Atrial Fibrillation Begets Heart Failure and Vice Versa
How is the development of atrial fibrillation (AF) temporally related to heart failure (HF)?
Individuals who participated in the Framingham Heart Study, and who developed new-onset AF (n = 1,737) and/or HF (1,166) between 1980-2012 were subjects of this study. AF was diagnosed on the basis of office or hospital electrocardiograms, or ambulatory monitoring. Ejection fraction (EF) was determined by echocardiography or radionuclide study. HF classification was based on the EF: HF with preserved EF (HFpEF), if the EF was ≥45%, and HF with reduced EF (HFrEF), if the EF was <45%.
Among the 1,166 patients who developed new-onset HF (age 79 ± 11 years, 53% women), 479 (41%) had HFpEF, and 516 (44%) were diagnosed with HFrEF, and the remaining 15% could not be classified. Of the patients with new-onset HF, 38% had no AF at baseline or during follow-up, 32% had prevalent AF, 18% had AF diagnosed within 30 days of the HF diagnosis, and 12% developed AF after the HF diagnosis. Of the 1,737 patients who developed AF (age 75 ± 12 years, 48% women), 1,101 (63%) remained free of HF, 145 (8%) were diagnosed with HF at the time of the AF diagnosis, 214 (12%) were diagnosed with HF concurrently or within 30 days of the AF diagnosis, and 277 (16%) were diagnosed with new-onset HF after the AF diagnosis. Prevalent AF was more strongly associated with incident HFpEF than with HFrEF. Prevalent HF was associated with incident AF (hazard ratio, 2.2; 95% confidence interval, 1.3-3.8). The mortality risk was higher in patients with both AF and HF, as compared to those without these conditions. The risk was higher in patients with new-onset HFrEF and prevalent AF, as compared to those with new-onset HFpEF and prevalent AF.
In this retrospective analysis, more than one-half of the patients with HF developed AF, and about one-third of the patients with AF developed HF.
This study confirms the close association between AF and HF, and also confirms the results of earlier studies. These findings are not surprising since both conditions share risk factors such as hypertension, diastolic dysfunction, valvular heart disease, and sleep apnea. Primary prevention of either condition by risk factor modification is critically important in an aging population. In patients with AF and HF, restoration of sinus rhythm with catheter ablation or even drugs that are not associated with toxicity is likely to improve outcomes. Lastly, patients who receive contemporary care for HF, especially those with a reduced EF, are likely to fare better than participants in this study who did not have benefit of the evidence-based therapeutic options available today.
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