Med-Surg Final

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CARDIOVASCULAR

Dsyrhythmias
* Etiology
* Disturbances in automaticity – initiation of impulse is altered * Disturbances in conduction – alteration in the speed the impulse travels * Reentry of impulses – cardiac tissue is depolarized multiple times by the same impulse * Speed, distance and location can be changed or affected (blockages cause change in heart rhythm) * Risk factors

* Cardiovascular disease, MI
* MI – death of tissue – no electricity can conduct through it, so it has to alter the pathway of the impulse after an MI * Hypoxemia
* Electrolyte imbalance
* Spiked T waves from potassium imbalance
* Drug use or toxicity
* Beta blockers can slow heart too much
* Hypovolemia
* Shock

Labs and Diagnostic Tests
* Labs
* Electrolytes
* K (important) and Na
* Hemoglobin and hematocrit
* BUN and creatinine
* Kidneys – your kidneys help your pH balance (increase puts more stress on heart because there is more Cr in the blood) * Type and cross match
* Cardiac markers
* Urinalysis
* PT, PTT, INR platelet counts
* Because of blood thinners (PT and Coumadin & PTT and heparin) * Diagnostic tests
* Chest x-ray – enlargement of the heart and congestion of the lungs * Arterial blood gas (ABG)
* pH
* show you what your O2 level is
* how well your heart and lungs are working together to supply body with oxygen * EKG – electrical impulse of the heart
* Echocardiogram – details of how the chambers are working * Stress test – can the O2 demand by met by the body * Nuclear
* Treadmill

Normal Intervals
* PR interval – 0.12 to 0.20 seconds
* QRS interval – 0.06 to 0.12 seconds
* QT interval – 0.34 to 0.43 seconds

Normal Sinus Rhythms
* Uniform P wave for every QRS with normal PR interval
* Heart rate: 60-100 bpm
* Rhythm: regular
* P wave: before each QRS, identical
* PR interval: .12 to .20
* QRS: < .12
* ST depression: seen with angina and ischemic changes (pre-heart attack) * “digging grave” – can get better
* Can be seen with hypokalemia
* ST elevation: seen with MI and necrotic changes
* “tombstone with name written on it”
* Can be seen with hyperkalemia (in need of extreme dialysis)

Ischemia, Injury & Infarct
* Ischemia
* T wave inversion
* ST depression > 1 mm
* Negative enzymes
* Injury
* ST elevation > 1 mm
* Positive enzymes
* Infarction
* Q waves (1-20% of Q waves are false)
* Positive enzymes

Sinus Bradycardia
* Heart rate: < 60 bpm
* Rhythm: regular
* P wave: before each QRS, identical
* PR interval: .12 to .20
* QRS: < .12
* Normal in athletes and during sleep
* Due to sinus node disease
* Increased parasympathetic tone
* Drug effect (digoxin, verapamil)
* The slower the rate, the lower the cardiac output

Sinus Tachycardia
* Heart rate: > 100 bpm
* Rhythm: regular
* P wave: before each QRS, identical
* PR interval: .12 to .20
* QRS: < .12
* Usually due to increased sympathetic discharge to maintain or to increase cardiac output * Drug effect
* Danger in CAD
* Increases myocardial oxygen demand and may decrease diastolic filling * Increased heart rate with fever, stress
* Think about the physiological situation that is affecting the patient (fluid intake, dehydration, fever, what might be going on that we expect to cause tachycardia)

Sinus Arrhythmia
* Heart rate: usually 60-100 bpm
* Rhythm: irregular
* P wave: before each QRS, identical
* PR interval: .12 to .20
* QRS: < .12

Assessments and Interventions for Sinus Bradycardia
* Physiology and Etiology
* SA node fires...
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