Cardiology Flashcards
3 things that describe typical chest pain:
- ) Substernal location
- ) Worse with exertion
- ) Better with rest or nitroglycerin
What causes stable angina?
A fixed atherosclerotic lesion that narrows the coronary arteries and an imbalance between oxygen demand and available blood supply.
Does ischemic pain change with body position or breathing?
NO
How would you describe the clinical features of stable angina?
- Substernal chest pain that is gradual in onset and lasts less than 10-15 minutes. Usually described as heaviness, pressure, squeezing, tightness.
- Brought on by exertion
- relieved with rest or nitro
How do you workup CAD?
- ) Resting EKG
2. ) Stress Test: either EKG or Echo
What does an EKG in stable angina look like?
Usually it is normal
What do you see as ischemia on an EKG stress test?
ST segment depression
If a patient has a positive stress test, what is the next best step?
They should undergo cardiac catheterization.
What medications can you use to induce a pharmacologic stress test in patients who are unable to exercise?
-IV adenosine, dobutamine or dipyramidole
What is the definitive test for CAD?
Coronary angiography
What is the medical therapy offered to treat CAD?
- Beta blockers
- Aspirin
- Nitrates
- CCBs
Which specific form of medical therapy has been shown to decrease morbidity by reducing the risk of an MI in patients with CAD?
ASPIRIN
MOA of beta-blockers
Blocks sympathetic stimulation of the heart thereby reducing HR, BP, and contractility thus cardiac workload.
MOA of nitrates
Generalized vasodilation. Reduces preload myocardial oxygen demand.
Side effects of nitrates:
- Headache
- Orthostatic hypotension
- Tolerance
- Syncope
MOA of CCBs
Cause coronary vasodilation and afterload reduction, in addition to reducing contractility
Does revascularization reduce the incidence of MI?
NO
What are the main indications for CABG
- Three vessel disease with >70% stenosis in each vessel
- Left main coronary disease with >50% stenosis
- LV dysfunction
Describe the pathophysiology of Unstable Angina Pectoris
Oxygen demand is unchanged but supply is decreased secondary to reduced resting coronary flow.
How do you distinguish between unstable angina and NSTEMi?
biomarkers. NSTEMi will have elevations of troponins or CK-MB but unstable angina will not
Medical Management of Unstable Angina/NSTEMI
- ASA
- Clopidogren
- Beta-blockers
- LMWH (Enoxaparin based on Essence Trial)
- Nitrates
- O2
- GPIIb/IIIa inhibitors
- morphine
- Electrolyte replacement
Pathophysiology of Variant (Prinzmetal) Angina
-Transient coronary vasospasm that is usually accompanied by a fixed atherosclerotic lesion but can also occur in normal coronary arteries.
What is the hallmark finding of Prinzmetal Angina on an EKG?
-Transient ST segment elevation (transmural ischemia)
Tx of Prinzmetal Angina?
-CCBs and Nitrates (vasodilators)
Definitive testing for diagnosis of Prinzmetal Angina?
-Coronary angiography: displays coronary vasospasm when the patient is given IV ergonovine or Ach to provoke vasoconstriction
Explain the pathophysiology of an MI
Acute atheromatous plaque rupture into a vessel lumen with thrombus formation on top of the lesion which subsequently causes occlusion of the vessel compromising cardiac blood supply leading to necrosis of the myocardium.
Which populations are more likely to have painless MIs or MIs that do not present with classical symptoms?
- Women
- diabetics
- elderly
- post-op patients
What is sudden cardiac death usually the result of?
VFib
What clinical features are seen in a right ventricular infarct, what should you NOT do.
- Inferior EKG changes
- Hypotension
- JVD
- clear lungs
- Hepatomegaly
- DO NOT GIVE NITRATES OR DIURETICS this will cause CV collapse as they are now preload dependent.
What are the various EKG markers of infarction?
- Peaked T waves: occur early and may be missed
- ST elevation: indicates transmural injury
- Q Waves: evidence of necrosis (old MI)
- T-wave inversion
- ST segment depression: subendocardial injury
What is the difference between STEMI and NSTEMI in terms of infarction territory?
STEMI = transmural NSTEMI = subendocardial (inner 1/3 of wall)
When does Troponin I and T:
- Begin to increase
- Peak
- Return to normal
- Begins to increase within 3-5 hours
- Peaks at 24-48 hours
- Returns to normal in 5-14 days
When does CK-MB:
- Begin to increase
- Peak
- Return to normal
- Begins to increase in 4-8 hours
- Peaks in 24 hours
- Returns to normal in 48-72 hours which makes it useful for detecting recurrent infarction
What is the medical therapy for management of an MI?
- Aspirin
- Beta-blockers
- ACE inhibitors
- Statins
- O2
- Morphine
- Nitrates
- Heparin
What medications have been shown to reduce mortality and should be part of long term maintenance therapy for MI?
- Aspirin
- Beta blockers
- ACE inhibitors
- Statins (reduce the risk of further coronary events but not mortality)
What is the door to balloon time for MI?
90 minutes
After receiving a stent what medications should a patient definitely go home on?
- ASA + Clopidogrel for 30 days in pts w/ bare metal stent
- ASA + Clopidogrel for 12 months in pts w/ drug eluting stent
What is the most common cause of in-hospital mortality post-MI?
Pump Failure/CHF: may lead to cardiogenic shock.
What is the most common cause of death in the first few days following an MI?
Ventricular arrhythmia (VFib or VTach)
Mechanical complications of MI
- Free wall rupture
- Rupture of IV septum
- Papillary muscle rupture
- Ventricular pseudoaneurysm
- Ventricular aneurysm
When does ventricular free wall rupture present, how does it present and what do you do?
- Usually within the first 2 weeks after MI.
- leads to hemopericardium and cardiac tamponade
- Immediate pericardiocentesis, hemodynamic stabilization
How does papillary muscle rupture present, and what do you do about it?
- Presents as acute Mitral Regurgitation
- Emergent surgery w/ afterload reduction with sodium nitroprusside or intra aortic balloon pump
How do you treat acute pericarditis following an MI
-ASA. NSAIDs and corticosteroids are contraindicated as they may hinder myocardial scar formation.
What is Dressler Syndrome?
“Postmyocardial infarction syndrome”
-Immunologically based syndrome consisting of fever, malaise, pericarditis, leukocytosis, and pleuritis occurring weeks to months after an MI
How do you treat Dressler Syndrome?
- ASA
- Ibuprofen is a second option
Signs of Digoxin Toxicity
GI: N/V anorexia
CV: ectopic beats, AV block, AFib
CNS: visual disturbance, disorientation, yellow vision
Medications that have been shown to lower mortality in systolic heart failure
- ACE inhibitors and ARBs
- Beta-blockers
- Aldosterone antagonists (spironolactone)
- Hydralazine + nitrate
Causes of systolic heart failure
Ischemic heart disease HTN Valvular heart disease Myocarditis Alcohol abuse Radiation, hemochromatosis Thyroid Disease
Causes of high output heart failure
- Chronic anemia
- Pregnancy
- Hyperthyroidism
- AV Fistulas
- Wet Beriberi
- Paget disease of bone
- MR
- Aortic Insufficiency
Causes of diastolic heart failure
- HTN leading to myocardial hypertrophy
- Valvular disease like AS, MS, and AR
- Restrictive cardiomyopathy (amyloidosis, sarcoidosis, hemochromatosis
Symptoms of left sided heart failure
- Dyspnea
- Orthopnea
- Paroxysmal nocturnal dyspnea
- Nocturnal cough
- Confusion and memory impairment 2/2 decreased brain perfusion
- Diaphoresis and cool extremities at rest
Signs of left sided heart failure (cont)
- Displaced PMI
- S3 ventricular gallop
- S4 gallop
- Crackles/rales at lung base
- Dullness to percussion and decreased tactile fremitus of lower lung fields caused by pleural effusion
- Increased intensity of pulmonic component of S2 indicating pulmonary HTN
Symptoms of right sided heart failure
- Peripheral pitting edema
- NOcturia
- JVD
- Hepatomegaly
- Ascites
- Right ventricular heave
NYHA Class I
Symptoms only occur with vigorous activity
NYHA Class II
Symptoms occur with prolonged or moderate exertion
NYHA Class III
Symptoms occur with usual activities of daily living
NYHA Class IV
Symptoms occur at rest.
What tests do you order for a new patient with CHF?
- CXR (r/o COPD, check for cardiomegaly or pulmonary edema)
- EKG
- Echo (r/o pericardial effusion, estimate EF)
- CBC
- Cardiac Enzymes (r/o MI)
What level of BNP correlates with the presence of decompensated CHF
> 150
What levels of NT-pro BNP virtually exclude the diagnosis of HF?
<300
Which beta blockers have benefit in HF?
Carvedilol, metoprolol, and bisoprolol
What are 3 medications that are contraindicated in patients with CHF?
- Metformin (lactic acidosis)
- Thiazolidinediones (fluid retention)
- NSAIDs (may increase risk of CHF exacerbation)
What medications have proven mortality benefit in diastolic dysfunction?
NONE
What are premature atrial complexes
Early beat arising in the atria, firing on its own
What are some causes of premature atrial complexes?
Adrenergic excess, drugs, alcohol, tobacco, electrolyte imbalance, ischemia, and infection
What do premature atrial complexes look like on an EKG?
-Early P waves that differ in morphology from normal sinus P waves because they originate in the atria and not the sinus node. QRS complexes are normal because conduction below the atria is normal.
Tx for symptomatic premature atrial contractions?
Beta blockers
What is a premature ventricular complex?
An early beat that fires on its own from a focus in the ventricle which then spreads to the other ventricle.
Causes of premature ventricular complexes
Hypoxia, electrolyte abnormalities, stimulants, caffeine, medications, structural heart disease
What do premature ventricular complexes look like on an EKG?
- Wide QRS: since conduction is not through the normal conduction pathway but rather through the ventricular muscle, it is slower than normal and causes a widened QRS.
- Wide, bizarre QRS complexes followed by a compensatory pause are seen; a P wave is not usually seen because it is buried within the wide QRS complex.
Define sick sinus syndrome and the associated symptoms.
Sinus node dysfunction characterized by a persistent spontaneous sinus bradycardia. Sx include dizziness, confusion, syncope, fatigue, and CHF. May require a pacemaker.
What is a first degree AV block?
PR interval is persistently prolonged to >0.20 seconds but a QRS wave follows each P wave
Does first degree AV block require treatment?
Usually not.
What is a mobitz type I (Wenckebach) block?
It is characterized by progressive prolongation of the PR interval until a . P wave fails to conduct.
Does Mobitz type I usually require treatment?
Usually not
What is Mobitz type II block?
It is characterized by the sudden failure of a P wave to conduct without a preceding PR interval prolongation. With the failure of the P wave to conduct there is subsequently no QRS that follows.
Where is the site of the block in Type I AV block and Mobitz Type I block?
Usually within the AV node.
Where is the site of the block in a Mobitz type II block?
Usually within the His-Purkinje system.
Does Mobitz type II require treatment?
Yes, implantation with a pacemaker is usually necessary.
What is a third degree AV block?
It is the absence of conduction of atrial impulses to the ventricles. There is no relationship between the P waves and the QRS complexes. Characterized by AV dissociation.
Does third degree heart block require treatment?
Yes, pacemaker implantation is necessary.
What maintains the ventricular rate in a third degree AV block?
There is usually a ventricular pacemaker/escape rhythm that maintains a ventricular rate of 25-40 bpm.
What is the most common type of cardiomyopathy?
Dilated cardiomyopathy
List some causes of dilated cardiomyopathy
- Idiopathic
- CAD
- Toxic: alcohol, doxorubicin, adriamycin
- Metabolic: thiamine or selenium deficiency, hypophosphatemia, uremia
- Infectious: Viral, Chagas, Lyme, HIV
- Thyroid dz
- Peripartum cardiomyopathy
- Collagen Vascular Disease: SLE, Scleroderma
- Prolonged uncontrolled tachycardia
- Catecholamine induced: pheochromocytoma, cocaine
- Familial/genetic
Signs and sx of dilated cardiomyopathy:
- Symptoms of left and right sided CHF
- S3 and S4
- Murmurs of mitral or tricuspid insufficiency
- Cardiomegaly
- Existing arrhythmia
- Sudden death
What is AFib
Multiple foci in the atria fire continuously in a chaotic pattern causing a totally irregular rapid ventricular rate. Instead of intermittently contracting, the atria quiver continuously. Atrial rate is usually over 400 bpm, but most impulses are blocked at the AV node so ventricular rate ranged between 75 and 175.
Clinical features of AFib
- Fatigue and exertional dyspnea
- Palpitations, dizziness, angina, or syncope
- Irregularly irregular pulse
- Blood stasis secondary to ineffective contraction, leads to formation of intramural thrombi which can embolize to the brain.
What are the 3 main goals in the treatment of AFib/AFlutter?
- ) Control ventricular rate
- ) Restore normal sinus rhythm
- ) Assess the need for anticoagulation
Tx of acute AFib in a hemodynamically unstable patient?
Immediate electrical cardioversion
Tx of acute AFib in a hemodynamically stable patient
- ) Rate control: BBs or CCBs
* *If CHF or LV dysfunction consider digoxin or amiodarone for rate control - ) Cardioversion to sinus rhythm after rate control is achieved
What medications can you use for pharmacologic cardioversion in AFib?
- Parenteral ibutilide
- Procainamide
- Flecainide
- Sotalol
- Amiodarone
Anticoagulation Guidelines for AFib (long!)
- ) If AFib is present for >48 hours or unknown period of time, the risk of embolization during cardioversion is 3-5%. Anticoagulate patients for 3 weeks before and 4 weeks after cardioversion. INR of 2-3 is the goal range.
- ) To avoid waiting 3 weeks for anticoagulation before cardioversion, obtain a TEE to image the left atrium. If there is no thrombus, start IV heparin and perform cardioversion within 24 hours. Patients still require 4 weeks of anticoagulation after cardioversion.
How do you treat CHRONIC AFib?
Rate control with a BB or CCB
Which patients with AFib do not require anticoagulation?
If a patient has “lone AFib” that is AFib with the absence of underlying heart disease or other CV risk factors and is under the age of 60, they do not require anticoagulation.
What happens if you give a shock during T wave
You cause VFib!
Difference between cardioversion and defibrillation
- Cardioversion is when you give a shock in synchrony with the QRS. The purpose is to terminate certain dysrhythmias like PSVT or VT
- Defibrillation is delivery of a shock that is not in synchrony with the QRS. The purpose is to convert a dysrhythmia to normal sinus rhythm.
Indications for cardioversion
- AFib
- AFlutter
- VT w/o a pulse
- SVT
Indications for defibrillation
- VFib
- VT w/o a pulse
Pathophysiology of AFlutter
One irritable automaticity focus in the atria fires at about 250-350 bpm giving rise to regular atrial contractions. The atrial rate is around 300 bpm. The long refractory period in the AV node allows only one out of every two or three flutter waves to conduct to the ventricles.
Causes of AFlutter
- Heart failure (most common)
- CAD
- Rheumatic heart disease
- COPD
- ASD
In what type of patients do you normally see multifocal atrial tachycardia?
-Patients with severe pulmonary disease (COPD)
What are the EKG findings in MAT?
Variable P wave morphology and variable PR and RR intervals. At least THREE different P wave morphologies are required to make an accurate diagnosis.
Treatment of MAT
- Treat the underlying pulmonary disease
- If no LV dysfunction: CCBs, BBs, digoxin, amiodarone, IV flecainide, IV propafenone
- If LV dysfunction: digoxin, diltiazem, or amiodarone
- Electrocardioversion should not be used.
Pathophysiology of Paroxysmal SVT AVNRT
There are two pathways, one is fast and the other is slow within the AV node so the reentrant circuit is within the AV node.
What is the most common cause of SVT?
AVNRT
What do you see on an EKG in AVNRT?
Narrow QRS waves with no discernible P waves. The P waves are buried within the QRS complexes. This is because the circuit is short and conduciton is rapid, so impulses exit to activate the atria and ventricles simultaneously.
What are the two types of SVT?
AVNRT and Orthodromic AVRT
What is Orthodromic AV Reentrant Tachycardia?
An accessory pathway between the atria and ventricles that conducts retrogradely. It is called a concealed bypass tract. With orthodromic AVRT the accessory pathway is at some distance from the AV node, therefore the reentrant circuit is longer and there is a difference in the timing of the activation of the atria and ventricles.
What do you see on an EKG with orthodromic AV reentrant tachycardia?
Narrow QRS complexes with P waves which may or may not be discernible depending on the rate. This is because the accessory pathway is at some distance from the AV node, therefore the reentrant circuit is longer, and there is a difference in the timing of the activation of the atria and ventricles.
Causes of SVT
- Ischemic heart disease
- Digoxin toxicity: paroxysmal atrial tach w/ 2:1 block is the most common arrhythmia associated with dig toxicity
- AV node reentry
- AFlutter with RVR
- AV reciprocating tachycardia
- Excessive caffeine or alcohol consumption
Treatment for SVT
Maneuvers that stimulate the vagus will delay AV conduction and thus block the reentry mechanisms. You can try valsalva maneuver, carotid sinus massage, breath holding or head immersion in cold water.
Pharmacologic tx for SVT
- IV adenosine
- IV verapamil
- IV esmolol
- Digoxin
MOA of adenosine
It works by decreasing SA and AV nodal action.
Prevention of SVT
- Verapamil or beta blockers
- Radiofrequency ablation of either the AV node or the accessory pathway
Side effects of adenosine
Headache Flushing SOB Chest pressure Nausea FEELS LIKE DEATH
What is WPW syndrome?
When there is an accessory conduction pathway from the atria to the ventricles through the bundle of Kent which causes premature ventricular excitation because it lacks the delay seen in the AV node.