[1] Tabba Heart Inst, Dept Infect Control, Fed Area B, Karachi 74800, Karachi, Pakistan
[2] Aga Khan Univ Hosp, Dept Med, Karachi, Pakistan
[3] Natl Med Ctr, Dept Nursing, Karachi, Pakistan
[4] Tabba Heart Inst, Dept Cardiol, Karachi 74800, Karachi, Pakistan