What is the most common cause of diastolic heart dysfunction?

Hypertension is the Most Common Cause of Diastolic Heart Dysfunction

Hypertension is definitively the most common cause of diastolic heart dysfunction, leading to left ventricular hypertrophy and impaired ventricular relaxation and filling. 1 This pathological process develops over time as a consequence of chronic pressure overload on the left ventricle.

Pathophysiology of Diastolic Dysfunction in Hypertension

Diastolic dysfunction occurs when the left ventricle loses its ability to relax normally during diastole, impairing ventricular filling. The process typically develops through several mechanisms:

1. Left Ventricular Hypertrophy (LVH):

   • Chronic hypertension causes increased afterload on the left ventricle
   • The heart responds with compensatory hypertrophy of the ventricular wall
   • This hypertrophy reduces chamber compliance and impairs relaxation 2

2. Structural Changes:

   • Increased myocardial fibrosis
   • Altered collagen deposition
   • Medial hypertrophy of intramural arterioles 2

3. Functional Impairment:

   • Prolonged ventricular relaxation
   • Reduced ventricular compliance
   • Elevated left ventricular filling pressures
   • Increased dependency on atrial contraction for ventricular filling 2

Epidemiology and Risk Factors

Diastolic dysfunction with preserved ejection fraction is particularly prevalent among:

• Elderly patients
• Women
• Patients with hypertension, diabetes mellitus, or both
• Patients with coronary artery disease or atrial fibrillation 2

The aging process itself contributes to diastolic dysfunction through:

• Decreased elastic properties of the heart and great vessels
• Increased systolic blood pressure
• Increased myocardial stiffness
• Structural changes due to fibrosis
• Decline in relaxation and compliance 2

Clinical Manifestations

Diastolic dysfunction can present with:

• Exercise intolerance and dyspnea
• Pulmonary congestion
• Signs of elevated filling pressures
• Normal or near-normal heart size on imaging 1

The hemodynamic consequences include:

• Elevation of ventricular filling pressure
• Increased left atrial pressure
• Elevated pulmonary venous and pulmonary capillary pressures
• Eventual increase in pulmonary artery and right heart pressures 2

Diagnostic Approach

Diastolic dysfunction should be suspected when a patient presents with symptoms and signs of heart failure but has normal or near-normal ventricular systolic function 2. Diagnosis typically involves:

1. Echocardiography:

   • Assessment of left ventricular mass (more sensitive than ECG or chest X-ray for LVH) 2
   • Evaluation of diastolic filling parameters
   • Measurement of left atrial size
   • Assessment of E/A ratio and other Doppler indices 1

2. Other Modalities:

   • Cardiac MRI for tissue characterization
   • Invasive hemodynamic assessment in selected cases

Common Pitfalls in Diagnosis

• Failing to consider diastolic dysfunction in patients with normal ejection fraction
• Overlooking the contribution of atrial fibrillation to symptom exacerbation
• Not recognizing that diastolic dysfunction often precedes detectable systolic dysfunction 3
• Underestimating the prevalence of diastolic dysfunction in hypertensive patients without obvious LVH

Other Causes of Diastolic Dysfunction

While hypertension is the most common cause, other important etiologies include:

• Coronary artery disease and myocardial ischemia
• Age-related changes
• Hypertrophic cardiomyopathy
• Restrictive cardiomyopathies
• Infiltrative disorders (amyloidosis, sarcoidosis)
• Aortic stenosis 4
• Diabetes mellitus

Understanding the primary cause is essential for targeted management and improved outcomes in patients with diastolic dysfunction.