1. Westmead Clinical School, Westmead Hospital, University of Sydney, Westmead 2145, Australia
2. Cardiology Department, Westmead Hospital, Westmead 2145, Australia
3. Department of Respiratory and Sleep Medicine, Westmead Hospital, Westmead 2145, Australia
4. Department of Infectious Diseases, Westmead Hospital, Westmead 2145, Australia
5. Southwestern Clinical School, University of New South Wales, Kensington 2052, Australia