chapter 27: assessment of the cardiovascular system

Focused review of cardiovascular anatomy, physiology, conduction, hemodynamics, and diagnostic assessment based on Ichee chapter 27.

Pericardium

The outer lining around the heart; complications include pericarditis or pericardial effusion.

Myocardium

The muscle layer of the heart responsible for contractions.

Endocardium

The innermost layer of the heart that lines all valves, ventricles, and atria.

Pulmonary arteries

Vessels that carry deoxygenated blood away from the heart to the pulmonary system for gas exchange.

Pulmonary veins

Vessels that carry oxygenated blood from the pulmonary system back to the heart.

LAD (Left Anterior Descending)

One of the major coronary arteries; it has the highest mortality risk if blocked.

Automaticity

The pacing function of the heart, allowing electrical impulses to be created spontaneously and repetitively.

SA node

The primary pacemaker of the heart with an intrinsic rate of $60 \text{ to } 100 \text{ beats per minute}$; represented by the P wave on an EKG.

AV node

The secondary pacemaker of the heart with an intrinsic rate of $40 \text{ to } 60 \text{ beats per minute}$; it slows the impulse to allow for atrial kick.

Depolarization

The process where sodium and calcium ions move into heart cells, resulting in electrical contraction.

Cardiac output ($CO$)

The amount of blood pumped from the left ventricle per minute; calculated by the formula $CO = \text{stroke volume} \times \text{heart rate}$.

Stroke volume ($SV$)

The volume of blood ejected per contraction from the left ventricle; typical values are $50 \text{ to } 75 \text{ ml/beat}$.

Preload

The myocardial stretch at the end of diastole, representing the volume of blood in the ventricles.

Starling's Law

States that stroke volume increases in response to an increase in the volume of blood filling the heart (increased preload equals increased cardiac output).

Afterload

The resistance the ventricles must pump against to circulate blood, often caused by hypertension or aortic stenosis.

PND (Paroxysmal Nocturnal Dyspnea)

A sudden episode of severe shortness of breath that awakens a person from sleep, typically after lying down for several hours.

$S_3$ (Ventricular gallop)

A heart sound that serves as an early sign of heart failure, though it may be normal in patients under the age of $35$.

$S_4$ (Atrial gallop)

A heart sound indicating decreased compliance of either ventricle.

Troponin

A serum marker specific to cardiac muscle; any rise indicates cardiac necrosis or acute myocardial infarction (MI).

Lexiscan

A medication used in nuclear stress tests for patients who cannot exercise; it dilates blood vessels to mimic the heart's response to exercise.

Cardiac Catheterization

The most definitive and invasive test used to confirm heart disorders, identify CAD, and locate the extent of the disease process.