The heart is composed of two atria and two ventricles, which are functionally divided into right and left side with each side containing one atrium and one ventricle. This chapter gives an overview of the clinical evaluation procedure of patients with heart diseases, the signs and symptoms related to the heart ailments and various tests that are performed to correctly diagnose an ailment. It also discusses different types of heart ailments, such as pericarditis, dyspnea, orthopnea, and hypertrophy and chamber enlargement of the heart, as well as some other common cardiac and ventricular problems. When three or more ventricular extrasystoles occur together, it is as termed ventricular tachycardia (VT). It usually indicates severe underlying myocardial disease. The chapter also provides graphic examples of ECG results as specimens of cardiac rhythms, including the rhythms of both tachyarrhythmias and bradyarrhythmias. In the QRS complex, the initial downwards deflection is a Q (or q) wave and any negative deflection after this is an S. Any upward deflection is an R. If there is a second deflection in the same direction, it is denoted by adding a prime, so we have R’, R’’ and S’.