Table 1.

Vital signs, laboratory data and electrocardiographic features of patients in this study

Case	Vital signs	Laboratory values	ECG features
Case 1	HR 54/min BP 120/54 mmHg SpO2 98%	Na+ 135 mmol/l K+ 10.36 mmol/l Ca2+ 2.1 mmol/l Mg2+ 1.8 mg/dl	Sinus bradycardia with variable AV block with short QT interval
Case 2	HR 70/min BP 100/60 mmHg SpO2 100%	Na+ 146.8 mmol/l K+ 8.23 mmol/l Ca2+ 2.3 mmol/l Mg2+ 1.7 mg/dl	Sinus node dysfunction with junctional escape rhythm and ectopic atrial rhythm with short QT interval
Case 3	HR 95/min BP 120/76 mmHg SpO2 100%	Na+ 126.4 mmol/l K+ 7.24 mmol/l Ca2+ 2.2 mmol/l Mg2+ 2 mg/dl	P waves were small, T wave inversion in leads II, III, aVF and V1-3, QRS duration of 77 ms (narrow QRS)