Diastolic dysfunction is a condition where the heart’s lower chambers, known as the ventricles, encounter difficulty relaxing and filling with blood between beats. This issue means the heart cannot properly prepare for its next contraction. It is a commonly encountered heart condition, and an echocardiogram, often referred to as an echo, serves as the primary diagnostic tool for its identification.
Understanding Diastolic Dysfunction
Diastolic dysfunction specifically refers to a problem with the heart’s filling phase, in contrast to systolic dysfunction, which involves the heart’s pumping ability. During diastole, the heart muscle should relax and expand to allow blood from the atria (upper chambers) to fill the ventricles. When this relaxation is impaired or the ventricular walls become stiff, the ventricles struggle to fill adequately, leading to reduced blood volume being pumped out with each beat.
Proper ventricular filling ensures enough blood circulates throughout the body. When filling is compromised, the body may not receive enough oxygenated blood, leading to symptoms like shortness of breath, especially during exertion, or fatigue. Early identification helps manage its progression and address underlying causes.
How Echocardiography Helps
An echocardiogram is a non-invasive imaging test that uses sound waves to create live images of the heart. This technique allows medical professionals to visualize the heart’s structure and observe its movement in real-time, making it effective for diagnosis.
Beyond structural visualization, echocardiography also measures blood flow patterns and pressures within the heart chambers. This capability is useful for assessing diastolic function, detecting subtle changes in blood movement into the ventricles during relaxation. It provides dynamic data, offering insights into the heart’s mechanical performance that static imaging cannot.
Key Echocardiogram Measurements
Echocardiography assesses several specific measurements to identify diastolic dysfunction.
The E/A ratio evaluates blood flow across the mitral valve, which separates the left atrium from the left ventricle. The “E wave” represents early diastolic filling, while the “A wave” indicates late diastolic filling caused by atrial contraction; their ratio helps characterize filling patterns. A normal E/A ratio is between 0.8 and 2.0. An E/A ratio less than 0.8 may indicate impaired relaxation, while a ratio greater than 2.0 can suggest restrictive filling.
The E/e’ ratio combines early mitral inflow velocity (E) with mitral annular tissue velocity (e’). The “e’ wave” reflects the relaxation of the heart muscle itself. This ratio helps estimate left ventricular filling pressures, with values greater than 15 suggesting elevated pressure. A mean E/e’ ratio of 8 or less indicates normal left ventricular filling pressures, while a ratio of 13 or higher points to elevated pressures.
An enlarged left atrium, quantified by the Left Atrial Volume Index (LAVI), can also signal increased filling pressures. An LAVI greater than 34 mL/m² indicates an enlarged left atrium. Elevated pressures, especially in the left ventricle, can cause the left atrium to enlarge.
Tricuspid Regurgitation Velocity (TRV) estimates pulmonary artery systolic pressure, which may be elevated in severe diastolic dysfunction. A peak TRV greater than 2.8 m/s suggests increased pulmonary artery pressure, often from elevated left heart chamber pressures. Pulmonary vein flow patterns (S, D, Ar waves) also provide information on left atrial pressure and ventricular filling. Left Ventricular Hypertrophy (LVH), a thickening of the heart muscle, is a common finding associated with diastolic dysfunction, as a stiffened ventricle impairs relaxation and filling.
How Findings Are Interpreted
Interpreting echocardiogram findings for diastolic dysfunction involves analyzing a combination of measurements rather than relying on any single parameter. Cardiologists use a systematic approach to classify the severity of diastolic dysfunction. This approach considers various criteria to diagnose and grade the dysfunction.
For instance, if the E/A ratio is less than 0.8 and the peak E velocity is less than or equal to 50 cm/s, it may indicate Grade I diastolic dysfunction, characterized by impaired relaxation and often normal left atrial pressure. If the E/A ratio is between 0.8 and 2.0, or if the E/A ratio is less than 0.8 but the peak E velocity is greater than 50 cm/s, additional parameters like LAVI, TRV, and E/e’ ratio are evaluated to differentiate between normal function and Grade II (pseudonormal) dysfunction, which involves elevated filling pressures.
Grade III diastolic dysfunction, or “restrictive filling,” is characterized by a high E-wave amplitude, low A-wave amplitude, and an E/A ratio greater than 2.0. This grade is accompanied by an enlarged left atrium and an E/e’ ratio greater than 15. Interpretation requires a medical professional to synthesize all data, considering the interplay between measurements to determine overall diastolic function and its clinical implications.
Living With Diastolic Dysfunction
Understanding diastolic dysfunction is the first step in its management after diagnosis. While echocardiography diagnoses, managing the condition involves addressing underlying health issues. These include managing high blood pressure, controlling diabetes, and addressing other cardiovascular risk factors.
Lifestyle adjustments play an important role in supporting heart health. These involve adopting a balanced diet, engaging in regular physical activity as advised by a healthcare provider, and maintaining a healthy weight. Consistent follow-up with a doctor is important to monitor the condition’s progression and adjust management strategies as needed.