ST segment elevation in ECG is seen in all of the following except:
Early repolarization variant
Constrictive pericarditis
Ventricular aneurysm
Prizmetal angina
In constrictive pericarditis, ECG does not show ST elevation, it frequently shows low voltage QRS complexes and diffuse flattening or inversion of the T waves. 1/3rd of the patients shows changes consistent with atrial fibrillation. Constrictive pericarditis: Is inflammation of pericardium which leads to the formation of a thickened, fibrotic, adherent pericardium that restricts diastolic filling and produces chronically elevated venous pressures. Clinical features: Patients presents with progressive dyspnea, fatigue, and weakness. On examination: JVP is elevated with a rapid y descent. Kussmaul sign and pulsus paradoxus is present. Apex of hea retract with systole and a pericardial knock may be heard in early diastole. Chest radiograph may show cardiomegaly and pericardial calcification. Echocardiography shows thickened pericardium and septal bounce reflecting the rapid early filling. Reference: 1. Current Medical Diagnosis and Treatment, 2012, Chapter 10 2. Harrison's Internal Medicine, 18th Edition, Chapter 239