvement 0.759-0.774; P = 0.019). CONCLUSION: This novel cumulative ECG risk score was independently associated with SCD and was particularly effective for LVEF >35% where risk stratification is currently unavailable. These findings warrant further evaluation in prospective clinical investigations.

Cardiac structural and functional profile of patients with delayed QRS transition zone and sudden cardiac death.

AIMS: Delayed QRS transition zone in the precordial leads of the 12-lead electrocardiogram (ECG) has been recently associated with increased risk of sudden cardiac death (SCD), but the underlying mechanisms are unknown. We correlated echocardiographic findings with ECG and clinical characteristics to investigate how alterations in cardiac structure and function contribute to this risk marker. METHODS AND RESULTS: From the ongoing population-based Oregon Sudden Unexpected Death Study (catchment population ∼1 million), SCD cases with prior ECG available (n = 627) were compared with controls (n = 801). Subjects with delayed transition at V5 or later were identified, and clinical and echocardiographic patterns associated with delayed transition were analysed. Delayed transition was present in 31% of the SCD cases and 17% of the controls. These subjects were older and more likely to have cardiovascular risk factors and history of myocardial infarction. Delayed transition was associated with increased left ventricular (LV) mass (122.7 ± 40.2 vs. 102.9 ± 33.7 g/m2; P < 0.001), larger LV diameter (53.3 ± 10.4 vs. 49.2 ± 8.0 mm; P < 0.001), and lower LV ejection fraction (LVEF) (46.4 ± 15.7 vs. 55.6 ± 12.5%; P < 0.001). In multivariate analysis, delayed transition was independently associated with myocardial infarction, reduced LVEF, and LV hypertrophy. The association between delayed transition and SCD was independent of the LVEF (OR 1.57; 95% CI 1.04-2.38; P = 0.032). CONCLUSION: The underpinnings of delayed QRS transition zone extend beyond previous myocardial infarction and reduced LVEF. Since the association with sudden death is independent of these factors, this novel marker of myocardial electrical remodelling should be explored as a potential risk predictor of SCD.