Blocked airflow in coronary arteries

Causes - artherosclerosis (MI & unstable angina), coronary spasm (variant angina, CSA)

RF - High LDL, low HDL, DM, smoking, obesity, HTN, hypothyroidism, low fiber, oral contraceptives

Chest discomfort from myocardial ischemia (limited in duration and doesn't cause permanent damage) O2 demand > workload;

Causes:

• Artherosclerosis or CA spasms

Precipitated by:

Exertion, HTN, aortic stenosis, severe anemia, hypoxia

Abdominal distress - bloating sensation; brief and fleeting - usually not angina

Triggers - overexertion, heavy meal, cold weather, emotional

• Predictable, pt knows triggers
• Elevated BP
• Usually assoc with a fixed artherosclerotic plaque
• Usually relieved by nitroglycerin and rest

Refers to unstable angina or an acute MI

• The plaque in the coronary artery ruptures, resulting in platelet aggregation, thrombus formation and vasoconstriction (blocked blood flow to heart)

• Occurs at rest or with exertion (a lot less than stable angina) and causes severe activity limitation
• Pain greater than 20 min
• May precede MI
• Poss causes - cocaine use, spasmodics

• Caused by coronary artery spasm
• Typically occurs at rest, regularly
• Confirmed by acetylcholine (causes it to occur)
• Relief - sublingual nitro, Ca channel blockers

• Sudden reduction of coronary blood flow that results in TISSUE LOSS
• Zone of reversible ischemia - may be saved by time and speed
• Most occur in LV
• Great and longer than CK elevation = the worse the MI

1. Anterior - larger, WORST prognosis bc it is from an obstructed LAD artery which supplies LV
2. Inferoposterior
3. Transmural - involves whole thickness of myocardium; abn Q wave; Very serious!
4. Nontransmural - ST (end of QRS to T) changes or T wave abnormalities

Electrical Dysfunctions

(A way to classify)

• NSTEMI (Non-ST segment elevation) - w/o ST waves or Q waves; may see ST wave depression or T wave inversion
• STEMI - Not quickly reversed even with nitro administration

Unstable angina, dyspnea, fatigue

Beginning:

• Substernal aching, pressure, radiating to back and jaw
• Occuring w/o cause, usually in the morning
• Lasting 30 min or more
• N/V
• Diaphoresis
• Dyspnea
• Feeling of fear or anxiety
• Dysrhythmias
• Palpitations
• Epigastric distress
• Dizziness
• Disorientation/acute confusion
• Feeling "short of breath"

• Pulmonary edema - crackles
• Dysrhythmias
• S4 sounds

• RV fill pressure elevation
• JVD
• Clear lung fields

ACS (diagnosis)

Enzymes - Trop I (0.03), Trop T (0.2), myoglobin (12-90)

Echocardiography - heart wall thickness, motion and ischemia

Stress test - pt who don't show ECG abnormalities (positive is good)

• Morphine - 2-4 mg IV q 15 min; can cause hypotension and bradycardia (vasodilator)
• Nitroglycerin - reduce preload of LV and afterload = reduce cardiac workload; sublingual q 5 min 3 times, then IV drip

• Aspirin - 325 mg, chew for quicker absorption
• Plavix
• Ticlid
• GP IIb/IIIa: Reopro and Integrillin - very potent, given IV

• Heparin- PTT @ 6 hrs then q 6 hrs after; hold if used a streptokinase
• LMWH (Lovenox)

• B-Blockers - esp for high risk pt; watch vitals; reduce HR, contractility which reduce cardiac workload and O2 demand
• ACE inhibitors ("prils") - Reduce mortality risk

• Only used with STEMI
• Give early!! Greatest benefit w/in 3 hrs
• Contraindicated - stroke
• Bleeding
• Hemorrhagic or ischemic w/in 1 year
• BP > 180/110,
• Major trauma or surgery w/in 1 mo.
• Peptic ulcer
• Pregnancy
• Current anticoagulant use

Ex - "-plase" and streptokinase (allergic reaction poss esp when it's been used before)

Risks -intracranial hemorrhage

• "-statins" and nicotinic acid
• Prescribed post MI
• Bile acid sequestrants - lower LDL
• Statin intolerance - Zetia

• Heart Failure
• Myocardial rupture
• Ventricular aneurysm
• Cardiogenic Shock

• Dyspnea
• Rales (crackles at base)
• Hypoxemia

• Diuretics (Lasix) to pull off fluid; severe = vasodilators like nitro
• Intra-arterial balloon pump - in sync with contractions, temporary hemodynamic support
• LV assistive devices - mechanical pump; occasionally results in recovery; used as bridge to heart transplant

• Intraventricular septum ruptures
• Rare
• Will hear loud systolic murmur

• Occurs at site of large infarction
• Unlikely to rupture, but will cause ventricular arrhythmias and low CO

• Loss of contractile force and decreased ventricular filling
• Hypotension < 90
• Tachycardia
• End organ hypoperfusion
• UO < 30 mL/hr
• Pulmonary congestion
•  Mental confusion
• Diaphoresis
• Cold extremities
• Treatment - Dopamine (temporary), angioplasty (remove clot), CABG

• Relieve discomfort
• Reverse ischemia - "zone"
• Limit infarction size
• Reduce cardiac workload
• Treat complications
• MEDICAL EMERGENCY

• IV
• O2
• Get on leads for ECG
• NO prolonged bedrest - ortho hypotension, decreases work capacity of heart, DVT
• Quiet, calm
• Reorient pt - clock, calendar
• Bedrest first 24 hr
• If no complications, can sit up, do passive exercise
• Depression
• Stool Softeners
• Smoking cessation
• Diet - soft @ beginning, sodium reduction
• Assess pain - subsides w/in 12-24 hrs post MI; Prolonged pain = ischemia, pericarditis, PE, pneumothorax, gastritis, ulcer
• Cath if urinary retention

Percutaneous transluminal coronary angioplasty

Stent use

Balloon guided with US to artherosclerotic region - inflated to dilate artery

Complications - restenosis, MI, death, stroke

Nursing Interventions - aspirin, plavix, statin, avoid strenuous activities for 6 weeks, chk for bleeding, chk for reocclusion, chest discomfort, assess ECG, neurostatus, dye reaction, hypotension

Midline sternotomy, graft from internal mammary artery or saphenous vein

Cardiopulmonary bypass (with heart stopped)

Complications - MI, occlude another artery with emboli, stroke, bleeding, infection, A.fib, 25-30% develop cognitive dysfxn within months or years

• Bypass machine use
• Chest tubes present
• Ventilator
• ET tube - won't be able to talk
• WIll hear alarms
• Lg incision

• Fluid, electrolyte monitoring
• Altered LOC- not r/t bypass or anesthesia; look for abn pupil responses, seizures; Mon 30-60 min then q 2-3 hrs
• Hypotension - fm hypovolemia; may need vasopressor (norepi) & dopamine
• Pain-distinguish fm sternotomy or angina; angina pain will radiate, sternotomy pain worse with cough
• Hypothermia - can cause HTN, warm slowly at 1.8 degrees/hr; Shivering is BAD
• Hypertension - fm bypass machine, SNS, hypothermia
• Bleeding
• Tubes - patent, report drainage > 150 mL/hr
• Cardiac tamponade

• Fluids from CABG compress myocardium
• S/S: cessation of drainage, JVD, lungs clear, pulses parodoxis (BP increases more than 10 mmHg on expiration), CV collapse
• Echocardiogram or CXR
• Tx: Vol expansion, emergency sternotomy

Assess:

• Pulses
• Skin temp
• O2 sats
• dysrhythmias
• UO