Rate: V-rate of ~35-40 bpm (seee-loowww), two atrial rates possibly present, both have roughly 1620 ms P-P or ~35-40 bpm Rhythm: regular P-waves: 2 types present, both not likely to be sinus, low atrial PRi: normal with both focii but one is a bit shorter than the other QRSd: 90ms
Rhythm: ectopic atrial bradycardia (I'm having a hard time picturing a junctional rhythm with such a slow AVN transit to have the P-waves precede the QRS's and the QRS's be narrow)
Axis: -5 deg (normal), decent R-wave progression QTi/QTc: normal, U-waves visible in V2-V4 ST/T-waves: III almost looks like ST-E, but that is probably the Ta-wave; otherwise unremarkable
DDx? SSS comes to mind, B-blocker/Ca-channel blocker/antiarrhtyhmic OD, digitoxicity. I would have figured ischemia of the SAN would have shown up, electrolytes (but no other interval abnormalities suggesting it), high vagal tone (why no AVN block?). Other considerations include pacemaker failure, congenital cardiac disease.
Thanks for a great website John! I would put my money on a wandering atrial pacemaker, as the P wave morphology (pacemaker site) progressively shifts. In view of a history of chest pain, this could be due to either SA nodal ischemia (possibly due to ischemia of a dominant circumflex artery - circumflex ischaemia can sometimes occur in the abscence of ECG ST changes) or a Bezold-Jarisch reflex (high vagal tone) due to left ventricular inferior wall ischemia. Ruan Louw www.heartrhythm.co.za
I agree with Ruan that this is probably a Shifting Atrial Pacemaker between a sinus bradycardia and an ectopic atrial rhythm/bradycardia with varying degrees of atrial fusion which would account for the changing P-wave morphology. Each focus is vying for control as the dominant pacemaker of the heart as they discharge at similar rates.
Rate: V-rate of ~35-40 bpm (seee-loowww), two atrial rates possibly present, both have roughly 1620 ms P-P or ~35-40 bpm
ReplyDeleteRhythm: regular
P-waves: 2 types present, both not likely to be sinus, low atrial
PRi: normal with both focii but one is a bit shorter than the other
QRSd: 90ms
Rhythm: ectopic atrial bradycardia (I'm having a hard time picturing a junctional rhythm with such a slow AVN transit to have the P-waves precede the QRS's and the QRS's be narrow)
Axis: -5 deg (normal), decent R-wave progression
QTi/QTc: normal, U-waves visible in V2-V4
ST/T-waves: III almost looks like ST-E, but that is probably the Ta-wave; otherwise unremarkable
DDx? SSS comes to mind, B-blocker/Ca-channel blocker/antiarrhtyhmic OD, digitoxicity. I would have figured ischemia of the SAN would have shown up, electrolytes (but no other interval abnormalities suggesting it), high vagal tone (why no AVN block?). Other considerations include pacemaker failure, congenital cardiac disease.
Very neat strip.
Thanks for a great website John! I would put my money on a wandering atrial pacemaker, as the P wave morphology (pacemaker site) progressively shifts. In view of a history of chest pain, this could be due to either SA nodal ischemia (possibly due to ischemia of a dominant circumflex artery - circumflex ischaemia can sometimes occur in the abscence of ECG ST changes) or a Bezold-Jarisch reflex (high vagal tone) due to left ventricular inferior wall ischemia.
ReplyDeleteRuan Louw www.heartrhythm.co.za
I agree with Ruan that this is probably a Shifting Atrial Pacemaker between a sinus bradycardia and an ectopic atrial rhythm/bradycardia with varying degrees of atrial fusion which would account for the changing P-wave morphology. Each focus is vying for control as the dominant pacemaker of the heart as they discharge at similar rates.
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