Cardiovascular Disorders Flashcards
How do you measure cardiac output
Cardiac output = HR x stroke volume
Stroke volume is how much blood is moved with each beat
Central Venous Pressure - how do we measure it and what can it tell us?
Central Venous Pressure can be measured with a central line.
It goes into the Right Atrium
It also can tell us what the preload might be
In sepsis, the CVP gets low because of decreased preload
Normal is between 8-12mmHg
What is wedge pressure and how is measured?
Filling pressuring in the left atrium
It is measured with a pulmonary catheter
Helps determine functionality of the Mitral valve
What happens during diastole?
The filling of the ventricles with the opening of the tricuspid valve (RV) and the mitral valve (LV)
What happens during systole?
The contraction of the ventricles with the opening of the aortic valve (LV) and the pulmonic valve (RV)
Mean arterial pressure
Mean arterial pressure (MAP) is the average pressure exerted on the arteries and serves as a surrogate for measuring afterload, which is the pressure against which the LV must eject blood.
MAP = (2XDBP + SBP)/3
What does aortic stenosis sound like?
Systolic, “blowing”, rough harsh murmur at 2nd right ICS, usually radiating to the neck
Remember that it radiates to the neck**
What does mitral stenosis sound like?
Loud S1 murmur, low pitched, mid-diastolic; apical “crescendo” rumble
How does an ACE-I affect the Renin-Angiotensin-Aldosterone System (RAAS)
When BP falls, kidneys release Renin.
Renin cleaves Angiotensinogen into Angiotensin I which then works its way to the lung.
Angiotensin I is then cleaved into Angiotensin II by angiotensin converting enzyme (ACE).
Angiotensin II causes the blood pressure to rise.
When BP rises, the adrenals will retain salt. If BP gets too high, adrenals will release salt in order to release water in order to drop the BP
In an ACE-I, Angiotensin I is never converted into Angiotensin II so it cannot raise the BP.
AV Blocks
1st Degree: Prolonged PR interval always followed by QRS
2nd Degree Type 1 - Wenckebach: PR interval lengthens until a QRS is dropped
2nd Degree Type 2 - Mobitz: PR interval is usually normal however some P waves are not conducted and the beat is therefore dropped.
3rd Degree - Complete Heart Block: Para-systole, P waves and QRS are independent, wide QRS
Causes and treatment of hypertensive emergency
-Abrupt cessation of antihypertensives
-Cocaine or meth use (don’t use beta blockers with cocaine or meth - causes increase in BP)
-Pre-eclampsia or eclampsia
Treatment - Nicardipine infusion, Hydralazine or labetalol
-Or can restart home meds slowly
HTNsive Emergency defined as SBP>180 and DBP>120 with evidence of end organ damage.
-papilledema, proteinuria, hematuria, renal failure, AMS, EKG changes (ST depressions)
The 5 P’s of Peripheral Vascular Disease
Pallor
Poikilothermy (cold)
Parasthesias
Pulses (decreased)
Pain (claudicaton)
Management of an acute ischemic limb
Presentation: Cold, pulseless, cyanotic
Consult vascular surgery
Heparinize empirically
CT Angio to find where the occlusion is
Thrombectomy to remove if possible
Amputate if needed
Management of HLD
Statins - inhibit HMG CoA reductase - good at decreasing LDL
Fibrates - good for lowering triglycerides and increasing HDL
Niacin - lowers triglycerides, lowers LDL and increases HDL
What is a scoring measuring that can be used to determine risk for ACS?
HEART SCORE
History
EKG
Age
Risk Factors
Troponin
0-3 is low risk
4-6 is medium risk and should consider observation
7-10 is high risk and should observe and treat
Three types of Acute Coronary Syndrome
STEMI - ST elevations. Usually caused by a plaque rupture in one of the larger coronary arteries causing a clot
NSTEMI - EKG shows no ST elevations (could be ST depressions) but troponin is elevated. Could be caused by narrowing of a larger artery or occlusion of a smaller vessel
Unstable angina - Whereas most CAD causes symptoms during exertion, the symptoms will appear at rest.
When should not give Nitro during a STEMI
When ST changes are in the inferior leads (II, III and AVF) because it is R sided and thought to be more preload dependent. Nitro could drop preload.
Priorities for ACS
ASA 81mg chewed - makes platelets less sticky
Nitroglycerin 0.4mg SL every 5 minutes as needed for chest pain (except in inferior MI) - this will cause vasodilation and decrease BP to hopefully get blood passed the clot.
- Short half life. Can reverse with fluids
Oxygen if necessary
Morphine 2-4mg IV with caution
- Lowers anxiety and pain but can drop BP and preload
If STEMI - give heparin and revascularize with either PCI or thrombolytics
If NTEMI - give heparin, get ECHO and then consider coronary angiogram
What is the timeframe for PCI after onset of cardiac symptoms
within 3 hours
Otherwise you will need thrombolytics
When is CABG indicated?
If the CAD is noted to be affecting the:
left main coronary artery
Three major vessels (LAD, LCX, RCA)
Diffuse disease not amenable to PCI
Cardiogenic Shock: Causes, symptoms and treatment
Acute pump failure, usually by massive MI because a large enough portion of the heart does not move d/t ischemia
Signs and symptoms include: hypotension, pulmonary edema, tachyarrhythmia, oliguria, acidosis, and cyanosis
Largely fatal
Treatment includes:
Revascularization
Antiarrythmic agents
Vasopressors
VAD
Balloon Pump
Basics of how a Balloon Pump works
Utilized in cardiogenic shock and is a place holder for a CABG
Inserted through the femoral vein into the aorta
It will time itself with an EKG and inflate during diastole in order to push blood into coronary arteries and hopefully past occlusion
It deflates just prior to systole, helping to empty and suck out the LV
Creates a larger MAP
Differences in systolic and diastolic Heart Failure
Systolic Dysfunction: Failure of the heart’s pumping function - HFrEF
–Ejection fraction drops
–Increase in fluid to the lungs (crackles) because of LV backwards pressure
–results in fluid in the tissue because of RV backwards pressure into the vasculature causing dependent edema.
Diastolic Dysfunction: Failure of the heart’s filling function - HFpEF
–EF is largely normal (50-65%)
–Inadequate stroke volume because of hypertrophy of the ventricular wall
Risk factors for Heart Failure
AsCVD
Viral infections of the heart muscle (myocarditis)
Severe ETOH use - ETOH cardiomyopathy
Arrhythmias