Heart Rhythm Program, Southlake Regional Health Center, Newmarket, Ontario, Canada
Corresponding Author:Yaariv Khaykin, 105-712 Davis Drive, Newmarket, Ontario, Canada, L4E 4M5.
Atrial fibrillation is a common cardiac arrhythmia. It is
well known to occur in older patients with comorbid conditions such congestive
heart failure and ischemic heart disease [1-3].
In these otherwise sick individuals it is associated with higher long term
morbidity and mortality .
In their paper published in the February issue of JAFIB, Dr.
Barrios and colleagues further examine the association between atrial
fibrillation, classical coronary risk factors, proven cardiovascular preventive
therapies and end-organ damage in 2024 patients with documented hypertension
and coronary heart disease. Patients were stratified as having or not having
atrial fibrillation according to the baseline 12-lead ECG which was also used
to derive heart rate. The presence of end-organ damage was coded based on
clinical history. Overall about 17% of the patients had atrial fibrillation.
These patients were generally older with an equal prevalence between genders,
contrary to male predominance reported in other studies . Patients with atrial fibrillation had a somewhat lower
ejection fraction and were more likely to be sedentary and diabetic and less
likely to suffer from dyslipidemia. Many more of these patients had left
ventricular hypertrophy, congestive heart, peripheral arterial disease, renal
impairment and history of stroke. Their heart rate was generally faster than
that of the sinus rhythm patients. According to their risk profile, more of the
atrial fibrillation patients were anticoagulated and treated for diabetes and
fewer were treated for dyslipidemia. The likelihood of being on a diuretic, ARB
or alpha-blocker was higher among patients with atrial fibrillation.
Surprisingly few patients in the registry had good control of their risk
factors with little appreciable difference between patients with and without
AF. The authors then did an interesting analysis further stratifying patients
with atrial fibrillation into cohorts based on heart rate <63 bpm, 63-82 bpm
and >82 bpm. The comparison between sinus rhythm patients and those with AF
among patients with baseline heart rate > 82 bpm parallels main study
findings. On the other hand, the comparison between AF patients stratified by
heart rate reveals several interesting findings: higher heart rate seemed
associated with current smoking status, left ventricular hypertrophy, higher
blood pressure and less adequate blood pressure control, lower use of beta
blockers, higher use of calcium channel blockers and to a lesser extent,
history of peripheral arterial disease. Since no outcome measures are reported,
it is impossible to comment on the association between atrial fibrillation and
cardiovascular mortality in this study.
All in all this study re-iterates the well-known association
between atrial fibrillation and cardiovascular disease. The findings suggest
better rate control in AF patients treated with beta-blockers compared to
calcium channel blockers as well as a good association between heart rate and
blood pressure control in these patients. As many other epidemiologic studies
of chronic disease management in the real world, Dr. Barrios et al re-emphasize
the importance of better adherence to clinical practice guidelines and focus on
cardiovascular risk control.
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