CVS Flashcards
How do the LV and RV contract differently?
The LV contracts concentrically while the RV twists and contracts.
Afterload is also known as….
Wall tension across the ventricles at the end of systole.
P1: SVR (120)
P2: Pleural pressure (0-5)
T = [(P1-P2) x radius] divided by wall thickness. The smaller the delta P, the less the afterload. Lessen afterload by decreasing P1 (vasodilation) or increasing P2 (PEEP).
Preload is also known as…
Wall tension across the ventricle at the end of diastole. It generally represents the volume that stretches the ventricles before contraction.
What is a normal ejection fraction and what is a normal stroke volume?
EF = ESV/EDV (EF = 75/120, EF = 63%), normal EF = >60%
SV = EDV - ESV
Usually about 70mL in a 70kg male.
How does PPV affect the two ventricles?
To an extent, PPV props the LV up and decreases the pressure difference between the LV and intrathoracic space. This helps more than the detriment it causes to aortic compression so net benefit for the LV.
However, it also compresses the pulmonary vasculature and forces the RV to work harder, possibly decreasing LV preload. RV preload is already reduced due to great vessel compression.
*Generally speaking, PPV reduces CO, except in the case of high SVR.
Delta down must have a _____% change in order for a patient to be considered fluid responsive. They must be in sinus rhythm, paralyzed and be on a controlled tidal volume @10ml/kg for it to be considered accurate.
10
Murmur intensity is graded on a scale from 1-6. What grade is associated with a corresponding thrill?
4
1: only a cardiologist can hear
(6: you can hear that thing without a stethoscope!)
When describing a heart murmur, what characteristics are worth mentioning?
Shape (crescendo) Timing Location (A, P, T, M) Radiation (carotids, subclavians) Intensity (1-6)
Useful labs when assessing a CVS patient:
Troponins (HS, I, T) BNP Lactate SvO2 Extended lytes BUN:Cr CBC
There are five types of MI. What are they?
- Atherosclerosis
- Oxygen imbalance
- Sudden death
- PCI mediated
- CABG mediated
Standard therapy for NSTEMI pathway:
+ASA (162-325)
+P2Y12 inhibitors (Plavix 300/150, Ticagralor 180/90)
+Statins (Atorvastatin 80mg)
-Beta blockers (Metoprolol 5/25), or ACE-I if BP/HR high
-Nitrates (10mcg/min TNG infusion, TNG patch, TNG spray)
-Anticoagulation (Enoxaparin, heparin)
-O2/MSO4
-Optimize Mg++, K+
-Integrillin if there is a high clot burden
-Pantaloc 80mg bolus, then 8mg/hr infusion
Killip Score (assesses HF in setting of MI)
I - No HF
II - Pulmonary edema <50%, S3, SBP > 90
III - Pulmonary edema >50%, S3, SBP > 90
IV - Cardiogenic shock, SBP < 90
Target electrolyte levels for MI:
Ca++ > 1.0
K+ 4.0-5.0
Mg++ >0.8
When converting AFib, which PO cardioverting agent tends to lower BP less? Beta blockers or CCBs?
Beta Blockers.
STEMI Imposters
BER Pericarditis LBBB LVH Paced Increased ICP Aortic dissection (more likely affects RCA)
Timelines for PCI vs TNK and what study is it based on?
For PCI, door to balloon must occur < 90 minutes, or consider it if access to TNK is delayed > 2 hours.
PRAGUE/DANAMI-2
Absolute contraindications for TNK/tPA:
- Hx of ICH
- Hx of ischemic CVA < 3mo
- Known cerebral vascular lesion
- Metastatic intracranial malignancy
- Possible aortic dissection
- Active bleeding or bleeding diathesis
- Significant head/face trauma < 3mo
When is thrombolysis considered effective?
When ST segments decrease by at least 50% and ischemic symptoms are completely resolved within 90 min.
*Runs of idioventricular rhythm are highly indicative of reperfusion and successful thrombolysis. Do not treat them. They are usually self limiting.
Why do successful TNK patients still need to go for angio?
If there was 90% occluded vessel that received the thrombus, the 90% occlusion is still there after the TNK dissolves the thrombus.
Complications of untreated STEMI…
Q waves (necrosed tissue) LV wall rupture LVA Papillary muscle rupture Dysrhythmias Cardiogenic shock
Front line vasoactive therapies for cardiogenic shock:
Always start them on levophed first, then start the dobutamine. Consider milrinone only in tachycardia and extreme cases since it stays in the system for so long and is hard to correct.
There are two types of HF. Diastolic (preserved EF) and systolic (reduced EF). What must your EF be less than to be considered as systolic failure?
<40%
What does the NYHA score measure? What study suggests that an NYHA score of 4 should get ACE-Is?
Heart failure
Class 1: No symptoms
Class 2: Slight SOB/angina on physical activity
Class 3: Marked limitation on walking 20-100m. Comfortable at rest.
Class 4: Severe limitations. Symptomatic even at rest.
CONSENSUS-1
Chronic Tx for HF:
*ACE-I/ARB
*Beta blockers
*Spironolactone
TNG patch
Diuretics
CRT/ICD
Acute Tx for HF:
Lasix (IV dose should = home PO dose) Nitro (start at 10mcg/min and move up quickly) Oxygen Position BIPAP/CPAP Dobutamine
Cardinal signs of a right sided MI:
- Hypotension
- Clear lungs (except with posterior-medial papillary muscle rupture)
- JVD
- Increased CVP
- Bradycardia
- V4R findings, or STE III > II
- *Avoid TNG, MSO4
What does the TIMI score measure?
Ha! It actually measures two things!
1 - Risk score for STEMI (0 to 14). A score of 8 or higher comes with a 8.8% chance of death.
2 - Flow during percutaneous coronary angioplasty (0 to 3). 3 is normal perfusion/flow.
What are the goals of therapy when starting a nitroglycerin infusion for ACS?
Target total pain relief, but limit yourself using the patient’s blood pressure.
What does the Forrester score assess?
Cardiogenic shock. A true Forrester needs a PAC. I. Warm and dry II. Warm and wet III. Cold and dry IV. Cold and wet
Causes of right sided heart failure:
RVMI
Pulmonary HTN
PE
What wall of the RV is affected in RCA occlusion?
The lateral wall. The septum is supplied by the LAD and remains functioning normally. A fluid bolus for RVMI can help improve CO since the septum becomes a more effective pumping mechanism when distended.
Well, shiiiiiiit. How you going tell the difference between a PE and an RVMI?
(Both will likely have hypotension, JVD, clear lungs/SOB, high CVP)
- 15-lead (ITWs/S1Q3T3 vs STE)
- Hx (Virchow’s vs Frammingham’s).
- Perform an echocardiogram (subxiphoid view)
- Tachycardia (PE) vs bradycardia (RVMI)
What is Virchow’s triangle?
Stasis: Bed rest, long flight, varicose veins, F# limb
Hypercoaguability: CA, pregnancy, smoking
Endothelial Injury
Describe an alternate mechanism of hypoxemia in PE:
It’s not dead space ventilation. Vessels surrounding PE release cytokines that cause inflammation, increased A-C thickness and, therefore, shunt.
Right heart strain pattern on ECG and labs
Sinus tachycardia with right axis deviation
ITWs in septal leads
Elevated BNP and troponins
CT and echo
D-dimer (a negative result can rule out a PE)
Main difference when treating PE vs RVMI:
Provide fluid bolus in RVMI will improve preload. It assists with septal pumping. Do not bolus if RV failure present. Assess CVP.
A fluid bolus will decrease coronary perfusion pressures (Ohm’s Law) in PE and decrease DO2.
PEs will get heparin and possibly tPA. RVMIs will get TNK/PCI and ACS pathway.
PE treatment:
- tPA
- Anticoagulation
- Oxygenation
- Permissive hypotension