Cardiac Flashcards
Bainbridge reflex
Also called atrial reflex-
Reflex tachycardia in response to increased CVP+ stretch of Right atrial receptors and helps equalize pressures in both sides
How to calculate cardiac output (CO)
HR×SV
Heart rate × stroke volume
How to calculate Cardiac index?
Cardiac output ÷ BSA = CI in L/min/m2
Calculate mean arterial pressure
SBP+ 2(DBP)/3
Add Systolic BP to 2 times the diastolic BP and divide by 3
Diastolic BP is 2/3 of cardiac cycle. Immediately at birth it’s 1/2 of the cardiac cycle
What is the PAOP and normal values?
when the balloon of a pulmonary artery catheter is inflated, the turbulence behind the balloon is blocked and you get the Pulmonary artery occlusive pressure (used to be pulmonary artery wedge pressure) and sometimes is called pulmonary capillary wedge pressure
PAOP represents pressures in the left side of the heart and pulmonary filling pressures, pulmonary vascular bed
normal value should be 5-12 mmHg
What is endocardial cushion defect?
also called
-atrioventricular canal (AV canal or AVC)
-atrioventricular septal defect (AVSD)
1.) ASD
2. VSD
3.) improperly formed mitral and/or tricuspid valves.
specifically the left sided (mitral valve) has three cusps rather than the two cusps that normally form the valve (one of the normal cusps is divided into two : this is called a cleft or a cut in the mitral valve causing regurgitation.
1/3 of all children born with av canal defect also have down syndrome
SVR
the mean pressure difference in the systemic vascular bed divided by blood flow. It indicates the resistance the left ventricle must pump against
What do large A waves indicate on the PAOP tracing?
large A waves may be seen with increased pressure during atrial contraction. This could be caused by mitral stenosis, an ischemic left ventricle or a failure of a left ventricle.
Hill’s sign
a popliteal blood pressure that is at least 20 mmHg higher than the brachial blood pressure can be a sign of aortic insufficiency
what is pulsus alternans
the pulses alternate between strong and weak
- -most commonly seen in left ventricular failure when the weakened myocardium cant maintain an even pressure w/ each contraction
- -also seen in CHF
medication for sustained SVT or supraventricular tachycardia
0.1 mg/kg adenosine (rapid IV)
if not effective increase to 0.2mg/kg
MOA: slows conduction time through the AV node, interrupting the re-entry pathways through the AV node, restoring NSR.
–used to suppress or eliminate SVT, also used in diagnostic studies to establish the cause of SVT
adverse effects of Adenosine
transient arrhythmias, flushing, dyspnea and (rarely)apnea
in 30% of patients SVT recurs
which part of the electrocardiogram represents ventricular depolarization?
the QRS complex represents ventricular depolarization
on the ECG the T wave represents…..
ventricular repolarization
Bigeminy
a PVC occurring every other beat
pairs of PVC’s are referred to as_____
couplets
normal value for CVP
2-6 mmHg
normal value for PCWP
5-12 mmhg
normal value for PAP
mean pulmonary artery pressure is 14 (plus or minus 3) up to 20
what is torsades de pointes associated with?
it is a polymorphic ventricular tachycardia associated with long QT syndrome
meds to give: lidocaine and magnesium sulfate
what meds would you avoid giving d/t their association w/ prolonged QT
amiodarone and procainamide
Nadolol (brand Corgard)
- class
- MOA
- indications
- contraindications
- adverse effects
class: antianginal agent, antiarrhythmic agent, class II antihypertensive, antimigraine, beta-adrenergic blocker (non-selective)
MOA: competitively blocks response to beta-1 and beta2-adrenergic stimulation
-nonselective beta-adrenergic blockers (propranolol, nadolol) reduce portal pressure by producing splanchnic vasoconstriction (beta2 effect) thus reducing portal blood flow.
uses: prevention fatal arrhythmias in prolonged QT syndrome as they shorten QT interval, HTN, stable angina, afib (rate control), SVT in pediatric (limited data)
contraindications: bronchial asthma, sinus bradycardia, heart block >1st degree, cardiogenic shock, uncompensated HF
SE: drowsiness, insomnia, atrioventricular block, bradycardia, cardiac failure, cold extremities, edema, hypotention
what electrolyte abnormality to watch out for when giving angiotensin II receptor inhibitor (drug ends with “sartan” such as losartan) ?
hyperkalemia (kidneys will secrete water and sodium, and retain potassium)
milrinone
causes increases in intracellular calcium and positive inotropic effect
vasodilation
decrease of afterload
Cor pulmonale
failure of R side of heard d/t high pressures in the pulmonary artery and R ventricle
most common cogenital heart defect in children
VSD
manifestations seen in PDA
- machine like murmur
- ductal shuntin causes low diastolics and waterhammer pulse (strong then collapses)
- PDA can cause congestive HF
common manifestations of aortic stenosis
- chest pain
- syncope
- activity intolerance
4 defects of TOF
- VSD
- pulmonary stenosis
- hypertrophy of R ventricle
- dextroposition of the aorta
blood flow in tricuspid atresia
blood flows from R atrium through the ASD to the left side of the heart then to R ventricle through the vsd then goes out to the lungs
describe the fontan
fontant diverts blood away from the R ventricle. a baffle is placed inside the R atrium to divert systemic venous return toward the pulmonary artery
signs of device migration (eg after coil embolization)
hemodynamic instability (hypotension), ectopic beats
treatments for pulmonary hypertension
Inhaled nitric oxide
Calcium channel blockers
Intravenous of inhaled epoprostenol (Flolan)
Intravenous or subcutaneous treprostinil (Remodulin)
Oral medications including Bosentan (Tracleer), Abrisentan (Letairis), Sildenafil (Revatio) and Tadalafil (Adcirca)
signs of cardiac tamponade
tachycardia
increased CVP (>6)
hypotension
decreased chest tube drainage
most common trigger of myocarditis in children
coxsackie virus (hand-foot-and mouth disease)
