Question 1

What is a patient's cardiac output if they have a stroke volume of 80ml and a heart rate of 80?

Accepted Answer

6400ml. To figure out a patient's cardiac output you multiply the patient's stroke volume by their heart rate.

Question 2

You are about to attempt resuscitation on a patient in cardiac arrest with an automated external defibrillation device. What is the most critical factor to success?

Accepted Answer

When attempting resuscitation on a patient in cardiac arrest with an automated external defibrillation device, time is the most critical factor to success. Early defibrillation is critical to increasing the survival of out-of-hospital cardiac arrest patients. Early defibrillation is paramount to improving successful resuscitation because the most frequent presenting initial rhythm is ventricular fibrillation. The most effective method to abolish ventricular fibrillations is defibrillation; the sooner the defibrillation is delivered, the better the chance of successful conversion.

Question 3

What term is most associated with myocardial contractions?

Accepted Answer

Frank-Starling's law, Starling's law, and Frank-Starling's mechanism are associated with myocardial contractions; each of these terms is interchangeably used. Starling's law of the heart discusses the increase in myocardial contraction when the muscle fibers are stretched by increases in preload. The enhanced recoil results in more forceful expulsion of a larger amount of blood. This increase in stroke volume will then translate into improved cardiac output and eventually into improved blood pressure.

Question 4

What is the filling of the pericardial sac with fluid, which in turn limits the filling of the heart?

Accepted Answer

Pericardial Tamponade is the filling of the pericardial sac with fluid, which in turn limits the filling of the heart. A patient that presents a distant heart sounds, distended neck veins and narrow pulse pressure indicates pericardial Tamponade - classic Beck's triad. This patient will need emergency management that includes pericardiocentesis and rapid transport.

Question 5

What do preload, cardiac contractility and afterload reflect?

Accepted Answer

Preload, cardiac contractility, and afterload reflect stroke volume. The average stroke volume is 60-100 milliliters. The stroke volume is the amount of blood ejected by the heart on contraction, is measured in milliliters, and can increase significantly in a healthy heart.

Question 6

If a patient has a stroke volume of 80mLs and a heart rate of 60, what is their cardiac output?

Accepted Answer

In this scenario, the cardiac output would be 4800mLs. To determine a patient's cardiac output, you have to multiply their stroke volume by their heart rate.

Question 7

What is the function of intercalated discs that are located in the cardiac muscle fibers?

Accepted Answer

Intercalated discs that are located in the cardiac muscle fibers connect the fibers in order to conduct electrical impulses quickly from one muscle to the next.

Question 8

What decreases when hypovolemia reduces preload?

Accepted Answer

Cardiac output is decreased when hypovolemia reduces preload, the blood available to the pump. Adequate tissue perfusion is dependent on a functional and well-oxygenated pump, adequate volume, and an intact container. The fluid-container-volume ratio must match.

Quiz 2: Cardiology