Simultaneous evaluation of electrical activity and functional and anatomical cardiac changes by echocardiographic examination provides criteria for the diagnosis of arrhythmias and their hemodynamic consequences. Structural echocardiography views the kinetics of atrial and ventricular walls and the behavior of the valve apparatus during the cardiac cycle, establishing morphological and functional parameters which might identify atrial and ventricular arrhythmias. Changes in transvalvular systolic and diastolic flow velocities or tissue velocities in conjunction with simultaneous analysis of the temporal relationship between ventricular and atrial activity provide criteria for a positive and differential diagnosis of arrhythmias. In the same situation provided by arrhythmias, echocardiography can measure and quantify the hemodynamic parameters of ventricular function.