From the Guidelines
Pericarditis causes PR segment depression due to the inflammatory process affecting the pericardium, which alters the electrical activity recorded during the PR interval, specifically affecting atrial repolarization. The inflammatory process in the pericardial sac surrounding the heart creates a current of injury that affects atrial repolarization, leading to a relative negativity of the injured epicardial surface of the atria compared to the endocardial surface, resulting in PR segment depression on the electrocardiogram (ECG) 1. This depression is often seen in multiple leads and is one of the earliest and most specific ECG findings in acute pericarditis, preceding the more commonly recognized ST segment elevation. The characteristics of the ECG changes in pericarditis are outlined in the guidelines, which note that the PR segment deviations are opposite to P polarity, and that the ST segment is always depressed in aVR, frequently in V1, and occasionally in V2 1.
Some key points to consider in the diagnosis and management of pericarditis include:
- The use of ECG to diagnose pericarditis, with findings such as PR segment depression and ST segment elevation 1
- The importance of differentiating pericarditis from other conditions that cause ST elevation, such as myocardial infarction 1
- The role of nonsteroidal anti-inflammatory drugs (NSAIDs) and colchicine in the treatment of pericarditis, with NSAIDs being the mainstay of treatment and colchicine being effective for the initial attack and prevention of recurrences 1
- The need for hospitalization to determine the etiology and observe for tamponade, as well as the effect of treatment 1
The guidelines also note that cardiac troponin I and CK-MB may be elevated in patients with acute pericarditis, particularly those with ST elevation on ECG 1. However, the presence of PR segment depression remains a key diagnostic finding in pericarditis, and its resolution is an important indicator of the response to treatment. Overall, the diagnosis and management of pericarditis require a comprehensive approach that takes into account the clinical presentation, ECG findings, and response to treatment.
From the Research
Pericarditis and PR Segment Depression
- Pericarditis is characterized by inflammation of the pericardium, which can lead to various electrocardiographic changes, including PR segment depression 2.
- The development of PR segment depression in pericarditis is attributed to the inflammation of the pericardium, which can affect the atrial tissue and lead to changes in the PR interval 3.
- PR segment depression is a common finding in acute pericarditis, occurring in approximately 25-50% of cases, and is often accompanied by ST-segment elevation 2.
- The exact mechanism of PR segment depression in pericarditis is not fully understood, but it is thought to be related to the inflammatory process and the resulting changes in the atrial tissue 3.
Diagnosis and Treatment of Pericarditis
- Pericarditis is diagnosed based on the presence of two or more of the following criteria: sharp, pleuritic chest pain; new widespread electrocardiographic ST-segment elevation and PR depression; a new or increased pericardial effusion; or a pericardial friction rub 2.
- Treatment of pericarditis typically involves the use of nonsteroidal anti-inflammatory drugs (NSAIDs), colchicine, and corticosteroids, depending on the severity and cause of the disease 2, 4, 5, 6.
- Colchicine is a key component of treatment for acute and recurrent pericarditis, and has been shown to reduce the risk of recurrence 5, 6.
- Corticosteroids are often used in cases where NSAIDs and colchicine are not effective, or in patients with specific medical conditions such as systemic autoimmune diseases or postpericardiotomy syndrome 4, 5.