Diastolic heart failure, also known as heart failure with preserved ejection fraction (HFpEF), is a condition where the heart’s left ventricle becomes stiff and cannot relax properly. This impairs the heart’s ability to fill with blood during the diastolic phase, leading to inadequate cardiac output and symptoms of heart failure despite a normal pumping function. It is a common form of heart failure and presents unique diagnostic and therapeutic challenges.
Understanding the Physiology of Diastolic Heart Failure
The heart cycle consists of two phases: systole (contraction) and diastole (relaxation). In diastolic heart failure, the relaxation and filling phase is compromised. The stiffened ventricle cannot accommodate incoming blood effectively, increasing pressure in the heart and lungs. Unlike systolic heart failure, where the ejection fraction is reduced, diastolic heart failure maintains a normal or near-normal ejection fraction, but the filling abnormalities lead to symptoms of congestion and poor circulation.
Symptoms of Diastolic Heart Failure
Common Clinical Symptoms
Symptoms often overlap with other heart failure types but have distinguishing features due to preserved ejection fraction.
Shortness of breath (dyspnea): This is the most common symptom, occurring initially with exertion and later at rest or when lying flat (orthopnea).
Fatigue and weakness: Due to inadequate blood flow and oxygen delivery to muscles.
Peripheral edema: Swelling of legs, ankles, and feet caused by fluid retention.
Exercise intolerance: Patients often notice decreased ability to perform physical activities.
Paroxysmal nocturnal dyspnea: Sudden nighttime breathlessness disrupting sleep.
Palpitations: Awareness of abnormal or rapid heartbeats, sometimes related to arrhythmias common in diastolic dysfunction.
Signs Detected on Physical Examination
Physical findings may include:
Elevated jugular venous pressure indicating right heart congestion.
Crackles or rales on lung auscultation due to pulmonary congestion.
Displaced or sustained apical impulse reflecting left ventricular hypertrophy.
Presence of an S4 heart sound caused by a stiff left ventricle.
Causes and Risk Factors of Diastolic Heart Failure
Underlying Cardiac Conditions
Several cardiac diseases lead to diastolic dysfunction:
Hypertension: Chronic high blood pressure causes left ventricular hypertrophy and increased stiffness.
Coronary artery disease: Ischemia can impair myocardial relaxation.
Cardiomyopathies: Restrictive and hypertrophic cardiomyopathies increase myocardial stiffness.
Non-Cardiac Risk Factors
Age: Incidence increases with age due to myocardial changes and vascular stiffness.
Diabetes mellitus: Leads to microvascular disease and myocardial fibrosis.
Obesity: Associated with systemic inflammation and increased cardiac workload.
Chronic kidney disease: Causes volume overload and contributes to myocardial fibrosis.
Sleep apnea: Leads to intermittent hypoxia, increasing cardiac stress.
Pathophysiology of Diastolic Heart Failure
Diastolic dysfunction results from impaired myocardial relaxation and increased ventricular stiffness. This involves complex changes:
Myocardial fibrosis: Excess collagen deposition reduces ventricular compliance.
Altered calcium handling: Impaired calcium reuptake during diastole slows relaxation.
Left ventricular hypertrophy: Muscle thickening reduces chamber size and compliance.
Elevated filling pressures: Leads to pulmonary congestion and right heart strain.
These changes reduce ventricular filling during diastole, impair stroke volume, and elevate atrial and pulmonary pressures causing symptoms.
Diagnostic Evaluation of Diastolic Heart Failure
Clinical History and Physical Examination
Accurate history taking focuses on symptoms suggestive of heart failure and associated risk factors. Physical exam helps detect signs of congestion and heart abnormalities.
Imaging Studies
Echocardiography: Key tool to assess diastolic function by measuring transmitral flow patterns, tissue Doppler velocities, left atrial size, and left ventricular wall thickness. Preserved ejection fraction with impaired relaxation pattern confirms diagnosis.
Chest X-ray: Reveals cardiomegaly and pulmonary congestion.
Cardiac MRI: Provides detailed myocardial characterization and fibrosis assessment in complex cases.
Laboratory Tests
B-type natriuretic peptide (BNP) or NT-proBNP: Elevated levels support heart failure diagnosis but can be lower than in systolic failure.
Blood tests: To evaluate kidney function, electrolytes, blood sugar, and thyroid status.
Invasive Hemodynamic Studies
In select cases, right heart catheterization measures filling pressures directly to confirm diagnosis and evaluate severity.
Treatment of Diastolic Heart Failure
Goals of Treatment
The primary aims are to relieve symptoms, improve quality of life, manage underlying causes, and prevent disease progression.
Lifestyle Modifications
Dietary sodium restriction: Helps reduce fluid retention and congestion.
Weight management: Obesity exacerbates symptoms and should be addressed.
Regular physical activity: Tailored exercise improves functional capacity and cardiac health.
Smoking cessation and limiting alcohol: Reduce cardiovascular risk factors.
Pharmacologic Therapies
Currently, no therapies specifically target diastolic dysfunction, but treatment focuses on symptom control and managing comorbidities.
Diuretics: Used to relieve congestion by removing excess fluid but must be used cautiously to avoid excessive preload reduction.
Antihypertensives: Control blood pressure, reducing left ventricular hypertrophy and stiffness. ACE inhibitors, ARBs, and calcium channel blockers are commonly used.
Beta-blockers: Slow heart rate to allow more diastolic filling time and reduce myocardial oxygen demand.
Aldosterone antagonists: May reduce fibrosis and improve outcomes in select patients.
Treating atrial fibrillation: Important to maintain rhythm or control rate since arrhythmias worsen diastolic filling.
Emerging Therapies and Research
New treatments targeting myocardial fibrosis, inflammation, and metabolic dysfunction are under investigation. Sodium-glucose cotransporter 2 (SGLT2) inhibitors show promise in improving heart failure outcomes including HFpEF.
Complications and Prognosis
Diastolic heart failure is associated with significant morbidity and mortality. Complications include:
- Progression to advanced heart failure with frequent hospitalizations.
- Atrial fibrillation increasing stroke risk.
- Right-sided heart failure due to pulmonary hypertension.
- Reduced quality of life due to persistent symptoms.
Prognosis depends on underlying cause, comorbidities, and adequacy of management. Early detection and comprehensive treatment improve outcomes.
Prevention of Diastolic Heart Failure
Preventive strategies focus on addressing modifiable risk factors:
- Effective control of hypertension and diabetes.
- Weight loss and exercise to reduce cardiac workload.
- Avoiding excessive alcohol and smoking.
- Regular cardiovascular health screening in at-risk populations.
When to Seek Medical Attention
Patients should consult a healthcare provider if they experience:
- New or worsening shortness of breath.
- Swelling in legs or abdomen.
- Fatigue interfering with daily activities.
- Palpitations or irregular heartbeat.
- Sudden weight gain from fluid retention.
Conclusion
Diastolic heart failure is a complex syndrome caused by impaired ventricular relaxation leading to heart failure symptoms despite preserved systolic function. Diagnosis requires careful clinical evaluation, imaging, and laboratory tests. Treatment targets symptom relief and management of underlying causes. Continued research aims to develop more effective therapies to improve patient outcomes. Early diagnosis and comprehensive care are vital to enhance quality of life and reduce complications.
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