Pre-syncope and a bizarre wide complex

Written by Magnus Nossen with edits by Grauer.

The following ECG is from a man in his 70s with a history of atrial fibrillation (AF). He presents to your emergency department with chest discomfort and recent episodes of presyncope.

Does this ECG show findings consistent with occlusion myocardial infarction (OMI)? If not — What else could be going on?

ECG #1

Shortly after the above ECG was recorded, the patient went into cardiac arrest. Cardiopulmonary resuscitation (CPR) was performed — and the patient woke up during resuscitation efforts before defibrillation was possible. Below are two print outs from the cardiac monitor showing onset and termination of the ventricular arrhythmia causing the cardiac arrest.

Initiation of polymorphic ventricular tachycardia

Spontaneous termination of polymorphic ventricular tachycardia

The above printouts from the cardiac monitor show two spontaneously-recorded 4-lead rhythm strips. The second lead from the top is lead V1. Note the unusual RBBB-type QRS morphology in this lead V1 both before and after the episode of PMVT. 

The patient again went into cardiac arrest. He was quickly defibrillated — and awoke soon after, at which time ECG #2 (shown below) was recorded. 

ECG #2

ECG interpretation: Both ECG #1 and ECG #2, as well as the rhythm strips show a bizarre looking QRS complex. There is a RBBB-like QRS morphology in the right sided chest leads. The QRS is very wide — at least 180ms ( = 4.5 small boxes in duration). There is significant ST elevation (most pronounced in right sided leads) — with T-wave inversion in affected leads. 

• The ST-segment elevation is not typical of ischemia. Instead — the ECG is consistent with Brugada morphology. (Brugada morphology can be caused by a number of different conditions, of which Brugada Syndrome is the best known.). 

The figure below is a magnified view of leads V1-V3 from ECG #2. The brown arrows point to sinus P-waves. The vertical blue line marks the beginning of the QRS, while the red line marks the end of the QRS and the beginning of the ST segment. 

Case Continuation: This patient was on flecainide therapy (50 mg twice daily) for rhythm control of atrial fibrillation (AF). For "breakthrough" AF episodes — he would take an additional 100mg of flecainide. If this did not successfully convert his AF to sinus rhythm — the patient was told to go to the A&E (Accident and Emergency) Service for electrical cardioversion. 

• On the day of the presentation — the patient had taken an extra 100mg flecainide tablet for "breakthrough" AF. 
• Unfortunately — the flecainide precipitated a Brugada ECG pattern, that then degenerated to a series of PMVT (PolyMorphic VT) episodes, with need for resuscitation including multiple defibrillations. 

Serum potassium and magnesium levels were normal.

• Ongoing treatment included multiple doses of IV magnesium sulfate during the first 24 hours after admission. In addition, the patient was buffered with sodium bicarbonate in an attempt to negate the sodium channel blocking effect of flecainide. 

The patient continued to have several brief episodes of PMVT which resolved spontaneously. 

• It was decided to sedate and intubate the patient. Should multiple additional defibrillations be required — it would be safer and easier to accomplish this with the patient intubated and sedated. 

ECG #3 (shown below) was recorded on the 2nd hospital day. At this time, the patient was extubated, and had been stable for many hours without further VT. 

ECG #3

ECG above with atrial fibrillation. Persitent Brugada ECG pattern, here type 2.

Throughout the patient's hospital stay — troponin did not show a significant rise. Cardiac cath was normal. No more episodes of VT were noted.

• The patient was diagnosed with Brugada Syndrome and an ICD was placed.
• Genetic panel was negative (Only 20-30% of patients meeting the diagnostic criteria for Brugada Syndrome have a positive genetic test). There was however, a positive family history of SCD (Sudden Cardiac Death). 
• Flecainide was discontinued — after which a Brugada-2 ECG pattern was intermittently seen, but there was no recurrence of the Brugada-1 pattern.

ECG #4 (shown below) was recorded during follow-up.

Brugada Syndrome (BrS) was first described in 1992. What began as an electrocardiographic curiosity has later gained much attention due to the increased risk of sudden death in young and otherwise healthy individuals. The syndrome has been the subject of great interest in both clinical and basic research.

Brugada Syndrome is a hereditary arrhythmogenic disorder (channelopathy) with characteristic electrocardiographic changes in the form of ST-segment elevation in the right-sided precordial leads (V1 – V3), and an increased risk of PMVT and VFib.

• Inheritance is autosomal dominant. 
• To date, a mutation has been detected in 20-30% of patients with BrS. 

A long list of factors that can cause a Brugada ECG pattern has been described, including certain medications, electrolyte imbalances and various drugs. 

• Drugs that have been implicated include antiarrhythmic agents (ie, flecainide, verapamil and propranolol) — Antidepressants (ie, amitryptiline) — and drugs that increase vagal tone such as acetylcholine. 
• A Brugada ECG pattern can also be seen after cocaine or alcohol use. 
• NOTE: The ECG changes in Brugada syndrome can be dynamic. Many patients will intermittently have a normal ECG — only to unpredictably and spontaneously change to a Brugada ECG pattern. 
• 3 Types of Brugada ECG patterns can be seen (See figure below). At times all 3 of these Brugada types may be seen in the same recording. 

Types of Brugada ECG pattern

 

(Figure above reproduced from LITFL -2022 )

• Type 1 ECG: Coved ST segment elevation ≥2 mm which continues in T-wave inversion in lead V1 and/or V2.
  
  
• Type 2 ECG: Saddleback shaped ST segment elevation with J point elevated ≥2 mm in leads V1 and/or V2
  
  
• Type 3 ECG: Similar to type 2 criteria but the terminal portion of the ST segment is elevated <1 mm  
  

============================================

Regarding Today's CASE:

The patient in today’s case was diagnosed with Brugada syndrome (BrS) by having a positive family history of SCD, a Brugada-1 ECG pattern (after being put on flecainide) — and documented PMVT degenerating to ventricular fibrillation. An ICD (implantable cardioverter defibrilator) was placed.

Another clinical entity called Brugada Phenocopy (BrP) produces ECG patterns indistinguishable from that of Brugada Syndrome. The distinction between BrS and BrP can sometimes be a difficult one, especially as the typical ECG pattern in BrS can be intermittent — and genetic testing in BrS in the majority of cases does not reveal any causal genetic mutation. 

For example; A patient with true BrS can have a normal baseline ECG and then develop fever-induced Brugada-1 ECG changes. On the other hand, a patient without true Brugada Syndrome may, while febrile have a Brugada-1 ECG pattern that disappears when the fever wears off — this would qualify as BrP. The gene test for each of these patients could be normal. Unless there is further information like documentation of typical ventricular arrhythmia ssociated with BrS; syncope; or a family history of SCD — the two patients are really indistinguishable.

Having a spontaneous Brugada-1 ECG pattern is an indication for further work up and referral to a specialist. Having a Brugada-1 ECG pattern in the setting of a possible trigger should prompt further investigation. Referral to a cardiologist who specializes in the work-up and treatment of patients with channelopathies is likely warranted in equivical cases where the distinction between BrS and BrP is difficult. Sodium channel blocker provocation test could be considered as part of the diagnostic work-up and  electrophysiological studies should be part of risk stratification. 

More related cases from this blog:

Brugada Phenocopy and Cocaine

Cardiac arrest, severe acidosis, and a bizarre ECG

A Patient with Cocaine Chest Pain and Prehospital Computer interpretation of ***STEMI***

Troubles with Flecainide

Wide-complex tachycardia: VT, aberrant, or "other?"

A young woman with palpitations. What med is she on? With what medication is she non-compliant? What management?

An elderly patient with syncope, dyspnea, and weakness, but no Chest Pain, and mild hyperkalemia

Right Bundle Branch Block with New Anterior ST elevation

Here, Flecainide toxicity in the setting of ventricular paced rhythm mimics hyperK: Weakness and Dyspnea with a Sine Wave. It's not what you think!

Please see this 2022 case by dr Meyers for a discussion on Brugada phenocopy. 

============================================

Learning Points: 

• Patients with Brugada syndrome may have a normal ECG. The characteristic ECG changes may occur only intermittently, or after a triggering stressor.
  
  
• Always perform a follow-up ECG after prescribing or increasing the dose of a class 1a antiarrhythmic drug, as this may unmask the Brugada ECG pattern.
  
  
• Distinguishing between BrS and BrP is a clinical challenge — making it difficult to determine which patients need ICD placement.

References: 

• Brugada syndrome: A comprehensive review of pathophysiological mechanisms and risk stratification strategies  (Ka Hou Christien Li, Sharen Lee, Chengye Yin, Et .al — IJC Heart & Vasc, 2020)
• Brugada Syndrome • LITFL • ECG Library Diagnosis  (J. Larkin and M. Cadogan — Life In The Fast Lane, 2022)
• Brugada phenocopy: A new electrocardiogram phenomenon (Daniel D. Anselm, Jennifer M. Evans, Adrian Baranchuk — World J Cardiol, 2014)
• Brugada phenocopy vs. Brugada syndrome (Galih J. Adytia, Henry Sutanto — Current Problems in Card, 2024)
• Provocation testing to unmask channelopathies (Manoj N. Obeyesekere, George J. Klein. et al — Circulation: Arrhythm & Electrophys, 2011)
• Implantable loop recorders in patients with Brugada syndrome: the BruLoop study (Bergonti et al — Eur Heart J, 2024)

 

===================================

MY Comment, by KEN GRAUER, MD (8/23/2024):

===================================

I found today's case by Dr. Nossen to be especially interesting — given its combination of clinical features including the history of presyncopal episodes — then cardiac arrest from PMVT (PolyMorphic VT) degenerating to VFib shortly after arrival in the ED (Emergency Department) — presumed precipitation of the arrest by excess Flecainide — and initial ECGs with marked QRS widening, a RBBB pattern and a worrisome STEMI-mimic — with ultimate conclusion that the patient had Brugada Syndrome, leading to ICD placement prior to discharge.

• For illustrative purposes in Figure-1 — I've reproduced the repeat ECG, obtained after defibrillation.

Figure-1: The repeat ECG in today's case, obtained after defibrillation.

MY Thoughts Related to Today's CASE:

I was not sure how to interpret the 2 initial ECGs in today's case. Both tracings contain significant baseline artifact (especially in lead II) — making it hard to identify atrial activity. I agree with Dr. Nossen that the underlying rhythm appears to be sinus — though this is difficult to confirm given variability in the R-R interval and uncertainty about atrial activity.

I focus attention in ECG #2, obtained following successful defibrillation (Figure-1):

• Although the QRS complex in Figure-1 looks wide — the rhythm appears to be supraventricular. How wide the QRS is in ECG #2 is difficult to say — given the distinct notch that we see in lead V2 (RED arrows) — and the hard-to-define boundaries of the QRS in multiple leads.
• I thought some form of RBBB conduction was present (given QRS widening with predominant R waves in V1,V2 — and wide terminal S waves in lateral leads I and aVL).
• The markedly elevated ST segment shape in lead V1, with slow ST segment descent into deep terminal T wave inversion strongly suggests a Brugada-1 ECG pattern in this lead.
• On the other hand — the notching in lead V2 that seemingly occurs at the J-point (RED arrows) — with Shark-Fin-like ST elevation in this lead, looked more like an acute STEMI in this older patient who presented with chest discomfort.
• Yet the reduced QRST amplitudes and unusual ST-T wave shape in lateral chest leads V4,V5,V6 — looked more like continuation of a Brugada pattern than like an acute stemi.
• And, this patient was on Flecainide — and he apparently took some "extra" doses of this medication.

My Impression of ECG #2:

I thought a combination of factors was operative.

• Serum K+ was normal — so hyperkalemia was not a factor.
• Tun et al (EP Lab Digest 11(6), 2011) — and Aizawa et al (Circulation 128(10):1048-1054, 2013) — have shown that the QRS complex in anterior leads with a Brugada-1 ECG pattern may show complete or incomplete RBBB and/or no BBB. And when complete RBBB is present — it may mask the Brugada-1 pattern (and presumably vice versa) — which may explain some of my difficulty distinguishing between what represents a Brugada-1 pattern, RBBB conduction, and a possible acute anterior STEMI.
• Added to the above — is the likelihood of excess Flecainide. As I reviewed in My Comment in the May 21, 2023 post in Dr. Smith's ECG Blog — excess Flecainide may result in marked QRS widening with bizarre morphology. Additional adverse physiologic effects of excess Flecainide may include: i) Prolongation of all intervals (PR-QRS-QTc); ii) Depressed contractility with resultant hypotension; iii) Depression of all major conduction pathways (in the AV Node; His-Purkinje system; and in the ventricles — leading to impaired automaticity); and, iv) Predisposition to lethal arrhythmias (VT/VFib; Asystole). Whether the patient in today's case took enough "extra" Flecainide to produce any or all of these effects is unknown.
• 
  
• NOTE: As per follow-up from Dr. Nossen — subsequent evaluation ruled out acute infarction. This left a combination effect from RBBB-like conduction — Brugada Syndrome — possible "memory effect" (from the VT/VFib and defibrillation) — and excess Flecainide — as explanatory factors for the "picture" presented in ECG #2. 

Final LEARNING Points:

• The gamut of Brugada ECG patterns continues to expand. Many factors may explain the variability in these Brugada ECG patterns — including presence or absence of RBBB conduction — the possibility of associated infarction — potential Brugada precipitants (such as Flecainide in today's case) — and the timing of the ECG recording, given the dynamic nature of Brugada ECG patterns.
• Today's case differs from most patients with Brugada pattern ECGs that we have presented in Dr. Smith's ECG Blog — in that despite whatever effect Flecainide use may have had, today's patient was diagnosed with Brugada Syndrome, with resultant ICD placement prior to discharge.
• In contrast — Most patients on this ECG Blog with Brugada patterns have had Brugada Phenocopy (See My Comment at the bottom of the page in the May 5, 2022 post — the November 25, 2022 post — and the July 22, 2023 post, among other cases of Brugada Phenocopy). The "good news" about Brugada Phenocopy — is that correction of the underlying condition may result in resolution of the Brugada-1 ECG pattern (with a far better prognosis compared to patients with true Brugada Syndrome).
• Among conditions other than Brugada Syndrome that may produce a Brugada-1 ECG pattern include (among others) — acute febrile illness — variations in autonomic tone (as may occur with syncope) — hypothermia — ischemia or infarction — cardiac arrest — electrolyte disorders (especially hyperkalemia — but also hypokalemia/hyponatremia) — and various medications. 
• The 2 most common precipitants of Brugada Phenocopy that we've seen on Dr. Smith's ECG Blog have been: i) Acute febrile illness; and, ii) Hyperkalemia.
• 
  
• Finally — Patients with a Brugada pattern ECG will often be referred from the ED for further evaluation. Definitely refer these patients IF worrisome symptoms are associated with the abnormal ECG pattern (ie, If the patient had syncope-presyncope and/or malignant arrhythmias) and/or if there is a positive family history of sudden death or malignant arrhythmia. Such patients are clearly at higher risk and merit specialized testing by clinicians experienced in the intricacies of Brugada Syndrome (and whether ICD placement should be recommended).
• That said — Recent data suggest that in the absence of a positive family history and worrisome symptoms — development of a Brugada-1 ECG pattern only on provocative drug testing is associated with a very low event rate and a much better longterm prognosis compared to patients who develop a spontaneous Brugada-1 ECG pattern (Gaita et al — Circulation 148(20): 1543-1555, 2023 — Wilde and Saenen — Editorial: Circulation 148(20): 1556-1558, 2023 — Krahn et al — JACC 8(3):386-405, 2022 — Sayed et al — StatPearls, 2023).