Case number PHHO2014US001660, is an initial report received on 29 Jan 2014, from clinical study. This 75-year-old male subject (BMI 53.0) (center number unknown) was enrolled in a study to evaluate the safety and immunogenicity of a cell-based quadrivalent subunit influenza and cell-based trivalent subunit influenza in adults ages >=18 years of age. The ongoing medical history of the subject included borderline hypertension (since 2006) and sleep apnea (since 1992, type of sleep apnea not available). It was reported that the subject was overweight (since 1968), body mass index 53.0. Concomitant medications at the time of enrollment included ibuprofen, glucosamine and multivitamin. The subject received study vaccine on 05 Dec 2013 at 15:33 hours (visit 1). The subject blood pressure was at 133/91 mmHg, and physical examination revealed normal results (not specified). On 19 Dec 2013, the PCP referred the subject to a cardiologist, and lisinopril was added to the subject therapy for hypertension. The treatment detail for sleep apnea was not provided. On 09 Jan 2014, the subject visited the cardiologist and presented with shortness of breath, dyspnea on exertion and increased swelling in the lower extremities. The subject was then sent to the emergency room (same day) and tests revealed pulse at 130 /min, blood pressure at 145/90 mmHg, oxygen saturation at 94% and ejection fraction (EF) was 50 - 55%. An ECG revealed atrial fibrillation and a transesophageal ECG which was consistent with clinical diagnosis of congestive heart failure. The subject was diagnosed with atrial fibrillation with rapid ventricular rate and congestive heart failure and was admitted on the same day. On the same day, an echocardiogram was performed which was within normal limits, showed mild pulmonary hypertension, no mass or thrombus was noted. The subject received treatment with diuretics (intravenous LASIX) and was placed on DIGOXIN (intravenous). Laboratory tests revealed red blood cell count (RBC) at 4.05, haemoglobin (hgb) at 13.2, hematocrit (HCT) at 38.9. The subjects serum electrolytes, kidney function tests, liver function tests and thyroid profile revealed normal results. On 10 Jan 2014, the subject had an electrical cardioversion. On the same day, the subject received DIGOXIN orally. A chest x-ray performed on 10 Jan 2014, revealed midline trachea, stable cardiomediastinal silhouette (left costophrenic angles was not included), right mid lung scarring and probable basilar layering effusions. On 12 Jan 2014, the subject recovered completely from the events of atrial fibrillation with rapid ventricular rate and congestive heart failure and was discharged on the same day. The investigator considered the events of with atrial fibrillation with rapid ventricular rate and congestive heart failure to be serious (hospitalization). The investigator reported that the event of atrial fibrillation with rapid ventricular rate was suspected to treatment with study vaccine and congestive heart failure as not suspected to treatment with study vaccine. The investigator stated rationale for causality assessment to study treatment that the timing of the vaccine and onset of symptoms raised suspicion of possible link. He also stated that the link is possible though unlikely. The investigator reported that the subjects risk factors predispose to cardiac disease and could contribute to these issues. Other possible contributory factors for the event of atrial fibrillation with rapid ventricular rate were reported as hypertension and obesity. Follow up information received on 05 Feb 2014: Added concomitant medications, laboratory test details, symptoms, treatment medications, and updated the rationale for causality assessment.