Page 42 - ADD-ON ABLATION SURGERY IN PATIENTS WITH ATRIAL FIBRILLATION

Chapter 2
the SF-36.The important differences between the above-mentioned studies and the present study are the following: the previous studies were non-randomised, non-controlled and non-blinded, only paroxysmal AF patients were investigated, concomitant underlying heart disease was not specified nor treated and rhythm follow-up was incompletely documented and evaluated at 12-month follow-up. In other words, it cannot be determined whether improvement of HrQoL was either achieved by complete absence of arrhythmia, by asymptomatic episodes of AF, or by treating underlying heart disease.
Study limitations
Two generic questionnaires (EuroQoL and RAND SF-36) were used for HrQoL assessment.Although widely used, it is possible that important aspects or changes in HrQoL in patients with AF are not measured. Moreover, scoring was highly dependant on other physical, non-cardiac, impairments the patient perceived at that time the questionnaire was completed. Longer follow-up might mask the true picture of recovery and enhanced HrQoL after cardiac surgery, because the longer follow-up is carried out, the more non-cardiac co-morbidity will develop. Usage of AF-specific questionnaires, such as used by Badia33 might be helpful in the future. Secondly, the high number of patients in SR in the control group has important consequences for the study design, since the sample size calculation was based on the assumption that 25% of the patients in the control group, would spontaneously convert to SR: thus a larger sample size might have been needed to detect the effect of add-on surgery on rhythm outcome. On the other hand, we believe that our follow-up was much more extensive than in previous studies. Our follow-up protocol might be considered different from the new standards described in the 2006 ACC/AHA/ESC Guidelines and by the recommendation of the Workforce on Evidence-Based Surgery of the Society of Thoracic Surgeons10,34. These standards were not yet available when the study was conducted. Rhythm follow-up was performed by standardized EKG and Holter registration, which is in itself an improvement in comparison to follow- up in several other studies. Meanwhile, several devices for continuous rhythm monitoring have been developed that will further improve rhythm evaluation in future intervention studies.
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