What are the echocardiographic features of constrictive pericarditis?

Echocardiographic Features of Constrictive Pericarditis

Echocardiographic abnormalities are always present in constrictive pericarditis, though no single finding is absolutely diagnostic—the diagnosis requires integration of multiple 2D, M-mode, and Doppler features that reflect the pathophysiology of impaired ventricular filling due to pericardial constriction. 1

M-Mode and 2D Echocardiographic Features

Pericardial Abnormalities

• Pericardial thickening and calcifications are frequently visible, though importantly, pericardial thickening is absent in 18% of surgically proven cases 2
• Transoesophageal echocardiography (TEE) provides superior measurement of pericardial thickness when needed 2

Cardiac Chamber Characteristics

• Biatrial enlargement (RA and LA) with normal-sized ventricles and preserved systolic function is a hallmark finding 2
• The left ventricle maintains normal appearance despite the hemodynamic compromise 1

Ventricular Septal Motion Abnormalities

• Early pathological outward and inward movement of the interventricular septum producing the "dip-plateau phenomenon" or "septal bounce" 2
• Respiration-related ventricular septal shift is one of the three most important independent predictors of constrictive pericarditis 3
• In mild cases, a single septal "wobble" occurs during normal respiration; moderate cases show a "double wobble" where the septum bows into the LV cavity in early diastole, relaxes, then deviates again after atrial contraction; severe cases demonstrate pan-diastolic motion into the LV cavity 4

Left Ventricular Wall Motion

• Flattening waves at the LV posterior wall reflecting restricted filling 2
• LV diameter does not increase after the early rapid filling phase 2
• Flattening of left ventricular endocardial motion in mid and late diastole 5

Venous Congestion Signs

• Inferior vena cava (IVC) and hepatic veins are dilated with restricted respiratory fluctuations 2
• IVC distention without collapse on deep inspiration indicates elevated central venous pressure 1

Doppler Echocardiographic Features

Atrioventricular Valve Inflow Patterns

• Respiratory variation >25% in flow velocities over the AV valves is the classic Doppler finding 2
• Restricted filling of both ventricles with exaggerated respiratory variation 2
• Mitral inflow E velocity variation is diagnostically significant, though this finding may be less reliable in atrial fibrillation 2

Tissue Doppler Findings

• Medial mitral annular e' velocity ≥9 cm/s is highly specific for constrictive pericarditis and helps differentiate it from restrictive cardiomyopathy 3
• An e' velocity ≥8 cm/s provides 95% sensitivity and 96% specificity for diagnosing constriction 6
• The ratio of medial to lateral mitral annular e' velocity is also diagnostically useful 3

Hepatic Vein Flow

• Hepatic vein expiratory diastolic reversal ratio ≥0.79 is an independent predictor of constrictive pericarditis 3
• Hepatic diastolic vein flow reversal in expiration is observed even when other flow velocity patterns are inconclusive, particularly in atrial fibrillation 2

Pulmonary Venous Flow

• Exaggerated respiratory variation in pulmonary venous flow velocities is highly characteristic 1

Diagnostic Algorithm Using Mayo Clinic Criteria

The most robust diagnostic approach combines three independent variables: 3

1. Ventricular septal shift (respiration-related)
2. Medial mitral annular e' ≥9 cm/s
3. Hepatic vein expiratory diastolic reversal ratio ≥0.79

• Septal shift plus either e' ≥9 cm/s OR hepatic vein ratio ≥0.79 provides 87% sensitivity and 91% specificity 3
• All three factors present increases specificity to 97% but reduces sensitivity to 64% 3

Critical Caveats and Pitfalls

Normal Pericardial Thickness Does Not Exclude Constriction

• Pericardiectomy should not be denied based solely on normal pericardial thickness when clinical, echocardiographic, or hemodynamic features indicate constriction 2
• Up to 20% of constrictive pericarditis cases have normal pericardial thickness 7

Atrial Fibrillation Complicates Diagnosis

• Diagnosis is more difficult in atrial fibrillation, but hepatic vein flow patterns remain useful 2
• All Mayo Clinic criteria except mitral inflow velocity variation remain valid in atrial fibrillation 3

Occult or Early Constriction

• In early or occult forms, classic signs may be absent 2
• Provocation testing with head-up tilting or sitting position to decrease preload may unmask constrictive physiology 2
• Rapid infusion of 1-2 liters of normal saline may be necessary to establish the diagnosis 2

Patients with Elevated Atrial Pressures

• Mixed constriction and restriction may demonstrate <25% respiratory changes 2
• Provocation maneuvers become particularly important in these cases 2

COPD Mimics Constriction

• In chronic obstructive lung disease, mitral inflow velocity decreases nearly 100% during inspiration 2
• Key differentiating feature: In COPD, mitral E-velocity is highest at end-expiration, whereas in constriction it is highest immediately after start of expiration 2
• Superior vena cava flow increases with inspiration in COPD but does not change significantly with respiration in constriction 2

Additional Confounding Factors

• Constrictive hemodynamics may be masked or complicated by valvular disease or coronary artery disease 2
• Severe tricuspid regurgitation can mimic constrictive physiology 3

Additional Echocardiographic Signs

• Premature opening of the pulmonary valve may be observed 5
• Relatively preserved left ventricular longitudinal deformation with attenuated circumferential deformation helps differentiate constriction from restrictive cardiomyopathy 8