Exam 1 Flashcards
(32 cards)
Normal Sinus Rhythm
Rate 60-100 bpm
Regular Rhythm
QRS w/ each P-wave
Sinus Bradycardia
Rate < 60 bpm
Causes: MI, surgical procedure, medications (digoxin, beta-blockers, morphine, vagal stimulation
Symptoms: some pts. maybe asymptomatic (athletes, etc.); syncope, dizziness, lightheadedness, confusion, dyspnea, n/v, decreased UOP, cool & clammy skin
Treatment (if symptomatic): provide O2, increase intravascular volume (IV fluids), atropine is the drug of choice (increases HR), pacing may be necessary if other interventions unsuccessful
Sinus Tachycardia
Rate > 100 bpm
Causes: Sympathetic nervous system stimulation, drugs (caffeine, nicotine, epinephrine, dopamine, atropine), compensatory response to decreased BP or CO (shock, infection, MI, HF), pain, fear, anxiety
Symptoms: fatigue, weakness, SOB, palpitations, chest pain
Treatment: treat the underlying cause (fever = antipyretics, anxiety = provide reassurance, pain = administers meds as ordered, hypovolemia = replace fluids or blood), medications (digoxin, beta-blockers, diuretics)
Supraventricular Tachycardia
P-wave present but difficult to identify, PR interval not measurable, rate 150-250 bpm
Causes: emotions, stimulants, rheumatic heart disease, digoxin toxicity, MI
Symptoms: chest pain, palpitations, fatigue, anxiety, SOB, hypotension, dizziness, syncope
Treatment: vagal stimulation (have patient bear down), administer adenosine, cardioversion, ablation
Atrial Fibrillation
Most common dysrhythmia, risk increased with age, increases the risk of stroke
NO distinct p-wave (may be mistaken for fibrillation beats), PR interval absent, irregular rhythm, rate varies
Cause: multiple rapid-firing impulses from atria (350-600x/min.); HTN, CAD, DM, HF, mitral valve disease, obesity, caucasian, thrombolytic event
Treatment: GOAL = anticoagulation and rate control, medications (anticoagulants & antidysrhythmics), cardioversion, ablation, pacemaker for rate control
Atrial Flutter
P-wave absent (can be mistaken for flutter waves which appear “saw-toothed”), PR interval not measurable, rhythm can be regular or irregular, rate varies
Causes/Symptoms/Treatment: same as A. fib
3rd Degree Heart Block
LIFE-THREATENING - can progress to asystole
Electrical impulses blocked btwn. atria and ventricles
P wave sam size and shape but no correlation to QRS, no true PR interval, QRS usually widened, rate varies
Causes: MI, severe heart disease
Treatment: temporary pacing until a permanent pacemaker can be placed once the patient is stable
Premature Ventricular Contractions
Not medical emergency but could be a red flag
P-wave not present before PVC, QRS widened, irregular rhythm, the rate varies
Causes: MI, heart failure, caffeine, alcohol, nicotine, stress, infection, surgery, electrolyte imbalance, digoxin toxicity
Treatment: If patient medically stable then continue to observe, begin treatment if the patient shows s/s of poor cardiac output (fatigue, hypotension, cool extremities, dizziness, thready pulse, etc.) or if any “danger signs” ( > 6 PVCs/min, multifocal PVCs, run of V. tach), treat underlying cause, antiarrhythmics
Ventricular Tachycardia
May be intermittent or sustained
LIFE-THREATENING, significantly decreased cardiac output
Pulseless V. tach is a SHOCKABLE RHYTHM
No p-wave, no PR interval, wide QRS, rate > 150 bpm
Causes: ischemic heart disease, MI, cardiomyopathy, valvular heart disease, HF, drug toxicity, electrolyte imbalance
Treatment: depends on the severity of the patient, cardiovert (pulse)/defibrillate (pulseless), medications, ablation, pacemaker or ICD placement
Torsades De Pointes
LIFE-THREATENING
No p-wave, no PR interval, QRS usually same shape (widened, varied amplitude), rhythm & rate vary
Causes: MI, severe heart disease, low magnesium, drugs that prolong QT
Treatment: Magnesium sulfate, treat underlying cause (correct electrolyte imbalance, remove med that is prolonging QT), cardioversion
** if pulseless, begin CPR and follow treatment guidelines for V. Fib and pulseless V. tach
Ventricular Fibrillation
Results from electrical chaos w/i cardiac tissue
LIFE-THREATENING
SHOCKABLE RHYTHM
No p-wave, no PR interval, no QRS, irregular rhythm, cannot measure the rate
Causes: CAD, MI, electrolyte imbalance, medications, SVT, shock, surgery, trauma
Symptoms: LOC, loss of pulse, apnea, pt. becomes faint
Treatment: check pulse, initiate CPR, maintain airway, defibrillate, medications
Idioventricular/Agonal
Dying heart, final attempts of heart to make electrical impulse, usually seen in end-stage heart disease
NOT a shockable rhythm
Asystole
Lethal dysrhythmia, pt. will NOT have a pulse, immediate interventions necessary
NOT a shockable rhythm
No p-wave, no PR interval, no QRS, no rhythm, no rate
Treatment: treat cause (H’s and T’s), CPR, medications, airway maintenance
Temporary Pacemaker
Types
- Transvenous - through a vein (usually r. femoral), lead wire threaded through the skin and large vein into the right atrium, electrical impulse stimulates atria to produce a contraction, can also be used for ventricular pacing
- Transcutaneous - electrical impulse sent through skin and body to the heart, stimulating a contraction
Permanent Pacemaker
- Necessary when heart is unable to maintain a normal rate or cardiac output
- Surgically implanted under the skin in the upper right or left chest
- lead wire inserted in heart through large vein
Atrial Pacing
Inserted in the right atrium, stimulates atria and then follows normal conduction through the heart
Ventricular Pacing
Inserted through the left or right ventricle, stimulates depolarization of ventricular muscle
Sequential Pacing
Most common permanent pacemaker
Stimulates depolarization of atria AND ventricles
Leads usually placed in right atrium and ventricle
AKA “dual-chambered pacemaker”
Biventricular Pacing
Used when ventricles contract at different times, decreasing cardiac output
Three leads are placed: one in atria, one in right ventricle, one in left ventricle
__________ is the ability of cardiac cells to depolarize in response to the electrical impulse generated by a pacemaker.
Capture
What indicates capture?
P wave or QRS after every pacer spike
What is the difference between capture and mechanical capture?
Capture indicates electrical impulse but does NOT always mean there is a contraction
Contraction = pulse present = mechanical capture
Percent of Capture
Number of pacer spikes followed by a complex / Total number of pacer spikes
Failure to Capture
Complex does not follow pacer spike meaning, cardiac cells did not depolarize in response to stimulation from pacemaker
