Intracardiac Flashcards
(58 cards)
The determinants of Myocardial Oxygen Demand (MVO2) are:
Wall Tension
Contractility
What are the determinants of coronary blood flow?
- Perfusion pressure and vascular tone of the coronary arteries (duh)
- The time available for perfusion (since perfusion only happens during diastole, perfusion time with decrease with an increase in HR)
- Severity of intraluminal obstructions (blockages)
- Presence or absence of collateral circulation
The area of the heart most vulnerable to ischemia is:
the subendocardium of the LV
It has the highest intracavitary pressure and the greatest metabolic requirements
LV coronary perfusion pressure is determined by:
The aortic diastolic pressure and the LV diastolic pressure (LVDP)
What is the MOST important cause of intraoperative and perioperative ischemia?
Tachycardia
What is the coronary vascular reserve?
The difference between the auto regulated flow through the coronary arteries and the amount of flow it CAN acheive under maximal vasodilation
Supply Ischemia results from:
transient coronary occlusion (like from a clot or vasospasm)
Demand Ischemia results from:
the inability to increase coronary blood flow and oxygen delivery in response to an increased MVO2
Coronary goals for patients with CAD are:
Slow (heartrate)
Small (ventricle size)
Well Perfused
To maintain MVO2 you’re aiming for ______ heart rate and _____ Blood Pressure
Slow heartrate
High blood pressure (vs hypotension)
What do the a and v waves of a PAOP waveform indicate?
A is for atrial systole
V is for ventricular systole
If you see an elevated a wave on a wedge, what does that tell you?
Primary Diastolic Dysfunction
There is decreased LV compliance. The LA is having to work very hard to pump into the LV
If you see an elevated V wave on a wedge waveform, what does that tell you?
There is pressure building up in the LA during LV contraction
This means there is mitral regurgitation or papillary muscle disfunction due to ischemia
Why would you run nitroglycerin and a pressor together?
If you want to increase the BP to improve perfusion pressure, but want to mitigate the increase in preload a pressor will cause
Which CCB has the largest negative inotropic effect?
Which one has the least?
Verapamil has the most
Nicardipine has the least
What is the normal area of the AV?
2 - 4 cm2
What is the normal diameter of the LVOT?
2 - 2.4 cm
What are the classic symptoms of AS?
Angina
Syncope
Dyspnea
AS usually becomes symptomatic when the orifice is reduced to:
0.8 - 1 cm2
How is atrial kick impacted by aortic stenosis?
Normally atrial kick only accounts for about 10% of ventricular filling, but as the LV gets stiffer and less compliant, filling becomes more dependent on atrial contraction
In AS, the atrial kick may account for up to 30-40% of LVEDP
What are the three big goals for hemodynamic management of a patient with AS?
Avoid Hypotension (their coronary perfusion pressure is already marginal)
Maintain sinus rhythm (they need atrial kick and an adequate stroke volume)
Avoid heart rate extremes (bradycardia will decrease CO and tachycardia will cause ischemia)
What are the three big goals for hemodynamic management of patients with HOCM?
- Avoiding extreme HR
- Maintain or increase preload (to prevent LVOT obstruction)
- No increase in contractility
- Maintain sinus rhythm (rely on atrial kick)
NOTE: very similar to AS, because similar problems with both
What causes acute aortic insufficiency?
bacterial endocarditis
aortic dissection
trauma
What the difference between eccentric and concentric hypertrophy?
Eccentric means the intraventricular size is increasing
Concentric means the ventricle thickness is increasing
They often occur together. Any amount of eccentric hypertrophy will usually cause some amount of concentric hypertrophy