Midterm B Flashcards
Pathophysiology of ischemic heart disease
Myocardial metabolic oxygen demand that exceeds myocardial oxygen supply
Top causes of ischemic heart disease
- Thrombosis
- Coronary arterial vasospasm
Top risk factors for coronary artery disease
- Male
- Increasing age
Most reversible risk factor for CAD
Smoking
What is angina pectoris
Chest pain and pressure due to ischemia of myocardium
What is chronic stable angina
Angina that occurs predictably with exertion
Criteria for unstable angina
1) Abrupt increase in severity or frequency
2) Angina at rest
3) New onset of angina
Angina pectoris is often absent unless the atherosclerotic lesion causes what percentage of coronary occlusion
50-75%
There is maximal compensatory dilation distal to an atherosclerotic lesion when it has reached __% occlusion
70
ECG diagnosis of angina
ST depression over 1mm with or without T wave inversion
Gold standard for angina diagnosis
Coronary angiography - determines anatomic extent of CAD and LV function
Nearly all MIs are caused by what?
Thrombotic occlusion of a coronary artery
3 criteria for diagnosing an MI
1) Clinical history of angina pectoris
2) Serial ECG changes indicative of MI - ST changes, T wave inversion, bundle branch block
3) Rise and fall of serum cardiac enzymes (troponin)
Treatment options for an MI (MONA)
- Morphine (to reduce pain/anxiety thus reducing myocardial oxygen demand)
- Oxygen
- Nitrates
- Aspirin (thin blood to get rid of clots)
Patient populations at greatest risk of cardiac complications under anesthesia
- Extensive CAD
- Recent history of MI
- Ventricular dysfunction
Valvular diseases that produce systolic murmurs
- Aortic or pulmonary stenosis
- Mitral or tricuspid regurgitation
Valvular diseases that produce diastolic murmurs
- Mitral or tricuspid stenosis
- Aortic or pulmonary regurgitation
Most common dysrhythmia with rheumatic mitral valve disease and left atrial enlargement
A-fib
Heart valve most often affected by rheumatic disease
Mitral valve
Effect of mitral stenosis on lungs
Could cause pulmonary edema due to high left atrial pressures that cause an increase in pulmonary venous pressure
A patient with mitral stenosis becomes symptomatic with a mitral valve area less than…
1cm^2
A transvalvular pressure gradient over __mmHg is indicative of severe mitral stenosis
10
Treatment of mitral stenosis
- Diuretics
- Rate control for a-fib with digoxin, b-blockers, ca2+ blockers
What should be avoided intra-op when managing a patient with mitral stenosis
- Tachycardia (b/c it further impairs LV filling)
- Increases in blood volume
- Decreases in SVR (b/c that could cause tachycardia which is not tolerated)
- Hypoxemia/hypercarbia (bc it could exacerbate pulmonary hypertension)
Principle pathologic change caused by mitral regurgitation
Left atrial volume overload
Severe mitral regurgitation is defined as having a regurgitant fraction over…
0.6
Fraction of stroke volume that enters left atrium in a patient with mitral regurgitation depends on what 3 factors
- Size of mitral valve orifice
- Heart rate
- Pressure gradient across mitral valve
What should be avoided during anesthetic management of a patient with mitral regurgitation
- Sudden decreases in HR
- Sudden increases in SVR
- Drug induced myocardial depression
How can the magnitude of regurgitant flow in a patient with MR be monitored intra-op?
With an echo/pulmonary catheter
What is mitral valve prolapse
Prolapse of one or both mitral leaflets into the left atrium during systole - can occur with or without mitral regurg
Mitral valve prolapse is associated with what heart sounds?
Mid-systolic click and late systolic murmur (click-murmur syndrome)
What is the most common form of valvular heart disease?
Mitral valve prolapse
Anesthetic management of a patient with mitral valve prolapse is similar to the management of what other valvular disease?
Mitral regurgitation
Aortic stenosis is considered critical when the transvalvular pressure rises above
50mmHg
Aortic stenosis is considered critical when the orifice area is below
0.8cm^2
Murmur associated with AS and location it is best heard
Systolic ejection murmur that radiates to the neck, best heard at 2nd right ICS
Anesthetic considerations for a patient with aortic stenosis
- Maintain normal sinus rhythm (loss of atrial contraction may cause decrease in stroke volume and blood pressure)
- Avoid tachy/bradycardia
- Avoid sudden changes in SVR
- Optimize intravascular fluid volume
Murmur associated with aortic regurgitation
Blowing murmur heard along right sternal border
During anesthetic management of a patient with AR, it is best to keep their HR under
80
What is the most common cause of tricuspid regurgitation?
Pulmonary hypertension which causes dilation of the right ventricle
Signs of tricuspid regurgitation
- Jugular vein distension
- Hepatomegaly
- Ascites
- Peripheral edema
Anesthetic considerations for a patient with tricuspid regurgitation
- Maintain fluid volume and CVPs high to facilitate adequate preload
- Avoid hypoxemia and hypercarbia because those increase PVR
- Use agents that produce PA vasodilation
What is the most common circulatory derangement in adults?
Systemic hypertension
Criteria for diagnosis of systemic HTN
Blood pressure over 140/90 on 2 occasions measured 1-2 weeks apart
Which type of HTN, essential or secondary, is most common?
Essential HTN - accounts for 95% of HTN cases
Most common cause of secondary HTN
Renovascular HTN from renal artery stenosis
How is a hypertensive crisis defined
Acute diastolic BP increases over 130mmHg
What is the desired decrease in BP during treatment of a hypertensive crisis?
Decrease MAP by 20% in first 2 hours, then additional decreases over next 1-2 days. DON’T decrease to normotensive levels right away.
Drug treatments for a hypertensive crisis
- Nitroprusside 0.5-10mcg/kg/min
- Hydralazine
- Nitroglycerin
Most common form of heart failure
Left sided heart failure
What is the most common cause of right sided heart failure?
Left sided heart failure
Systolic heart failure is defined as an ejection fraction below
45%
Class I heart failure
Ordinary physical activity does not cause symptoms
Class II heart failure
Symptoms occur with ordinary exertion
Class III heart failure
Symptoms occur with less than ordinary exertion
Class IV heart failure
Symptoms occur at rest
Hallmark symptoms of left sided CHF
- Pulmonary systems including dyspnea, tachypnea, orthopnea, PND, S3 heart sounds
- Rales
- Pulmonary edema
Hallmark symptoms of right sided CHF
Systemic venous congestion with JVD, organomegaly, RUQ tenderness, elevated liver enzymes, peripheral edema
Which lab and values are important in diagnosing CHF
Serum BNP (beta naturitic peptide) Under 100=negative 100-500=intermediate probability Over 500=indicative of CHF
Most useful test in the diagnosis of CHF
ECHO
What drugs are great to use intraop in a patient with CHF and why?
Opioids because they inhibit adrenergic activation
What is the most common cardiomyopathy
Dilated cardiomyopathy
Top cause of secondary cardiomyopathy
Amyloidosis
What is cor pulmonale
Chronic right ventricular enlargement
Top cause of cor pulmonale
Diseases that induce pulmonary HTN such as COPD
EKG manifestation of cor pulmonale
Peaked p waves in leads II, III, and AVF
What is pericardial effusion
Abnormal accumulation of fluid in the pericardial cavity
What is cardiac tamponade
Pericardial effusion with enough pressure to adversely affect heart function
What part of the heart is assessed with standard 6 limb leads
Frontal plane - heart activity moving up, down, right, and left
What part of the heart is seen with the 6 precordial leads (V1-V6)
Horizontal plane - view the heart’s activity moving anteriorly and posteriorly
Inferior heart leads
II, III, aVF
Left lateral heart leads
I, aVL, V5, V6
Interventricular septum leads
V1, V2
Anterior heart leads
V3, V4
Which leads should have a biphasic p wave
III, V1
Which leads should have a negative P wave
aVR
Normal PR interval
0.12-0.2 seconds
Which leads should show septal Q waves
I, aVL, V5, V6
QT interval duration is proportionate to what other value
Heart rate
R wave progression is seen in which leads
Precordial leads V1-V5
Most common uses for exercise stress test
Diagnosing CAD and identifying ischemia
Sestamibi imaging/technitium scanning is commonly used in tests involving the…
Myocardium or thyroid gland
Use of a transthoracic echocardiogram (TTE)
Assessing the overall health of the heart
Patients with ejection fractions less than __% tend to have severe disease and increased perioperative morbidity
50%
A transesophageal echo (TEE) can image certain parts of the heart better than a TTE and has a high sensitivity for locating what?
A blood clot inside the left atrium
What is a myocardial perfusion scan
A type of nuclear medicine test that injects a tracer (Thallium) into a vein and looks at Thallium uptake by the myocardium
What is the gold standard in evaluating coronary artery disease
Coronary angiography
What is a Holter monitor
Portable device for continuously monitoring various electrical activity of the CV system ofter 2 weeks at a time
Diseases commonly diagnosed by chest x-ray
- Pneumonia
- CHF
Pulmonary vessels are seen best on which chest x ray view?
Lateral
Grade of 4+ for arterial pulse
Bounding
Grade of 3+ for arterial pulse
Increased
Grade of 2+ for arterial pulse
Brisk, expected
Grade of 1+ for arterial pulse
Diminished, weaker than expected
Grade of 0 for arterial pulse
Absent, not palpable
What is claudication? What disease is it associated with?
Pain with walking that is relieved with rest. Associated with peripheral artery disease
What is pitting edema
Indentation persisting after the release of pressure on the skin
Purpose of The Allen’s Test
Assess adequacy of circulation to the hand prior to radial/ulnar artery cannulation
Clinical manifestations of Acute Arterial Occlusion “Cold Leg” (the 6 P’s)
- Pain
- Pallor
- Pulselessness
- Paresthesias
- Paralysis
- Poikilothermia (inability to regulate body temperature)
What is Raynaud’s phenomenon
Vasospastic disorder causing discoloration of the fingers and toes
Methods to diagnose a DVT
- D-dimer
- Doppler ultrasound
Top cause of aortic aneurysms
Hypertension
Where must BP be monitored in a patient having an aortic aneurysm surgery
On the right arm b/c the aortic cross clamp is just distal to left subclavian artery
When managing aortic aneurysm surgeries, maintain MAPs near ___ mmHg above the cross clamp and above __ mmHg distal to the cross clamp to maintain tissue perfusion
100 above cross clamp, 50 distal to cross clamp
What drug is administered before cross-clamping the aorta during aortic aneurysm surgery to improve renal cortical blood flow and GFR?
Mannitol
What is a myocardial infarction
When one of the coronary arteries becomes totally occluded and a region of the myocardium dies
Cardiac enzymes used to diagnose an MI
- Troponin
- CK-MB
- CK-nonspecific
ECG changes with an MI
1) T waves peaking
2) ST elevation
3) Appearance of Q waves
4) T waves eventually inverting
How do cardiac enzymes change with an MI?
- CK-MB rises within 6 hours after an MI then level out within 48 hours
- Troponin T and I remain elevated for 5 - 7 days, they are more specific but you can’t tell how recent an MI was just by using these
True or false - T wave inversion is diagnostic of an MI
False - it can also be seen with other conditions
What is a type of ST segment elevation seen in normal hearts?
J point elevation
What does the appearance of a pathologic Q wave indicate?
Irreversible myocardial death
True or False - pathologic Q waves are diagnostic of an MI
True
Why do Q waves form after an MI?
The part of the myocardium that dies becomes electrically silent and no longer conducts current, so all electrical forces move away from the area of infarction, causing a negative deflection
It is normal to see Q waves in which leads?
- Small Q waves in I, aVL, V5, V6.
- Sometimes II and III.
- Deep waves in aVR
What are the characteristics of pathologic Q waves?
- Greater than 0.04 seconds
- Depth is 1/3 the height of the R wave
What is the most common place in the heart to suffer an MI?
Left ventricle
Inferior infarcts are caused by occlusion of…
- Right coronary artery OR
- Descending branch of left coronary artery