In conclusion, pharmaceutical and device manufacturers or group purchasing organizations continue to make substantial payments to cardiac practitioners with a significant variation in payments made to different cardiology subspecialists. The largest number and total payments are to general cardiologists, whereas the highest median payments are made to cardiac electrophysiologists. The impact of these payments on practice patterns remains to be examined.
Note the last sentence. Even if some studies have measured impacts on practice patterns (and there are soft data to that effect) we know very little about the impact on patient outcomes, good or bad.