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Ketoacidosis in Patient With Type 1 Diabetes Mellitus Triggered Brugada Type Electrocardiogram: Brugada Phenocopy
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EP LAB DIGEST. 2024;24(1):17,21.
Various circumstances can provoke Brugada phenotype electrocardiography (ECG) and differentiating genuine Brugada syndrome from Brugada phenocopy can be challenging. In this manuscript, we present a patient with type 1 Brugada ECG pattern caused by severe ketoacidosis in a patient with type 1 diabetes mellitus. After correction of the metabolic imbalances, the ECG pattern resolved.
Case Presentation
A 20-year-old man was admitted to the hospital because of a hyperglycemic disorder. The patient has had type I diabetes for 16 years and is treated with subcutaneous injections of insulin. An insulin pump has been used for several years, and the dosage was increased a few weeks ago.
The patient reported polyurea for a couple of days, as well as gastrointestinal symptoms such as abdominal pain and diarrhea some hours before presentation. The patient’s last blood sugar measurement showed a blood sugar value of 200-300 mg/dL before going to bed. The dose to be applied by the insulin pump did not have to be adjusted due to these values. On admission, laboratory tests in the morning revealed metabolic acidosis (pH 6.9, bicarbonate 4.2 mmol/L, base excess -27.5) with significantly increased lactate and hyperkalemia (lactate 11.8 mmol/L, potassium 6.6 mmol/L). Ketone bodies in the urine diagnostics were increased threefold. The blood glucose was also massively increased at 998 mg/dl. In addition, laboratory tests revealed an acute renal failure AKIN St. II (creatinine 1.64 g/dl, eGFR 59 ml/min/m2), as well as significantly increased infection markers. Causative for the acute renal failure were a third-degree urinary obstruction combined with a urinary tract infection. To complete the symptom complex, abdominal sonography also revealed abdominal retention and paralytic intestinal loops in the sense of gastrointestinal paresis. When myocardial markers were also elevated (troponin T 178 ng/l [<14 ng/l], CK 454 U/l and CK-MB 29 U/l), a resting ECG (Figure 1) was performed and showed coved type ST-segment elevations in leads V1-V2 as type 1 Brugada ECG.
Echocardiographic findings were unremarkable. With continuous drug correction of the electrolyte and blood sugar imbalances, the ECG changes declined (Figure 2). Further clarifications regarding the presence of a structural heart disease using coronary computed tomography (Figures 3 and 4) were also without findings. Family history of sudden cardiac death was unremarkable.
To further evaluate the presence of Brugada syndrome, an ajmalin test (Figure 5) was carried out, which did not unmask a drug-induced Brugada ECG.
As a result of the findings, the ECG changes were explained by metabolic and electrolyte imbalances, and a Brugada phenocopy was diagnosed. Reconstructing the causal relationship, it was found that the patient damaged the insulin cartridge when it was inserted into the insulin pump, so the programmed insulin dose could not be administered by the pump.
Discussion
Brugada syndrome is diagnosed in patients with type 1 Brugada ECG pattern, which is characterized by J-point elevation of >2 mV with coved ST-elevation and T wave inversion in at least one right precordial ECG lead, V1 or V2, positioned in the 2nd, 3rd, or 4th intercostal space occurring either spontaneously, after provocative drug test with intravenous administration of Class I arrhythmic drugs, or fever induced.1,3 In patients with type 2 ECG pattern and ST-segment elevation in >1 lead among the right precordial leads V1, V2 positioned in the 2nd, 3rd, or 4th intercostal space, Brugada syndrome is diagnosed when provocative drug test induces type 1 ECG morphology.3
Brugada phenocopies are Brugada-like ECG patterns induced by reversible clinical conditions. Most cases of phenocopies are related to metabolic imbalances, ischemia, and pulmonary embolism,2 but can also be caused by mechanical compression of the right ventricular outflow tract.4 Possible mechanisms for Brugada phenocopies are speculative. It is thought that the pattern is induced by an imbalance between ion currents during phase 1 of the action potential or by conduction delays in the anterior myocardial wall.4 Typically, with Brugada phenocopy there is a complete regression of the ECG changes if the underlying cause resolved.5
The Table outlines the criteria to be used when discriminating Brugada syndrome from Brugada phenocopy.5
Therefore, the presence of characteristic Brugada-like ST-segment elevation in V1 to V3, which was reversible after the resolution of an underlying clinical condition, the low probability of a genuine Brugada syndrome because of patient history, and the negative drug challenge favor the diagnosis of Brugada phenocopy in this case.
Disclosure: The author has completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest, and reports no conflicts of interest regarding the content herein.
References
1. Zeppenfeld K, Tfelt-Hansen J, de Riva M, et al. 2022 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death. Eur Heart J. 2022;43(40):3997-4126. doi:10.1093/eurheartj/ehac262
2. de Oliveira Neto NR, de Oliveira WS, Mastrocola F, Sacilotto L. Brugada phenocopy: mechanisms, diagnosis, and implications. J Electrocardiol. 2019;55:45-50. doi:10.1016/j.jelectrocard.2019.04.017
3. Priori SG, Wilde AA, Horie M, et al. HRS/EHRA/APHRS expert consensus statement on the diagnosis and management of patients with inherited primary arrhythmia syndromes: document endorsed by HRS, EHRA, and APHRS in May 2013 and by ACCF, AHA, PACES, and AEPC in June 2013. Heart Rhythm. 2013;10(12):1932-1963. doi:10.1016/j.hrthm.2013.05.014
4. Pérez-Riera AR, Barbosa Barros R, Daminello-Raimundo R, Resende Barbosa MPC, de Abreu LC. Brugada phenocopy caused by a compressive mediastinal tumor. Ann Noninvasive Electrocardiol. 2018;23(3):e12509. doi:10.1111/anec.12509
5. Anselm DD. Brugada phenocopy: a new electrocardiogram phenomenon. World J Cardiol. 2014;6(3):81-86. doi:10.4330/wjc.v6.i3.81
