a. High blood pressure
- People who have hypertension have increased afterload since high blood pressure forces against artery walls are high and the heart has to work harder to pump blood; therefore decrease in cardiac output.
b. Massive bleeding
- Excessive bleeding results in decreased blood volume from blood loss therefore reduced cardiac output.
c. The Drug Dopamine
- Dopamine can be prescripted to increase heart rate and contractility; while it can increase in cardiac output in 4 micrograms/kg/min.
d. Running a sprint
- When sprinting, cardiac output and heart rate increases as the muscles in the body would need more oxygen thus the heart increases stroke volume.
e. Hyperthyroidism with increased secretion of thyroid hormones
- Hyperthyroidism increases preload and contractility while a decrease in systemic vascular resistance causing increased cardiac output.
f. Massive myocardial infarction (cardiac tissue death)
- Myocardial infarction is caused by the decreased or whole cessation of blood flow in a portion of the myocardium. Because of this, there is a decrease in preload and contractility therefore a decrease in cardiac output.
g. Hypothermia
- Exposure to ambient temperatures of 4.5-6.5 degrees C increases cardiac output achieved by an increase of stroke volume rather than heart rate.
h. Emotional distress
- Emotional distress signals the release of cortisol and adrenaline which makes the heart beat faster therefore the increase in heart rate.
References:
Ertek, S., Cicero, A. F. (2013). State of the art paper
Hyperthyroidism and cardiovascular complications: a narrative review on the basis of pathophysiology. Archives of Medical Science, 9(5), 944-952. https://doi.org/10.5114/aoms.2013.38685
Hanna JN, McN Hill P, Sinclair JD. Human cardiorespiratory responses to acute cold exposure. Clin Exp Pharmacol Physiol. 1975 May-Jun;2(3):229-38. doi: 10.1111/j.1440-1681.1975.tb03028.x. PMID: 1149328.
Hemorrhagic Shock. (2021). https://www.cvphysiology.com/Blood%20Pressure/BP031
Ojha N, Dhamoon AS. Myocardial Infarction. [Updated 2022 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537076/