Is left ventricular diastolic dysfunction a form of heart failure?

Left Ventricular Diastolic Dysfunction and Heart Failure

Yes, left ventricular diastolic dysfunction is a recognized form of heart failure, specifically heart failure with preserved ejection fraction (HFpEF), as established by major cardiology guidelines. 1

Understanding Diastolic Dysfunction as Heart Failure

Left ventricular diastolic dysfunction occurs when the heart's ability to relax and fill with blood during diastole is impaired, leading to increased filling pressures despite normal contractile function. This condition is characterized by:

• Normal or near-normal left ventricular ejection fraction (LVEF ≥40%)
• Evidence of structural heart abnormalities (left atrial enlargement, LV hypertrophy)
• Abnormal diastolic parameters on echocardiography
• Clinical signs and symptoms of heart failure

Classification in Heart Failure Guidelines

The American College of Cardiology/American Heart Association (ACC/AHA) guidelines specifically recognize diastolic dysfunction as a form of heart failure when it leads to clinical symptoms. The 2009 ACC/AHA guidelines incorporated this concept by classifying heart failure into:

1. Heart failure with reduced ejection fraction (HFrEF)
2. Heart failure with preserved ejection fraction (HFpEF) - primarily caused by diastolic dysfunction 1

Diagnostic Criteria

For a definitive diagnosis of heart failure due to diastolic dysfunction, the following criteria should be met:

• Typical symptoms and signs of heart failure
• Normal LVEF (typically ≥50%)
• Evidence of abnormal LV relaxation, filling, or diastolic stiffness 1

The 2016 ASE/EACVI guidelines recommend evaluating four key variables to determine diastolic dysfunction:

• Annular e' velocity (septal e' < 7 cm/sec, lateral e' < 10 cm/sec)
• Average E/e' ratio > 14
• Left atrial maximum volume index > 34 mL/m²
• Peak tricuspid regurgitation velocity > 2.8 m/sec 1

Pathophysiology and Clinical Significance

Diastolic dysfunction progresses through several stages:

1. Stage I (Impaired Relaxation): Reduced early LV filling with normal pressures
2. Stage II (Pseudonormalization): Normal-appearing filling pattern due to opposing increased left atrial pressures
3. Stage III (Restrictive): Severe restrictive filling with markedly decreased LV compliance 2

The morbidity and mortality associated with HFpEF may be nearly as profound as that with reduced LVEF, with frequent hospitalizations characterizing these patients. 1

Diagnostic Challenges

Diagnosing diastolic heart failure can be challenging because:

• It cannot be reliably distinguished from systolic heart failure based on history, physical examination, or basic tests alone
• Echocardiographic parameters like E/e' ratio show only modest correlation with invasive filling pressures (pooled correlation coefficient r = 0.56) 1
• Multiple echocardiographic parameters must be assessed together rather than relying on a single measurement

Clinical Implications

Patients with diastolic heart failure typically present with:

• Exercise intolerance and dyspnea
• Pulmonary congestion
• Signs of elevated filling pressures
• Normal or near-normal heart size on imaging 2

Common underlying conditions include:

• Hypertension (most common)
• Diabetes mellitus
• Coronary artery disease
• Aging
• Obesity 1

Understanding left ventricular diastolic dysfunction as a form of heart failure is crucial for appropriate diagnosis and management, as treatment approaches differ from those for systolic heart failure.