Module 7: Cardiovascular Part 1

What is preload?

The volume of blood in the ventricles at the end of diastole that stretches the heart before it contracts.

What increases preload?

Fluid overload or venous constriction.

What decreases preload?

Dehydration, hemorrhage, or nitrates that dilate veins.

What is afterload?

The resistance the heart must overcome to eject blood during systole.

What increases afterload?

Hypertension or vasoconstriction.

What decreases afterload?

Vasodilators or medications that lower vascular resistance.

What is contractility?

The strength of the heart’s contraction independent of preload.

What factors improve contractility?

Inotropes like dobutamine or digoxin.

What factors reduce contractility?

Acidosis, hypoxia, or myocardial ischemia.

What is stroke volume (SV)?

The amount of blood pumped from one ventricle with each heartbeat (normal 60–100 mL).

What determines stroke volume?

Preload, afterload, and contractility.

What is cardiac output (CO)?

The total amount of blood the heart pumps per minute (CO = HR × SV).

What happens when cardiac output is low?

Fatigue, hypotension, poor perfusion, and decreased organ function.

What do baroreceptors do?

Detect changes in blood pressure and adjust heart rate and vessel tone.

Where are baroreceptors located?

In the carotid sinus and aortic arch.

What do chemoreceptors respond to?

Changes in oxygen, carbon dioxide, and blood pH levels.

What is the RAAS system?

The renin–angiotensin–aldosterone system increases blood pressure by causing vasoconstriction and fluid retention.

What activates the RAAS system?

Low blood pressure, low sodium, or reduced renal perfusion.

What do ACE inhibitors do?

Block the conversion of angiotensin I to angiotensin II, reducing vasoconstriction and blood pressure.

What do ARBs do?

Block angiotensin II receptors, leading to vessel relaxation and reduced afterload.

What do natriuretic peptides (ANP/BNP) do?

Promote sodium and water loss to decrease blood volume and pressure.

What condition raises BNP levels?

Heart failure due to overstretching of the heart chambers.

What do beta-blockers do?

Block beta-1 receptors in the heart to lower heart rate, contractility, and oxygen demand.

When are beta-blockers commonly used?

Hypertension, angina, heart failure, and after myocardial infarction.

What do calcium channel blockers (CCBs) do?

Block calcium entry into muscle cells, causing vasodilation and reduced heart rate.

What are calcium channel blockers used for?

Hypertension, angina, and supraventricular tachycardia (SVT).

What side effects are associated with calcium channel blockers?

Edema, bradycardia, dizziness; avoid grapefruit juice.

What do nitrates do?

Relax venous smooth muscle, decreasing preload and relieving angina pain.

What should patients avoid while taking nitrates?

Phosphodiesterase-5 inhibitors (e.g., sildenafil) due to severe hypotension risk.

What do diuretics do?

Increase sodium and water excretion to reduce fluid volume and blood pressure.

What should nurses monitor when giving diuretics?

Electrolytes (especially potassium), I&O, and daily weight.

What does digoxin do?

Increases contractility and slows the heart rate by affecting the AV node.

What are signs of digoxin toxicity?

Nausea, vomiting, vision changes (yellow-green halos), and bradycardia.

What do vasodilators do?

Relax arterial smooth muscle to reduce afterload and improve cardiac output.

What should nurses assess when giving vasodilators?

Continuous blood pressure; watch for reflex tachycardia.

What vital sign must always be checked before giving a beta-blocker or CCB?

Heart rate — hold if below 60 bpm or systolic BP < 90 mmHg.

Why is daily weight important for cardiac patients?

It helps detect fluid retention early in heart failure.

How much weight gain should be reported to a provider?

2 pounds in a day or 5 pounds in a week.

Why are electrolyte levels important in cardiac pharmacology?

Imbalances can cause arrhythmias and increase toxicity risk for drugs like digoxin.

What are early signs of poor perfusion?

Cool extremities, decreased urine output, altered mental status, weak pulses.

What is the nurse’s role before giving any cardiovascular medication?

Assess vital signs, monitor rhythm, review labs, and teach patients side effects.

What lifestyle changes support cardiovascular health?

Low-sodium diet, regular exercise, medication adherence, avoiding smoking and alcohol.