cardiac dysrhythmias

ability to spontaneously depolarize without external stimulus

ease or difficulty to invoke depolarization

ability to transmit impulse to other cells

ability of cardiac cells to shorten in response to electrical simulation; squeeze of the heart

• normal QRS = .12
• normal PR = .12 - .20

• electrolytes
• fluid volume
• hypoxemia/myocardial ischemia
• mechanical factors (cardiomegaly; myocardial scar)
• body temperature

• HR<60 bpm
• causes:
• 1. sinus node disease
• 2. meds
• 3. hypoxia
• 4. well conditioned athletes
• treatment (if pt. is symptomatic):
• 1. O2
• 2. IV access
• 3. consider temporary pacing
• 4. meds - atropine sulfate : anticholinergic; 0.5mg IV Q3-5min max3mg

• HR>100bpm (usually 100-150)
• always has a cause :anxiety, pain, fever, activity, dehydration, heart failure, anemia
• fix the cause and the rhythm will be fixed
• meds - beta blockers & CCB
• O2

• irregularly irregular (QRS comes irregularly) with no meaningful P waves
• loss of atrial kick (20-30% decrease in CO)
• blood pools and clots in the atria, so high risk for embolus

• atrial rate>250bpm
• sawtooth P wave

• cardioversion
• CCB
• beta blockers
• digoxin
• amiodarone
• diltiazem
• anticoagulate

• HR 150-250
• always regular
• paroxysmal (abrupt start and stop)
• may or may not see p waves
• treatment for stable SVT:
• 1. valsalva maneuver
• 2. adenosine - drug of choice
• 3. carotid massage
• 4. O2
• treatment for unstable SVT:
• 1. adenosine
• 2. CCB
• 3. beta blocker
• 4 cardioversion

• caused by early atrial depolarization (P wave) before next scheduled sinus beat
• causes: emotion, stress, anxiety, fatigue, infection, lack of sleep, meds, caffeine, heart failure, MI, electrolyte imbalance
• treat the cause if become symptomatic

• irritable ectopic site in ventricle
• QRS wide and bizarre
• t wave deflected opposite to the QRS
• cause: increased age, hypoxia, MI, CHF, stress, meds, electrolyte imbalance, caffeine, alcohol, tobacco
• treatment: eliminate cause; consider antiarrhythmic (amiodarone, lidocaine)

• cause: significant cardiac disease, K or Mag imbalance, artifacts (loose leads, brushing teeth); be sure to check the patient
• treatment for stable with a pulse:
• 1. amiodarone
• 2. lidocaine
• 3. magnesium
• 4. potassium
• 5. cardioversion
• treatment for unstable with no pulse:
• 1. CPR
• 2. defibrillate
• 3. epinephrine
• 4. vasopressin
• 5. amiodarone
• 6. lidocaine
• 7. resuscitation

• electrical chaos; no perfusion
• always fatal unless terminated
• treatment : immediate electrical shock
• causes:
• 1. heart disease, CAD, cardiomyopathy
• 2. hypovolemia, hypoxia
• 3. acidosis
• 4. hypokalemia, glycemia, thermia
• 5. hyperkalemia
• 6. toxins
• 7. cardiac tamponade
• 8. trauma, tension pneumothorax, thrombus

• flat line; no electrical impulses
• treatment :
• 1. CPR
• 2. epinephrine and vasopressin
• 3. treat the cause

• PR interval > .20
• usually asymptomatic

• PR lengthens progressively until QRS is dropped
• treat symptoms

• PR interval is constant
• some beats are conducted = p wave then QRS
• some beats nonconducted = p wave then no QRS
• unstable and usually requires  pacemaker
• cause :
• 1. MI; AV node disease
• treatment :
• 1. atropine, dopamine, epinephrine
• 2. pacemaker

• no communication between atria and ventricles
• no relationship between P waves and QRS
• CO is decreased
• P waves are a constant distance no matter what
• Treat as symptomatic bradycardia
• cause :
• 1. meds (dig toxicity)
• 2. acute MI; myocarditis
• 3. degenerative heart disease
• treatment :
• 1. treat symptoms
• 2. temporary pacing
• 3. atropine, epi, dopamine

• asynchronous
• high energy level
• for pulseless V tach and V fib

• low energy shock
• for unstable SVT, a fib, a flutter, V tach with a pulse
• premedicate with sedation and pain meds