This ECG belongs to a 56-year-old patient who was admitted by your colleague the previous night with hypercapnic respiratory failure. She was in cardiogenic shock with pulmonary edema. After intubation and mechanical ventilation, she was started on parenteral furosemide infusion and intravenous dobutamine. The ECG shown was obtained prior to the ICU rounds the following day. Are you worried?
Thanks for your interest and queries.
As for the first question. The atrial activity is too erratic, disorganized and inconsistent to result from a macro-rentry, that is atrial flutter. It is due to atrial fibrillation. You may call it coarse, given the fact that the fibrillatory waves are sometimes evident in some leads, not all!
As for the second question, the R wave in aVR is dominant throughout! the slight variation might be related to lead placement.
As for why the QRS is upright. I burrowed a few images from an amazing slide set (courtesy Dr. Sarita Choudhary) to explain the point. In a normal situation, the main vector from cardiac depolarization in directed towards the cardiac apex. However, in a patient with a lead pacing at the RV apex, ventricular depolarization STARTS at the apex and travels towards the base of the heart.
An since aVR (the cavity lead is situated over the base of the heart), it at times records a positive QRS complex (depending on the patient's body habitus, orientation of the heart in the mediastinum, height of the diaphragm ... etc). As you would imagine, a more horizontal position will likely make QRS negative in aVR as opposed to a vertically oriented position.
In a normal situation, because aVR will be looking at right angles to the main ventricular depolarization vector, R/S ratio in aVR tends to be the ~1. The more horizontal the heart, you would appreciate a deeper S wave than R (vector moving away from aVR) and in a more vertical position, the R/A ratio will be >1, as the main depolarization vector migrates closer to aVR.
Thanks you dr Hatim it is really an interesting puzzle that we learned from . Can I ask for further calcification about the ? Flutter like waves even more clear in the consequence ECG or it’s jus a coarse fibrillation . Also what was the reason of positive aVR initially that is changed later?
sorry for taking from your precious time.
Thank you dr Hatim
Thanks for all your responses. I had deliberately censored some information to assess your ‘approach’ to a rather complicated ECG. Let’s go through it systematically.
There is no ORGANIZED atrial activity noted. When evaluating the interval between two QRS complexes, there is erratic fibrillatory activity consistent with AF. However, if that were the case, one would expect an irregular R-R interval!! The fact that the cycle length is constant suggest that you are either dealing with a concomitant complete AV block OR … … … a paced rhythm! Let’s have a closer look at the ECG.
In such a situation, further interpretation of the ECG becomes challenging without specialized validated ECG criteria (e.g. modified Sgarbossa criteria) or a previous ECG for comparison. The following is the patient’s ECG on admission the previous night, which shows no major changes
EXCEPT FOR the new prominent and pathological U waves seen across the precordial leads (this is what I was expecting you all to pick up!). A U wave is a delayed after depolarization. Some suggest that it’s due delayed depolarization of the papillary muscles, or Purkinji fibers or the myocardial M-fibers. A U wave becomes significant when it is >1-2 mm in amplitude and/or more than 25% of the amplitude of the T wave. In this patient and knowing that she was being aggressively diuresed overnight, this ECG finding should prompt an immediate evaluation for the levels of serum K and Mg (2.3 mmol/L and 0.52 mmol/L, respectively). Other causes include hypocalcemia, severe bradycardia, left ventricular hypertrophy, hypertrophic cardiomyopathy, hyperthyroidism, acute intracranial hemorrhage and intracranial hypertension. Some drugs in common use may induce U waves on the surface ECG e.g. Digoxin, class I antiarrhythmic drugs (e.g. procainamide), class III antiarrhythmic drugs e.g. amiodarone and old generation antipsychotic drugs e.g. thioridazine. An INTERTED U wave is an important ECG finding and highly specific for acute myocardial ischemia.
This last ECG was obtained after initial correction of electrolyte abnormalities (K 3.0 mmol/L and Mg 0.87 mmol/L)
The amplitude of the U wave has decreased considerably. It completely resolved with further correction and so did the QT interval, which returned back to baseline values as on the admission ECG.
Additional suggested reading:
Relevant chapter in Critical decisions in emergency and acute care electrocardiography by WJ Brady and JD Truwit.
Sovari AA, Farokhi F, Kocheril AG. Inverted U wave, a specific electrocardiographic sign of cardiac ischemia. Am J Emerg Med. 2007 Feb;25(2):235-7
Gerson MC, McHenry PL. Resting U wave inversion as a marker of stenosis of the left anterior descending coronary artery. Am J Med. 1980 Oct;69(4):545-50
Pérez Riera AR, Ferreira C, Filho CF, Ferreira M, Meneghini A, Uchida AH, Schapachnik E, Dubner S, Zhang L. The enigmatic sixth wave of the electrocardiogram: the U wave. Cardiol J. 2008;15(5):408-21
I’m worried ,
- there is advance conduction system disease ( base line lead II not clear) but there is AVB either complete as regular QRS with AFib or fluter if we agreed on those fibrillary wave in V1 and distal lead II, or infra-hisian block -wide QRS- (although I cant see clear 2:1 blocks, unless can be with 1st AVB)
-positive aVR , is concerning, either extreme axis Northwest or lead misplaced but aVL is agains. Or medication intoxication e.g TCA.
-LBBB , we don’t know if it is new but even if old this poor R wave even at V6 is strange!! Ischemia to be considered especially with this cardiogenic shock .
assessment of detailed initial presentation , review of previous ECGs , medications , labs mainly Trop, electrolytes and bedside ECHO .
For me this ECG shows first degree AV block with prolong PR interval ( unless that notch over t waves are U waves!) and is difficult to say it's sinus or it's junctional rhythm! There is pathological deep Q waves in V2 and V3 STE in anterior leads goes with LBBB here which with sgarbossa critira will be normal. This can be ischemia caused by CPR or excessive dubtomaine infusion, I will send trop sample Stat with serial ECG and I will check dobutamine dose
hello dr Hatim
thank you for your effort and participation in our learning
regarding this ECG:
there is wide QRS complexes with no obvious p wave before it: which suggest this rythum is starting from the ventricle. with deep s wave in v2: sugest it is starting from the RV. the other thing that it dosent look like ventricle escape rythum because the rate is around 60. I think it is Accelarted idioventricular rythum, which means this pt was having occlusion ( which was missed ) and had restortion of reperfusion.
other thing i can think off:
- junctional escape rythum with LBBB and subtle concordant ST elevation in lead1 , i will need to repeat the ECG to see if it progress and fulfill the sgarbossa criteria
fibrillary wave of Atrial fibrillation, there is no obvious upright p-wave in limb lead I or AVF which indicates this rhythem is most likely to be atrial fibrillation . and since there is regular ventricular rhythm with equal R-R interval this could be Atrial fibrillation with complete hear block and this patient would require temporary pacing .
I'm worried 😷 because ECG showed 1.up right T wave in aVR ( predict poor progno-sis and death) 2. ST elevation in V2 -V4. 3.T wave inversion in lead II ,aVF, aVL , V4,V5 . I want to rule out ACS