Inclusion Criteria1. Age ≥ 18 years.
2. Patients who have undergone cardiac surgery. This includes coronary artery bypass grafting and all open heart procedures such as valvular repairs/replacement.
Exclusion Criteria1. Previously enrolled in the VISION Cardiac Surgery Study.
2. Patients who have undergone an isolated pericardial window, pericardiectomy, permanent pacemaker or defibrillator implantation.