What is left ventricular (LV) diastolic dysfunction in heart failure (HF)?

Left Ventricular Diastolic Dysfunction in Heart Failure

Left ventricular (LV) diastolic dysfunction in heart failure is characterized by impaired ventricular relaxation and increased stiffness, leading to elevated filling pressures despite preserved ejection fraction.

Definition and Pathophysiology

• Diastolic dysfunction refers to an impairment of ventricular relaxation as the primary mechanism leading to heart failure symptoms, often with preserved left ventricular systolic function 1
• It is characterized by a stiff left ventricle with decreased compliance and impaired relaxation, which leads to increased end-diastolic pressure 2
• Approximately 20-40% of patients with heart failure have preserved left ventricular systolic function with diastolic dysfunction as the underlying mechanism 1

Epidemiology

• Heart failure with preserved ejection fraction (HFpEF) due to diastolic dysfunction is primarily seen in elderly women, most of whom have hypertension 1
• These patients experience significant dyspnea and fatigue, limiting exercise tolerance and quality of life, with frequent hospitalizations for clinical stabilization 1
• The mortality risk appears lower than in heart failure with reduced ejection fraction, but still has major socioeconomic implications 1

Recognized Causes of Diastolic Dysfunction

• Several myocardial disorders are associated with diastolic dysfunction 1:
  • Restrictive cardiomyopathy
  • Obstructive and non-obstructive hypertrophic cardiomyopathy
  • Infiltrative cardiomyopathies (amyloidosis, sarcoidosis, hemochromatosis)
  • Hypertension (most common cause)
  • Coronary artery disease
  • Diabetes mellitus
  • Aging-related cardiovascular changes

Diagnostic Criteria

The diagnosis of diastolic heart failure requires four conditions to be satisfied 1:

1. Symptoms typical of heart failure
2. Signs typical of heart failure
3. Normal or only mildly reduced LVEF and LV not dilated
4. Relevant structural heart disease (LV hypertrophy/LA enlargement) and/or diastolic dysfunction

Diagnostic Methods

• Echocardiography is the primary non-invasive method for diagnosing diastolic dysfunction 1, 3
• Doppler echocardiography can help assess diastolic function parameters 1
• The diagnosis is generally based on finding typical heart failure symptoms and signs in a patient with normal LVEF and no valvular abnormalities 1
• Definitive diagnosis can be made when ventricular relaxation is slowed, associated with elevated LV filling pressure in a patient with normal LV volumes and contractility 1
• BNP levels in association with echocardiographic filling patterns can improve diagnostic accuracy 1

Echocardiographic Parameters for Assessment

• Mitral inflow velocities and pulmonary vein velocities provide important data 1
• Mitral annular velocities, including E/e' ratio, help assess filling pressures 1
• Left atrial size and function assessment 1
• LV global longitudinal strain and diastolic strain rate measurements 1

Diastolic Stress Testing

• Indicated in patients with dyspnea and grade 1 diastolic dysfunction at rest 1
• Performed using supine bike or treadmill stress testing 1
• The test is considered positive when all three conditions are met during exercise 1:
  • Average E/e' > 14 or septal E/e' ratio > 15
  • Peak TR velocity > 2.8 m/sec
  • Septal e' velocity < 7 cm/sec

Management Principles

Unlike heart failure with reduced ejection fraction, few clinical trials guide the management of diastolic dysfunction 1. Treatment principles include:

• Control of blood pressure 1, 2
• Promotion of regression of left ventricular hypertrophy 2
• Avoiding tachycardia to prolong diastolic filling time 2, 4
• Treatment of symptoms of congestion 2
• Maintaining normal atrial contraction when possible 2

Pharmacological Management

• Diuretics are the mainstay for preventing pulmonary congestion 2, 5
• Beta-blockers are useful in preventing tachycardia and prolonging LV diastolic filling time 2, 4
• ACE inhibitors and ARBs may be beneficial, especially in patients with hypertension 2, 5
• Calcium channel blockers may be appropriate in certain cases 3, 4
• Avoid digitalis except in atrial fibrillation to control heart rate 3

Prognosis

• Moderate to severe LV diastolic dysfunction predicts subsequent hospitalization for heart failure and death from heart disease 6
• Asymptomatic LV diastolic dysfunction in patients with coronary heart disease predicts adverse cardiovascular outcomes 6
• The presence of diastolic dysfunction provides important prognostic information independent from pulmonary artery systolic pressure 1

Common Pitfalls and Caveats

• Diastolic filling patterns can be altered by nonspecific and transient changes in loading conditions, aging, heart rate changes, or mitral regurgitation 1
• Differential diagnosis must exclude other conditions that may present similarly, including valvular disease, high-output states, pulmonary disease, and episodic systolic dysfunction 1
• Treatment that is effective for systolic heart failure may not be appropriate for diastolic heart failure (e.g., positive inotropic agents and arterial vasodilators are generally not useful) 4