Is left ventricular diastolic dysfunction considered heart failure?

Left Ventricular Diastolic Dysfunction and Heart Failure

Left ventricular diastolic dysfunction alone is not considered heart failure, but it is a precursor to heart failure with preserved ejection fraction (HFpEF) when accompanied by clinical symptoms and elevated cardiac filling pressures. 1, 2

Understanding Diastolic Dysfunction vs. Heart Failure

Diastolic dysfunction refers to impaired relaxation or filling of the ventricles during the diastolic phase of the cardiac cycle. This condition alone does not constitute heart failure but represents an important pathophysiological abnormality that may progress to clinical heart failure.

According to the 2016 European Society of Cardiology (ESC) guidelines, heart failure is defined as:

• A clinical syndrome characterized by typical symptoms (e.g., breathlessness, ankle swelling, fatigue)
• That may be accompanied by signs (e.g., elevated jugular venous pressure, pulmonary crackles, peripheral edema)
• Caused by a structural and/or functional cardiac abnormality
• Resulting in reduced cardiac output and/or elevated intracardiac pressures 1

Diagnostic Criteria for Heart Failure with Preserved Ejection Fraction

For diastolic dysfunction to be classified as HFpEF, the following conditions must be met:

1. Signs or symptoms of heart failure
2. Preserved left ventricular ejection fraction (LVEF ≥50%)
3. Evidence of diastolic LV dysfunction 3

The European Society of Cardiology classifies heart failure into three categories based on ejection fraction:

• HFrEF: Heart failure with reduced ejection fraction (LVEF <40%)
• HFmrEF: Heart failure with mid-range ejection fraction (LVEF 40-49%)
• HFpEF: Heart failure with preserved ejection fraction (LVEF ≥50%) 1

Echocardiographic Assessment of Diastolic Function

The 2016 ASE/EACVI guidelines recommend focusing on four key variables to assess diastolic function:

• Annular e' velocity
• Average E/e' ratio
• Left atrial maximum volume index
• Peak tricuspid regurgitation velocity 2

Echocardiographic parameters used to assess diastolic function include:

Parameter	Normal	Abnormal
Mitral annular velocity e'	>7 cm/s (septal), >10 cm/s (lateral)	<7 cm/s (septal), <10 cm/s (lateral)
E/e' ratio	<14	>14
Left atrial volume index	<34 ml/m²	>34 ml/m²
Tricuspid regurgitation velocity	<2.8 m/s	>2.8 m/s

However, it's important to note that existing data only show modest correlations of E/e' with invasive filling pressures and outcomes in HFpEF. A systematic review found that the pooled correlation coefficient r was only 0.56 for the relation between E/e' and invasively measured filling pressures 1.

Grading of Diastolic Dysfunction

Diastolic dysfunction can be classified into three grades:

1. Grade I: Impaired relaxation with normal filling pressures

   • E/A ratio <1
   • Normal filling pressures
   • Reduced mitral annular velocity e'

2. Grade II: Pseudonormalized filling pattern

   • E/A ratio appears normal (>1)
   • Elevated left atrial pressures
   • E/e' ratio >14
   • Left atrial volume index >34 ml/m²

3. Grade III: Restrictive filling pattern

   • E/A ratio >2.5
   • Deceleration time <150 ms
   • Isovolumetric relaxation time <50 ms
   • Severely reduced septal and lateral e' velocities (3-4 cm/s) 2

Clinical Implications

• Diastolic dysfunction without symptoms and elevated filling pressures is not heart failure
• Diastolic dysfunction with symptoms but normal filling pressures is not heart failure
• Diastolic dysfunction with symptoms and elevated filling pressures constitutes HFpEF 3

Diagnostic Challenges

Diagnosing diastolic dysfunction in certain populations presents unique challenges:

• Atrial fibrillation: The algorithm of the 2016 recommendations cannot be directly applied due to variability in cycle length, absence of atrial contraction, and frequent left atrial enlargement regardless of LV filling pressures 4

• Elderly patients: May have delayed diagnosis due to attribution of symptoms to aging or deconditioning 2

Management Considerations

While diastolic dysfunction alone is not heart failure, its management is important to prevent progression to HFpEF. Treatment approaches include:

1. Blood pressure control
2. Promoting regression of left ventricular hypertrophy
3. Avoiding tachycardia
4. Treating symptoms of congestion when present
5. Maintaining normal atrial contraction when possible 5

Pharmacological options may include:

• Beta-blockers to lower heart rate and increase diastolic filling time
• ACE inhibitors to improve relaxation and cardiac distensibility
• Diuretics for episodes of fluid overload (used cautiously) 1

However, it's important to note that there is limited evidence from clinical trials for the treatment of isolated diastolic dysfunction, as most trials have focused on established heart failure 1.