Description
Diastolic dysfunction is a condition in which the heart's ventricles have difficulty relaxing and filling with blood during the diastolic phase of the cardiac cycle. It is often diagnosed through echocardiography, which can assess the filling patterns of the ventricles and detect abnormalities in diastolic function. Diastolic dysfunction can be graded from I to III, with increasing severity. Grade I is mild dysfunction, and Grade III is the most severe. Common causes include hypertension, aging, coronary artery disease, and conditions like diabetes and obesity. Patients may experience symptoms such as shortness of breath, fatigue, and fluid retention, similar to systolic heart failure. Management often includes controlling underlying conditions, optimizing blood pressure, and medications to improve diastolic function.
The prognosis for diastolic dysfunction varies but is generally better than systolic heart failure, especially with early diagnosis and appropriate treatment. Patients with diastolic dysfunction require regular follow-up and monitoring to assess changes in cardiac function and adjust treatment as needed.
Résumé
- Diastolic dysfunction refers to the heart's inability to fill properly without increased pressure. It accounts for approximately 50% of heart failure cases, often affecting older women with obesity and comorbidities like hypertension and diabetes. Patients with preserved ejection fraction have a worse prognosis than those with decreased ejection fraction.
- The diastolic phase includes isovolumic relaxation, early rapid filling, diastasis, and atrial contraction. Structural issues like hypertrophy and fibrosis, as well as functional issues like ischemia and calcium overload, can cause diastolic dysfunction. It is classified into stages from impaired relaxation to severe irreversible dysfunction.
- Indices for measuring diastolic function include isovolumic relaxation time (IVRT), mitral inflow patterns (E/A ratio), pulmonary vein flow, propagation velocity, and left atrial size. Doppler tissue imaging is also used. Mital valve and flow patterns, deceleration time, and myocardial performance index are crucial measurements.
- Mitral inflow patterns are affected by conditions like sinus tachycardia, atrial fibrillation, and mitral valve disease. Propagation velocity helps gauge the pace of ventricular filling, while pulmonary vein flow shows systolic and diastolic components along with atrial flow reversal.
- Pulmonary artery pressure is calculated using Doppler, and pulmonary vein flow patterns can give insights. Left atrial volume increase is a chronic indicator measured by Simpson method. Isovolumic relaxation time (IVRT) is the duration of relaxation before the mitral valve opens.
- Stages of diastolic dysfunction vary. Stage one features impaired relaxation, prolonged IVRT, and decreased suction, while stage two shows a restored early mitral inflow due to a high left atrial pressure. Stage three is characterized by a non-compliant left ventricular chamber, and stage four is irreversible.
- To estimate end-diastolic pressure, one can use tissue Doppler which determines the ratio of e to e’ interval. Global diastolic strain rate, stress echo, and La strains are other emerging techniques. In atrial fibrillation, average measurements over multiple cycles are recommended.
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