How do you differentiate between diastolic and systolic heart failure?

Differentiating Diastolic vs Systolic Heart Failure

The definitive differentiation between diastolic and systolic heart failure requires echocardiography or radionuclide imaging to measure left ventricular ejection fraction (LVEF), as clinical presentation alone cannot distinguish between these two entities. 1

Key Diagnostic Distinctions

Ejection Fraction: The Primary Differentiator

• Systolic heart failure is defined by LVEF <40% with a dilated left ventricle and large end-diastolic volumes 1
• Diastolic heart failure is defined by LVEF >40-50% (preserved) with a normal or only slightly enlarged ventricle 1, 2
• Clinical symptoms and signs are identical between both conditions, making objective cardiac imaging mandatory for diagnosis 1, 3

Underlying Pathophysiology

• In systolic heart failure, the heart cannot pump blood effectively forward, leading to decreased cardiac output and compensatory neurohormonal activation 1
• In diastolic heart failure, impaired ventricular filling is the core problem, caused by diminished relaxation during early diastole or reduced compliance 1
• The stiff ventricle in diastolic heart failure elevates filling pressures, causing pulmonary congestion despite preserved systolic function 1
• Stroke volume and cardiac output remain normal at rest in diastolic heart failure due to elevated filling pressures, but become compromised during exercise 1

Clinical Presentation: Identical But Contextual Clues Exist

Symptoms and Signs (Cannot Differentiate Alone)

• Both conditions present with breathlessness, fatigue, and ankle swelling 1, 4
• Physical examination findings include pulmonary rales, pleural effusion, raised jugular venous pressure, and hepatomegaly in both types 4
• History, physical examination, electrocardiography, and chest radiography cannot reliably differentiate between the two 5

Epidemiologic and Clinical Context

• Diastolic heart failure is primarily a disease of elderly women with hypertension, representing 20-60% of all heart failure patients 1
• Systolic heart failure more commonly presents with marked cardiomegaly on imaging 2
• Diastolic heart failure typically shows pulmonary congestion with a normal or only slightly enlarged ventricle 2

Diagnostic Criteria for Diastolic Heart Failure

Three conditions must be met for diagnosis: 1

• Symptoms and signs of heart failure present
• Preserved LVEF >40-50% on echocardiography
• No significant valvular abnormalities on echocardiography

Important caveat: Symptoms alone are insufficient for diagnosis, and objective evidence of cardiac dysfunction at rest is mandatory 4. Poor correlation exists between symptom severity and degree of cardiac dysfunction 4.

Prognostic Differences

• Diastolic heart failure carries lower annual mortality (approximately 8%) compared to systolic heart failure (19%), but morbidity remains substantial 1
• Grade 2 diastolic dysfunction carries substantially increased mortality, with survival rates of only 39% in certain populations 4
• Both conditions activate similar neurohormonal systems 1, 6

Treatment Implications: Why Differentiation Matters

Systolic Heart Failure Management

• ACE inhibitors are the cornerstone of therapy for all symptomatic patients and reduce mortality 1
• Diuretics manage volume overload 1
• Beta-blockers reduce mortality and sudden death 1
• Positive inotropic agents may be beneficial given the impaired contractility 1
• Calcium channel blockers are usually contraindicated 2

Diastolic Heart Failure Management

• The goal is to reduce elevated filling pressures without significantly reducing cardiac output, requiring judicious medication dosing to avoid hypotension 1
• ACE inhibitors or ARBs provide blood pressure control while directly improving ventricular relaxation and promoting regression of left ventricular hypertrophy 4
• Beta-blockers or calcium channel blockers improve diastolic filling by reducing heart rate, allowing more time for ventricular filling 1, 4
• Diuretics and nitrates reduce elevated filling pressures but must be started at small doses with careful monitoring to prevent hypotension 1, 4
• Positive inotropic agents are not useful since systolic function is normal or near-normal 1
• Target blood pressure is <130/80 mmHg 4
• Rate control is essential if atrial fibrillation develops, using agents that suppress AV conduction 1

Common Pitfalls to Avoid

• Never rely on clinical presentation alone to differentiate—always obtain echocardiography 1, 3
• Beware of Stage II diastolic dysfunction (pseudonormalization) where Doppler echocardiographic transmitral flow pattern appears normal despite marked diastolic dysfunction 5
• Avoid aggressive diuresis in diastolic heart failure as excessive preload reduction can compromise cardiac output despite elevated filling pressures 1, 4
• Do not use digitalis in diastolic heart failure except for rate control in atrial fibrillation 2