From the Guidelines
Hyperdynamic circulation is a physiological state characterized by increased cardiac output, decreased systemic vascular resistance, and tachycardia, commonly occurring in clinical scenarios such as sepsis, liver cirrhosis, pregnancy, severe anemia, and thyrotoxicosis. This condition typically presents with warm extremities, bounding pulses, and widened pulse pressure. In hyperdynamic circulation, the heart works harder than normal, pumping blood more rapidly throughout the body. This occurs as a compensatory mechanism when the body needs to increase oxygen delivery to tissues or when peripheral blood vessels are abnormally dilated.
Key Characteristics
- Increased cardiac output
- Decreased systemic vascular resistance
- Tachycardia
- Warm extremities
- Bounding pulses
- Widened pulse pressure The underlying pathophysiology often involves inflammatory mediators or hormonal changes that cause peripheral vasodilation, leading to decreased afterload and increased cardiac output, as seen in decompensated cirrhosis which demonstrates a hyperdynamic circulation with decreased systemic vascular resistance manifested by low arterial blood pressure and increased cardiac output 1.
Clinical Scenarios
- Sepsis
- Liver cirrhosis
- Pregnancy
- Severe anemia
- Thyrotoxicosis Treatment depends on addressing the underlying cause rather than the circulatory changes themselves. For example, in sepsis, antibiotics and fluid resuscitation are primary interventions, while in cirrhosis, management of portal hypertension becomes important. Monitoring of vital signs, particularly heart rate and blood pressure, is essential in patients with hyperdynamic circulation as they may be at risk for cardiovascular decompensation if the heart cannot maintain the increased workload. In pregnancy, a hyperdynamic circulation is common due to increased cardiac output and circulating plasma volume, accompanied by a reduction in peripheral vascular resistance 1.
From the Research
Definition of Hyperdynamic Circulation
Hyperdynamic circulation is characterized by:
- Increased cardiac output and heart rate
- Decreased systemic vascular resistance
- Low arterial blood pressure This condition is often associated with liver cirrhosis and portal hypertension 2, 3.
Pathogenesis of Hyperdynamic Circulation
The development of hyperdynamic circulation is attributed to:
- Portal hypertension, which leads to the formation of portosystemic collaterals
- Increased venous return to the heart, resulting in increased cardiac output
- Vasodilation of the systemic and splanchnic circulations, caused by the overproduction of nitric oxide (NO) and other vasodilators
- Activation of neurohumoral vasoconstrictive systems, including the systemic nervous system, renin-angiotensin-aldosterone system, and vasopressin 2, 3.
Clinical Implications of Hyperdynamic Circulation
Hyperdynamic circulation is a late consequence of portal hypertension in cirrhosis, and its clinical implications include:
- High cardiac output and increased heart rate
- Reduced total systemic vascular resistance
- Increased total blood volume
- Manifestations such as varices, ascites, hepatic encephalopathy, and hepatorenal syndrome
- Less known manifestations, including hepatopulmonary syndrome, portopulmonary hypertension, and cirrhotic cardiomyopathy 4.
Hyperdynamic Circulation in Other Conditions
Hyperdynamic circulation is not exclusive to liver cirrhosis and portal hypertension. It can also occur in other conditions, such as sepsis, where it is characterized by increased cardiac output, stroke volume, and microvascular blood flow, and decreased total peripheral resistance 5, 6.