What is the difference between diastolic and systolic heart failure in terms of pathophysiology, management, and treatment?

Systolic vs. Diastolic Heart Failure: Key Differences

Systolic heart failure is characterized by a dilated left ventricle with reduced ejection fraction (<40%), while diastolic heart failure presents with preserved ejection fraction (>40-50%) and a normal or minimally enlarged ventricle—this fundamental distinction drives completely different treatment approaches. 1

Pathophysiology

Systolic Heart Failure

• Impaired contractility is the primary defect, resulting in reduced ejection fraction, ventricular dilation, and large end-diastolic volumes 1
• The heart cannot pump blood effectively forward, leading to decreased cardiac output and compensatory neurohormonal activation 2

Diastolic Heart Failure

• Impaired ventricular filling is the core problem, caused by diminished relaxation during early diastole or reduced compliance during early-to-late diastole 2
• The stiff ventricle elevates filling pressures (left atrial, pulmonary venous, and pulmonary capillary pressures), causing pulmonary congestion despite preserved systolic function 2
• Stroke volume and cardiac output remain normal at rest due to elevated filling pressures, but become compromised during exercise when increased output is required 2

Clinical Presentation

Both conditions present identically with breathlessness, fatigue, and ankle swelling—symptoms alone cannot distinguish between them. 1

Key Epidemiologic Differences

• Diastolic heart failure predominantly affects elderly women with hypertension, representing 20-60% of all heart failure cases 1
• Systolic heart failure has broader demographic distribution 3

Prognosis

• Diastolic heart failure carries lower annual mortality (8%) compared to systolic heart failure (19%), though morbidity remains substantial 4, 5
• Grade 2 diastolic dysfunction significantly increases mortality risk, with survival rates as low as 39% in certain populations 5

Management Approach

Systolic Heart Failure Treatment

ACE inhibitors are the cornerstone of therapy for all symptomatic patients and those with significantly reduced left ventricular function, even if asymptomatic. 2

• ACE inhibitors reduce mortality and should be initiated unless contraindicated 2
• Beta-blockers reduce mortality and prevent sudden death 1
• Diuretics manage volume overload 2
• Positive inotropic agents may be beneficial given the impaired contractility 2

Diastolic Heart Failure Treatment

The goal is to reduce elevated filling pressures without significantly reducing cardiac output—this requires judicious medication dosing to avoid hypotension. 2

Primary Therapeutic Targets

• Blood pressure control is paramount, targeting <130/80 mmHg 5
• Treat underlying causes: revascularization for coronary disease, control of hypertension, management of diabetes 2, 6

Pharmacologic Approach

• Diuretics and nitrates (Class I recommendation) reduce elevated filling pressures, but must be started at small doses with careful monitoring to prevent hypotension since cardiac output depends on elevated filling pressure 2
• Beta-blockers or calcium channel blockers (Class II recommendation) improve diastolic filling by reducing heart rate, allowing more time for ventricular filling 2, 5
• ACE inhibitors or ARBs provide blood pressure control while promoting regression of left ventricular hypertrophy and improving ventricular relaxation 5
• Rate control is essential if atrial fibrillation develops, using agents that suppress AV conduction (Class I recommendation) 2

Contraindicated Therapies

• Positive inotropic agents (Class III recommendation) are not useful since systolic function is normal or near-normal 2
• Aggressive diuresis risks hypotension and low cardiac output state 7

Critical Management Caveat

For asymptomatic diastolic dysfunction, focus exclusively on controlling underlying conditions (hypertension, coronary disease, diabetes) rather than initiating heart failure medications—there is no proven benefit from pharmacologic therapy without symptoms. 6

Diagnostic Distinction

Echocardiography or radionuclide imaging is mandatory to distinguish between systolic and diastolic heart failure, as clinical presentation is identical. 2

Diastolic Heart Failure Diagnosis Requires Three Criteria:

1. Symptoms/signs of heart failure present 1
2. Preserved LVEF >40-50% 1
3. Evidence of diastolic dysfunction (preferably documented but not mandatory) 7

Important Diagnostic Pitfall

• Poor correlation exists between symptom severity and degree of cardiac dysfunction—clinical assessment alone is unreliable 5
• B-type natriuretic peptide elevation does not distinguish between diastolic and systolic heart failure 7

Neurohormonal Activation

Both conditions activate similar neurohormonal systems (sympathetic nervous system and renin-angiotensin system), though the stimuli producing these two different phenotypes remain largely unknown 3, 2