Do you ever feel confused by pacemaker rhythms?  You are not alone!   Pacemakers are electronic devices, and have rapidly evolved in their capabilities.  Often, we call the manufacturer's representative to come and interrogate a patient's pacemaker to determine if it is behaving as it was programmed.  Without knowing the programming of the individual pacemaker, it can be hard to evaluate the patient's rhythm.

If you went to school a few years ago, and were taught by teachers who went to school many years before that, you may be way behind in your pacemaker knowledge. If you or your teachers have not worked in an electrophysiology setting, you are almost sure to be lacking in the very latest information.  I still find many of my students do not know that dual-chamber pacemakers can sense a patient's own (native) p wave, and track those p waves, triggering paced QRS complexes for each Q wave.  This allows a patient with good sinus node function to be paced at the rate which best fits his or her needs.

Modern pacemakers can pace and sense the right atrium, the right ventricle, and often the left ventricle.  Some devices can defibrillate and cardiovert tachycardias. Some are programmed to overdrive tachycardias to gain control of the heart, then slow down.

PACEMAKER MEDIATED TACHYCARDIA is a term for several different mechanisms that cause inappropriately fast rates in a paced patient.  It is a very interesting topic, which I will not attempt to discuss here, because it has been done to perfection by DR. KEN GRAUER, MD, with assistance from JASON ROEDIGER, CCT, CRAT in Dr. Grauer's ECG Consult #13   Please follow this link to a concise, complete, and illustrated discussion of PMT.

If you have ECGs you would like to submit to the Guru for others to comment on, please scan and email good quality jpeg or png images to [email protected] , or post them on the ECG Guru Facebook page.