Torsades de pointes; ventricular fibrillation; cardiac arrest; This is a literature report.  A 65-year-old female patient received BNT162b2 (BNT162B2), as dose 3 (booster), single (Batch/Lot number: unknown) for covid-19 immunisation. The patient's relevant medical history included: "hypertension" (unspecified if ongoing); "Left bundle branch block" (unspecified if ongoing); "implantable loop recorder" (unspecified if ongoing). The patient's concomitant medications were not reported. Past drug history included: Procainamide, reaction(s): "negative procainamide challenge", notes: 10 mg/kg intravenous infusion over 10 minutes. Vaccination history included: Bnt162b2 (dose 1), for COVID-19 immunisation; Bnt162b2 (dose 2), for COVID-19 immunisation, reaction(s): "myocarditis", "syncope", "nonsustained ventricular arrhythmia". The following information was reported: TORSADE DE POINTES (hospitalization, medically significant, life threatening), 12 hrs after the suspect product(s) administration, outcome "recovering", described as "Torsades de pointes"; VENTRICULAR FIBRILLATION (hospitalization, medically significant, life threatening), 12 hrs after the suspect product(s) administration, outcome "recovering"; CARDIAC ARREST (hospitalization, medically significant, life threatening), outcome "recovering". The patient was hospitalized for torsade de pointes, ventricular fibrillation, cardiac arrest (hospitalization duration: 28 day(s)). The patient underwent the following laboratory tests and procedures: Angiocardiogram: demonstrated normal coronary arteries; Blood calcium: 8.4 mg/dl, notes: mildly low; Blood magnesium: 2.4 mg/dl, notes: normal; Blood potassium: 3.9 mmol/L, notes: normal; 2.7 mmol/L, notes: 3 hours later; Body temperature: 33.2 Centigrade; Cardiac electrophysiologic study: demonstrated normal sinus node function, normal at, notes: atrioventricular node function, and mildly abnormal His-Purkinje system conduction with negative procainamide challenge; Echocardiogram: demonstrated a left ventricular ejection fraction, notes: of 45%-50% with left ventricular dyssynchrony and normal left ventricular wall thickness; Showed a reduced ejection fraction of 19%, notes: initial; Normalized to 50%, notes: after starting metoprolol succinate; Ejection fraction: 19 %, notes: reduced; 50 %, notes: normalized; Electrocardiogram: demonstrated sinus rhythm with left bundle branch, notes: block, premature atrial complexes, and premature ventricular complexes; demonstrated an accelerated idioventricular rhythm; demonstrated sinus rhythm with left bundle branch, notes: block; demonstrated progressive QT prolongation with a ma, notes: maximum QTc of 705 ms; Electrocardiogram QRS complex: 0.164 seconds; 0.160 seconds, notes: at baseline; 0.170 seconds, notes: increased, After completion of the procainamide infusion; 0.160 seconds, notes: ms; 0.170 seconds; Electrocardiogram QT interval: 0.454 seconds; 0.540 seconds; 0.780 seconds; 0.517 seconds; 0.525 seconds, notes: at baseline; 0.630 seconds, notes: increased, After completion of the procainamide infusion; 0.592 seconds; 0.705 seconds; Heart rate: 78, notes: beats per minute; 79, notes: beats per minute; 72, notes: beats per minute; 49, notes: beats/min; application of an automated external defibrillator: demonstrated ventricular fibrillation; HV interval: 0.065 seconds, notes: at baseline; 0.073 seconds, notes: prolonged, following procainamide 10 mg/kg intravenous infusion over 10 minutes; 0.380 seconds; 0.290 seconds; 0.330 seconds; 0.390 seconds, notes: increased, After completion of the procainamide infusion; 0.610 seconds; 0.380 seconds; Magnetic resonance imaging head: demonstrated anoxic brain injury; SARS-CoV-2 test: negative, notes: on admission; Troponin I: 30 ng/L, notes: initial; 18697 ng/L, notes: rose, 10 hours later. Therapeutic measures were taken as a result of torsade de pointes, ventricular fibrillation, cardiac arrest.; Sender's Comments: Based on available information, a possible contributory role of BNT162B2 vaccine can not be excluded for the reported event of Cardiac arrest, torsade de pointes , ventricular fibrillation due to temporal relationship. Case will be re-assessed upon the additional information provided. The impact of this report on the benefit/risk profile of the Pfizer product is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to regulatory authorities, Ethics Committees, and Investigators, as appropriate,Linked Report(s) : US-PFIZER INC-202201015027 same patient/drug, different event;