Assessing potential divers with a history of congenital heart disease.

This article describes a structured approach to assessing the medical fitness of potential divers who have a history of congenital heart disease. The importance of a complete and accurate cardiac history, including details of surgery and other interventions is emphasized. Specific assessment of intracardiac shunts, exercise capacity and ability to deal with the physical challenge of diving, risk of diving-included pulmonary oedema, of arrhythmia and of incapacity in case of arrhythmia and the consequences of surgical and catheter treatment are discussed, including the risks associated with lung injury and the pressure limitations of implanted devices like pacemakers. Clinical assessment will usually include echocardiography and exercise testing with additional investigations such as MRI scanning, CT of heart or lungs, cardiopulmonary exercise testing and ECG monitoring, as required. Examples of different congenital lesions are given applying this approach (atrial septal defect, tetralogy of Fallot, bicuspid aortic valve and the Fontan circulation). The approach is based on an individual cardiologist's opinion and is not specifically evidence-based, but seeks to apply what is known in other areas of diving medicine to this potentially complex group of patients.