Fig. 7.

Malignant arrhythmic events and timeline of therapies. a. Representative ventricular fibrillation episode terminated by direct current cardioversion. b. R–R interval plot of ventricular fibrillation. c. The timeline of malignant ventricular events and the therapies. The green circles, blue circles and red dots indicate ventricular arrhythmias with frequency <200 bpm, 200–300 bpm, and events terminated by ICD shocks, respectively. The area of the dots indicates the duration of ventricular arrhythmias. Dashed and solid blue lines indicate the start and withdrawal of oral calcium supplement. d. The ECG tracings before and immediately after the application of intravenous calcium. The QTc intervals on V5 lead were 383 ms and 373 ms, respectively. The T wave on precordial leads showed more intensive trend after calcium application.