1. Department of Cardiology and Internal Diseases; Specialistic Hospital; Gorlice Poland
2. Department of Internal Medicine and Toxicology; Specialistic Hospital St Lucas; Tarnów Poland
3. Jagiellonian University Medical College; First Department of Cardiology; Interventional Electrocardiology and Hypertension; Kraków Poland
4. Division of Cardiology; Kingston General Hospital; Queen's University; Kingston ON Canada