What is the clinical significance of an echocardiogram showing normal left ventricular systolic function (ejection fraction 55‑60 %), normal size, wall thickness, wall motion and diastolic function, a normal trileaflet aortic valve, mild tricuspid regurgitation, but severe left atrial enlargement (left‑atrial volume index 56 mL/m²) and right atrial dilation?

Clinical Significance of This Echocardiogram

The most clinically significant finding is the severe left atrial enlargement (LA volume index 56 mL/m²), which indicates chronic elevated left ventricular filling pressures and substantially increases risk for atrial fibrillation, stroke, heart failure hospitalization, and mortality—despite the currently preserved left ventricular systolic function. 1

Key Findings and Their Implications

Severe Left Atrial Enlargement (Most Critical Finding)

• LA volume index of 56 mL/m² is severely elevated (normal <34 mL/m², severely increased >48 mL/m²), indicating chronic diastolic dysfunction with elevated filling pressures even though the report states "normal diastolic function" 1
• This degree of LA enlargement carries independent prognostic significance with hazard ratios for adverse cardiovascular outcomes, regardless of ejection fraction 1
• Severe LA dilation is a sensitive marker of long-standing cardiac stress and predicts future development of atrial fibrillation, heart failure decompensation, and increased mortality risk 2, 3

Right Atrial Dilation (Secondary Important Finding)

• Right atrial enlargement in conjunction with LA dilation suggests elevated right-sided pressures and possible pulmonary hypertension, even with only mild tricuspid regurgitation 2
• The combination of bilateral atrial enlargement indicates chronic volume and pressure overload affecting both sides of the heart 3
• Atrial enlargement occurs as an early event before right ventricular dilation in the progression of functional tricuspid regurgitation 3

Mild Tricuspid Regurgitation

• While classified as "mild," functional tricuspid regurgitation combined with right atrial dilation is an early indicator of right heart remodeling 3
• Tricuspid annular dilation and atrial enlargement comprise early events in functional TR, occurring before right ventricular dilation 3
• In patients with atrial fibrillation (if present), even mild-to-moderate functional TR independently predicts adverse outcomes including heart failure and mortality 2, 4

Preserved Left Ventricular Function (Reassuring but Requires Context)

• EF 55-60% is normal (normal ≥50-53%) 5, 6
• Normal LV size, wall thickness, and wall motion are favorable findings 5
• However, normal EF does not exclude subclinical LV dysfunction in the setting of severe atrial enlargement—advanced strain imaging might reveal early longitudinal dysfunction not apparent on standard echo 7

Clinical Management Implications

Immediate Diagnostic Workup Needed

• Investigate the underlying cause of severe LA enlargement: chronic hypertension, valvular disease (particularly mitral valve pathology that may have been underestimated), atrial fibrillation, restrictive cardiomyopathy, or infiltrative disease 1
• Obtain 12-lead ECG to assess for atrial fibrillation, left atrial abnormality, or conduction disease 2
• Measure pulmonary artery systolic pressure (PASP) from tricuspid regurgitation jet velocity if not already done—TR velocity >3 m/s (PASP >40 mmHg) indicates pulmonary hypertension requiring specific management 1
• Consider BNP/NT-proBNP levels to assess for subclinical heart failure 4

Risk Stratification

• This patient is at high risk for developing atrial fibrillation if not already present, given the severe LA enlargement 2
• Increased risk for thromboembolic events and stroke, particularly if atrial fibrillation develops 2
• Risk for progression to heart failure with preserved ejection fraction (HFpEF), as severe LA enlargement indicates chronic diastolic dysfunction 1
• The combination of bilateral atrial enlargement and functional TR predicts adverse outcomes including heart failure hospitalization and mortality 2, 4

Therapeutic Interventions

• Aggressive blood pressure control targeting <130/80 mmHg if hypertension is present, as this is the most common cause of LA enlargement 5
• Optimize management of any underlying left-sided valvular disease 8
• Consider anticoagulation assessment if atrial fibrillation is present or develops, using CHA₂DS₂-VASc score 2
• Diuretic therapy may be needed if volume overload is contributing to atrial enlargement 4
• Neurohormonal blockade with ACE inhibitors/ARBs and beta-blockers for ventricular remodeling prevention 5

Follow-Up Strategy

• Serial echocardiography is indicated to monitor for progression of TR, development of RV dysfunction, worsening atrial enlargement, or decline in LV systolic function 5, 1
• Repeat echo in 6-12 months given the severe LA enlargement, or sooner if symptoms develop 5
• Monitor for development of atrial fibrillation with periodic ECGs or ambulatory monitoring if palpitations occur 2
• If symptoms of dyspnea or exercise intolerance develop, consider cardiopulmonary exercise testing to assess functional capacity and hemodynamic response 8

Common Pitfalls to Avoid

• Do not dismiss severe LA enlargement simply because EF is normal—this represents significant chronic cardiac pathology requiring investigation and management 1
• Do not assume "normal diastolic function" is accurate when LA volume index is 56 mL/m²—severe LA enlargement itself indicates chronic diastolic dysfunction regardless of other diastolic parameters 1
• Mild TR should not be ignored in the context of bilateral atrial enlargement—this represents early functional TR that may progress and independently predicts adverse outcomes 2, 3, 4
• Do not delay workup for underlying causes—severe LA enlargement of this magnitude requires explanation and treatment of the underlying etiology 1
• Recognize that preserved EF may mask subclinical longitudinal LV dysfunction—consider advanced imaging with strain if clinical suspicion exists 7