↑↓Dysrhythmias pt.1, pt.2, drugs

Dysrhythmias

Problem with impulse formation or conduction leading to decreased cardiac output and poor perfusion

Primary nursing priority for dysrhythmias

Identify cause and treat underlying problem

Myocardial infarction effect on rhythm

Dead heart tissue irritates or blocks normal conduction

Potassium role in cardiac function

Responsible for repolarization (resets each beat)

Hypokalemia effect

Increases cardiotoxicity and risk for PVCs

Magnesium role

Maintains steady heartbeat

Calcium role

Controls SA node firing, AV node speed, and muscle contraction

Hypoxia effect on heart

Starves heart of energy needed to contract

Hypovolemia effect

Forces heart to beat faster due to low volume

Hormonal changes effect

Increase SA node firing (stress hormones)

Stimulants effect

Caffeine, nicotine, alcohol irritate heart and disrupt timing

Hypotension in dysrhythmias

Decreased blood pumped out

Skin changes in poor perfusion

Pale, clammy, cyanotic

Urine output change

Decreased due to poor kidney perfusion

Impending doom feeling

Decreased cerebral perfusion

SA node function

Controls atrial depolarization (P wave)

Normal PR interval

0.12–0.20 seconds

Sinus tachycardia HR

Greater than 100 bpm

Cause of sinus tachycardia

Pain, fever, anxiety, hypovolemia

Sinus tachycardia treatment

Treat cause, beta blockers, calcium channel blockers

Sinus bradycardia HR

Less than 60 bpm

Symptoms of bradycardia

Dizziness, weakness, hypotension

Primary treatment for symptomatic bradycardia

Atropine

Backup treatment for atropine failure

Dopamine or epinephrine

QRS complex meaning

Ventricular depolarization

Normal QRS duration

0.04–0.10 seconds

T wave meaning

Ventricular repolarization

SVT definition

Rapid atrial rhythm 100–280 bpm

SVT key feature

No visible P waves

SVT treatment

Vagal maneuvers, adenosine, cardioversion if unstable

Adenosine action

Slows AV node conduction (short half-life)

Atrial fibrillation definition

Chaotic atrial activity 350–600 bpm

AFib complication

Stroke due to clot formation

AFib treatment

Beta blockers, calcium channel blockers, digoxin, anticoagulants

PVC definition

Early ventricular beat

PVC cause

Electrolyte imbalance, stimulants

PVC treatment

Correct cause, replace K/Mg, beta blockers

Ventricular tachycardia definition

Rapid ventricular rhythm >140 bpm

VT complication

Can lead to ventricular fibrillation

VT treatment

Cardioversion, amiodarone, defibrillation if pulseless

Ventricular fibrillation definition

Chaotic ventricular activity with no cardiac output

VFib treatment

Immediate defibrillation and CPR

Heart block definition

Impaired conduction through AV node

First-degree AV block

PR interval >0.20 seconds

Mobitz I

Widening PR until dropped beat

Mobitz II

Fixed PR with dropped beats

Third-degree block

No communication between atria and ventricles

Third-degree treatment

Pacing, dopamine, epinephrine

Pacemaker purpose

Regulate heart rate for bradycardia or block

Transcutaneous pacing

External temporary pacing

Transvenous pacing

Invasive temporary pacing

Permanent pacemaker

Implanted device for long-term rhythm control

Failure to sense

Pacemaker misses intrinsic beats

Oversensing

Pacemaker detects false signals and withholds pacing

Undersensing

Pacemaker fires unnecessarily

Failure to capture

Pacer spike without contraction

Failure to pace

No pacing when needed

Class I antiarrhythmics

Sodium channel blockers

Class II antiarrhythmics

Beta blockers

Class III antiarrhythmics

Potassium channel blockers

Class IV antiarrhythmics

Calcium channel blockers

Beta blockers action

Decrease SA node firing and contractility

Amiodarone use

VT and VF treatment

Amiodarone adverse effects

Pulmonary toxicity, thyroid issues, liver damage

Calcium channel blockers use

AFib, SVT

Adenosine use

Terminate SVT

Digoxin use

AFib rate control

Atropine use

Symptomatic bradycardia