Is grade I diastolic dysfunction (impaired relaxation) due to left‑ventricular stiffness, commonly seen in older adults with hypertension, and what is the recommended management?

Grade 1 Diastolic Dysfunction: Pathophysiology and Clinical Context

Yes, your understanding is essentially correct—Grade 1 diastolic dysfunction reflects impaired myocardial relaxation (not primarily stiffness), is extremely common with aging and hypertension, and represents the earliest stage of diastolic abnormality. However, the primary mechanism is delayed relaxation rather than increased chamber stiffness, which distinguishes it from more advanced grades. 1

Core Pathophysiology

Grade 1 diastolic dysfunction is defined by impaired left ventricular relaxation with normal or low filling pressures. 1, 2 The fundamental abnormality is slowed myocardial relaxation during early diastole, not increased chamber stiffness—that develops later as dysfunction progresses. 1, 3

Key Mechanisms

• Impaired relaxation is the dominant abnormality: the left ventricle takes longer to relax after systolic contraction, reducing the early diastolic filling rate. 1, 4
• Chamber stiffness remains normal in Grade 1; increased stiffness characterizes more advanced grades (II and III). 1, 4
• Filling pressures are normal or low at rest, distinguishing Grade 1 from all higher grades where pressures become elevated. 1, 2

Diagnostic Criteria (2016 ASE/EACVI Guidelines)

Grade 1 is diagnosed when the following echocardiographic pattern is present:

• E/A ratio ≤ 0.8 with peak E velocity ≤ 50 cm/s 1, 2
• Average E/e′ < 14 (typically < 8 in Grade 1) 1, 2, 5
• Left atrial volume index < 34 mL/m² 1, 2
• Tricuspid regurgitation velocity < 2.8 m/s 1, 2
• Prolonged deceleration time (> 200 ms) reflecting slow pressure decline 2

These parameters collectively confirm impaired relaxation without elevated filling pressures. 1, 2

Common Etiologies

Hypertension

Hypertension is the most common cause of Grade 1 diastolic dysfunction. 1, 3, 6 Chronic pressure overload leads to:

• Slowed myocardial relaxation before structural changes develop 3, 7
• Eventual left ventricular hypertrophy if hypertension remains uncontrolled 1, 7
• Progression to higher diastolic grades with chronically elevated filling pressures 3, 6, 7

Aging

Normal aging is independently associated with slowed left ventricular relaxation, making Grade 1 patterns common in elderly individuals even without overt cardiac disease. 1 Age-related mechanisms include:

• Increased myocardial stiffness compared to younger individuals 1
• Slowing of active relaxation processes 1
• Decreased mitral E/A ratio and reduced e′ velocity with advancing age 1

An E/A ratio < 1 may be normal in older adults and must be interpreted in clinical context. 2

Other Contributors

• Coronary artery disease (even subclinical) 1, 4, 8
• Diabetes and metabolic disorders 9
• Obesity 9
• Left ventricular hypertrophy from any cause 1, 3, 7

Clinical Significance

Grade 1 represents an early, compensated stage where cardiac output and filling pressures remain normal during routine activities. 2, 9 However:

• It serves as a critical precursor to heart failure with preserved ejection fraction (HFpEF) 3, 7
• Progression to Grade 2 occurs as severity advances and filling pressures rise 2, 9
• Detection should prompt aggressive management of underlying risk factors 9

Management Strategy

Blood Pressure Control

Aggressive blood pressure control is the cornerstone of preventing progression. 1, 9, 6

• ACE inhibitors or angiotensin receptor blockers are first-line agents, showing efficacy in improving diastolic function indices 1, 6
• Beta-blockers and calcium channel blockers have demonstrated some benefit 1, 6
• Target blood pressure per current hypertension guidelines 1

Risk Factor Modification

Address all modifiable contributors: 9

• Manage coronary artery disease aggressively 9
• Control diabetes and metabolic disorders 9
• Promote weight loss in overweight/obese patients 9
• Sodium restriction to < 2 g/day 9

Exercise Training

Endurance-type exercise training can improve diastolic function indices in Grade 1 dysfunction. 9 Key recommendations:

• Dynamic endurance training is superior to static resistance training 9
• Exercise should be carefully supervised, monitoring for excessive dyspnea 9
• Avoid exercise training if hemodynamically significant aortic stenosis is present until corrected 9
• A 2-year high-intensity program reduced left ventricular stiffness in previously sedentary middle-aged individuals 9

Monitoring

• Regular echocardiographic assessment to monitor for progression 9
• Diastolic stress testing when resting echo does not explain exertional symptoms 2, 9

Important Caveats

Diagnostic Pitfalls

• Acute volume depletion or aggressive diuresis can lower peak E velocity, mimicking Grade 1 2
• Sinus tachycardia may cause E and A wave fusion, limiting accurate measurement 2
• The Valsalva maneuver can unmask pseudonormalization; a decrease in E/A during strain suggests elevated baseline pressures inconsistent with true Grade 1 1, 2

Algorithm Limitations

The grading algorithm is not applicable in: 2

• Atrial fibrillation
• Moderate-to-severe mitral valve disease
• Left bundle branch block
• Paced ventricular rhythms
• Ventricular assist device support

Prognostic Considerations

While Grade 1 has better prognosis than systolic dysfunction (annual mortality ~8% vs. 19%), morbidity can be substantial. 4 Early recognition and treatment of underlying conditions is essential to prevent progression to symptomatic heart failure. 4, 8, 7