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.

Adherence with oral anticoagulation in non-valvular atrial fibrillation: a comparison of vitamin K antagonists and non-vitamin K antagonists.

Aims: The purpose of this study was to describe adherence with non-vitamin K antagonists (NOACs) and vitamin K antagonists (VKA) in patients with non-valvular atrial fibrillation (NVAF). Methods and results: By linkage of Danish nationwide registers, we identified patients with NVAF who claimed a prescription of a NOAC (dabigatran, rivaroxaban, and apixaban), or a VKA. Adherence was evaluated according to Proportions of Days Covered, refill gaps, and switch in treatment. Adjusted analyses were calculated with logistic regression and Cox proportional hazard models. Between 2011 and 2014, 46 675 patients with NVAF claimed a prescription of anticoagulation (OAC): 57.3% used VKA, 29.8% dabigatran, 8.5% rivaroxaban, and 4.4% apixaban. During the first 180 days, PDC >80% was the highest among users of rivaroxaban. Compared with rivaroxaban, OR was 0.79 with apixaban (95% CI 0.69-0.92), 0.72 with dabigatran (95% CI 0.66-0.80), and 0.76 with VKAs (95% CI 0.69-0.83). HR for refill gaps between 7 and 89 days of length were (rivaroxaban as reference): apixaban 1.52(95% CI 1.36-1.69), dabigatran 1.72 (95% CI 1.60-1.85), and VKA 2.36(95% CI 2.20-2.52). Refill gaps of more than 89 days occurred in 11.5% of VKA recipients, with substantially lower rates for patients treated with NOAC. Switch between OACs was the highest in users of dabigatran (21.0%) and the lowest in users of apixaban (8.6%). Conclusion: Among NVAF patients treated with OAC, 42.7% received a NOAC. PDC > 80%, and periods without refill gaps were the highest among users of rivaroxaban. Refill gaps occurred most often with VKA, switch was most common with dabigatran use.