Randomised clinical trials are the gold standard for testing the effectiveness of clinical interventions. However, increasing complexity and associated costs may limit their application in the investigation of key cardiovascular knowledge gaps such as the re-evaluation of generic pharmacotherapies. The registry-based randomised clinical trial (RRCT) leverages data sampling from nationwide quality registries to facilitate high participant inclusion rates at comparably low costs and, therefore, may offer a mechanism by which such clinical questions may be answered. To date, a number of studies have been conducted using such trial designs, but uncritical use of the RRCT design may lead to erroneous conclusions. The current review provides insights into the strengths and weaknesses of the RRCT, as well as provides an exploratory example of how a trial may be designed to test the long-term effectiveness of beta blockers in patients with myocardial infarction who have preserved left ventricular systolic function.