Letâ€™s look at a more typical case of wide complex tachycardia.
This case comes from Lt. Jason Kinley of Xenia Fire Division.
Hereâ€™s the story.
EMS is called for a 89 year old male with chest pain. Onset 30 minutes ago. Non-radiating. Patient is A+OX4. Skin is moist. Skin color is good. No increase in respiratory effort. Meds for diabetes, hypertension, and unspecified heart problem (patient is a poor historian). The patient is reluctant to go to the hospital. He states he was seen 4 days ago for a possible TIA.
Here are the computer measurements:
- HR: 150
- PR: *
- QRS: 126
- QT/QTc: 304/475
- P-R-T: * -51 110
The treating paramedics correctly identified this as a regular wide complex tachycardia. Because the patient was hemodynamically stable, they initiated a 150 mg bolus of Amiodarone over 10 minutes, with no change to the heart rhythm.
Because according to the 2005 AHA ECC guidelines, thatâ€™s the drug you give for undifferentiated regular wide complex tachycardia. Itâ€™s supposed to be therapeutic for both ventricular and supraventricular tachycardias.
You will remember the patient stated that he was seen 4 days prior for a possible TIA. Well, it turns out that the same EMS system brought him to the hospital. As luck would have it, they performed a prehospital 12 lead ECG at that time.
Here it is.
- HR: 100
- PR: 232
- QRS: 134
- QT/QTc: 350/451
- P-R-T: 50 -56 91
Now compare the QRS morphology in the first PH12ECG to the PH12ECG taken 4 days prior, when the patient was in borderline sinus tachycardia with 1Â°AVB.
Is it a match? You bet! This patient has a pre-existing intraventricular conduction defect (or atypical LBBB). Note the S-wave in lead V6.
Was this patient in ventricular tachycardia? No.
Considering the heart rate of exactly 150, the pseudo-R wave in lead V1 during the tachycardia, and the recently history of possible TIA, 2:1 atrial flutter is the most likely explanation.
However, the first rule applies! In the absence of an â€œoldâ€ ECG for comparison, itâ€™s VT until proven otherwise.
The patient didnâ€™t covert to sinus rhythm, but it was a well-executed call, and no harm came to the patient.
* 3:1 atrial flutter is also a possibility. Note the heart rate of exactly 100.
Differential diagnosis of wide complex tachycardias – Part 4