Pericardial Effusion and Its Characteristic ECG Features

Pericardial effusion, which refers to the abnormal accumulation of fluid around the heart, can present distinct electrocardiogram (ECG) findings that are crucial for clinical diagnosis. One of the most notable ECG characteristics associated with pericardial effusion is low voltage in either the limb leads or precordial leads. Specifically, the QRS amplitude in precordial leads often falls below 1 mV, while in limb leads, it may drop below 0.5 mV.

Why Does Low Voltage Occur in ECG?

This low voltage phenomenon occurs due to the insulating effect of the fluid surrounding the heart, which interferes with the transmission of electrical impulses from the myocardium to the body surface. As a result, the recorded electrical activity on the ECG becomes diminished.

ECG Changes Related to Cardiac Tamponade

In addition to low voltage, patients with significant pericardial effusion may develop cardiac tamponade, a serious complication that can impair cardiac function. In such cases, the heart compensates by increasing its rate, leading to sinus tachycardia, which is another common ECG finding.

Arrhythmias Associated with Pericardial Effusion

Moreover, pericardial effusion may be accompanied by various arrhythmias. Patients often exhibit atrial or ventricular premature beats, which can be readily detected on a standard ECG. These rhythm disturbances may be due to irritation of the myocardium or conduction system caused by the fluid buildup around the heart.

Understanding these ECG changes is essential for timely diagnosis and management of pericardial effusion. Clinicians should remain vigilant for these signs, especially in patients presenting with unexplained tachycardia or reduced QRS amplitude.