Case Files: MI Flashcards
Diagnoses that may mimic acute MI but will not benefit by anticoagulation or Thrombolysis
Acute pericarditis, aortic dissection
Examples of thrombolytics?
Tissue plasminogen activator, streptokinase, reteplase
MI chest pain can radiate to?
Arm, Lower jaw, neck
NSTEMI vs STEMI?
Incomplete vessel occlusion (only subendocardium affected) vs transmural
MI symptoms in a diabetic older than 70?
Painless discomfort associated with dyspnea, pulmonary edema, ventricular arrhythmias
S4 gallop associated with an MI suggests?
Myocardial noncompliance because of ischemia
S3 gallop in the presence of MI represents?
Severe systolic dysfunction or
Mitral regurgitation caused by ischemic papillary muscle dysfunction
ECG changes in an acute MI?
Tall, positive, hyperacute T waves
ST segment elevation
T-wave inversion (hours to days)
Diminished R wave amplitude (Q waves)
Q waves represent?
Myocardial necrosis and replacement by scar tissue
Persistent ST segment elevation represents?
Left ventricular aneurysm
Leads that correspond to the anterior surface of the heart? Supplied by which artery?
V2-V4. LAD
Leads to correspond to the inferior surface of the heart? Supplied by which artery?
II, III, aVF. RCA
Leads that correspond to the lateral surface of the heart? Supplied by what artery?
I, aVL, V5, V6. LCX.
Cardiac enzymes and when they rise
Troponin I (6 hours to 7-10 days) Troponin T (6 hours to 10-14 days) CK-MB (4-8 hours to 2-3 days)
Rule out MI if?
Two sets of normal troponin levels 4 to 6 hours apart
The diagnosis of acute MI if two of the following:
- Chest pain persisting for more than 30 minutes
- atypical ECG findings
- elevated cardiac enzyme levels
Aortic dissection presents with what findings? (Not MI symptoms)
- Unequal pulses and blood pressures in the arms
- New murmur of aortic insufficiency
- Widened mediastinum
Acute pericarditis often presents with?
- Chest pain
- pericardial friction rub
- Diffuse ST segment elevation
Patient with acute MI. What antiplatelet agents are given?
Aspirin, heparin
Patient with acute MI. What drugs are given to limit infarct size (and how)?
- Beta blockers are used to decrease myocardial oxygen demand and 2. nitrates are given to increase coronary bloodflow
Morphine may be given to patients with acute MI to?
- Reduce pain
2. reduce tachycardia
Maximal benefit of thrombolytics if given within? Major risk? Risk outweighs the benefit when?
1-3 hours. Bleeding. After 12 hours.
Thrombolytic therapy is indicated if all of the following criteria are met:
- Clinical complaints are consistent with ischemic type chest pain
- ST segment elevation more than 1 mm in at least two anatomically contiguous leads
- No contraindications
- Patient is younger than 75 years
Contraindications for thrombolytics?
Recent major surgery, aortic dissection, Pregnancy, Uncontrolled hypertension
Percutaneous coronary intervention?
Angioplasty and stenting
Percutaneous coronary intervention vs Thrombolysis
Provides greater survival benefit and lower risk of serious bleeding
Percutaneous coronary intervention can be used in these patients who would gain no survival benefit from thrombolytic therapy
Hypotensive, cardiogenic shock
Mortality in acute MI is usually a result of?
- Myocardial pump failure and resulting cardiogenic shock
2. ventricular arrhythmias
These complications of acute MI usually occur within the first 24 hours? Treat with?
Ventricular tachycardia and ventricular fibrillation. Treat with direct-current cardioversion followed by intravenous antiarrhythmics such as amiodarone
Ventricular tachycardia ventricular fibrillation are life-threatening because?
Prevent ventricular contraction leading to pulseless and cardiovascular collapse
Benign ventricular arrhythmia is not suppressed by antiarrhythmics after an acute MI. Description of rhythm?
Accelerated idioventricular rhythm. Wide complex escape rhythm between 60 and 110 BPM that accompanies reperfusion
Sinus bradycardia is frequently seen after what type of MI? Treatment?
Inferior MI because the right coronary artery supplies of the sinoatrial node. No treatment unless it causes hypotension in which case, treat with atropine
Examples of AV conduction disturbances? Treatment?
First-degree AV block, Mobitz I second degree AV block
Tx: atropine
AV conduction disturbances caused below the AV node? Treatment?
Mobitz II second degree AV block, third degree AV block, left bundle branch block, right bundle branch block. Treat with pacemaker.
Most severe form of left ventricular pump failure?
Cardiogenic shock
Patients with pulmonary hypertension are evaluated by?
Pulmonary artery (Swan-Ganz) catheterization.
Diagnosis of cardiogenic shock if?
- Systolic arterial pressure less than 80.
- Markedly reduced cardiac index less than 1.8
- Elevated left ventricular filling pressure greater than 18
Findings in patient with cardiogenic shock?
hypertension, cold extremities, pulmonary edema, elevated jugular venous pressure
Findings in patient after right coronary artery occlusion and inferior infarction?
Right ventricular infarction
- Hypertension,
- elevated JVP
- clear lung fields,bno pulmonary edema
- ST segment elevation in a right-sided EKG
Treatment of right ventricular infarction?
Volume replacement with saline or colloid solution
Do not give these types of drugs to patients with right-sided ventricular infarction?
Patients need to increase preload. Do not give diuretics or nitrates
Papillary muscle dysfunction is a complication of what type of infarction? Can lead to?
Left ventricular infarction. Can lead to mitral regurgitation
Development of acute heart failure and shock in association with a new holosystolic murmur suggests?
Ventral septal rupture
Most catastrophic mechanical complication of infarction? Leads to?
Ventricular wall rupture. Leads to cardiac tapenade
If ST segment elevation persists weeks after MRI, think?
Ventricular aneurysm
Treatment of Dressler syndrome?
Anti-inflammatory drugs, including NSAIDs and prednisone
Post MI risk stratification protocol?
- Submaximal exercise stress testing to detect residual ischemia
- Evaluation of left ventricular systolic function with echocardiography
Post MI patients with severe left ventricular dysfunction are at an increased risk for? May benefit from?
Sudden cardiac death from ventricular arrhythmias. May benefit from implantable cardioverter-defibrillator
Most important risk factor for secondary MI?
Smoking cessation reduces risk by more than 50%
Drug most important for post MI patients with impaired systolic function, diabetes or hypertension?
ACE inhibitors
Unstable angina - mech?
Alternating patterns of Thrombus formation and dissolution
MI, Unstable angina, Chronic stable angina. Treat with?
All three - ASA and anti platelets
Heparin - UA and MI
tPA - MI
Chance of hemorrhage stroke in pt with unstable angina?
1%
CABG?
Coronary bypass
If inferior wall ischemia, effect on HR?
Ischemia to AV node or vegas nerve stimulation
60 y/o pt with inferior wall ST depression. HR:58, BP: 122/77 Tx?
ASA
O2
Nitroglycerin
B-blocker (don’t give if HR<50)
(Anti-platelet, but small absolute benefit)
Heparin (but commits you to go to cath lab)
Pt becomes hypotension with cardiac ischemia treatment - next steps?
Can’t give b-blocker
Give heparin
If give heparin, need to go to cath lab
EKG shows with acute ST segment elevation MI. Next step in therapy?
Aspirin and beta blocker. Assess whether he is a candidate for rapid reperfusion (thrombolytics)
