Elsevier

Heart Rhythm

Volume 9, Issue 12, December 2012, Pages 1923-1929
Heart Rhythm

Clinical
Atrial fibrillation
Patients originally diagnosed with idiopathic atrial fibrillation more often suffer from insidious coronary artery disease compared to healthy sinus rhythm controls

https://doi.org/10.1016/j.hrthm.2012.08.013Get rights and content

Background

Idiopathic atrial fibrillation (AF) refers to a clinically lacking cardiovascular or pulmonary disease generating the pathophysiologic substrate for the arrhythmia. However, because idiopathic AF is associated with an increased event rate, it could be a harbinger of as-yet undetected underlying heart disease.

Objective

The purpose of this study was to determine the prevalence of coronary artery disease (CAD) in patients diagnosed with idiopathic paroxysmal AF.

Methods

Of the 3243 patients who underwent cardiac computed tomographic angiography (CTA) in our center between January 2008 and March 2011, we identified a total of 115 consecutive idiopathic paroxysmal AF patients who underwent CTA before electrophysiologic ablation. Patients were compared with 275 age-, sex-, and PROCAM risk score–matched healthy controls in permanent sinus rhythm. All patients were free of hypertension, diabetes, congestive heart failure, previous known coronary artery and peripheral vascular disease, previous stroke, thyroid, pulmonary, and renal disease, and structural abnormalities on echocardiography.

Results

Controls more often showed a family history of CAD (38% vs 15%, P <.001), had a higher prevalence of smoking (25% vs 14%, P = .021), higher fasting blood glucose levels (5.5 ± 0.7 mmol/L vs 5.4 ± 0.6 mmol/L, P = .025), and smaller atrial diameters (37 ± 4 mm vs 40 ± 5 mm, P <.001) compared to AF patients. Notwithstanding the above, idiopathic AF patients significantly more often suffered from subclinical CAD compared to controls (49% vs 34%, P = .008). Multivariable regression analysis revealed that beside (as expected) age and gender, a history of AF and left atrial diameter were significant predictors of underlying CAD.

Conclusion

Half of patients originally diagnosed with idiopathic paroxysmal AF show concealed underlying CAD. The detection and treatment of CAD at an early stage could improve the prognosis of these patients.

Introduction

Atrial fibrillation (AF) is a well-established risk factor for cardiovascular events such as stroke and myocardial infarction. These vascular complications represent the major threat associated with AF.1 The RACE study reported an annual event rate for developing a vascular endpoint (cardiovascular death, heart failure, or thromboembolic complication) of 8% in the general AF patient.2 Even in the subset of patients who have AF in the absence of any detectable cardiovascular disease, annual morbidity and mortality rates are 4%.3, 4 Given that this so-called idiopathic AF is associated with a significant cardiovascular event rate, it could be a harbinger of as-yet undetected underlying vascular disease. Concerning this issue, a matched comparison between idiopathic AF patients and healthy sinus rhythm (SR) patients has not yet been performed. The purpose of this study was to compare the prevalence of subclinical coronary artery disease (CAD) in patients with idiopathic AF and in matched healthy SR controls.

Section snippets

Study population

We performed a case-control study of 3243 patients who underwent cardiac computed tomographic (CT) angiography (CTA) in our center between January 2008 and March 2011. Before CTA was performed, patient characteristics were collected and the PROCAM risk score was determined.5 All patients were in SR during CTA. Blood sampling was performed after an overnight fast. The study was approved by the Institutional Review Board, and all patients gave written informed consent.

Cases had to be idiopathic

Study population

Baseline characteristics for cases and controls are listed in Table 1. As stated earlier, all cases had idiopathic paroxysmal AF who were in SR during CTA; none of the cases had a mixed form of atrial flutter and AF. CTA was performed with a 64-slice CT scanner (Brilliance 64, Philips Healthcare, Best, The Netherlands) in 2387 patients and a 2*128-slice dual-source CT scanner (Somatom Flash, Siemens Healthcare, Forchheim, Germany) in 856 patients.

CTA findings

Despite a slightly more favorable baseline

Main findings

In this study, we investigated the prevalence of unsuspected CAD using CTA in a well-defined population of idiopathic AF patients compared to healthy SR controls. We found that, despite a more favorable baseline profile, half of patients originally diagnosed with idiopathic AF showed concealed and sometimes advanced underlying CAD. Beside (as expected) age and gender, a history of AF and left atrial diameter were predictors for the presence of coronary artery disease.

Idiopathic AF is often

Conclusion

Patients originally diagnosed with idiopathic AF have more concealed and sometimes advanced underlying CAD compared to healthy SR controls. Age, male sex, a history of AF, and left atrial diameter were predictors of presence of coronary artery disease. The detection and treatment of CAD at an early stage could improve the prognosis of these patients. At present, it seems potentially beneficial to check idiopathic AF patients for the presence of CAD.

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    This work was funded by the Maastricht University Medical Center.

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