A 55-year-old man presents to the ED with a two-week history of malaise, lethargy, and “the flu.” He arrived at the ‘Copa early this morning with increasing shortness of breath. He thinks he may have had a fever a few days ago, but hasn’t noticed one in the past 48 hours. He denies any chest pain or discomfort.
His vital signs in triage were blood pressure of 90/64 mm Hg, a pulse of 80 beats/min, and a respiratory rate of 18 breaths/min. Rales were heard in the right lower lobe. The patient was presumed to have pneumonia, and treatment with intravenous antibiotics was begun.
As you review the laboratory data, you see that the white blood cell count normal & CXR shows vague bi-basilar infiltrates. The intern suspected a viral etiology. The ECG performed as part of the initial workup but was put on the wrong chart until Hickman found it after Dr Horwood told him to find it or go home, shows a ventricular rate of 80 beats/min; PR interval, 171 ms; QRS duration, 92 ms; QT/QTc interval, 363/419 ms; P axis, 25º; R axis, 29º; and T axis, 51º. What is your interpretation of this ECG?
This patient has acute generalized viral pericarditis. Sinus tachycardia (ST) segment elevations are present in all leads with the exception of aVL. This is a result of generalized inflammation of the pericardium and its effects upon the myocardium. The abnormalities seen on the ECG are not due to ischemia; the changes occur globally over the entire surface of the heart and are not consistent with a specific myocardial region supplied by a single coronary artery. With time and resolution of the inflammatory process, the ST elevations will likely return to baseline, but may also be replaced with widespread T-wave inversions.
Electrocardiographic Manifestations
The ECG is useful in the diagnosis of acute pericarditis, with abnormalities found in approximately 90 percent of cases. Changes on ECG classically occur in four stages (Table 2).9,10 Not all cases of pericarditis include each of these four stages. In fact, all four stages are present in only 50 percent of patients or less. Stage I typically occurs during the first few days of pericardial inflammation and is mainly characterized by diffuse ST-segment elevation. This stage may last up to two weeks. Stage II is characterized by return of the ST segments to baseline and flattening of the T wave and may last from days to several weeks. Stage III usually begins at the end of the second or third week and is characterized by inversion of the T waves in the opposite direction of the ST segment; this stage may last several weeks. Stage IV represents the gradual resolution of the T-wave changes and may last up to three months.11
Stages of Acute Pericarditis on ECG
- Stage I - Diffuse concave-upward ST-segment elevation with concordance of T waves; ST-segment depression in aVR or V1; PR-segment depression; low voltage; absence of reciprocal ST-segment changes
- Stage II - ST segments return to baseline; T-wave flattening
- Stage III - T-wave inversion
- Stage IV - Gradual resolution of T-wave inversion
