Electrocardiographic Features of Acute Pericarditis

Acute pericarditis is a condition characterized by inflammation of the pericardium, and it presents distinct electrocardiographic (ECG) patterns that evolve through several stages. These changes are crucial for accurate diagnosis and differentiation from other cardiac conditions such as myocardial infarction.

Stage 1: ST-Segment Elevation

The first stage of acute pericarditis typically involves widespread ST-segment elevation with a concave upward morphology. This elevation is observed in most leads except for aVR and sometimes lead I. The changes are often most prominent in the limb leads, particularly leads II and III. Additionally, tall, peaked T waves may be present without the reciprocal ST-segment depression commonly seen in myocardial infarction. This stage can last from a few days up to two weeks.

Stage 2: Return of ST Segments to Baseline

Within a few days following the initial presentation, the ST segments typically return to the baseline level. This normalization indicates a transition phase in the evolution of the ECG changes associated with pericarditis. Patients may experience a temporary return to near-normal readings before further alterations occur.

Stage 3: Diffuse T-Wave Inversion

In the third stage, diffuse T-wave inversions develop across multiple leads. These inversions become more pronounced and reach their maximum depth during this phase. This pattern reflects the ongoing inflammatory process and is a key diagnostic feature of pericarditis when correlated with clinical symptoms and other findings.

Stage 4: Resolution of ECG Changes

Eventually, usually after a period of about three months, the T waves gradually return to an upright position. This marks the final stage of the ECG evolution in acute pericarditis, indicating resolution of the acute inflammatory episode. However, the timeline can vary depending on the severity of the condition and individual patient factors.

Recognizing these ECG patterns and their progression is essential for timely diagnosis and management of acute pericarditis. Clinicians should also consider clinical context, laboratory findings, and imaging studies to confirm the diagnosis and rule out other life-threatening conditions.