What is the recommended management for a patient with a dilated left atrium, right atrium, and right ventricle, but a normal left ventricle, presenting with potential signs of heart failure, such as shortness of breath, fatigue, or swelling in the legs?

Management of Dilated Biatrial and Right Ventricular Enlargement with Normal Left Ventricle

This pattern of isolated right heart and biatrial dilation with preserved left ventricular size and function demands immediate systematic evaluation for primary right heart pathology, particularly pulmonary hypertension, tricuspid regurgitation, arrhythmogenic right ventricular cardiomyopathy (ARVC), and atrial arrhythmias, as the normal left ventricle excludes typical left-sided heart failure as the primary driver. 1

Diagnostic Approach

Immediate Echocardiographic Assessment

• Quantify tricuspid regurgitation severity using vena contracta width, effective regurgitant orifice area, and regurgitant volume, as severe TR directly causes right atrial and ventricular volume overload 2

• Measure right ventricular systolic function using TAPSE, S' velocity, and fractional area change to distinguish volume overload from intrinsic RV dysfunction 3

• Estimate pulmonary artery systolic pressure from tricuspid regurgitation velocity and right atrial pressure, as pulmonary hypertension creates RV pressure overload leading to RV and RA dilation 1

• Assess for RV free wall dyskinesia or aneurysmal outpouching, which are hallmark features of ARVC that commonly presents with dilated RA/RV but preserved LV 4

• Document rhythm status as atrial fibrillation is both a cause and consequence of biatrial enlargement, creating a vicious cycle of progressive dilation 2

Advanced Imaging When Indicated

• Obtain cardiac MRI if ARVC is suspected, as it demonstrates RV free wall dyskinesia, aneurysmal outpouching with diffuse free wall enhancement, and fatty infiltration with sensitivity of 93-100% 4, 5

• Use contrast-enhanced cardiac MRI to differentiate intracardiac masses if mobile structures are seen in the right atrium, as thrombi carry 80-100% mortality if untreated 5

• Perform transesophageal echocardiography for definitive characterization of any atrial masses, with sensitivity of 93-100% and specificity of 99% 5

Systematic Evaluation for Underlying Etiologies

Primary Right Heart Conditions

• Severe tricuspid regurgitation causes direct volume overload with blood flowing backward into the right atrium during systole, receiving both normal venous return and regurgitant volume 1

• Pulmonary hypertension (mean PA pressure >20 mmHg) creates RV pressure overload that leads to RV dilation, dysfunction, and secondary RA enlargement 6

• ARVC predominantly affects young individuals with genetically predisposed cardiomyopathy, presenting with dilated RA/RV, RV free wall dyskinesia, and life-threatening ventricular arrhythmias 4

Atrial Arrhythmias

• Chronic atrial fibrillation causes progressive atrial dilation through myocyte disarray and fibrotic changes that compromise atrial contractile function 2

• Left atrial enlargement reflects chronic pressure or volume overload from multiple etiologies including valvular disease, LV diastolic dysfunction, or hypertension, even when LV size appears normal 2

Right Ventricular Failure Manifestations

• RV failure presents with increased RV size, decreased systolic function, high right atrial pressure with dilated inferior vena cava, and leftward deviation of the interventricular septum 3, 1

• Clinical signs include swelling of neck veins with elevated jugular venous pressure, ankle edema, congestive hepatomegaly, and eventually ascites as fluid accumulation becomes generalized 6

Management Strategy

Immediate Interventions

• Initiate anticoagulation with warfarin after even one or two episodes of paroxysmal atrial fibrillation, as the threshold for thromboembolism risk is low in patients with biatrial enlargement 2

• Maintain aggressive strategy for preserving sinus rhythm when atrial fibrillation develops, as AF is associated with progressive heart failure and mortality in patients with atrial enlargement 2

• Obtain urgent surgical consultation if mobile right atrial masses are identified, as they carry life-threatening embolization risk and anticoagulation alone is insufficient 5

Specific Therapies Based on Etiology

For severe tricuspid regurgitation:

• Consider tricuspid valve repair or replacement when TR is severe with progressive RV dilation or dysfunction, particularly if symptoms are present 2

For ARVC:

• Implant automated implantable cardioverter-defibrillator (AICD) in all confirmed cases to prevent sudden cardiac death from ventricular arrhythmias 4
• Initiate beta-blockers, low-dose diuretics, ACE inhibitors, spironolactone, and amiodarone as medical therapy 4

For pulmonary hypertension:

• Treat underlying cause (left heart disease, pulmonary disease, chronic thromboembolic disease) with targeted therapies based on specific etiology 6

For right ventricular failure:

• Optimize volume status with diuretics to reduce systemic venous hypertension while maintaining adequate preload 6
• Avoid excessive RV unloading that can cause leftward septal shift and worsen hemodynamics 3

Serial Monitoring

• Repeat echocardiography in 1-2 years if no significant underlying cause is identified and patient is asymptomatic, to assess for progression of chamber dilation or development of ventricular dysfunction 2

• Perform serial examinations comparing 2D/3D measurements of RV size, RA volume, and RV systolic function to detect progressive dilation or declining function 3

Critical Pitfalls to Avoid

• Do not assume left heart failure is the cause when the left ventricle is normal in size and function, as this pattern indicates primary right heart or biatrial pathology requiring different management 1

• Do not overlook ARVC in younger patients with dilated RA/RV, as this carries high risk of sudden cardiac death and requires ICD implantation 4

• Do not delay anticoagulation in patients who develop even brief episodes of atrial fibrillation, as stroke risk is elevated even with paroxysmal AF in the setting of biatrial enlargement 2

• Do not miss mobile right atrial thrombi or masses, as they require urgent intervention with thrombolysis or surgical embolectomy to prevent fatal pulmonary embolism 5

• Do not rely on single-dimension measurements for atrial size assessment, as volumetric assessment using biplane disk summation technique is substantially more accurate for risk stratification 2