Dysrhythmias Flashcards
EKG placement
“clouds over grass, smoke over fire, brown in the middle”
R-arm: white L-arm: black
V1 (precordium): brown,
r-side of sternum 4th ICS
R-Leg: green L-leg: red
P wave
depolarization & contraction of ATRIA
QRS complex
depolarization & contraction of VENTRICLES
** 0.06 - 0.10 seconds ** (1.5 - 2.5 small boxes)
T wave
REPOLARIZATION of ventricles
- -inverted w/ injury
- -peaked w. HYPERKALEMIA
PR interval
time it takes SA impulse to reach Purkinje fibers
–beginning of P to beginning of QRS–
** 0.12 - 0.20 seconds ** (3 - 5 small boxes)
ST segment
ELEVATED = INFARCT
DEPRESSED = INJURY
–end of QRS to beginning of T wave–
**should be level w/ ISOELECTRIC LINE **
QT interval (time)
** 0.32 - 0.44 seconds **
5 steps to interpreting EKG
1) RATE
- -# of complexes on 6sec strip x 10
- -number of large boxes b/t 2 complexes / 300
- -number of small boxes b/t 2 complexes / 1500
2) REGULAR RHYTHM?
- -assess r-r (ventricular)
- -assess p-p (atrial)
3) P WAVES
- -present? upright? smooth?
4) P WAVES + QRS
- -is there a P wave for every QRS complex?
5) INTERVAL DURATION
- -PR interval (0.12 - 0.20)
- -QRS duration (0.06 - 0.10)
- -QT interval (0.32 - 0.44)
sinus arrhythmia
normal rate but has IRREGULAR RHYTHM
- -no manifestations
- -no treatment
sinus tachycardia
normal rhythm but has FAST RATE
s/s:
- fast pulse / heart racing
- SOB
- dizzy
tx:
- treat underlying cause (not normal @ rest
- –some reasons include: hypovolemia, fever, pain, anxiety, anemia, hypoxia
sinus bradycardia
normal rhythm but has S L O W RATE
s/s:
- may result from vagal response or ischemia
- IICP
- AMI
- hypothermia
- drugs
- acidosis
- *normal in athletes
***ONLY TX IF SYMPTOMATIC*** tx: -- IV ATROPINE 0.5 - 1.0 mg -increases HR; relieves CP by ridding ischemia --pacemaker if profound or chronic
premature atrial complexes (PACs)
“ectopic atrial beat”
variable rate and irregular rhythm
- -often asymptomatic
- -may precede a dysrhythmia
- -no tx required
- -advise to reduce caffeine, alcohol, stress; stop smoke
paroxysmal supraventricular tachycardia (PSVT)
- regular rhythm
- RATE: 150 - 280 bpm
- not enough time to fill*
- using all myocardial O2*
- HIDDEN P waves (in prev. T wave)
causes:
- fever, sepsis, hyperthyroidism, heart disease, MI
s/s:
-c/o racing heart, anxiety, dyspnea, dizzy, angina, diaphoresis, fatigue, polyuria (incr. CO)
tx:
- VAGAL MANEUVERS (valsalva, suction)
- O2
- IV ADENOSINE (w/ continuous monitor strip)
- -1st 6 mg + 20mL NS bolus rapid! over 1-3 sec
- –if pt. does not convert out of SVT w/i 1 - 2 mins
- -2nd 12 mg + 20mL NS bolus *rapid!
- -3rd 12 mg + 20mL NS bolus *rapid!
- synchronized CARDIOVERSION (avoids VF)
atrial flutter
“SAWTOOTH pattern”
- regular rhythm
- RATE: 101 - 150 bpm
- P : QRS ratios (2:1, 4:1, 6:1)
causes:
-SNS stimulation, heart disease, MI, PE
s/s:
- c/o palpitations
- decreased CO (hypoten, dizzy, cool/clammy, low UO)
tx:
- BB or CCB to slow ventricular rate + AMIODERONE
- -start amioderone drip once stabile
- synchronized cardioversion
a-fib
- irregular rhythm
- fast rate: 100-180
- undistinguishable P waves (atria are quivering)
- –* DECR. CARDIAC FILLING *
causes:
-HF, heart disease, HTN, hyperthyroidism
s/s:
-high ventricular rate causes decr. CO s/s
(hypotension, dizzy, cool/clammy, low UO)
-irregular peripheral pulses
-RISK OF THROMBUS FORMATION
tx:
- synchronized cardioverison (sync w/ R-wave)
- meds to reduce ventricular rate:
- -BB, CCB,
- **DIGOXIN ** (0.5 - 2.0 mg/mL)
- anticoagulant to PRVENT STROKE
Digoxin administration
positive ionotrope to INCREASE CONTRACTILITY»_space; INCREASE STROKE VOLUME»_space;
d e c r e a s e s ventricular rate
**ONLY USE FOR A-FIB if HF IS PRESENT! **
s/s of toxicity:
-vision color changes (yellow halo), bradycardia, heart block, bronchospasm,
tx toxicity:
- Digibind
- IV potassium chloride
**HOLD OF HR < 60 bpm
**hyPOkalemia makes toxicity likely
premature ventricular contractions (PVCs)
- -no P wave before PVC (b/c start at ventricle)
- -QRS is wide b/c impulse starts in PURKINJE FIBERS
- -have apical-radial deficit
- -precursor to lethal arrhythmia
- -precipitated by HYPOkalemia
causes:
- stress, anxiety, stimulants, alcohol, acidosis, hypoxia, electrolytes, reperfusion (irritating to heart)
- greatest occurrence after MI**
tx:
- -TREAT ONLY IF SYMPTOMATIC or w/ heart disease
- no stimulants
- BB or antidysrhythmic
V-tach
“3 or more consecutive PVCs”
- no P-waves (unidentifiable)
- QRS wide & bizarre ( > 0.12 sec)
- rate: 100-250
- regular rhythm
** can have v-tach w/ or w/o pulse
tx:
treat if SUSTAINED (> 30 sec), symptomatic, or w/ heart disease»_space;> SLOW HR DOWN so SA can take over (amioderone)
–if amioderone doesn’t work»_space; CARDIOVERT
if PULSELESS: check for carotid pulse b/t each!!!
1) CPR (keep blood circulating manually)
2) DEFIBRILLATE
3) EPINEPHRINE
4) AMIODERONE
v-fib
fine or coarse
- rate too rapid and rhythm very irregular;
- no identifiable waves; vary is size and shape
- **CARDIAC ARREST
- **DEATH W/I 4 MINUTES
triggered by myocardial ischemia/ infarction
tx:
* *most effective tx = EARLY DEFIBRILLATION! **
1) CPR (keep blood circulating manually)
2) DEFIBRILLATE
3) EPINEPHRINE
4) AMIODERONE
amioderone administration
300 mg IV push OVER 10 MINS
maintenance drip:
–360 mg IV over 6 hours ( 1mg/min )»_space;> THEN
540 mg IV over 18 hours ( 0.5mg/min )
asystole
* shock to make sure its not fine v-fib*
** verify in at least TWO LEADS **
** ARE ALL LEADS ON PT?! **
heart blocks
1st:
- -PR > 0.20 SLOWED CONDUCTION
2nd type I:
–PR interval gets longer and longer until not followed by a QRS
2nd type II:
- -slow ventricular rate; some P waves not followed by QRS
- -**PACEMAKER or ATROPINE 0.5 - 1.0 mg
3rd (complete)
–P waves and QRS DO NOT CORRELATE
(each are contracting on their own; out of synch)
–PACEMAKER! immediately!*
cardioversion vs. defibrillation
CARDIOVERSION
- -current is SYNCHRONIZED with pt heart rhythm
- -requires SEDATION
- -100 J
- -elective
- -“all clear”
DEFIBRILLATION
- -current is NOT synchronized w/ pt heart rhythm
- -no sedation required
- -360 J (b/c of chaotic rhythm)
- -“all clear”
automatic implantable cardioverter defibrillators (AICD)
PACES & DEFIBRILLATES
- pacing for brady
- defibrillates for VT or VF (looks for fast HR)
