Evaluation of the Cardiovascular System Flashcards
EKG:
How is peripheral perfusion observed?
- temperature of extremities
- mucus membrane CRT
How is the arterial pulse quality observed?
- difference between systolic and diastolic pressure
- bounding vs. weak pulse
Where is it normal to see jugular vein pulsation? What is suggestive of heart failure?
lower 1/3 of the neck
pulsation and increased filling in the higher 2/3 of the neck = higher right atrial pressure
What are the most common causes of peripheral edema? What are the most common locations?
hypoproteinemia, right heart insufficiency
- pectoral
- legs
- abdomen
- prepuce/udder
What is the most common cause of pulmonary edema? What clinical signs are associated?
left heart insufficiency
- tachypnea, dyspnea
- foamy nasal discharge (froth)
What signs are associated with right and left heart failure?
RIGHT = congestion of peripheral tissues, ascites, liver congestion, GIT congestions
LEFT = decreased cardiac output, pulmonary congestion/edema, cyanosis, hypoxia, orthopnea, cough
How is BCS affected by cardiac disease?
cardiac cachexia and growth deficits
Where is the equine heart auscultated?
above the point of the elbow under the shoulder point, push under the muscle mass
What is the normal heart rate in horses at rest, walk, trot, and gallop?
- 28-48 bpm
- 50-100 bpm
- 70-120 bpm
- 140-240 bpm
always assess at rest AND during exercise
What are the 4 heart sounds? What happens at each?
- S1 = mitral and tricuspid (AV) valve closure
- S2 = aorta and pulmonary (semilunar) valve closure
- S3 = early diastolic ventricular filling
- S4 = atrial contraction
What happens during systole and diastole?
SYSTOLE = contraction and ejection; S1-S2
DIASTOLE = relaxation and filling; S2-S1
Describe normal systole.
mitral and tricuspid (AV) valves close during ventricular contraction to eject blood through the open aorta and pulmonary artery
- LV to aorta
- RV to pulm artery
Describe normal diastole.
ventricles relax - tricuspid and mitral valves open and aortic and pulmonary valves close to allow for ventricular filling
What are the points of maximal intensity of valve sounds?
LEFT SIDE:
- M = above elbow
- A = push forward and up
- P = push even more forward
RIGHT SIDE:
- T = above elbow and a little forward
What are the 6 grades of heart murmurs?
- very faint, localized at PMI, hardly audible
- weak, easily heard at PMI
- moderate, easily heard, irradiation
- intense, large zone or irradiation
- intense, large irradiation, precordial thrill
- intense, precordial thrill, heard without stethoscope
What is the most common type of heart murmur in horses? When do they occur?
regurgitation murmurs that occur when valves do not completely close and allow blood leakage
- SYSTOLIC: mitral (left), tricuspid (right)
- DIASTOLIC: aortic (left), pulmonary (left)
What occurs during a systolic regurgitation murmur?
leakage of AV valves causing abnormal blood flow from the LV to the LA (mitral) and RV to the RA (tricuspid)
What occurs during a diastolic regurgitation murmur?
leakage of semilunar valves causing abnormal blood flow from the aorta to the LV (aortic) and pulmonary artery to RV (pulmonic)
How are murmurs categorized?
- proto (beginning)
- holo (middle)
- tele (end)
- systolic (S1-S2), diastolic (S2-S1)
What are the 4 pitches of murmurs?
- crescendo - increasing intensity
- decrescendo - decreasing intensity
- crescendo-decrescendo - increasing intensity, peak, then decreases
- plateau - constant intensity
What are the most common causes of regularly irregular and irregularly irregular heart rhythms?
2nd degree AV block - prolonged pause, common in athletes
atrial fibrillation - always pathologic, chaotic
What is the main indication for echocardiography? Others?
cardiac murmurs
- dysrhythmias
- congenital defects
- poor performance
- decreased cardiac sounds
- fever of unknown origin
- collapse, weakness
- signs are cardiac insufficiency
- severe respiratory problem
What is echocardiography able to assess?
- shape
- size
- motion
- abnormalities
How does M-mode ultrasonography visualize the heart? What is it used to assess?
time-motion single line gives a one dimensional view of the heart
chamber size and thickness
How are Dopplers used to assess the heart?
assesses velocity, direction, and character of blood flow
What are 3 utilities of echocardiography? Limitation?
- visualization and measurement of the heart
- assessment of performance
- localization and assessment of flow disturbances
unable to see consequences of cardiac dysfunction, still require a physical exam
What are ECGs used for? What are 4 major indications?
assesses HR, rhythm, conduction times, and waves
- poor performance
- arrhythmia on auscultation
- valvular insufficiency
- myocardial disease
Where is the sino-atrial node found? What is its function?
right atrium
pacemaker and conductor of heart rhythm —> highest rate of depolarization
What is the function of the atrio-venticular node?
gatekeeper that controls what impulses get though the atria and reach the ventricles
- delayed impulses
What is the function of bundle (Purkinje) branches?
spreads impulses, leading to contraction of the ventricles
- slower HR, but overruled by SA
What are the 3 major waves seen on an ECG?
- P wave - depolarization of the atria
- QRS complex - depolarization of ventricles
- T wave - repolarization of ventricles
How is the P wave unique in equine ECGs?
commonly biphasic
What are the most common laboratory analyses used for the cardiovascular system?
- CBC (anemia), fibrinogen (inflammation)
- biochemistry (abnormal electrolytes)
- blood gas
- blood culture (endocarditis)
- urinary output and analysis
- cardiac enzymes and proteins
- vitamin E and selenium
- toxicology screening
What 3 cardiac enzymes are testing for in horses?
- Iso-CK
- Iso-LDH
- Troponins* - protein complexes that regulate the interaction between actin and myosin
How does cardiac troponin I differ in human and equine medicine?
HUMAN = sensitive and specific to myocardial damage, not influenced by exercise, skeletal muscle damage, and renal insufficiency
EQUINE = influenced by exercise causing dynamic changes
