Chapter 10 Flashcards
Electronic pacemakers
Artificial pacemakers, are devices that deliver an electrical impulse to the myocardium to cause the cells to depolarize. Provides small amount of electrical current in a predetermined interval to mimic the nl pacemaker of the heart.
How do pacemakers affect the atria
It aids in reestablishing nl electrical conduction of impulses, correct dysrhythmias
Standard rate of pacemakers
70-72 bpm
Where is the pacemaker placed
Atria, ventricles or both
Atrioventricular pacing
Provides direct stimulation of the atria and ventricles in a sequence patterns known as atrioventricular sequential pacing. It allows for an atrial kick. Used for pts with heart failure
Atrial kick
Provides the extra blood supply needed for approximately 10-30% of the normal cardiac output
Ventricular pacemaker
delivers direct stimulation to the ventricles and produces a ventricular contractions
Atrial pacemaker
Used alone when the conduction system from the atrioventricular node through the ventricles is intact and functioning
Evaluating Pacemaker Function
The most important aspect of care is to verity the effectiveness of the pacemaker and determine the presence of a pulse with each captured beat.
How is a capture seen in an ECG?
Captures are represented by a pacing spike immediately prior to the waveform
Pacing spike
Could be atria, ventricular, or both. It is an artifact indicating the stimulation of electrical current from the pacemaker generator. The current is a quick delivery and is reflected as a this pike followed by a P wave or a wide QRS complex or both.
Atrial pacing
Pacing spike will be followed by a P wave.
Ventricular pacing
Pacing spike will be followed by a wide QRS complex, which looks similar to a LBBB
LBBB pattern
Rhythm has a P wave and the QRS complex measures 0.12 sec or greater. L ventricle takes longer than the R to depolarize because of its size
AV Delay
Similar to the measurement of the PR interval on a nl rhythm tracing. Measured form the atrial spike to the ventricle spike.