**5.2 Electrocardiograph**

Sinus tachycardia, QRS complexes of diminished voltage (**Figure 5**), and the presence of electrical alternans (**Figure 6**) were the electrocardiographic changes in pericardial effusion. The presence and severity of cardiac tamponade and also inflammatory mechanisms may contribute to the development of low QRS voltage in patients with pericardial effusion [4]. Electrical alternans is the result of a specific type of cardiac motion within the pericardium. The volume of the effusion, viscosity of the fluid, and heart rate are thought to be interrelated in the production of electrical alternans.
