@article {6166, title = {Atrial ectopy as a predictor of incident atrial fibrillation: a cohort study.}, journal = {Ann Intern Med}, volume = {159}, year = {2013}, month = {2013 Dec 03}, pages = {721-8}, abstract = {

BACKGROUND: Atrial fibrillation (AF) prediction models have unclear clinical utility given the absence of AF prevention therapies and the immutability of many risk factors. Premature atrial contractions (PACs) play a critical role in AF pathogenesis and may be modifiable.

OBJECTIVE: To investigate whether PAC count improves model performance for AF risk.

DESIGN: Prospective cohort study.

SETTING: 4 U.S. communities.

PATIENTS: A random subset of 1260 adults without prevalent AF enrolled in the Cardiovascular Health Study between 1989 and 1990.

MEASUREMENTS: The PAC count was quantified by 24-hour electrocardiography. Participants were followed for the diagnosis of incident AF or death. The Framingham AF risk algorithm was used as the comparator prediction model.

RESULTS: In adjusted analyses, doubling the hourly PAC count was associated with a significant increase in AF risk (hazard ratio, 1.17 [95\% CI, 1.13 to 1.22]; P < 0.001) and overall mortality (hazard ratio, 1.06 [CI, 1.03 to 1.09]; P < 0.001). Compared with the Framingham model, PAC count alone resulted in similar AF risk discrimination at 5 and 10 years of follow-up and superior risk discrimination at 15 years. The addition of PAC count to the Framingham model resulted in significant 10-year AF risk discrimination improvement (c-statistic, 0.65 vs. 0.72; P < 0.001), net reclassification improvement (23.2\% [CI, 12.8\% to 33.6\%]; P < 0.001), and integrated discrimination improvement (5.6\% [CI, 4.2\% to 7.0\%]; P < 0.001). The specificity for predicting AF at 15 years exceeded 90\% for PAC counts more than 32 beats/h.

LIMITATION: This study does not establish a causal link between PACs and AF.

CONCLUSION: The addition of PAC count to a validated AF risk algorithm provides superior AF risk discrimination and significantly improves risk reclassification. Further study is needed to determine whether PAC modification can prospectively reduce AF risk.

PRIMARY FUNDING SOURCE: American Heart Association, Joseph Drown Foundation, and National Institutes of Health.

}, keywords = {Aged, Atrial Fibrillation, Atrial Function, Cause of Death, Electrocardiography, Female, Humans, Male, Models, Statistical, Myocardial Contraction, Prospective Studies, Risk Assessment}, issn = {1539-3704}, doi = {10.7326/0003-4819-159-11-201312030-00004}, author = {Dewland, Thomas A and Vittinghoff, Eric and Mandyam, Mala C and Heckbert, Susan R and Siscovick, David S and Stein, Phyllis K and Psaty, Bruce M and Sotoodehnia, Nona and Gottdiener, John S and Marcus, Gregory M} } @article {6077, title = {Long-term outcomes of left anterior fascicular block in the absence of overt cardiovascular disease.}, journal = {JAMA}, volume = {309}, year = {2013}, month = {2013 Apr 17}, pages = {1587-8}, keywords = {Aged, Atrial Fibrillation, Biomarkers, Bundle-Branch Block, Cohort Studies, Electrocardiography, Endomyocardial Fibrosis, Female, Heart Failure, Humans, Kaplan-Meier Estimate, Male, Prognosis, Risk}, issn = {1538-3598}, doi = {10.1001/jama.2013.2729}, author = {Mandyam, Mala C and Soliman, Elsayed Z and Heckbert, Susan R and Vittinghoff, Eric and Marcus, Gregory M} } @article {5998, title = {The QT interval and risk of incident atrial fibrillation.}, journal = {Heart Rhythm}, volume = {10}, year = {2013}, month = {2013 Oct}, pages = {1562-8}, abstract = {

BACKGROUND: Abnormal atrial repolarization is important in the development of atrial fibrillation (AF), but no direct measurement is available in clinical medicine.

OBJECTIVE: To determine whether the QT interval, a marker of ventricular repolarization, could be used to predict incident AF.

METHODS: We examined a prolonged QT interval corrected by using the Framingham formula (QT(Fram)) as a predictor of incident AF in the Atherosclerosis Risk in Communities (ARIC) study. The Cardiovascular Health Study (CHS) and Health, Aging, and Body Composition (ABC) study were used for validation. Secondary predictors included QT duration as a continuous variable, a short QT interval, and QT intervals corrected by using other formulas.

RESULTS: Among 14,538 ARIC study participants, a prolonged QT(Fram) predicted a roughly 2-fold increased risk of AF (hazard ratio [HR] 2.05; 95\% confidence interval [CI] 1.42-2.96; P < .001). No substantive attenuation was observed after adjustment for age, race, sex, study center, body mass index, hypertension, diabetes, coronary disease, and heart failure. The findings were validated in Cardiovascular Health Study and Health, Aging, and Body Composition study and were similar across various QT correction methods. Also in the ARIC study, each 10-ms increase in QT(Fram) was associated with an increased unadjusted (HR 1.14; 95\% CI 1.10-1.17; P < .001) and adjusted (HR 1.11; 95\% CI 1.07-1.14; P < .001) risk of AF. Findings regarding a short QT interval were inconsistent across cohorts.

CONCLUSIONS: A prolonged QT interval is associated with an increased risk of incident AF.

}, keywords = {Aged, Atrial Fibrillation, Cohort Studies, Electrocardiography, Female, Humans, Incidence, Long QT Syndrome, Male, Middle Aged, Risk Factors}, issn = {1556-3871}, doi = {10.1016/j.hrthm.2013.07.023}, author = {Mandyam, Mala C and Soliman, Elsayed Z and Alonso, Alvaro and Dewland, Thomas A and Heckbert, Susan R and Vittinghoff, Eric and Cummings, Steven R and Ellinor, Patrick T and Chaitman, Bernard R and Stocke, Karen and Applegate, William B and Arking, Dan E and Butler, Javed and Loehr, Laura R and Magnani, Jared W and Murphy, Rachel A and Satterfield, Suzanne and Newman, Anne B and Marcus, Gregory M} } @article {9237, title = {Inflammation and Incident Conduction Disease.}, journal = {J Am Heart Assoc}, volume = {12}, year = {2023}, month = {2023 Jan 03}, pages = {e027247}, keywords = {Cardiac Conduction System Disease, Electrocardiography, Heart Block, Humans, Inflammation}, issn = {2047-9980}, doi = {10.1161/JAHA.122.027247}, author = {Frimodt-M{\o}ller, Emilie K and Gottdiener, John S and Soliman, Elsayed Z and Kizer, Jorge R and Vittinghoff, Eric and Psaty, Bruce M and Biering-S{\o}rensen, Tor and Marcus, Gregory M} }