A good example of ventricular fibrillation converted by electric defibrillation to what appears to be a sinus rhythm. There is significant artifact in the post-conversion strip, but the last beat on the strip appears to have a P-QRS-T sequence.
Of course, V Fib presents without pulses, and must be defibrillated as soon as possible. Best results are achieved by defibrillating a perfused heart, so if there is any delay from onset of V Fib, CPR should be performed to perfuse the heart prior to defibrillation.
A good example of ventricular fibrillation. The patient is pulseless, CPR has been performed, and the ED staff is about to defibrillate. Characteristics of V Fib are: a chaotic, wavy baseline without clear P waves, QRS complexes, or T waves. Baseline artifact (baseline going up and down) can be seen with CPR and other movement of the electrodes on the patient's body as resuscitation efforts are underway. The patient will ALWAYS be unconscious and pulseless in V Fib. If this rhythm is seen in a patient who is awake or has pulses, it is ARTIFACT - check your electrodes!
This is a rhythm strip from a NIPS procedure (non-invasive programmed stimulaltion), which is a programming test for an implantable cardioverter defibrillator (ICD). The test is done under light anesthesia, similar to that used for colonoscopy. In this example, the patient is in normal sinus rhythm at the beginning of the procedure. The pacemaker technician overdrives the patient's rate to observe the pacing function, then a stimulus is delivered to cause ventricular fibrillation (V Fib). Initially, the ventricular rhythm is somewhat organized and coarse (V flutter), but it will rapidly deteriorate if not corrected. Before it deteriorates, the ICD delivers a shock, and the patient's rhythm is restored. In this example, bi-ventricular pacing was conducted for a few minutes before the patient resumed NSR. The patient is then recovered from the anesthesia and discharged home.
For your students, this is a good example of the relative safety of shocking the well-perfused heart. Although it is possible to put the heart into an intractable V Fib with this test, the ICD usually is able to convert the potentially lethal rhythm easily. It is a good reminder that we need to perfuse the heart well before performing defibrillation on a person with unwitnessed cardiac arrest.
