Chronic constrictive pericarditis

ECG 6: This tracing shows a sinus rhythm, left atrial enlargement (prolonged P-wave, fragmented from V2 to V5, prolonged negative component in V1), narrow QRS with right conduction delay pattern (low voltage rsr’ pattern), diffuse (inferior and precordial leads) and shallow negative T-waves;

Comments: Chronic constrictive pericarditis is a rare condition; this is a standard case of diagnosis of elimination to be evoked when faced with a clinical picture of unexplained right heart failure. Typically, there is fibrous thickening of the pericardium, diffuse or localized, with calcification. This thick, pericardial retractile shell leads to constriction, elevated filling pressures and adiastoly (impairment of ventricular diastolic filling). Anamnesis allows searching for a history of tuberculosis, mediastinal radiotherapy, chronic renal failure, previous history of cardiac surgery or secondary pericardial cancer. Symptomatology can vary depending on the severity of dyspnea, of right-sided signs (jugular turgor, hepato-jugular reflux, hepatomegaly, ascites, edema of the lower limbs) and of a paradoxical pulse. Pulmonary radiography can show a non-enlarged heart with calcifications surrounding the cardiac silhouette. Cardiac ultrasound shows a thickened, dense, hyperechogenic pericardium, a moderately dilated atrial mass, which contrasts with normal or decreased ventricles, pulmonary veins and dilated inferior vena cava. The respiratory variations in cardiac flows are typical ; at inspiration, the tricuspid flow increases, while mitral flow decreases. The inspiratory compression of the left ventricle is suggestive of a severe disease. A hemodynamic study by right-sided catheterization revealed a dip-plateau pattern on the right intraventricular pressure curve. A subsequent MRI confirmed the diagnosis. The main differential diagnosis to evoke is that of a restrictive cardiomyopathy. Surgical treatment with radical pericardiectomy and decortication can be proposed for severe forms. It sometimes allows healing with resumption of a normal diastolic expansion; the result may however be only partial in calcified forms.

Chronic constrictive pericarditis is accompanied by aspecific electrocardiographic signs with fewer interindividual variations than for acute pericarditis, their respective anatomo-clinical picture being less dissimilar.

•  A deep alteration of the structure and anatomy of the atria is frequent due to the small thickness of the atrial myocardium. This results in frequent paroxysmal or permanent atrial fibrillation in one-third of patients (especially in calcified forms) and changes in the duration and morphology of the P-waves in sinus rhythm (signs of left atrial enlargement, notched P-waves, bifid in limb leads or left precordiall leads and/or widened with prolongation of the terminal negativity in V1).
• In chronic constrictive pericarditis, the reduction in ventricular compliance may be accompanied by an overload of the right cavities which may modify the pattern of the QRS-complexes with a clockwise rotation (SIQ3 pattern, discrete right axis deflection) and a right bundle branch block most often incomplete (low-voltage rsr’ in V1). The characteristic pattern of chronic constrictive pericarditis is the decrease in QRS voltages observed in half of the patients in the frontal leads and more rarely in the precordial leads. A true low voltage is however rarely observed. A pericardiectomy with resection of all or part of the pericardium most often allows evidencing an increase in voltages and a regression of the right axis deviation.
• The presence of negative or flattened T-waves (diffuse subepicardial ischemia) is the most common electrocardiographic abnormality. Repolarization disorders are stable, permanent, prolonged, may be diffuse (present in frontal leads and preferentially in left precordial leads) or more localized. The ST-segment is mostly isoelectric or slightly depressed.

Take-home message: Constrictive chronic pericarditis is accompanied by inconsistent aspecific electrocardiographic signs: left atrial enlargement, frequent atrial arrhythmias, right axis deflection, possible reduction in voltages, diffuse negative T-waves.