Term
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Definition
Represents early ventricular repolarization
From the end of the QRS complex (J point) to the start of the T wave
Normal amplitude is isoelectric
Elevation or depression > 1 mm or 1 small box
Depression may indicate ischemia or digoxin toxicity
Elevation may indicate myocardial injury |
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Term
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Definition
Follows ST segment
Represents ventricular repolarization
Usually positive deflection, rounded & slightly asymmetrical
R on T—ectopic stimuli may cause ventricular depolarization, may cause ventricular arrhythmia
May be tall, peaked, inverted or flat with ischemia, K & Ca imbalances & medications |
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Term
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Definition
Time required for ventricular depolarization & repolarization
Measure from beginning of QRS complex to end of T wave
Duration varies with age, sex & HR
With regular rhythm—QT shouldn’t exceed ½ distance between 2 consecutive R waves
Normal—0.34-0.43 sec
Hold QT medications if QT > 0.44 sec
Prolonged QT can lead to Torsades de Pointes (form of VT refractory to treatment |
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Term
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Definition
Represents repolarization of the His-Purkinje system
May not appear on EKG
Follows T wave
Configuration is typically rounded
Deflection is upright
If prominent, may indicate hypercalcemia, hypokalemia or digoxin toxicity |
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Term
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Definition
S = survey the ABCs
L = Look for symptoms
O = Observe
No Sx, Sx not serious, no AVB
W = Weigh in
Serious Sx |
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Term
| Sinus Tachycardia(ST) Treatment |
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Definition
Treat the underlying cause
Antianxiety measures
Analgesia
Antipyretics
Oxygen
CCB
Beta blockers |
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Term
| Premature Atrial Contractions (PACs) |
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Definition
Originate from ectopic focus
P wave is early
P wave is shaped differently
May be
Blocked by AV node
Delayed by AV node
Conducted normally |
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Term
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Definition
Absence of coordinated atrial contractions
Loss of atrial kick
Decreased ventricular filling
Blood pools in atria—at risk for thrombi/emboli
Atrial rate—350-500 firings/minute
Irregular ventricular response |
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Term
| Atrial Fibrillation Etiology |
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Definition
Underlying HD
Alcohol—‘holiday heart’ syndrome
Caffeine
Electrolyte imbalance
Hyperthyroidism
Commonly occurs after cardiac surgery
Commonly occurs with pulmonary problems
Incidence increases with age |
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Term
| Atrial Fibrillation Clinical manifestations |
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Definition
Palpitations
Chest pain
Dyspnea
Fatigue
Lightheadedness
Syncope
Pulse deficit |
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Term
| Atrial Fibrillation Assessment |
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Definition
Symptoms depend on ventricular rate
1/3 of patients have thromboemboli
Highest risk for patients with valve disease & AF
Observe for changes in mentation, speech, sensory & motor function |
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Term
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Definition
Rate versus rhythm control
Rate control
Increases diastolic filling time
Increases stroke volume
Increases cardiac output
Goal is HR 60-80 bpm at rest & 90-115 bpm with activity
Drug therapy for rate control
Digoxin, β-blocker, CCB |
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Term
| AF Treatment Antiarrhythmics for chemical cardioversion |
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Definition
Quinidine & procainamide
Amiodarone (Cordarone)
Can cause pulmonary fibrosis
Dofetilde (Tikosyn)
Can prolong QT interval
Torsades de Pointes |
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Term
| AF Treatment: Electrical cardioversion |
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Definition
TEE to asses for thrombus
Anticoagulant therapy to reduce embolic risk
Ablate & pace
Destroys triggers for abnormal impulses
Need permanent pacemaker
Atrial kick not restored
Still at risk for emboli |
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Term
| Atrial Flutter ( What is it?) |
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Definition
Atrial rate > 250
Ventricular rate depends on number of impulses passing through AV node
Atrial oscillations appear as sawtooth waves |
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Term
| Atrial Flutter: Treatment |
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Definition
Electrical cardioversion preferred treatment
CCB, beta blockers & digoxin may be used
Medications to convert atrial flutter to NSR
Amiodarone (caution in older adults)
Rythmol, procainamide, flecainide
Medications to slow rate
Calcium channel blockers
Beta-adrenergic blockers |
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Term
| Premature Ventricular Contractions ( Causes) |
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Definition
Due to increased irritability of myocardial muscle fibers
May be insignificant or 2° morbidity
MI
Ischemia
Hypoxia
Hypomagnesemia
Hypercalcemia
Anemia |
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Term
| Premature Ventricular Contractions (assessment) |
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Definition
Symptomatic or asymptomatic
Palpitations
Chest discomfort
Perfusion
Risk for VT/VF
R on T |
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Term
| Premature Ventricular Contractions (Interventions) |
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Definition
Eliminate cause
Ie, stress, caffeine, altered electrolytes
Medications
Lidocaine, amiodarone, beta blockers |
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Term
| Ventricular Tachycardia (describe) |
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Definition
Classified as 3 or > PVCs occurring at a rapid rate—usually > 140 bpm
SA node may continue to fire |
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Term
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Definition
Electrolyte imbalance
Cardiomyopathy
MI
Digitalis toxicity
CNS disorders |
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Term
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Definition
Treat reversible causes of VT
O2, potassium, magnesium
Medications
Procainamide, sotalol, amiodarone, lidocaine to ↓ myocardial irritability
OR
Pulse? Cardioversion
Pulseless? Defibrillate, CPR, ACLS
Ablation
Implantation of AICD |
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Term
| Ventricular Fibrillation ( describe) |
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Definition
No ventricular contraction
No CO
No perfusion
Causes: CAD, MI, hypokalemia, hypomagnesemia, antiarrhythmic drug therapy |
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Term
| Ventricular Fibrillation ( assessment & interventions) |
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Definition
Assessment
Loss of consciousness
Pulselessness
Apnea
Death
Interventions
CPR
Defibrillation
ACLS |
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Term
| Cardioversion ( describe) |
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Definition
Start at 50 Joules energy
Uses: A-fib, A-flutter & V-tach with pulse |
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Term
| Defibrillation ( describe) |
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Definition
Used for V-Fib & pulseless V-tach
Passage of DC electric shock through the heart
Goal: depolarization so SA node resumes pacemaker function
Output 360 Joules (watts/second) |
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