Table of contents: • Properties of the myocardium • Electrocardiogram: general aspects • Pathophysiology of atrial and ventricular overload • Pathophysiology of driving disorders • Pathophysiology of rhythm disorders • Pathophysiology of cardiac perfusion disorders • Heart exploration methods • Exploring the vascular system • Methods of functional exploration of the respiratory system – spirometry • References • ANNEX 1 – Elecetrocariograms • ANNEX 2 – Spirometries • ANNEX 3 – ECG interpretation