Citation: Negrete AM. Heart of the Matter - A Woman with Palpitations [Internet]. Cook County Emergency Medicine Residency;Available from: https://cookcountyem.com/blog/2023/9/22/heart-of-the-matter-a-woman-with-palpitations
A 46-year-old woman presents with palpitations to the Cook County Emergency Department.
Rate?
Rhythm?
Axis?
Intervals?
QRST?
Interpretation: Tachycardic rate with wide complex, regular monomorphic rhythm. The axis is right axis deviated.
Discussion: Your approach to tachydysrhythmias should always be tmethodical. Is it Sinus? Stable? Wide or Narrow? Regular or Irregular? Monomorphic or Polymorphic?
In this case, the patient had no obvious sinus rhythm, was stable (mentating normally, stable vitals), and had a wide complex and regular monomorphic rhythm.
If she was hemodynamically unstable, the treatment would have been synchronized cardioversion. Luckily, the patient reported this had happened to her before; upon chart review it was apparent that she had been previously diagnosed with SVT with a right bundle branch block that was responsive to adenosine. For her current presentation, she was given 12mg of adenosine IV and converted to sinus rhythm. She was discharged home with cardiology follow up and her metoprolol dose was increased.
How do we differentiate between SVT with aberrancy and VT? When in doubt, assume the rhythm is ventricular tachycardia and proceed down your stable VT algorithm (you can always try adenosine, anti-arrhythmic medications such as amiodarone or procainamide, or synchronized cardioversion with sedation). Please see below for a link to the PROCAMIO trial that examined using procanimide and amiodarone for VT.
The most commonly used algorithm to differentiate between VT and SVT is the Brugada algorithm (see below). Our patient was diagnosed with SVT using this algorithm. In lead V6 her R/S is >1, therefore it was determined that her rhythm was SVT rather than VT.
Per Dr. Smith, other key features of VT include an older patient with cardiac disease (this favors VT) as well as the characteristic morphology of the upstroke of the QRS. If there is a slower, gradual initial part of the QRS this favors VT (see blog post below for full explanation).
Take away points:
· Have a methodical approach to tachycardia
· Assume wide complex tachycardia is ventricular tachycardia until proven otherwise!
· It is safer to assume all wide-complex, regular tachycardia is VT, because the treatment of SVT with aberrancy as if it is VT is safe, but misdiagnosing VT as SVT with aberrancy is potentially life-threatening.
· Adenosine is generally safe in VT. Per Dr. Mattu, it is not always benign, and many patients go on to have unstable VT even after conversion to sinus rhythm. Response to Adenosine does NOT rule out VT.
· Synchronized cardioversion or procainamide are your best options for VT treatment.
Authored by Alejandro Negrete, MD
References:
Ventricular tachycardia [Internet]. WikEM. [cited 2023 Sept 22];Available from: https://wikem.org/wiki/Ventricular_tachycardia
Buttner R and Burns E. Ventricular Tachycardia – Monomorphic VT [Internet]. Life in the Fast Lane • LITFL. 2023 [cited 2023 Sept 22];Available from: https://litfl.com/ventricular-tachycardia-monomorphic-ecg-library/
Swaminathan A. Core em: Ventricular tachycardia [Internet]. emDOCs.net - Emergency Medicine Education. 2017 [cited 2023 Sep 22];Available from: http://www.emdocs.net/core-em-ventricular-tachycardia/
Ortiz M, Martín A, Arribas F, Coll-Vinent B, Del Arco C, Peinado R, Almendral J; PROCAMIO Study Investigators. Randomized comparison of intravenous procainamide vs. intravenous amiodarone for the acute treatment of tolerated wide QRS tachycardia: the PROCAMIO study. Eur Heart J. 2017 May 1;38(17):1329-1335. doi: 10.1093/eurheartj/ehw230. PMID: 27354046; PMCID: PMC5410924.
Buttner R and Burns E. VT versus SVT [Internet]. Life in the Fast Lane • LITFL. 2023 [cited 2023 Sept 22];Available from: https://litfl.com/vt-versus-svt-ecg-library/
Salim R. SVT With Aberrancy Versus VT [Internet]. REBEL EM blog. 2013 [cited 2023 Sept 22]. Available at: https://rebelem.com/svt-aberrancy-versus-vt/.
Buttner R. VT versus SVT: It’s as easy as ABCDE [Internet]. Life in the Fast Lane • LITFL. 2023 [cited 2023 Sept 22];Available from: https://litfl.com/vt-versus-svt-its-as-easy-as-abcde/
Smith SW. Ventricular tachycardia? or SVT with aberrancy? [Internet]. Dr. Smith’s ECG Blog. 2019 [cited 2023 Sep 22];Available from: http://hqmeded-ecg.blogspot.com/2019/01/ventricular-tachycardia-or-svt-with.html