Page 75 - ADD-ON ABLATION SURGERY IN PATIENTS WITH ATRIAL FIBRILLATION

However these unsatisfactory results may be explained by the use of microwave energy to make lesions. Indeed, there are potential advantages of this energy source (MW probes can create a linear lesion easily, it can penetrate tissue more deeply than other energy sources, the lesion is more likely to be transmural with a greater volume of heated tissue for the same tissue surface temperature, its unidirectional focused energy avoids collateral damage, and there is lower risk of thromboembolism), it has important drawbacks (unfocused heat energy, no way to judge transmurality of ablation during surgery, and it is not capable of making transmural lesions on the beating heart) which limit its wide use in clinical practice. The major challenge to using microwaves is controlling the heating zone for a desired clinical outcome without incidentally heating nearby tissues or causing complications. Primary focus has been given to antenna cooling and arrays as a means to safely deliver more power and produce larger ablations, but research has also continued in antenna design, frequency comparisons, and power application algorithms34. However a review recently published has demonstrated that microwave ablation, as an intervention for the treatment of AF during concomitant surgery, is not currently recommended on the limited available evidence35.
Another critical point in our study is that only pulmonary vein isolation was
carried out without making additional left atrial and right atrial lesions, which are
necessary for a successful ablation as widely discussed before.
However, starting from comparable 1-year SR conversion with or without add-on
surgery, we wanted to further investigate whether SR conversion after cardiac
surgery was associated with enhanced QoL. For this purpose, a retrospective
analysis was performed (Chapter 3). Based on patients’ rhythm outcome at
6- and 12-month follow-up, a dummy regression analysis was carried out with
each questionnaire sub-scale as a dependant outcome variable. SR conversion at
discharge, between 3 and 6 months follow-up and between 6 and 12 months of
follow-up were tested for their significance. Overall, QoL was not influenced by
SR conversion nor by possible confounders such as age, gender and type of AF. In 9 addition, the relationship between SR conversion and QoL tended to attenuate
and wear off with post-operative time.
In conclusion, the results of these two studies with respect to QoL indicate that QoL does not improve in case SR restoration is achieved, regardless of whether this restoration was brought about by ablation surgery or the corrective effect of cardiac surgery on underlying heart disease.
General discussion
193