Cardiovascular Flashcards
What are two ways of measuring mean arterial pressure?
MAP = CO x TPR MAP = 2/3(diastolic pressure) + 1/3(systolic pressure)
What leads to an increased pulse pressure (systolic pressure - diastolic pressure)?
Hyperthyroidism Aortic regurgitation Arteriosclerosis Obstructive sleep apnea Exercise
What causes decreased pulse pressure?
Aortic stenosis
Cardiogenic shock
Cardiac tamponade
Advanced heart failure
What is the Fick principle
CO = (rate of O2 consumption)/(Arterial O2 content - Venous O2 content)
What is the normal ejection fraction? How is EF calculated?
Normal EF is > 55%
EF = SV/EDV or (EDV-ESV)/EDV
What types of vessels account for most of the total peripheral resistance?
Arterioles (they regulate capillary flow)
What causes normal splitting on inspiration?
Inspiration decreases pulmonary impedance and increases the capacity of pulmonary circulation while simultaneously decreasing intrathoracic pressure and thus increasing venous return to the RV causing an increased RV stroke volume
This all leads to delayed closure of the pulmonic valve (which normally closes after the aortic valve anyway) leading to a widened split of closure
What can cause wide splitting?
Seen in conditions that delay RV emptying
Pulmonic stenosis
Right bundle branch block
What can caused fixed splitting?
ASD: leads to left to right shunt which increases RA and RV volumes leading to increased flow through pulmonic valves
What can cause paradoxical splitting?
Seen in conditions that delay LV emptying (aortic stenosis, left bundle branch block)
Normal order of valve closure is reversed so that P2 sound occurs before delayed A2 sound - on inspiration P2 closes later and moves closer to A2 thereby “paradoxically” eliminating the split
What is indicated by a systolic murmur at the left sternal border?
Hypertrophic cardiomyopathy
Where would a ventricular septal defect be heard in the heart?
Tricuspid area (pansystolic murmur)
Where would an atrial septal defect be heard on auscultation?
Tricuspid area (diastolic murmur)
What are the effects on circulation of the following…
Hand grip:
Valsalva (phase II):
Rapid squatting:
Hand grip: Increases systemic vascular resistance
Valsalva (phase II): Decreases venous return
Rapid squatting: Increases venous return, increases preload, increases afterload with prolonged squatting
In mitral valve prolapse, what occurs when afterload is increased? What happens when venous return is decreased?
Increased afterload: Increased murmur intensity and later onset of click
Decreased venous return: Decreased murmur intensity and earlier onset of click
Arrange the following in order of speed of conduction:
Atria, AV node, Purkinje, Ventricles
Purkinje > Atria > Ventricles > AV node
What medications can prolong QT? (Some Risky Meds Can Prolong QT)
Sotalol Risperidone (antipsychotic) Macrolides Chloroquine Protease inhibitors (-navir) Quinidine (Class Ia and III) Thiazides
What is Romano-Ward syndrome?
An autosomal dominant congenital long QT syndrome
What is Jervell and Lange-Nielsen syndrome?
An autosomal recessive congenital long QT syndrome with sensorineural deafness
What is bypassed in Wolff-Parkinson-White syndrome? What can results?
The rate-slowing AV node
May result in reentry circuit leading to supraventricular tachycardia