Brugada ECG pattern during hyperkalemic diabetic ketoacidosis

A 31-year-old White gentleman with type 1 diabetes mellitus with known noncompliance with insulin causing frequent hospitalization due to diabetic ketoacidosis (DKA) was sent to the emergency department after he was found to be stuporous by his girlfriend. His medical history also includes intravenous drug use. On arrival, he had a blood pressure of 127/72 mmHg, heart rate 144 beat/min, temperature 99.9 ° F and his oxygen saturation was 100% on room air. Laboratory workup revealed an arterial pH of 7.049, pCO₂ 10 mmHg, pO₂ 137 mmHg, arterial HCO₃ 2.8 meq/l, Na 126 meq/l, random blood sugar 1090 mg/dl, blood urea nitrogen 51 mg/dl, creatinine 2.91 mg/dl, and beta hydroxybutyrate level 15 mmol/l. Urine drug screen was positive for amphetamines. His potassium level on admission was 8.4 meq/l and an electrocardiogram (ECG) showed hyper-acute T-waves and Brugada type 1 pattern with increased QRS duration (142 msec) associated with a high take-off of the ST-segment >2 mm in V1-V2, followed by down-sloping ST-segment and symmetrical T-wave inversion (Figure 1a). Nine hours later after appropriate treatment for DKA; potassium was 3.8 meq/l, venous pH was 7.328, and ECG showed resolution of ST-segment elevation (Figure 1b). He has not developed any malignant ventricular arrhythmias during hospitalization and denied family history of sudden cardiac death. He has made a successful recovery and provided a written informed consent for the publication of this report.

Figure 1.

(A) Twelve lead ECG on admission of a patient with severe DKA showing tall tented T-waves due to hyperkalemia. Notice the Brugada type 1 pattern with increased QRS duration (142 msec) and high take-off of the ST-segment >2 mm in V1-V2, followed by down-sloping ST-segment and symmetrical T-wave inversion. (B) Repeat ECG 8 h later after normalization of serum potassium and significant improvement in acidosis and shows resolution of Brugada type 1 pattern.

Brugada syndrome is a familial sudden cardiac death syndrome associated with increased risk of lethal ventricular tachyarrhythmia. A mutation of the SCN5A gene of the sodium (Na⁺) channel is evident in up to 30% of Brugada syndrome cases. ECG abnormalities in Brugada syndrome may be latent, only uncovered by certain illnesses or drug provocation testing with the cardiac Na-channel blocker ajmaline [Wilde et al. 2010]. Uncovering Brugada syndrome is important to save the patient and their next of kin from the risk of sudden death. On the other hand, there are multiple clinical entities known as ‘Brugada phenocopies’ which are etiologically distinct from true congenital Brugada syndrome. These include, but are not limited to, various metabolic conditions, ischemia, pulmonary embolism, myocardial and pericardial disease [Anselm et al. 2014]. Differentiation between both entities is not simple because their ECG patterns are visually identical and indistinguishable [Gottschalk et al. 2016]. An important report by Postema and colleagues illustrated a case of familial Brugada syndrome uncovered by hyperkalemia and acidosis [Postema et al. 2011]. On presentation, ECG revealed Brugada type 1 ECG pattern that resolved with resolution of hyperkalemia. Ajmaline testing of the patient and his 30-year-old son, who had no medical history, provoked Brugada type 1 ECG features [Postema et al. 2011]. In our case, we suspect that hyperkalemia and acidosis have evoked the Brugada type 1 ECG pattern. Hyperkalemia and acidosis can decrease Na⁺ current magnitude through inactivating the cardiac Na⁺ channel. This was previously reported, and the combination specifically carries a poor prognosis [Littmann et al. 2007]. We have not checked for SCN5A mutation and ajmaline provocation test in our patient. There have been no electrophysiological studies of the effect of Na⁺ channel blockade challenge after resolution of a Brugada sign. Further research is needed to investigate if patients with hyperkalemia and acidosis-induced Brugada ECG patterns have a hereditary anomaly in the Na⁺ channel, and whether they are more prone to ventricular arrhythmias. We aim to sensitize clinicians to the possibility that hyperkalemia and acidosis may be associated with a Brugada ECG pattern.