Cardiology - Exam 1: Don't Be Still, My Heart

Don't forget the take-home cases!

Also extra credit, the live animal exam, and stress points

T/F: Cats with heart failure cough

False

What are respiratory signs of acute, severe left heart failure in dogs?

Coughing and pulmonary edema

How does heart disease cause coughing with the absence of pulmonary edema?

An enlarged heart can press on the trachea

Dyspnea first manifests as increased _______, and can later worsen with pulmonary edema, leading to increased _______

Rate; Effort

Pleural effusion leads to an issue of the lungs expansion, leading to what signs?

Increased respiratory rate with short, shallow breaths

Inadequate oxygen to the brain leading to collapse is ______, which needs to be differentiated from a seizure

Syncope

Fluid accumulation in the abdomen is called ______

Ascites

Ascites is associated with ______ heart failure

Right (Heartworm disease)

Ascites can cause what lung sign?

Dyspnea

A clot at the trifurcation of the aorta in the sacral area is called _______, and causes paresis in cats

Saddle thrombus

Saddle thrombus is associated with heart disease in cats, and includes what signs of the distal limbs?

Cold and cyanotic feet

T/F: A dyspneic patient is concerning but considered stable

False, not stable

If the owner can feel that the heart rhythm is off, you should think ________

Atrial fibrillation

What must immediately be done with a dyspneic patient?

Oxygen supplementation, often with a truncated physical so that you can stabilize before you diagnose

A key sign in right heart disease is distended _______ veins

jugular

Increased inspiratory breaths tends to be a problem with the _______

Upper airway

T/F: peripheral edema (in the limbs) is associated with heart disease

False

What is an easy method to help distinguish whether the problem lies in the airway and not the heart?

Palpate the trachea, and a cough would indicate it is the airway, not the heart

Cats with asthma tend to have a strong ________ breathing

Expiratory

Cat murmurs are heard best on what area?

The sternum

The S1 sound is caused by ____ valve closure, while S2 is caused by _____valve closure

AV; aortic and pulmonary

T/F: You should always hear only two sounds when listening to the heart

True, three is abnormal in small animals

T/F: Loudness of a murmur correlates to severity

False, a super quiet murmur could mean valve has failed completely

What happens if a murmur goes from a grade 4 to a grade 1 instantly?

A chordae tendinae rupture

Loud crackles from the lungs indicates _____, while quiet ones indicate _____

Asthma in cats; Pleural effusion

T/F: The strength of pulses indicates blood flow

False, might just feel strong

Elbow abduction is a sign of severe ____

Dyspnea (need room to breath)

Recall, if the owner says the heart rhythm is off, think _______

Atrial fibrillation

Jugular distension and ascites is ______ sided heart failure, while pulmonary edema is ______ sided heart failure

Right; Left

Quiet heart sounds indicate that it is ______ and quiet lung sounds indicate that it is ____

Pericardial; Pleural

Coughing cat indicates ____ while coughing dogs indicate ____

Asthma/worms ; Respiratory

What is the most important contractile element for the heart?

What about relaxing?

Calcium contracts!

Magnesium relaxes

What is the surface recording of average electrical activity of the heart?

ECG

T/F: ECG measures contraction

False, just electrical activity

Each different angle of an ECG is called ______

a lead

What deflection shows when an electrical impulse travels toward a positive electrode?

Upward deflection

What two cases produce a flatline?

When electrical forces are equal, or

When there is no electrical activity

Atrial contraction follows the _____ wave

P wave (atrial depolarization)

Ventricular contraction follows the _______ wave

QRS (Ventricular depolarization)

Activation of the conduction system is called the _____ segment

P-R

________ events always precede mechanical events

electrical

The P wave is caused by depolarization of the _______, while the QRS wave is caused by the depolarization of the ______

Atria; Ventricles

The T wave represents __________

Ventricular polarization (end of contraction)

Heart muscle contractions are due to what type of polarization?

Depolarization

What pump causes depolarization?

Na/K pump

Recall that the inside of a myocardial cell is more ______ when referring to polarity

negative

What ion enters first and quickly, and which ion follows but slower?

Na+ enters quickly, Ca2+ channels open slower

Sarcoplasmic reticulum and T tubules release ______, causing contractions

Ca2+

When ______ leaves the cells, it signals the end of contraction, and the cell returns to a more ______ state

K+; negative

What polarization is when heart muscle relaxes and electrolytes move back across cell membrane?

Repolarization

______ wave is for ventricular repolarization

T wave

Every ________ wave must have a T wave

QRS (P wave is unnecessary)

The ability of the heart to beat without needing to be activated is _______

Automaticity

The _______ is the primary pacemaker and is the fastest

SA node

Recall the three pacemakers, in order of fastest to slowest

SA node, AV node, and purkinje fibers

If the fastest pacemaker fails, it reverts to the next fastest pacemaker. This process is known as ....

An escape

When there is an irritable focus, meaning a slow pacemaker takes over as the fast one, it is called ______

Aberrant rhythm

The electrical stimulus reducing the resting potential to cause a contraction is called _______

Excitability

The ____ period is when no stimulus will cause contraction, while the _____ period will cause a contraction if the stimulus is great enough

Refractory; Relative refractory

The _______ period is why the heart does not remain contracted during tetanus

Relative refractory, allows for relaxation

Activation of a muscle cell produces activity in the next cell, called _______

Conductivity

Conductivity velocity is the fastest in ________

Purkinje Fibers

T/F: ECG measures stimulus for contraction, not the contraction itself

True

_______ is how we can measure contractions

Echocardiogram

ECGs are typically done in what lateral recumbency?

Right

ECGs have a speed of _____ mm/sec

50

T/F: Complexes will be pushed together more the faster the paper speed

False, complexes will be more spread out, since the pen moves at the same speed, but over more paper

What is the advantage of a faster paper speed? What about a slower paper speed?

A faster paper speed (50) allows you to see individual complexes more clearly, while a slower paper speed (25) gives you more complexes to compare

The standard sensitivity of ECG is 1 cm = ____ mV

1

What are the bipolar leads?

What are the unipolar leads?

Bi: I, II, III

Uni: aVR, aVL, aVF

What does aVR, aVL, and aVF mean?

aVR means right arm,

aVL means left arm, and

aVF means left foot

If the impulse is away from the positive electrode, the deflection is ______

negative or downward

R wave should be positive in lead ____

one

In the QRS wave, which are positive?

R is positive,

Q and S are negative

Give the action of the following:

P.

QRS.

T.

P is atrial contraction,

QRS is ventricular contraction, and

T is ventricular relaxation

Normal mean electrical axis (MEA) points to the ______

Left ventricle

Normal MEA in dogs is ____ to _____.

What about cats?

Dogs: +40 to +100

Cats: 0 to +160

What lead should you select to calculate MEA?

The isoelectric lead (positive and negative deflections are equal)

Once you have the isoelectric lead, what lead should you locate on the diagram?

The lead 90 degrees to the isoelectric

Once you have the perpendicular lead to the isoelectric, what side of that lead should you pick?

If complexes are upright, pick the positive side.

Else, pick negative

Example: The isoelectric lead is aVL, and the perpendicular lead complexes are upright. What is the MEA? Is it normal?

MEA = +60

Cat normal = 0 - 160

Dog normal = 40 - 100

What degrees would indicate a right axis shift in dogs? How about cats?

Dogs range from +100 to -90, while

Cats range from +160 to -90

What are some common causes of right axis shift?

Something is wrong with the right side of the heart, like hypertrophy

What is the range of a left axis shift?

Dogs range from +40 to -90, while

Cats range from 0 to -90

T/F: A left axis shift is common

False, because the left side is normally large

If you see a cat with marked left axis deviation, or any ECG changes, you should say "Obviously that is ________" and sound really smart

Left anterior fascicular blocks

Increased size of P wave indicates _____

Atrial enlargment

Increased height of the R wave indicates ______

Left ventricle enlargement

A deep S wave indicates ______

Right ventricle enlargement

What rate would be associated with an escape rhythm?

Slow rate

What rate would be associated with an irritable focus?

Fast rate

If the ECG is irregularly irregular (all over), then it is _____

Atrial fibrillation

What are the three ways the heart can respond to increased demand?

Increases in heart rate,

Cardiac dilation (increase stroke volume), and

Hypertrophy (greater contractility)

T/F: Cardiac dilation always increases stroke volume

False, only to a point

What are the two types of hypertrophy?

Physiological, which is normal and good (exercise, good, only increases 10 - 20%), and

Pathological, which decreases function (4 fold increase in weight, congenital)

Primary cardiac hypertrophy is due to _______

Mutations in the cells

Secondary cardiac hypertrophy is due to _____

Sustained increase in cardiac workload

Secondary cardiac hypertrophy includes volume overload and pressure overload. What do these terms mean?

Volume overload is too much blood in the ventricle, leading to a more difficult contraction.

Pressure overload is often due to stenosis in vasculature, meaning that it is harder to pump blood through the thinner vessels

Pressure overlaod is associated with ______ hypertorphy

Volume overload is associated with _____ hypertorphy

Concentric (just hypertrophy), and

Eccentric (dilation + hypertrophy)