Informed consent is indispensable in contemporary medicine, especially in cases where the risks are high or there is true clinical equipoise, as in much invasive cardiology and cardiothoracic surgery practice. In this article we illustrate the principle of informed consent and describe how consent requirements have become more exacting in response to the rise of autonomy as the dominant principle in biomedical ethics. We outline some criticisms of informed consent, discuss why current requirements may never be achievable, and describe some of the vast literature aimed at "solving" the problem. We argue that respect for autonomy is just one of the principles of biomedical ethics and that the implementation of this principle must be weighed in the clinical context against the other principles, namely beneficence, non-maleficence and justice. The way we implement informed consent should be based on an ethical assessment of the clinical situation, including the invasiveness of the procedure, equipoise and the importance of patient values, and not on practical issues. We conclude that focusing on the whole decision-making process, effective communication, and a proportionate and individualised approach to consent could go some way to improve the experience of many patients in cardiology.