Aggressively managing risk factors improves outcomes after ablations

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 - AF Ablation
Source: Heart Rhythm 2012;9:632-696

Aggressive management of risk factors may be the key to improving patient outcomes following ablation for atrial fibrillation. Findings published Dec. 2 in the Journal of the American College of Cardiology suggest that in patients with a high body mass index and more than one cardiovascular risk factor, improved long-term outcomes are possible when several risk factors were addressed.

A nearly three-fold greater number of aggressively managed patients were free of arrhythmia at final follow-up, researchers found.

The Aggressive Risk Factor Reduction Study for Atrial Fibrillation (ARREST-AF) cohort study followed 61 risk-factor managed (RFM) patients and 88 control patients for a mean of 41.6 vs. 42.1 months, respectively.

Rajeev K. Pathak, MBBS, of the Royal Adelaide Hospital in Adelaide, Australia, and colleagues of the ARREST-AF study sent patients in the RFM group to a physician-directed clinic every three months on top of arrhythmia follow-ups. Patients were given instruction on structured weight management programs; thrice-daily home blood pressure monitoring; lifestyle advice and behavior modification; smoking cessation counseling; sleep-disordered breathing management; and pharmaceutical treatment for lipids, blood pressure and glucose, if needed.

All patients received catheter ablation and ablation was repeated if recurrent arrhythmia developed after three months. At all points, risk factors were more effectively managed with aggressive treatment.

From baseline to final follow-up, mean systolic blood pressure reduced by 34.1 mmHg in patients who undertook the aggressive therapy regimen as opposed to 20.6 mmHg in the control group. By the end, fewer antihypertensive agents were used among RFM patients, while the control group increased.

Among RFM patients, nearly six-fold fewer still had dyslipidemia by the end. Diet and lifestyle modification controlled cholesterol in 46.2 percent of RFM patients as opposed to 17 percent of control subjects.

Diabetes management was another major area of success for the RFM group. While at baseline 15 percent of patients in this group had a history of diabetes and 13 percent had impaired glucose tolerance, 100 percent of patients had HbA1c levels down below 7 percent by the end. Comparatively, in the control group 29 percent had success in reducing HbA1c levels below 7 percent.

More patients adhered to sleep-disordered breathing treatment and smoking cessation in the aggressively treated group as well.

As a result, left atrial volume decreased four times as much for RFM patients: on average 12.1 ml/m2 for aggressively treated patients as opposed to 2.9 ml/m2 in patients in the control. Interventricular septum thickness reduced by 2 mm in the RFM group; the control group reduced by 0.4 mm.

Arrhythmia-free survival occurred for 32.9 percent of RFM patients after one procedure and in 87 percent following more than one ablation. Among control patients, 9.7 percent had arrhythmia-free survival after one procedure and 17.8 percent after multiple procedures.

Control group was a strong and significant predictor of recurrent atrial fibrillation in multiple analyses (hazard ratio: 4.8).

While this study makes a strong case for modifying underlying atrial fibrillation-related risks, it was unable to determine the relative contribution each piece of risk modification played with the whole.

Commenting on this study, Hans Kottkamp, MD, from Hirslanden Hospital in Zurich, noted that the contribution of these factors could come from any number of reasons. For example, obesity can have an effect on left atrial enlargement, increased systemic inflammation, obstructive sleep apnea development and arterial stiffness, but not all obese patients have atrial fibrillation.

“Their study sheds further light on the substantial clinical role of modifiable factors, such as obesity and other cardiac risk factors and has significant clinical implications,” Kottkamp wrote.

Pathak et al stated that more therapies were needed directed at risks for atrial fibrillation to continue to improve outcomes.