From the Guidelines
Diagnosing diastolic dysfunction requires a comprehensive approach primarily using echocardiography, focusing on parameters such as mitral inflow patterns, tissue Doppler imaging of the mitral annulus, left atrial volume index, and tricuspid regurgitation velocity, as outlined in the 2016 American Society of Echocardiography and European Association of Cardiovascular Imaging guidelines 1. To diagnose diastolic dysfunction, begin with a transthoracic echocardiogram (TTE) to assess left ventricular filling patterns. Key parameters to evaluate include:
- Mitral inflow patterns (E/A ratio)
- Tissue Doppler imaging of the mitral annulus (e' velocity)
- Left atrial volume index (>34 mL/m²)
- Tricuspid regurgitation velocity (>2.8 m/s) Diastolic dysfunction is graded from I to III based on these findings, with:
- Grade I showing impaired relaxation (E/A ratio <0.8)
- Grade II showing pseudonormal filling (E/A ratio 0.8-2.0)
- Grade III showing restrictive filling (E/A ratio >2.0) The E/e' ratio is particularly important, with values >14 suggesting elevated left ventricular filling pressures, as noted in the 2012 European Society of Cardiology guidelines for the diagnosis and treatment of acute and chronic heart failure 1. Additional diagnostic tools, such as B-type natriuretic peptide (BNP) levels, can provide supporting evidence for diastolic dysfunction. Clinical correlation is essential, as symptoms like dyspnea, fatigue, and exercise intolerance often accompany diastolic dysfunction. Early diagnosis allows for appropriate management of underlying conditions like hypertension, diabetes, and coronary artery disease that contribute to diastolic dysfunction. Some key points to consider in the diagnosis of diastolic dysfunction include:
- The importance of using a combination of parameters to accurately diagnose and grade diastolic dysfunction
- The need for clinical correlation to interpret echocardiographic findings in the context of patient symptoms and medical history
- The role of diastolic dysfunction in preserved ejection fraction heart failure, where it is the primary pathophysiologic mechanism
- The potential for diastolic dysfunction to be an early sign of cardiac disease, even in asymptomatic patients.
From the Research
Diagnosing Diastolic Dysfunction
To diagnose diastolic dysfunction, several methods can be employed, including:
- Cardiac magnetic resonance imaging (MRI) to differentiate between normal and abnormal myocardial relaxation patterns 2
- Echocardiography with Doppler to assess left ventricular (LV) diastolic function, which is non-invasive, does not require radiation, and is portable 3
- Tissue Doppler (TD) imaging to demonstrate impaired LV relaxation in patients with preserved LV ejection fraction (LVEF) 3
- Comprehensive diastolic assessment incorporating many 2-dimensional, conventional, and tissue Doppler variables to accurately assess LV filling pressures 3
Echocardiographic Evaluation
Echocardiography is the primary imaging modality used for the clinical evaluation of LV diastolic function, and it can be used to:
- Estimate LV filling pressure using two-dimensional, transmitral, mitral annular, and pulmonary venous Doppler data 4
- Evaluate patients with dyspnea of unknown etiology and those with heart failure with preserved ejection fraction 4
- Assess the pathophysiology of diastolic dysfunction and provide a comprehensive review of its echocardiographic evaluation 4
Predictors of Diastolic Dysfunction
Several factors have been identified as predictors of diastolic dysfunction, including:
- Abnormal LV long-axis function, as assessed by average peak systolic annular velocity 5
- Mitral E/A ratio, age, body mass index, and relative wall thickness 5
- LV end-diastolic volume index and LV mass index 5
Role of Echocardiography
Echocardiography plays a crucial role in understanding the pathophysiology of diastolic dysfunction, its diagnosis, and utility in predicting outcomes, including: