Week 4 - Cardiovascular System

What is meant by "Congestive" heart failure?

A weakness in the heart that leads to buildup of fluid in the lungs and surrounding body tissues

What is the primary medication used to treat CHF? What does it do?

ACE-Inhibitor: Reduces blood pressure, inhibits activity of enzyme ACE, which decreases Angiotensin II, causing blood vessels to enlarge or dilate - Enalapril / Lisinopril / Benazepril Diuretics: Cause fluid in the body to be taken up by the kidneys and excreted as urine - Furosemide Vasodilators: Relax or dilate the blood vessels in the body and decrease pressure on the heart, allowing it to pump with greater ease - Nitroglycerine Positive Inotropes: Increase the force with which the heart muscle beats, allowing it to pump more blood forward to the lungs and the rest of the body - Vetmedin (Pimobendan)

Precordial Thrill

Abnormal pulsations (palpable heart murmurs) in the precordium

What are the clinical signs of left-sided CHF?

Coughing / Difficulty breathing / Exercise intolerance / Fainting / Heavy breathing

What are some of the causes of functional murmurs?

Defects in heart wall / Heartworm / Heart valve deficiencies or blockages / Dilated cardiomyopathy / Endocarditis

What is the most commonly seen cardiovascular disorder in the dog?

Dilated Cardiomyopathy (DCM)

List some clinical signs of congenital heart disease

Exercise intolerance / Difficulty breathing /

Define and describe the Cardiac Conduction System

Group of specialized cardiac muscle cells in the walls of the heart that send signals to the heart muscle causing it to contract

Define Innocent Murmurs and what animals these are often seen in

Heart murmur considered not serious and often resolve within time - Found most commonly in young dogs (grade III or less)

If you hear a loud heart murmur, does this mean that the heart disease is severe?

Not always

Does heart disease always lead to heart failure?

Not necessarily

List the most common rule-outs for pathologic murmurs in young animals, adult large and small breed dogs, and cats

The lack of symptoms or clinical signs / Age can be a factor - young puppies may develop an innocent heart murmur while rapidly growing

What are the clinical signs of right-sided CHF?

Rapid, shallow breathing / Distended abdomen / Lethargy / Weakness / Strong pulse in Jugular / Weakness / Swollen limbs from fluid accumulation

What is an EKG / ECG?

Recording of electrical activity of the heart - Electrodes are placed on the skin of the chest and connected in a specific order to a machine that, when turned on, measures electrical activity all over the heart

List the five components of the conduction system

SA node / AV node / Bundle of His / Bundle branches / Purkinje fibers

Trace the conduction signals of the heart

SA node sends an electrical impulse down to the AV node / Signal goes to all of the cardiac muscle cells in the wall of the atria and depolarizes them - atrial excitement / Cells contract after depolarization / Both atria contract in unison / Impulse goes through AV node to the Bundle of His / Atria relax and cells repolarize / Travels down the interventricular septum to both sides of the heart / Ventricular excitation / All muscle cells in the ventricles will be depolarized and will contract in unison / Both ventricles contact at the same time and send blood out of the heart / Ventricles relax and cells repolarize

What is the anatomical pacemaker?

Sinoatrial (SA) Node

Trace the flow of blood through the chambers and valves of the heart

Unoxygenated blood enters the right atrium from the superior and inferior vena cava / Blood flows through the tricuspid valve into the right ventricle / Blood flows through the pulmonic valve into the pulmonary artery / The right and left pulmonary arteries carry unoxygenated blood to the right and left lungs for gas exchange / Blood releases carbon dioxide as waste and picks up a fresh supply of oxygen / Oxygenated blood flows through the four pulmonary veins from the lungs into the left atrium / Blood flows through the bicuspid, or mitral valve into the left ventricle / Left ventricle contraction forces blood through the aortic valve into the aorta for distribution to the systemic circulation

Arrhythmia

Condition in which the heart beats with an irregular or abnormal rhythm

Be able to label a diagram for PMI of valve sounds

Left Thoracic Auscultation - Pulmonic, aortic, mitral / Right Thoracic Auscultation - Tricuspid

What are the three most commonly seen congenital heart defects and what breeds are predisposed?

Patent Ductus Arteriosus (PDA) - failure of a fetal blood vessel to close after birth / Pulmonic Stenosis - Narrowing of the valve makes it harder for the right side of the heart to pump blood to the lungs resulting in hypertrophy of the right ventricular walls - Most common in smaller breeds / Subaortic Stenosis - Large breeds such as German Shepherds, Golden Retrievers, and Rottweilers - Ridge of tough connective tissue that develops beneath the aortic valve, causing stenosis

What is the fibrous covering of the heart? What is its purpose?

Pericardium - Serous Parietal layer of pericardium lines the internal surface of the fibrous pericardium and attaches to large arteries / Serous Visceral layer of pericardium lines outer surface of the heart itself and forms the outer most layer of the heart wall which is pericardium Protects the heart and loosely attaches it to the diaphragm

Define Systole and describe what occurs

Phase of the heart beat when the heart muscle contracts and pumps blood from the chambers into the arteries

PMI

Point of Maximal Impulse or Intensity - Where the cardiac impulse can be best palpated on the chest wall

List the general treatment for CHF

Primary goal is to reduce fluid build-up and increase amount of blood being pumped by the heart to the rest of the body - Medications / Supplements / Diets

Name the four heart valves and note their locations

Pulmonary Valve - Between the right ventricle and pulmonary artery / Tricuspid Valve - between the right atrium and right ventricle / Mitral valve - between left atrium and left ventricle / Aortic valve - between left ventricle and aorta

Define Regurgitation as it applies tot he heart

The heart's Mitral valve does not closely tightly and allows blood to flow backward into the heart

Diastole

The phase of the heartbeat when the heart muscle relaxes and allows the chambers to fill with blood