Cardiology2

Question 1

whats the most common cause of ventricular hypertrophy

Answer 1

untreated hypertension

Question 2

what are some causes of ventricular hypertrophy

Answer 2

HTN, stenotic valvular disease, COPD

Question 3

Explain La Place’s Law as related to the heart & ventricular hypertrophy

Answer 3

The bigger chamber (ventricle), less pressure… as ventricle chamber deteriorates & dilates-symptoms of cardiac failure result

Question 4

Angina and MI are more common in LVH, secondary to:

Answer 4

increase in myocardial O2 consumption due to increased muscle mass and subendocardial ischemia (thickened muscle mass-nutrient vessels)

Question 5

what are some strategies/treatments of LVH, angina, MI

Answer 5

decreases pressure work by: beta blockers & calcium channel blockers that decrease contractility of heart decrease heart rate… treat volume overload with diuretics, bed rest, light meals, exercise, anti-anxiety drugs decreases sympathetic tone

Question 6

Explain compliance in relation to the Pressure-Volume Loops of ventricle

Answer 6

Compliance while mitral valve opens and ventricle fills
Noncompliant when aorta v. opens and ventricle ejects blood, and during isovolumetric relaxation after aortic v. closes and pressure returns to normal for ventricle

Question 7

ejection fraction

Answer 7

% left in ventricle after single beat (normal ejected is 55%) so you’d have 45% left if 100cc’s

Question 8

what’s the major difference between sympathetic stimulation in positive inotrope and parasympathetic stimulation of negative inotrope?

Answer 8

Sym. acts on both atrial and ventricle contraction vs.

para. acts on atrial only

Question 9

what are some conditons that cause negative inotrope

Answer 9

acidosis, myocardial ischemia, cadiomyopathies

Question 10

what drugs would create positive inotrope

Answer 10

dopamine, epi

Question 11

G proteins, adenyl cyclase, cAMP are all involved with increasing or decreasing:

Answer 11

contractility of heart=inotrope

Question 12

what would cause a positive staircase effect or post extra systolic potentiation… that is increase the contractility & HR

Answer 12

greater amount of free Ca++ in ICF

Question 13

Explain the “plateau” of Phase 2 during cardiac action potential

Answer 13

Inward flow of Ca++ mediated by channels induces Ca++ released from intracellular stores

Question 14

can you list the Phases of cardiac action potential

Answer 14

0-rapid depolarization 1-initial repolarization 2. plateau 3. repolarization 4. resting membrane potential

Question 15

what occurs for an action potential to be hyperpolarized? (more concerning skeletal)

Answer 15

resting membrane becomes more negative such as K+ moves inside cell. (hypokalemia)

Question 16

At this certain point of the cardiac action potential, a depolarization could lead to d.fib…..

Answer 16

supra normal period (between repolarization and resting membrane)

Question 17

Sequence of of action potential in heart

Answer 17

SA node, rapidly thru atrial intermodal traacts, AV node, Bundle of His, R/L bundle branches, Purkinje system, spreads thru out ventricles

Question 18

explain “automaticity” in reference to the cardiac tissue

Answer 18

Its resting membrane potential is unstable and will depolarize spontaneously

Question 19

List the latent pacemakers and their intrinsic firing rate/min

Answer 19

SA node-70-80
AV node 40-60
Bundle of His 40
Purkinje Fibers 10-15

Question 20

what would cause the need for a latent pacemaker to take over

Answer 20

Vagal tone & “heart block”

Question 21

Why would a pt with heart transplant not be able use atropine to increase heart rate

Answer 21

Their para/sym nerves don’t go directly to the heart

Question 22

List the waves on a EKG and what they represent

Answer 22

p wave-atrial contraction, QRS-ventricular depolarization and T-vent. repolarization