BackgroundTraditional cardiac rehabilitation programs are centre-based and clinically supervised, with their safety and effectiveness well established. Notwithstanding the established benefits, cardiac rehabilitation remains underutilised. A possible alternative would be a hybrid approach where both centre-based and tele-based methods are combined to deliver cardiac rehabilitation to eligible patients. The objective of this study was to determine the long-term cost-effectiveness of a hybrid cardiac telerehabilitation and if it should be recommended to be implemented in the Australian context.MethodsFollowing a comprehensive literature search, we chose the Telerehab III trial intervention that investigated the effectiveness of a long-term hybrid cardiac telerehabilitation program. We developed a decision analytic model to estimate the cost-effectiveness of the Telerehab III trial using a Markov process. The model included stable cardiac disease and hospitalisation health states and simulations were run using one-month cycles over a five-year time horizon. The threshold for cost-effectiveness was set at $AU 28,000 per quality-adjusted life-year (QALY). For the base analysis, we assumed that 80% completed the programme. We tested the robustness of the results using probabilistic sensitivity and scenario analyses.ResultsTelerehab III intervention was more effective but more costly and was not cost-effective, at a threshold of $28,000 per QALY. For every 1,000 patients who undergo cardiac rehabilitation, employing the telerehabilitation intervention would cost $650,000 more, and 5.7 QALYs would be gained, over five years, compared to current practice. Under probabilistic sensitivity analysis, the intervention was cost-effective in only 18% of simulations. Similarly, if the intervention compliance was increased to 90%, it was still unlikely to be cost-effective.ConclusionHybrid cardiac telerehabilitation is highly unlikely to be cost-effective compared to the current practice in Australia. Exploration of alternative models of delivering cardiac telerehabilitation is still required. The results presented in this study are useful for policymakers wanting to make informed decisions about investment in hybrid cardiac telerehabilitation programs.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12913-023-09546-w.