Evaluation of Cardiovascular System Involvement in Hospitalized Cases of Swine Flu

Introduction: Swine flu primarily affects respiratory system but there are case reports on involvement of cardiovascular system. Materials and Methods: A total of 79 cases of swine flu confirmed by RT-PCR admitted in tertiary care hospital were studied. Cardiovascular involvement was evaluated by clinical history and examination, Standard 12 lead ECG, Chest X-Ray, CPK-MB, NT-proBNP and Troponin I. Other laboratory investigations like complete blood count, renal function test, liver function test, blood sugar, CRP titre, and ABG were also done. All patients were treated as per WHO guidelines and followed-up during hospital stay. Results: There were 35 (44.3%) males (mean age 52.89 ± 17.7 and 44 (55.7%) females (mean age 47.36 ± 16.79). 49 Cases belong to category C and 15 cases each in category B1 and B2. 13 cases (16.46%) had one or more underlying pre-existing cardiovascular disease (PCVD). Cardiovascular manifestations at the time of admission were breathlessness (72.2%), chest pain (28.8%), palpitation (16.5%), presyncope (10.1%), syncope (7.6%) and giddiness (5.1%). ECG manifestation were prolonged QTc interval, RBBB, LBBB, AF, 1ST degree AV block and ST segment elevation. Evaluation of various cardiac biomarker shows involvement of cardiovascular system in 65.8% of the cases where at least one of the markers (Trop I, NT-pro BNP, CPK-MB) was elevated. 16 cases (20.2%) required mechanical respiratory support out of which 15 cases (93.8%) had evidence of cardiovascular involvement. Overall mortality was 8.9% (7 cases died) and all of them were having cardiovascular involvement. Involvement of cardiovascular system was associated with increase requirement for mechanical ventilator and high mortality (overall 13.5% with cardiovascular involvement and 15.4% in patients with PCVD). Conclusions: Cardiovascular system involvement in hospitalized cases of swine flu is found to be very common and associated with high morbidity and mortality.