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Case #22

You are in your office. The next patient is here and He is a healthy 51 year old male with no significant medical history. He exercises regularly, eats only organic vegetables and non-steroid raised meats, does not smoke, and both his parents are living ate the ages of 91 and 85 with only one with Alhzeimers Dementia and no Cardiac disease history. He is here for his regular yearly visit. You ask him if he has any complaints. He says, "You know, sometimes I feel my Heart Jump out of my chest". He states this happens maybe a few times a day, more often when he drinks a lot of his special Herbal tea which does have a lot of caffeine in it. He is a little concerned and is wondering if it means anything.

You begin your exam. Everything is with in normal limits, except for a few positive findings which include, Jugular Venous Pulse with 2 waves at regular intervals and an occasionally appearing large wave, A pulse that feels slightly irregular, and on auscultation of the precordium frequent irregularity which is difficult to determine if it's regular or always irregular. You decide this warrants an EKG to make sure he is not in Atrial fibrillation. The Rhythm strip from an EKG is below. First, what do you tell the patient, and second how do you correlate the physical findings with the EKG findings.

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First of all this is totally benign. The patient can be simply re-assured that PVC's are sometimes just normal and are why he experiences these feelings of "His heart jumping out of his chest" and that no further testing needs to be done

Secondly this is a great correlation for physical exam and EKG. So in the rhythm strips, specifically looking at II and III we see 2 complexes looking very different than the rest of the strip (1 and 5) and the rest of the strip looking like sinus rhythm @ 80's. Now what are these weird complexes? The three choices basically are PVC, PAC with aberrant conduction because they occur earlier than the regular R-R intervals. Looking really quickly, it is really tempting to say it is a PAC with aberrant conduction because it does not look like that wide of a complex as we are used to seeing with PVC's. But looking carefully, specifically at the p-p intervals, you can see the the Sinus node firing rate (p-p interval) never changed and marches right through the Premature complex. You can even see a notching of the complex where the p wave marches through especially in II and III. This is impossible with a PAC. If you have a PAC, the ectopic focus depolarizes the entire atrium, including the sinus node and resets the firing rate, so the P-P interval does not march through and is actually longer. With a PVC, the AV node is usually refractory and the ectopic focus in the ventricle usually does not make it retrograde through the AV node to depolarize the atrium hence leaving the sinus node firing at it's regular interval with no interruption, but with out conduction down the AV node because it is now refractory from the PVC. Hence the findings on the EKG.

What is even more interesting is that as we stated that with a PVC the sinus node keeps firing. This means that the Atrium are still contracting even though the Ventricle just contracted due to the PVC. This leads to an atrial contraction on a closed Tricuspid/Mitral Valve from the contraction of the PVC leading to that occasional large wave in the neck which is the Cannon A wave. So, if you looked at his neck long enough while listening to his heart, every time you heard a PVC, you would see a large wave "pop up" in the jugular venous pulse.