Electrocardiographic P terminal force in lead V1, its components, and the association with stroke and atrial fibrillation or flutter.

BACKGROUND: The electrocardiographic (ECG) marker P terminal force V1 (PTFV1) is generally perceived as a marker of left atrial pathology and has been associated with atrial fibrillation or flutter (AF). OBJECTIVE: The purpose of this study was to determine the association between PTFV1 components (duration and amplitude) and incident AF and stroke/transient ischemic attack (TIA). METHODS: The study included patients with an ECG recorded at the Copenhagen General Practitioners Laboratory in 2001 to 2011. PTFV1 ≥4 mV·ms was considered abnormal. Patients with abnormal PTFV1 were stratified into tertiles based on duration (PTDV1) and amplitude (PTAV1) values. Cox regressions adjusted for age, sex, and relevant comorbidities were used to investigate associations between abnormal PTFV1 components and AF and stroke/TIA. RESULTS: Of 267,636 patients, 5803 had AF and 18,176 had stroke/TIA (follow-up 6.5 years). Abnormal PTFV1 was present in 44,549 subjects (16.7%) and was associated with an increased risk of AF and stroke/TIA. Among patients with abnormal PTFV1, the highest tertile of PTDV1 (78-97 ms) was associated with the highest risk of AF (hazard ratio [HR] 1.37; 95% confidence interval [CI] 1.23-1.52) and highest risk of stroke/TIA (HR 1.13; 95% CI 1.05 -1.20). For PTAV1, the highest tertile (78-126 µV) conferred the highest risk of AF and stroke/TIA (HR 1.20; 95% CI 1.09-1.32; and HR 1.21; 95% CI 1.14-1.25, respectively). CONCLUSION: Abnormal PTFV1 was associated with an increased risk of AF and stroke/TIA. Increasing PTDV1 showed a dose-response relationship with the development of AF and stroke/TIA, whereas the association between PTAV1 and AF was less apparent.

Fascicular heart blocks and risk of adverse cardiovascular outcomes: Results from a large primary care population.

BACKGROUND: Fascicular heart blocks can progress to complete heart blocks, but this risk has not been evaluated in a large general population. OBJECTIVE: The purpose of this study was to investigate the association between various types of fascicular blocks diagnosed by electrocardiographic (ECG) readings and the risk of incident higher degree atrioventricular block (AVB), syncope, pacemaker implantation, and death. METHODS: We studied primary care patients referred for ECG recording between 2001 and 2015. Cox regression models were used to estimate hazard ratios (HRs) as well as absolute risks of cardiovascular outcomes. RESULTS: Of 358,958 primary care patients (median age 54 years; 55% women), 13,636 (3.8%) had any type of fascicular block. Patients were followed up to 15.9 years. We found increasing HRs of incident syncope, pacemaker implantation, and third-degree AVB with increasing complexity of fascicular block. Compared with no block, isolated left anterior fascicular block (LAFB) was associated with 0%-2% increased 10-year risk of developing third-degree AVB (HR 1.6; 95% confidence interval [CI] 1.25-2.05), whereas right bundle branch block combined with LAFB and first-degree AVB was associated with up to 23% increased 10-year risk (HR 11.0; 95% CI 7.7-15.7), depending on age and sex group. Except for left posterior fascicular block (HR 2.09; 95% CI 1.87-2.32), we did not find any relevant associations between fascicular block and death. CONCLUSION: We found that higher degrees of fascicular blocks were associated with increasing risk of syncope, pacemaker implantation, and complete heart block, but the association with death was negligible.

Prevalence and risk factors of prolonged QT interval and electrocardiographic abnormalities in persons living with HIV.

OBJECTIVE: Abnormal ECGs are associated with increased risk of arrhythmias and sudden cardiac death. We aimed to investigate the prevalence and associated risk factors of prolonged QTc and major ECG abnormalities, in persons living with HIV (PLWH) and uninfected controls. DESIGN: PLWH aged at least 40 years were recruited from the Copenhagen comorbidity in HIV infection (COCOMO) study and matched on sex and age to uninfected controls from the Copenhagen General Population Study. METHODS: ECGs were categorized according to Minnesota Code Manual of ECG Findings definition of major abnormalities. A QT interval corrected for heart rate (QTc) greater than 440 ms in men and greater than 460 ms in women was considered prolonged. Pathologic Q-waves were defined as presence of major Q-wave abnormalities. RESULTS: ECGs were available for 745 PLWH and 2977 controls. Prolonged QTc was prevalent in 9% of PLWH and 6% of controls, P = 0.052. Pathologic Q-waves were more common in PLWH (6%) than in controls (4%), P = 0.028. There was no difference in prevalence of major ECG abnormalities between PLWH and controls, P = 0.987.In adjusted analyses, HIV was associated with a 3.6 ms (1.8-5.4) longer QTc interval, P < 0.001, and HIV was independently associated with prolonged QTc [adjusted odds ratio: 1.59 (1.14-2.19)], P = 0.005. HIV was borderline associated to pathologic Q-waves after adjusting, P = 0.051. CONCLUSION: HIV was associated with higher odds ratio of prolonged QTc after adjustment for cardiovascular risk factors, but analyses were not adjusted for QT-prolonging medication. Although evidence indicated more pathologic Q-waves in PLWH, the risk seemed to be associated mainly with an adverse risk profile.

Clinical implications of electrocardiographic bundle branch block in primary care.

OBJECTIVES: Electrocardiographic bundle branch block (BBB) is common but the prognostic implications in primary care are unclear. We sought to investigate the relationship between electrocardiographic BBB subtypes and the risk of cardiovascular (CV) outcomes in a primary care population free of major CV disease. METHODS: Retrospective cohort study of primary care patients referred for electrocardiogram (ECG) recording between 2001 and 2011. Cox regression models were used to estimate hazard ratios (HR) as well as absolute risks of CV outcomes based on various BBB subtypes. RESULTS: We included 202 268 individuals with a median follow-up period of 7.8 years (Inter-quartile range [IQR] 4.9-10.6). Left bundle branch block (LBBB) was associated with heart failure (HF) in both men (HR 3.96, 95% CI 3.30 to 4.76) and women (HR 2.51, 95% CI 2.15 to 2.94) and with CV death in men (HR 1.80, 95% CI 1.38 to 2.35). Right bundle branch block (RBBB) was associated with pacemaker implantation in both men (HR 3.26, 95% CI 2.74 to 3.89) and women (HR 3.69, 95% CI 2.91 to 4.67), HF in both sexes and weakly associated with CV death in men. Regarding LBBB, we found an increasing hazard of HF with increasing QRS-interval duration (HR 1.25, 95% CI 1.11 to 1.42 per 10 ms increase in men and HR 1.23, 95% CI 1.08 to 1.40 per 10 ms increase in women). Absolute 10-year risk predictions across age-specific and sex-specific subgroups revealed clinically relevant differences between having various BBB subtypes. CONCLUSIONS: Opportunistic findings of BBB subtypes in primary care patients without major CV disease should be considered warnings of future HF and pacemaker implantation.

Electrocardiographic PR Interval Duration and Cardiovascular Risk: Results From the Copenhagen ECG Study.

BACKGROUND: Because of ambiguous reports in the literature, we aimed to investigate the association between PR interval and the risk of all-cause and cardiovascular death, heart failure, and pacemaker implantation, allowing for a nonlinear relationship. METHODS: We included 293,111 individuals, corresponding to one-third of the population in the greater region of Copenhagen. These individuals had a digital electrocardiogram recorded in a general practitioner's core facility from 2001-2011. Data on drug use, comorbidities, and outcomes were collected from Danish registries. We divided the population into 7 groups based on the population PR interval distribution. Cox models were used, with reference to a PR interval between 152 and 161 ms (40th to < 60th percentile). RESULTS: During follow-up, we identified 34,783 deaths from all causes, 9867 cardiovascular deaths, 9526 cases of incident heart failure, and 1805 pacemaker implantations. A short PR interval (< 125 ms; hazard ratio [HR], 1.23; 95% confidence interval [CI], 1.08-1.41; P = 0.001) as well as a long PR interval (> 200 ms; HR, 1.23; 95% CI, 1.14-1.32; P < 0.001) was associated with an increased risk of cardiovascular death after multivariable adjustment. A long PR interval conferred an increased risk of heart failure (> 200 ms; HR, 1.31; 95% CI, 1.22-1.42; P < 0.001). An increasing PR interval conferred an increased risk of pacemaker implantation, in a dose-response manner, with the highest risk associated with a PR interval > 200 ms (HR, 3.49; 95% CI, 2.96-4.11; P < 0.001). CONCLUSIONS: PR interval was significantly associated with the risk of the adverse outcomes investigated. The nonlinear relationships, in combination with relatively weak associations, could contribute to previously reported conflicting results on the subject.