Diastole

Definition

Diastole refers to the phase of the cardiac cycle when the heart muscle relaxes and the chambers of the heart fill with blood. This period is crucial for ensuring that the heart has enough blood volume to pump during the subsequent contraction, known as systole. During diastole, the atrioventricular valves open, allowing blood to flow from the atria into the ventricles, and it plays a significant role in determining overall heart function and efficiency.

5 Must Know Facts For Your Next Test

1. Diastole is divided into three phases: early rapid filling, diastasis (slower filling), and late filling due to atrial contraction.
2. Proper diastolic function is essential for maintaining adequate stroke volume and overall cardiac output.
3. Abnormalities in diastolic function can lead to conditions such as heart failure with preserved ejection fraction (HFpEF).
4. During diastole, the coronary arteries receive most of their blood supply, making it critical for myocardial oxygenation.
5. Diastolic dysfunction can occur due to age-related changes or conditions such as hypertension and diabetes.

Review Questions

• How does diastole contribute to the overall efficiency of the heart during the cardiac cycle?
  • Diastole allows the heart chambers to fill with blood before they contract during systole. This filling phase is critical because it ensures there is sufficient volume in the ventricles for an effective ejection of blood into circulation. If diastolic filling is impaired, it can reduce stroke volume, compromising overall cardiac efficiency and performance.
• What are the consequences of impaired diastolic function on cardiovascular health?
  • Impaired diastolic function can lead to a variety of cardiovascular issues, including heart failure with preserved ejection fraction (HFpEF). When diastole is compromised, it results in inadequate filling of the ventricles, which can cause symptoms such as shortness of breath and fatigue. Additionally, chronic diastolic dysfunction can contribute to increased pressure in the left atrium and pulmonary circulation, further complicating heart health.
• Evaluate the impact of age-related changes on diastolic function and how they influence treatment strategies in elderly patients.
  • As individuals age, structural changes in the heart, such as increased stiffness of the myocardium and impaired relaxation, often lead to diastolic dysfunction. This impacts treatment strategies for elderly patients as healthcare providers must focus not only on managing symptoms but also on optimizing diastolic function through lifestyle modifications and medications that improve heart relaxation. Understanding these age-related changes is crucial for developing effective management plans for older adults with cardiovascular conditions.

Related terms

Systole: The phase of the cardiac cycle when the heart muscle contracts and pumps blood out of the chambers.

Atrioventricular Valves: The valves located between the atria and ventricles that open during diastole to allow blood flow into the ventricles.

Cardiac Output: The amount of blood the heart pumps in one minute, influenced by both heart rate and stroke volume, which is affected by diastolic filling.