Pathophysiology of Hyperkalemia Presenting as Brugada Pattern on Electrocardiogram (ECG)

Diagnostic accuracy of emergency department ECGs in hyperkalemia detection: A cross-sectional study

OBJECTIVE

To assess the diagnostic accuracy of ECG readings in detecting hyperkalemia and predicting outcome in the ED.

METHODS

A retrospective cross-sectional analysis was conducted on ED patients, including patients with confirmed hyperkalemia (≥ 5 mmol/l) and a normokalemic control group. The predictive value of ECG readings for the detection of hyperkalemia was studied. For this purpose, the subjective probability of hyperkalemia was rated from 0-100 (Hyperkalemia Probability Scoring) by two attending acute care physicians. Logistic regression and ROC analysis were used to assess predictive power and sensitivity/specificity of Hyperkalemia Probability Scorings. Prediction of 7-day adverse outcomes (ICU admission, hemodialysis, in-hospital mortality) based on Hyperkalemia Probability Scorings was analyzed.

RESULTS

We studied 1608 patients, thereof 805 served as normokalemic control patients. Sensitivity and specificity of ECG readings for hyperkalemia detection were 0.47 and 0.76 for cardiologist 1, and 0.39 and 0.81 for cardiologist 2. The AUC was 0.63 (95 % CI 0.60-0.65) and 0.61 (95 % CI 0.59-0.63) for the respective cardiologists. With a Hyperkalemia Probability Scoring of 100 compared to 0, the Odds Ratios (ORs) of diagnosing hyperkalemia were 8.2 (95 % CI 5.3-12.6) and 9.1 (95 % CI 5.8-14.7), while the ORs for 7-day adverse outcomes were 2.14 (95 % CI 1.34-3.38) and 2.22 (95 % CI 1.39-3.49) respectively.

CONCLUSION

The ECG is not an accurate tool for ruling-in or ruling-out hyperkalemia in ED patients. Higher Hyperkalemia Probability Scorings are associated with 7-day adverse outcomes.

Irregular rhythm with wide-QRS complexes and repolarization abnormalities in the emergency department: A nightmare ECG

We present the ECG findings of a 49-year-old woman recorded in the emergency department, which reveal a wide-QRS, irregular rhythm. The ECG shows a broad terminal wave in the right precordial leads, along with a convex ST segment elevation, and is associated with a right axis deviation. While the initial presentation may appear complex, several diagnostic possibilities must be considered, as each could suggest a distinct management for this clinical case.

Electrocardiography is Unreliable to Detect Potential Lethal Hyperkalemia in Patients with Non-dialysis Chronic Kidney Disease

Hemodialysis patients with hypercalcemia are less likely to manifest the usual electrocardiographic changes associated with hyperkalemia than in those with normal renal function. This study was conducted to determine whether electrocardiography (ECG) is a reliable indicator to detect severe life-threatening hyperkalemia in non-dialysis CKD patients. The study was conducted at three referral university hospitals between July 2017 and June 2018. Severe hyperkalemia was defined as serum potassium concentration ≥ 8.0 mEq/L. Serum potassium, sodium, bicarbonate, calcium, and creatinine concentrations were measured and simultaneous 12-lead ECG was obtained. Patients with end-stage renal disease receiving renal replacement therapy were excluded. Also excluded were patients with the usual ECG abnormalities to hyperkalemia. Of the 438 patients screened, 10 (2.3%) aged 2-14 years with severe hyperkalemia and normal ECG findings were identified. Median serum potassium level was 8.6 mEq/L (range 8.2-9.0). All had regular sinus rhythm. P, QRS, ST segment, T morphology, PR and QT interval, and QRS duration were all normal. Hyperkalemia was associated with CKD, metabolic acidosis, and hypercalcemia in all cases. Therapy with intravenous 0.9% saline, sodium bicarbonate, glucose, insulin, calcium, and salbutamol corrected the hyperkalemia in 7 patients. The remaining three patients evinced arrhythmias requiring hemodialysis. Although rare, non-dialysis CKD patients with hypercalcemia may not manifest the usual electrographic abnormalities associated with hyperkalemia. Thus, a normal ECG finding in non-dialysis CKD patients should be interpreted with caution.

Brugada Pattern Manifesting During Hyperkalemia, Diabetic Ketoacidosis, and Acute Alcohol Intoxication

BACKGROUND Brugada syndrome is a rare ion channelopathy that can lead to sudden cardiac death and lethal arrhythmias in patients without a structural cardiac defect, the most common of which being the gain-of-function mutation of the SCN5a sodium ion channel involving phase 0 of the cardiac action potential. In 2012, BrS electrocardiogram findings were redefined and classified as either congenital Brugada syndrome (BrS) or Brugada phenocopies (BrP). Several etiologies of BrP have been reported, such as metabolic derangements, electrolyte abnormalities, cardiovascular diseases, and pulmonary embolism. CASE REPORT A 28-year-old man presented to the Emergency Department unresponsive. An initial ECG taken by Emergency Medical Services (EMS) was interpreted as a STEMI. An initial ECG in the ED showed a Brugada type I ECG pattern in leads V1-V2 and hyperacute T wave abnormalities, among other findings. Additionally, the patient had a serum potassium level of 9 mmol/L, glucose level of 1375 mmol/L, and peak cardiac troponin-I of 20.452 μg/L. All underlying medical conditions were stabilized, electrolyte and metabolic abnormalities were corrected, and subsequent normalization of electrocardiographic findings was achieved. CONCLUSIONS Distinguishing congenital Brugada syndrome from Brugada phenocopies can be difficult, especially when patients present to the ED with severe underlying conditions. Several factors can be used to direct clinical suspicion towards one or the other; however, confirmation may require EP studies and further tests. In this case, the following findings were suggestive of BrP: presence of an identifiable underlying abnormality, correction of the underlying condition resolves the ECG pattern, and the absence of family history of sudden cardiac death.