Chapter I Physiology of the Heart and Circulation System

Chapter II The Electrocardiogram and the Normal EKG

Chapter III Arrhythmia Determination

Chapter IV Arrhythmias and Select Disease Conditions

Chapter V The 12-Lead EKG



Course Exam

Tracings for Exam

Chapter I     Physiology of the Heart and Circulatory System

Anatomy and Physiology Update

The Thorax

The first part of this course is a review of the anatomical structures and the physiology of the cardiovascular system in relationship to the nursing care of the patient with a related disorder.  If you need to review the structures and/or function that we will be discussing, please refer to any basic anatomy textbook.  However, it is not required that you use any other reference.  All information needed to pass the test at then of this course will be including in the text.

We will list the most important structures of the thorax and entire CV system only so that you can relate these to the clinical approach that we will use.  Following is an illustration of the thorax and the heart in relationship to other structures noticed upon visual examination.  The thorax has a characteristic shape, size and movement.


Thorax – Be sure you can identify the following:

  1. Sternum – mid-chest, flat, non-protruding
  2. Ribs – slope of ribs, intercostals spaces, costal margins
  3. Heart – heartbeat, in some cases, can be visible as a pulsation in the thorax at lower costal margin
  4. Shoulder- should be relaxed, and at a 90-degree angle, look for abnormal angles and musculature that might indicate overuse of accessory muscles
  5. Neck veins – should not normally be visible
  6. Clavicle – clavicular line horizontal, no protrusions during breathing
  7. Respirations – normal respiration should look unlabored and comfortable

The Heart


Gross Structures

  1. Musculature-pericardium, fibrous and serous epicardium, visceral serous pericardium, myocardium, heart muscle.
  2. Muscle cell (microscopic structures) – central nucleus, sarcoplasm, sarcolemma, sarcomere, intercalated discs.

Chambers – Right side of the Heart

  1. Right atrium – the thin-walled atrium, low relative pressure receives blood from superior and inferior vena cavae, the coronary sinus and thebesian veins, and the outflow of blood through tricuspid valve.
  2. Right ventricle – relatively thing muscle wall, crescent-shaped, papillary muscles, chordate tendineae, low pressure, outflow though the pulmonic valve to the pulmonary artery.

Left Side of the Heart

  1. Left atrium – thicker muscle, medium pressure of blood, inflow of blood through four pulmonary veins.  Outflow is the through mitral valve.
  2. Left ventricle – largest muscle mass, high pressure blood flow, papillary muscles, spring-like pump action.  Outflow of blood through the aortic valve and the aorta.

Cardiac Anatomy:

The human heart is a hollow, four-chambered, muscular pump.  It is the major organ in the mediastinum.  The pericardium is the outermost layer of the heart.  It consists of parietal and visceral layers.  The pericardial sac, normally containing 5 to 20 cc of fluid, protects the myocardium and prevents friction during the pumping action of the heart.

Muscle tissue, the myocardium, makes up the walls of the heart chambers. The left ventricular myocardium is 5 to 7 times thicker than the right.  The inner surface of the myocardium is lined with endocardium, as are the cardiac valves and blood vessels. 

The heart is divided into chambers by intraventricular and intra-atrial septa.  Fibrous tissues separate the atria from the ventricles on the right and left sides of the heart.  The tricuspid and mitral valves, tighter called the atrioventricular (A-V) valves, allow for the passage of blood from the atria to the ventricles. 

Heart Valves

Atrioventricular Valves:

  1. Tricuspid – has three leaflets, controlled by papillary muscles; chordate tendineae.
  2. Mitral valve – two cusps, controlled by papillary muscles and the chordate tendineae.

Semilunar Valves:

  1. Pulmonic valve – three leaflet valve, formed by fibrous ring, tendinous tubercle midpoint free edges.
  2. Aortic valve – three leaflets, also formed by fibrous ring, tendinous tubercle midpoint free edges.

Vasculature of the Heart

  1. Right Coronary Artery – most branches of this artery anastomse distally with left anterior descending.
  2. Left Coronary Artery – divides into two main branches, left ant. Descending and left circumflex artery.
  3. 3. Great cardiac vein – largest system, forms coronary sinus, drains left ventricle primarily.
  4. Anterior cardiac veins – empty directly into right atrium.
  5. Thebesian Veins – smallest system, empty into right atrium.

Next: Conduction System of the Heart