[SCD-FORUM] 64E RE: An Unusual QRST Pattern in A Patient with Severe Hypokalemia. Dr. Perez Riera

[SCD Symposium]

Dear colleague from China: This nice case  report is a very  
interesting presentation of acquired forms of the Brugada syndrome  
(BrS)  Both Hypokalemia and Hyperkalemia increases transient outward  
current in phase1, adenosine triphosphate-sensitive potassium  
current, delayed modifier potassium current or decreases inward  
currents: L-type calcium current, fast Na+ current at the end of  
phase 1 of the AP can accentuate or unmask ST-segment elevation,  
similar to that found in the BrS, thus producing acquired forms (1).  
Drugs that reduce the Na+ current may precipitate the BrS ECG type 1   
pattern: Na+ channel blockers and membrane depolarization by  
Hyperkalemia.

Hypokalemia increases the risk of paroxysmal atrial fibrillation in  
BrS (2).

Hyperkalemia secondary to chronic renal failure may cause ECG changes  
mimicking the BrS (3). See the case in

http://www.scd-symposium.org/files/Hyperkalemia.ppt

Propofol Infusion Syndrome (PRIS): entity characterized by  
association of metabolic acidosis, rhabdomyolysis, hyperkalemia, and  
SCD after long-term, high-dose propofol infusion is other cause  
related of acquired BrS (4).

Finally, hyperkalemia induced by overdose of diphenhydramine is other  
cause of acquired form of BrS (5).

References

1)       Shimizu W. Acquired forms of the Brugada syndrome. J  
Electrocardiol. 2005;38:22-25.

2)        Notarstefano P, Pratola C, Toselli T, et al. Atrial  
fibrillation and recurrent ventricular fibrillation during  
hypokalemia in Brugada syndrome. Pacing Clin Electrophysiol.  
2005;28:1350-1353.

3)       Ortega-Carnicer J, Benezet J, Ruiz-Lorenzo F, Alcazar R.  
Transient Brugada-type electrocardiographic abnormalities in renal  
failure reversed by dialysis. Resuscitation. 2002;55:215-219

4)       Vernooy K, Delhaas T, Cremer OL,.Electrocardiographic  
changes predicting sudden death in propofol-related infusion  
syndrome. Heart Rhythm. 2006;3:131-137

5)       Lopez-Barbeito B, Lluis M, Delgado V, et al. Diphenhydramine  
overdose and Brugada sign. Pacing Clin Electrophysiol. 2005;28:730-732.



All the best

Andrés Ricardo Pérez Riera

Chief of Electro-Vectocardiology Sector of the Discipline of   
Cardiology, ABC Faculty of Medicine (FMABC), Foundation of ABC  
(FUABC) - Santo André - Sao Paulo - Brazil. Rua Sebastiao Afonso  885  
- Zip Code: 044417-100- Jardim Miriam   S.P  Brazil


>
> An Unusual QRST Pattern in A Patient with Severe Hypokalemia
> A 31-year-old male was admitted with muscle weakness of the  
> extremities, paralysis and
> dyspnea. The patient felt tired for 12 hours with nasal discharge,  
> nausea and one episode of
> vomiting, but had no fever or cough. The patient had been sent to a  
> local clinic where he
> received IV hydration. His muscle weakness got worse and he  
> developed paralysis 6 hours
> before the admission.
> In the past, the patient was in good general health. There was no  
> history of allergy to
> mediation or food. He denied history of hepatitis or tuberculosis.  
> There was no history of
> contact with industrial poison and radioactive substances. There  
> was no history of surgery or
> trauma.
> Physical examination: T: 36.4°C,P: 66/min,R: 20/min,BP: 130/60  
> mmHg. The patient
> was in no acute distress. There was exophthalmos bilaterally. The  
> thyroid was enlarged and
> felt to be somewhat solid, with normal mobility but no flow murmur.  
> Lungs were clear. Heart
> showed some irregularity, but no murmur. Physical reflexes were  
> within the normal range,
> but the extremity muscle strength was zero degree. Muscular tension  
> decreased in the arms,
> but increased in the legs.
> Stat electrocardiogram (EKG) showed Sinus arrhythmia with a rate of  
> 61/min. The P-R,
> QRS and Q-T intervals measured 260, 120 and 360 ms, respectively.  
> QU interval=670 ms.
> There was an rSr’ pattern of the QRS complex in leads V1 through  
> V3, with r < r’. There was
> ST segment downsloping elevation of 0.2 mV with inverted T wave in  
> leads V1 and V2. T
> wave was flat in lead V3. There was an Rs pattern with a tall R  
> wave (3.8 mV) and a late
> broad S wave in lead V5. There were prominent U waves in all the  
> leads,more so in the
> precordial leads.
>
> http://www.scd-symposium.org/files/wang1.pdf
>
>
> EKG diagnose:1) Sinus arrhythmia; 2) Io atrioventricular block; 3)  
> High
> voltage of the left ventricle; 4) Prominent U wave and QU  
> prolongation suggesting
> hypokalemia. 5) Atypucal Brugada ECG pattern.
>
> Stat blood test revealed K+ was only 1.46 mmol/l,which was improved  
> to 4.46mmol/l
> with potassium supplement over 24 hours. A follow up EKG  
> showed:Normal sinus rhythm
> with a rate of 83/min. The P-R, QRS and Q-T intervals measured  
> 160ms, 80 and 380 ms,
> respectively. There remained an rSr’ pattern of the QRS complex in  
> leads V1 and V2,but r>
> r’. The latter mimic a J wave, with a much lower amplitude when  
> compared to the prior
> electrocardiogram. There remained ST segment downsloping elevation  
> in leads V1 and V2
> (0.1—0.2mv) and T wave inversion in lead V1. But there was no  
> longer T wave inversion in
> leads V2 or V3. An upright R wave was appreciated in V3 as well as  
> in leads V4 and V5. There
> was a qRs pattern in lead V5, with a prominent J wave. The R wave  
> remained to be tall in V5
> (3.9mV). The u wave was no longer present in any leads.
>
> http://www.scd-symposium.org/files/wang2.pdf
>
> EKG diagnosis:1) Normal sinus
> rhythm.  2) High voltage of the left ventricle; 3) Atypical Brugada  
> EKG pattern.
> The patient was subsequetly found to have elevated T3 and T4,  
> therefore the final clinical
> diagnosis was “thyrotoxicosis with periodic paralysis”.
> Questions to the ECG expert Dr. Perez Riera:
>   1) Do you consider whether this patient has a Brugada pattern or  
> not?
>      2) Want is your interpretation of the ECG, especially  
> considering the unusual QRST
> pattern in the right precordial leads?
> Thank you,
> Hongyu Wang, MD
> Jiangping Li, MD
> Second Hospital of Shanxi Medical University
> PR. China



--
Dr. Sergio Dubner
President of Scientific Committee

Dr. Edgardo Schapachnik
President of Steering Committee




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