Right-sided heart failure

Article written and reviewed by Dr Luca Moretti

Right-sided heart failure is the syndrome in which the right ventricle cannot deliver adequate cardiac output to the pulmonary circulation without a pathological increase in systemic filling pressures. It may present as isolated right heart failure, predominate in left heart disease, or occur acutely in pulmonary embolism, right ventricular infarction, pulmonary hypertension, or cardiac surgical complications. It is not synonymous with peripheral edema or a single echocardiographic measurement. Systemic congestion may result from volume overload, tricuspid regurgitation, or constriction, while severe right heart dysfunction may produce shock before visible edema; diagnosis and treatment require integration of preload, afterload, and contractility. The physiology is particularly sensitive to pulmonary afterload and interdependence with the left ventricle. Small increases in vascular resistance may rapidly reduce cardiac output, dilate the ventricle, shift the septum, and also compromise left heart filling.

The main causes fall into four groups: increased afterload, loss of contractility, volume overload, and restricted filling. Pulmonary hypertension, embolism, and hypoxia belong to the first; infarction, myocarditis, and cardiomyopathies to the second; shunts and regurgitation to the third; tamponade and constrictive pericarditis to the fourth. A right ventricle acutely exposed to pressure cannot tolerate loads that a chronically adapted ventricle can sustain. In acute right heart failure, dilation, ischemia, and low cardiac output predominate; in the chronic form, hypertrophy and remodeling allow initial compensation, followed by ventricular-arterial uncoupling; effective therapy identifies the mechanism. Diuretics, oxygenation, reperfusion, valve correction, and treatment of pulmonary hypertension are not interchangeable; an intervention useful in one phenotype may cause collapse in another.

Etiology, pathogenesis, and pathophysiology

Pulmonary hypertension is the most important hemodynamic cause. In precapillary forms, vascular resistance and arterial elastance increase; in forms due to left heart disease, increased left atrial pressure is transmitted to the lungs and may be associated with vascular remodeling. Right heart catheterization distinguishes mean pulmonary pressure, wedge pressure, cardiac output, and vascular resistance, avoiding classifications based solely on echocardiography. Lung diseases and hypoxia cause vasoconstriction, loss of the vascular bed, and hyperinflation; the term cor pulmonale describes right heart abnormalities resulting from respiratory disease. Sleep apnea, chronic thromboembolism, and hypoventilation may contribute and require specific diagnosis. In acute pulmonary thromboembolism, obstruction and mediators abruptly increase afterload; the septum shifts, systemic blood pressure falls, right coronary perfusion decreases, and a cycle of ventricular ischemia develops.

Right ventricular infarction most often results from proximal right coronary artery occlusion and may be associated with inferior infarction. Loss of contractility, bradycardia, conduction block, and loss of atrial systole make cardiac output dependent on rhythm and preload; nitrates or indiscriminate diuresis may precipitate hypotension. Myocarditis, sarcoidosis, Chagas disease, and arrhythmogenic cardiomyopathy may affect the right ventricle; arrhythmogenic cardiomyopathy combines fibrofatty replacement, arrhythmias, and dysfunction, often biventricular; magnetic resonance imaging and genetics must be interpreted using specific criteria. Cardiotoxicity, sepsis, and peripartum cardiomyopathy may produce right heart involvement proportional to or greater than left heart involvement; right heart dysfunction in sepsis is also influenced by ventilation, acidosis, and vasoplegia.

Volume overload results from tricuspid or pulmonary regurgitation, atrial shunts, and anomalous venous return. Initially the ventricle dilates and preserves cardiac output; over time, wall stress, functional regurgitation, and venous congestion increase; secondary tricuspid regurgitation may be ventricular, due to annular dilation and tethering, or atrial, associated with fibrillation and atrial dilation. Device leads may interfere with leaflets and chordae and require three-dimensional assessment. After tetralogy of Fallot repair, chronic pulmonary regurgitation and scars lead to dilation and arrhythmias; the timing of valve replacement depends on volumes, function, symptoms, and risk, not on the murmur alone.

Tamponade, constriction, and increased intrathoracic pressure limit filling. In tamponade, the balance between pericardial and chamber pressures causes collapse and ventricular dependence; in constriction, the rigid pericardium produces respiratory pressure dissociation and accentuated ventricular interdependence. Positive-pressure ventilation, high PEEP, and hyperinflation reduce venous return and increase pulmonary vascular resistance, particularly with hypovolemia. Intubation of a patient with severe pulmonary hypertension is a high-risk phase because of vasodilation, acidosis, and loss of preload; elevated abdominal pressure impedes renal and portal venous return. Tense ascites may amplify kidney dysfunction and reduce the diuretic response, making assessment of the abdominal compartment useful.

The normal right ventricle has a thin wall, high compliance, and predominantly volume work. When afterload increases, initial hypertrophy maintains coupling; with progression, contractility no longer compensates for arterial elastance and right ventricular-pulmonary arterial uncoupling appears; dilation increases wall tension and oxygen consumption, while low systemic blood pressure reduces coronary perfusion. Ischemia and tricuspid regurgitation worsen contractility and volume overload, generating a self-perpetuating cycle; the septum is part of both ventricles. Leftward displacement reduces left ventricular compliance and filling; low systemic cardiac output may therefore result from right heart failure even with a normal left ventricular ejection fraction.

Venous congestion increases renal interstitial pressure, reduces the filtration gradient, and activates retention. In the liver it produces sinusoidal dilation, cholestasis, and centrilobular fibrosis; an acute fall in cardiac output may add hypoxic necrosis; the organ venous pressure gradient is more relevant than blood pressure alone. Intestinal edema impairs drug absorption and the mucosal barrier, promoting inflammation and malnutrition; protein loss and satiety from ascites contribute to sarcopenia. Sympathetic and renin-angiotensin activation retains sodium, but excess preload may worsen regurgitation and interdependence. The idea that the right ventricle must always be “filled” is therefore dangerous.

Clinical manifestations

Initial symptoms are reduced exercise tolerance, fatigability, and dyspnea. Dyspnea may result from the causative lung disease, low cardiac output, or inability to increase pulmonary blood flow; orthopnea and crackles suggest a left-sided component, but are not required. Dependent edema, weight gain, abdominal tightness, nausea, and early satiety reflect systemic congestion. In advanced stages, ascites, anasarca, muscle loss, and malabsorption appear, sometimes with stable weight because cachexia masks retention. Palpitations and syncope are particularly relevant in pulmonary hypertension and arrhythmogenic cardiomyopathies; exertional syncope indicates inability to increase cardiac output or an arrhythmia and carries high risk.

Examination of the jugular veins estimates right atrial pressure. A prominent v wave suggests tricuspid regurgitation, and a giant a wave suggests obstruction to filling or dissociation; Kussmaul’s sign appears when venous pressure increases during inspiration because of reduced right ventricular compliance. A parasternal impulse, an accentuated P2, and a holosystolic murmur accentuated during inspiration point toward pressure overload and tricuspid regurgitation; a right-sided third heart sound and a pulmonary murmur may be present. Pulsatile hepatomegaly, hepatojugular reflux, ascites, and edema quantify systemic compartment involvement; the absence of edema does not exclude an acute form with shock.

In low cardiac output, cold extremities, oliguria, altered mental status, a narrowed pulse pressure, and elevated lactate appear; hypotension is a late sign; tachycardia and renal deterioration may precede it. In right ventricular infarction, hypotension, elevated jugular venous pressure, and relatively clear lung fields are frequent; the classic triad has limited sensitivity, and a right-sided ECG should be obtained early. In pulmonary embolism, sudden dyspnea, pain, tachycardia, hypoxemia, and syncope predominate. Signs of venous thrombosis and predisposing factors complete the clinical probability assessment.

In chronic pulmonary hypertension, progression manifests as reduced walking distance, presyncope, edema, and an increasing need for diuretics. Functional class, walking distance, BNP, and hemodynamic parameters define the risk profile in precapillary forms. In lung diseases, cyanosis, hypercapnia, wheezing, or interstitial signs help identify the cause, but respiratory and right heart severity do not always coincide; sudden deterioration requires investigation for embolism, infection, or arrhythmia. In the form due to left heart disease, a history of HFpEF, HFrEF, or valvular disease is frequent; absence of pulmonary edema at the time of the visit does not exclude chronically elevated wedge pressure.

Atrial fibrillation and flutter are poorly tolerated when right heart dysfunction is advanced, because they eliminate the atrial contribution and shorten filling; a seemingly modest arrhythmia may cause disproportionate hemodynamic decompensation. Ventricular tachycardia is typical of arrhythmogenic cardiomyopathy and postsurgical scars. Previous syncope or cardioversions require electrophysiological assessment. Bradycardia and conduction block may complicate infarction, drug treatment, or infiltration; rhythm must be interpreted together with blood pressure and perfusion, not only the numerical heart rate.

Investigations and diagnosis

The ECG may show right axis deviation, a dominant R wave in V1, right bundle branch block, strain, P pulmonale, or arrhythmias, but a normal tracing does not exclude dysfunction. Leads V3R-V4R identify ST elevation in right ventricular infarction; the S1Q3T3 pattern in embolism has low sensitivity and specificity. BNP or NT-proBNP reflects wall stress and has prognostic value, but depends on kidney function, age, and the atrium. Troponin indicates injury and stratifies embolism or pulmonary hypertension without identifying the cause on its own. A complete blood count, creatinine, electrolytes, liver function, coagulation, blood gases, and lactate assess organ damage and precipitants; a marked rise in aminotransferases suggests hypoperfusion, while bilirubin and alkaline phosphatase reflect congestion.

Echocardiography assesses dimensions, thickness, wall motion, the septum, atrium, vena cava, tricuspid valve, and pericardium. TAPSE, S’, fractional area change, and strain describe different aspects and are load-dependent; no single measurement defines failure. The TAPSE/sPAP ratio is a surrogate for ventricular-arterial coupling and has prognostic value, but inherits the errors of both measurements; severe tricuspid regurgitation may make estimation of pulmonary pressure unreliable. Bedside ultrasound identifies dilation, effusion, and venous congestion, but requires context; a dilated vena cava during mechanical ventilation does not automatically equate to overload that can be corrected with diuresis.

Magnetic resonance imaging is the reference standard for right ventricular volumes and ejection fraction and characterizes scar, fat, inflammation, shunts, and congenital heart disease. It is central in suspected arrhythmogenic cardiomyopathy, but morphological criteria must not be applied in isolation in athletes. CT angiography diagnoses embolism and defines arteries, parenchyma, and compression; ventilation-perfusion scintigraphy is the most sensitive screening test for chronic thromboembolic pulmonary hypertension, and a normal study makes it unlikely. Pulmonary function tests, blood gas analysis, polysomnography, and high-resolution CT define pulmonary causes; assessment must separate hypertension proportional to respiratory disease from a dominant vascular phenotype.

Right heart catheterization measures atrial, ventricular, and pulmonary pressures, wedge pressure, oxygen saturations, and cardiac output. Pulmonary vascular resistance is the ratio of the transpulmonary gradient to cardiac output; errors in zeroing, wedge pressure, or the cardiac output method may change classification. The pressure waveform and stepwise oximetry identify regurgitation, constriction, and shunts. In shock, serial measurements guide treatment when the clinical picture is uncertain, but the catheter does not replace physiological interpretation. A fluid challenge or exercise may unmask an abnormal wedge pressure in suspected forms due to left heart disease. Vasoreactivity testing is indicated only in specific forms of pulmonary arterial hypertension, not indiscriminately.

The differential diagnosis includes cirrhosis, nephrotic syndrome, venous insufficiency, lymphedema, and drug-induced causes of edema. Albumin, urine testing, abdominal imaging, and the venous pattern help, but multiple mechanisms may coexist. Constriction and restrictive cardiomyopathy require respiratory analysis of flows, the septum, tissue Doppler, CT/MRI, and sometimes simultaneous hemodynamics; ventricular systolic discordance with respiration supports constriction. Tamponade is a clinical and hemodynamic diagnosis: echocardiographic collapse and respiratory variations depend on pressures and ventilation. If the patient is unstable, drainage must not be delayed by nonessential tests.

Treatment and prognosis

Acute treatment aims to maintain systemic blood pressure, optimize preload, reduce pulmonary afterload, and support contractility. The useful volume range is narrow: a small expansion may help in hypovolemic right ventricular infarction, while further loading in a dilated ventricle worsens septal displacement and regurgitation. Intravenous diuretics are fundamental in right-sided congestion; dose and combinations are guided by urine output, urinary sodium, kidney function, and perfusion. Ascites and abdominal pressure may require additional strategies, but ultrafiltration is not automatic. Norepinephrine supports blood pressure and coronary perfusion in shock; low-dose vasopressin may be added. Dobutamine or milrinone increases contractility but may cause hypotension and arrhythmias and requires monitoring.

Oxygen corrects hypoxemia; acidosis, hypercapnia, and hypothermia increase pulmonary vascular resistance and must be treated; ventilation uses sufficient but not excessive pressures, avoiding hyperinflation; induction and intubation require hemodynamic preparation. Inhaled nitric oxide or inhaled prostacyclin may selectively reduce right ventricular afterload in critical settings, particularly perioperatively or with pulmonary hypertension, without replacing treatment of the cause. In high-risk embolism, systemic, surgical, or percutaneous reperfusion is considered according to instability and contraindications. Right ventricular infarction requires revascularization, rhythm management, and caution with nitrates and diuretics.

In pulmonary arterial hypertension, specific combination therapy follows class, risk, and etiology in expert centers. In hypertension due to left heart or lung disease, PAH vasodilators are not prescribed routinely because they may increase edema or worsen gas exchange. In chronic thromboembolism, pulmonary endarterectomy, angioplasty, and medical therapy are integrated by a dedicated team; operability cannot be decided on peripheral anatomy alone. Respiratory treatment includes oxygen when indicated, sleep apnea therapy, bronchodilation, and rehabilitation. Correcting hypoxia reduces vasoconstriction but does not always normalize established vascular damage.

Chronic congestion requires loop diuretics, sometimes sequential blockade, with monitoring of potassium, sodium, and kidney function. Extreme restrictions may worsen nutrition; the goal is a sustainable balance and a plan for early recognition. Severe tricuspid regurgitation is treated after optimization of volume status and the underlying cause. Surgery or transcatheter interventions are evaluated before irreversible right heart and organ damage; anatomical selection includes coaptation, tethering, device leads, and pulmonary pressure. Selected cases of constriction require pericardiectomy; shunts and congenital valvular diseases are managed by dedicated teams; late closure of a shunt with irreversible pulmonary vascular resistance may be harmful.

Standard HFrEF therapies are used if left heart dysfunction coexists, but there is no validated quadruple therapy for isolated right heart failure. Excessive beta-blockade or systemic vasodilation may reduce cardiac output in advanced pulmonary hypertension; every drug must have a defined indication; sinus rhythm is valuable in advanced forms. Cardioversion and rhythm control may be necessary, with planned anesthesia; anticoagulation follows arrhythmia, thromboembolism, and specific indications. Exercise and rehabilitation improve capacity in a stable state, but syncope, hypoxemia, or decompensated heart failure require supervised programs. Nutrition and strength counteract sarcopenia.

Temporary mechanical support may include venoarterial ECMO or dedicated right ventricular devices, as a bridge to recovery, decision, or transplantation. The choice depends on the lungs, left ventricle, cause, and reversibility; increasing pulmonary flow may overload an inadequate left ventricle. Heart or heart-lung transplantation is reserved for selected irreversible disease; high fixed pulmonary vascular resistance increases risk after heart transplantation and requires assessment of reversibility. Prognosis depends on right ventricular-pulmonary arterial coupling, atrial pressure, cardiac output, kidney function, liver function, functional class, and response to treatment of the cause. Right heart dysfunction is a powerful predictor in almost every heart failure phenotype.

Complications

Shock due to right heart failure entails hypoperfusion and low cardiac output, frequently with hypotension and elevated venous pressures; progression to elevated lactate, oliguria, and neurological impairment may be rapid; delays in reperfusion or support increase multiorgan damage. Right ventricular ischemia worsens when systemic blood pressure falls and the wall is stretched. Vasopressors, afterload reduction, and revascularization interrupt the cycle according to the cause. Cardiac arrest in embolism or pulmonary hypertension carries a critical prognosis; resuscitation requires consideration of reperfusion and extracorporeal support in appropriately equipped systems.

Venous cardiorenal syndrome causes diuretic resistance, hyponatremia, and hyperkalemia; creatinine may improve with decongestion even without an increase in cardiac output; excessive volume reduction may instead cause true ischemic injury. Chronic hepatic congestion leads to congestive hepatopathy, fibrosis, and altered coagulation; hypoxic hepatitis with very high aminotransferases signals acute low cardiac output and a poor prognosis. Ascites and intestinal congestion promote malnutrition, infections, and reduced absorption. Paracentesis requires hemodynamic and etiological assessment and is not a substitute for control of the cardiac condition.

Progressive tricuspid regurgitation increases volume overload and congestion and may become less amenable to correction with tethering and organ damage; deferral until severe dysfunction reduces the benefit of interventions. Atrial fibrillation and flutter cause instability; ventricular arrhythmias occur in ischemia, arrhythmogenic cardiomyopathy, and scars; sudden death may result from arrhythmia, embolism, or hemodynamic collapse. Venous thrombosis and embolism may be a cause or consequence of immobility. Prophylaxis and anticoagulation are balanced against liver function, kidney function, and procedures.

Pleural effusions, hypoxemia, and respiratory failure aggravate afterload; ventilation may save life but precipitate collapse if its effect on venous return and pulmonary pressure is not anticipated. Biventricular dysfunction appears when the septum and low cardiac output compromise the left ventricle or when the underlying heart disease involves both ventricles. In this case, strategies directed at the right ventricle alone are insufficient. Sarcopenia, cachexia, and frailty reduce eligibility for interventions and transplantation; early assessment allows rehabilitation and decisions before irreversible damage.

Iatrogenic complications include excess fluids, intubation without preparation, systemic vasodilators, inotrope-induced arrhythmias, and diuretic-related imbalances; right heart physiology requires frequent reassessment because the margin between insufficient and excessive volume is narrow. In pulmonary hypertension, sudden interruption of prostacyclins may cause fatal rebound; continuity of infusions and trained staff are essential during hospitalizations and transfers; the terminal phase combines congestion, low cardiac output, and organ failure. Integrated palliative care addresses dyspnea, pain, and goals without precluding advanced therapies when appropriate.