Heart failure is a serious clinical syndrome where the heart is unable to pump enough blood to meet the body’s metabolic needs. This compromise leads to insufficient oxygen and nutrient delivery to tissues. Acute diastolic heart failure represents a sudden, severe worsening of this condition, specifically involving the heart’s ability to relax and fill with blood. The term “acute” signifies a rapid onset of severe symptoms, demanding immediate emergency medical attention for stabilization.
Understanding the Mechanics of Diastolic Failure
The heart operates in two distinct phases: systole, when the muscle contracts to eject blood, and diastole, the relaxation phase when the heart chambers refill. Diastolic failure occurs when the main pumping chamber, the left ventricle, becomes abnormally stiff and thick, preventing it from relaxing fully. This impaired relaxation means the ventricle cannot adequately expand to draw in the normal volume of blood from the lungs during the filling phase. Because the heart cannot expand properly, blood backs up and causes a sharp increase in pressure within the heart’s chambers.
This elevated pressure transmits backward into the pulmonary veins and capillaries of the lungs, leading to fluid accumulation. Diastolic failure is medically termed Heart Failure with Preserved Ejection Fraction (HFpEF) because the ejection fraction remains normal, typically above 50%. This preserved pumping strength differentiates it from systolic failure, confirming the underlying problem is an issue with filling, not with squeezing.
Common Conditions Leading to Acute Onset
Acute diastolic heart failure typically arises in individuals who have chronic underlying diseases that have gradually stiffened the heart muscle over time. The most significant predisposing factor is long-standing, uncontrolled hypertension, which affects an estimated 80% to 90% of patients with HFpEF. Other chronic conditions that contribute to heart wall thickening and stiffness include diabetes mellitus, coronary artery disease, and aortic stenosis.
An acute episode, or decompensation, is usually triggered by a sudden stressor that overwhelms the already stiffened heart. Common acute triggers involve situations that rapidly increase the heart’s workload or fluid volume. These include a sudden spike in blood pressure (hypertensive crisis), the onset of a rapid or irregular heart rhythm like atrial fibrillation, or non-adherence to prescribed medications or dietary restrictions. Infections such as pneumonia, sepsis, or silent myocardial ischemia can also trigger an acute event by placing excessive metabolic demand on the compromised heart.
Recognizing the Acute Symptoms
The hallmark of acute diastolic heart failure is the rapid onset of symptoms related to fluid congestion and the body’s inability to circulate oxygenated blood effectively. The most severe symptom is acute dyspnea, or severe shortness of breath, which can come on suddenly and is often debilitating. This breathlessness frequently worsens when the person lies flat, a specific symptom known as orthopnea, which is caused by the redistribution of fluid into the lungs.
As pressure builds in the lungs, it can lead to acute pulmonary edema, where fluid floods the air sacs. This causes a sensation often described as drowning, and the patient may cough up a pink, frothy sputum. Rapid fatigue and inability to perform minimal exertion are also common. Noticeable swelling, or edema, in the lower extremities can also be part of the acute presentation.
Emergency Diagnosis and Immediate Management
Patients presenting with acute symptoms require a swift and focused evaluation to confirm the diagnosis and determine the severity of the congestion. Diagnostic tools include a chest X-ray, which quickly reveals signs of pulmonary congestion. Blood tests are also crucial, particularly the measurement of B-type natriuretic peptide (BNP) or its precursor, NT-proBNP, which are hormones released by the heart muscle in response to increased wall stress.
An electrocardiogram (EKG) is performed to check for acute heart injury or a precipitating arrhythmia. Definitive diagnosis is often confirmed with an immediate echocardiogram, which visualizes the heart’s preserved ejection fraction and assesses the elevated filling pressures. Initial stabilization focuses on the reduction of fluid volume and relief of respiratory distress. This involves administering supplemental oxygen and using intravenous loop diuretics, such as furosemide, to rapidly remove excess fluid, and intravenous vasodilators for dangerously high blood pressure.