Cardiac Dysrhythmias Flashcards
Sinus bradycardia
a. Atrial and ventricular rhythms are regular.
b. Atrial and ventricular rates are less than 60 beats/min.
Sinus tachycardia
Heartbeat 100-180 bpm and regular
Medication to increase heart rate to at least 60 bpm with sinus bradycardia
atropine sulfate
How to determination of Heart Rate Using 6-Second Strip Method
To determine atrial rate, count the number of P waves in 6 seconds and multiply by 10 to obtain a full minute rate.
To determine ventricular rate, count the number of R waves or QRS complexes in 6 seconds and multiply by 10 to obtain a full minute rate.
Atrial fibrillation
No definitive P wave can be observed, only fibrillatory waves before each QRS.
P waves are chaotic
Interventions for atrial fibrillation
Oxygen, anticoagulant therapy, medications
Premature ventricular contractions
a.Early ventricular complexes result from increased irritability of the ventricles.
Ventricle contracts before the atrium.
b.PVCs frequently occur in repetitive patterns such as bigeminy, trigeminy, and quadrigeminy.
What electrolyte is responsible for dysthymias?
Potassium.
Ventricular tachycardia
a. Ventricular tachycardia occurs because of a repetitive firing of an irritable ventricular ectopic focus at a rate of 140 to 250 beats/min or more.
b. Ventricular tachycardia may present as a paroxysm of three self-limiting beats or more or may be a sustained rhythm.
c. Ventricular tachycardia can lead to cardiac arrest.
Ventricular fibrillation
a. Impulses from many irritable foci in the ventricles fire in a totally disorganized manner.
b. VF is a chaotic rapid rhythm in which the ventricles quiver and there is no cardiac output.
c. VF is fatal if not successfully terminated within 3 to 5 minutes.
Interventions for ventricular fibrillation
a. Defibrillate the client immediately, up to 3 times consecutively at 200, 300, and 360 joules (J).
b. Initiate CPR.
c. Administer oxygen as prescribed.
Vagal maneuvers
1.Description: Vagal maneuvers induce vagal stimulation of the cardiac conduction system and are used to terminate supraventricular tachydysrhythmias.
Valsalva maneuver
a. The physician instructs the client to bear down or induces a gag reflex in the client to stimulate a vagal response
b. Monitor the heart rate, rhythm, and BP.
Cardioversion
a. Cardioversion is synchronized countershock to convert an undesirable rhythm to a stable rhythm.
b. Cardioversion can be an elective procedure performed by the physician for stable tachydysrhythmias resistant to medical therapies or an emergent procedure for hemodynamically unstable ventricular or supraventricular tachydysrhythmias.
c. A lower amount of energy is used than with defibrillation.
d. The defibrillator is synchronized to the client’s R wave to avoid discharging the shock during the vulnerable period (T wave).
Defibrillation
Defibrillation is an asynchronous countershock used to terminate pulseless ventricular tachycardia (VT) or VF.
Synchronous (demand) pacemaker
A synchronous (demand) pacemaker senses the client’s rhythm and paces only if the client’s intrinsic rate falls below the set pacemaker rate for stimulating depolarization.
Asynchronous (fixed) pacemaker
An asynchronous (fixed rate) pacemaker paces at a preset rate regardless of the client’s intrinsic rhythm and is used when the client is asystolic or profoundly bradycardic.
Asytole
Absence of heart contractions; flatline
Heart block
Disorders interrupting the electrical transmissions from the SA node to the AV node to the ventricles.
Dobutamine
Andergenic agonist
Beta1 selective
Increases force of cardiac contractions
Treats cardiogenic shock following an MI
Meds for tachycardia
Epinephrine
Levophed (norepinephrine)
Atropine
Procardia (nifedipine )
What does a V. Tach strip look like?
Many QRS complexes with no defined P or T wave.
Clinical significance of V. Tach
Sustained has a decrease in CO with hypotension, pulmonary edema, deceased cerebral blood flow
Can be unstable with no pulse and lead to ventricular fibrillation
What does V. Fibrillation look like?
Heart rate isn’t measurable and the strip is chaotic and irregular. No P wave and the QRS interval isn’t measurable.
