cardiology Flashcards
What is seen in peripheral cyanosis vs. central cyanosis?
peripheral: normal oxygen saturation but less circulation to periphery due to cold, polycythemia
blue extremities but trunk, mucous membranes are pink
central: due to arterial desaturation, blue lips, mucus membranes, and trunk
What is differential cyanosis and what does it mean?
cyanosis of lower extremities / toes but no the fingers or upper extremities
aortic arch obstruction
persistent pulmonary hypertension
What is reverse differential cyanosis?
cyanosis of pre-ductal structures : fingers but not post ductal structures (toes)
transposition of the great vessels with right to left shunting of saturated blood
What does significant delay or absence of the femoral pulse compared to the radial pulse indicate
coarctation of the aorta
What does rapid rising or bounding pulses indicate
PDA
aortic valve insufficiency
When do you hear ejection clicks and what can it indicate
beginning of S1
thickened semilunar valve (bicuspid aortic valve, aortic stenosis pulmonic stenosis)
truncus arteriosus
enlarged aorta (tetralogy of fallot)
What is the difference between aortic stenosis and pulmonic stenosis on exam
pulmonic stenosis ejection click varies with inspiration
aortic stenosis ejection click does not
What does wide persistent fixed splitting of S2 indicate
ASD, pulmonic stenosis, RBBB
delayed right ventricular emptying
What are the characteristics of an innocent murmur
short and soft grade III/IV
louder supine
soft or disappear with valsalva
Describe a still’s murmur
systolic ejection murmur with a musical quality or vibratory character
hear best in the precordial area but not in the back
What is physiologic peripheral pulmonic stenosis
right and left pulmonary arteries are smaller than main pulmonary artery
harsh ejection murmur heard in the axilla and both right and left hemi-thoraces
improves by 12 months of age
Describe a venous hum
blood draining down the collapsed jugular veins
absent when supine
Valsalva, turning of the head, or compression of the jugular vein makes the murmur go away
How does the axis deviation change from birth to childhood
right ventricular dominance at birth results in right axis deviation (70-180) and large R wave in V1 at birth
in an older child > 100 is RAD, < -30 is LAD
What is a quick way to determine the axis?
if I and AVF are both + = normal
if I + and AVF - = look for LAD
if both are - = extreme axis deviation
if I - and AVF + = look for RAD
what is the rate of each mm on EKG tracing
0.04 ms
What is Dubin’s way to calculate the rate
number of large boxes between R-R
300, 150, 100, 75, 60, 50
What is a normal PR interval
3-5 small boxes or 120 to 200 ms
What is a normal QRS duration
< 120 ms or 3 small boxes
What is a normal QTc
< 450 usually 340 to 440
How do you calculate the QTc
QT / (RR) ^ 1/2
What is the problem with a prolonged QT
tendency to develop sudden death, syncope due to polymorphic VT or torsades
What are two syndromes to consider in a child who has a long QT and sensoriuneural deafness
Jervell
Lange-Nielsen syndrome
What are some causes of QT prolongation
TCA overdose hypocalcemia hypokalemia hypomagnesemia CNS insult starvation with electrolyte abnormalities Type 1a and type3 antiarrhythmics azithromycin
What does a normal p wave look like
3 small square in duration
2 mm in height
normal are up in I, II, AVF and down in AVR
What is seen on EKG in brugada syndrome
RV conduction delay and ST elevation in V1-V3
sodium chanelopathy
What is a sign of R atrial enlargement
normal width, increased amplitude
What is a sign of L atrial enlargement
wide p wave taking up most of the PR interval
m shaped p wave
What direction should the t wave be in V1
after birth for the first week, t wave is positive in V1,
after that it should be inverted
if it is not indicates RVH
What can cause peaked T waves
hyperkalemia
intracerebral hemorrhage
What causes ST segment elevation
MI, prinzmetal angina
pericarditis-most common, will be diffuse st elevation
What causes ST segment depression
subendocardial ischemia LHV with strain digitalis hypokalemia RVH
How is LVH diagnosed on an EKG
left axis deviation
voltage criteria: r wave less than the 5th percentile, S wave > 95% in V3R and V1 or R waves more than 95th % in V5 and V6
What are ways to diagnose RVH on EKG
upright or flat T wave in V1, in child < 1 week to 8 years of age
R > 25 mm in right chest leads
What is 1 degree AV block
PR interval > 200 ms (5 small boxes) or more than normal for age
What is 2 degree AV block Mobitz type 1
wenchebach progressive prolongation of the PR interval until the QRS drops
What is 2 degree AV block Mobitz type 2
normal PR interval with periodic drop of QRS
often requires a pacemaker
What is 3rd degree AV block
complete AV dissociation
often needs pacemaker
if rate is 40-60 with a normal QRS width likely a junctional escape rhythm
if rate is 20-40 and QRS is wide, likely a ventricular escape rhythm
What are some mechanisms that cause SVT
atrioventricular re-entry (accessory bypass tract): leading cause in children of SVT AV nodal re-entry automatic rhythms (accelerated atopic rhythms)
What are the indications for pacemaker in children with sick sinus syndrome
patient is symptomatic
patient has tachyarrhythmia that requires therapy and therapy might precipitate significant bradycardia
How might sick sinus syndrome present
abnormal sinus bradycardia, sinus pauses, sinus arrest, tachy-brady syndrome
esp in child who has had atrial surgery (ASD repair, fontan, transposition correction)
How should atrial flutter be managed
most effective treatment is synchronized cardioversion
vagal maneuvers slow rate for diagnosis
rule out PE, and thyroid disease if no prior cardiac history
can control rate with diltiazem, digoxin or a beta blocker
ablation is a definitive treatment
How should atrial fibrillation be managed
irregular ventricular rate 130-200
if new consider hyperthyroidism, hypomagnesemia, alcoholism/cocaine abuse and excessive caffeine and nicotine
anticoagulated 3 weeks prior to and 6 months after cardioversion
can again use beta blockers, diltiazem and digoxin for rate control
How is paroxysmal SVT treated
vagal maneuvers (ice), adenosine
no verapamil in those < 1 year
if unstable -> cardioversion
What is WPW
shortened PR interval and a delta wave prior to QRS since there a bypass bundle (kent bundle) that depolarizes faster than the AV node
How do you treat WPW and a narrow complex tachycardia? What do you not do?
Same as SVT. Vagal maneuvers, adenosine
Never: treat WPW in atrial fib or flutter with digoxin, verapamil or beta blockers
Instead: IV procainamide
shock if unstable
ablation is the definitive treatment of choice
What is the treatment for PVCs
if there are symptomatic: nothing
if paired and no underlying heart disease: no not treat
What do you do with ventricular tachycardia
if unstable: cardioversion
if stable: amiodarone
there is a benign form with child with a slow ventricular rhythm at the same rate or slightly faster than a sinus rhythm this does not need treatment and child is asymptomatic: if usually resolves with time
Causes of ventricular tachycardia
electrolyte disturbances myocardial disease (myocarditis or hypertrophic cardiomyopathy) ion channel disorders (Long QT) postoperative states ingestion hypoxia idiopathic
When to avoid verapamil
in children < 1 year atrial fibrillation in WPW atrial flutter wide complex tachycardias with beta blockers
What can be a side effect of adenosine
bronchoconstriction
treat with bronchodilator
What are the side effects to class 1a antiarrhythmics Quinidine and procainamide
both prolong the QT -> torsades
Quinidine: diarrhea, ITP, cinchonism: hearing loss, tinnitus and psychosis
Procainamide: blood dyscrasias (neutropenia, thrombocytopenia) drug induced lupus, caution in heart failure
What are the side effects to class 1b antiarrhythmics lidocaine
seizures
What are the side effects to class II antiarrhythmics beta blockers
bradycardia and potential aggravation of asthma
What are the side effects to class 3 antiarrhythmics bretylium and amiodarone
bretylium: transient hypertension that postural hypotension
amiodarone: corneal deposits, pulmonary fibrosis, gray skin, hyper/hypothyroidism, hepatic toxicity and sun sensitivity
When does left to right shunting start to become most apparent in a child
weeks 4-8 when pulmonary vascular resistance falls
What happens if left to right shunts are not corrected
persistent elevated pulmonary pressures results in fixed pulmonary vascular resistance (pulmonary hypertension) and subsequent right to left shunting -> lethal)
What are the main left to right shunting lesions
PDA ASD VSD AV canal defect L transposition of the great arteries sinus of Valsalva fistula
How does a PDA present
continuous murmur
rumbling, machine like
wide pulse pressure, bounding pulse
PDA is often closed surgically even in those who are asymptomatic
What type of VSDs are most common in which age group
in those less than 1 year: usually muscular septum and most close spontaneously
in those > 1 year: membranous septum and do not close spontaneously
How is a VSD diagnosed
harsh murmur at the lower left sternal border
if large, CXR with cardiac enlargement and pulmonary vascular markings
