RV dysfunction has been associated with increased mortality in the ICU and cardiac surgical patients. Thus, early identification of RV dysfunction at less severe stages will allow for earlier intervention and potentially better patient outcomes. However, so far, no studies have reported prospectively the prevalence of abnormal RV pressure waveform during cardiac surgery and in the ICU. The investigator's primary hypothesis is that the prevalence of abnormal RV pressure waveform occurs in more than 50% of cardiac surgical patients throughout their hospitalization. Those patients with abnormal RV pressure waveform will be more prone to post-operative complications related to RV dysfunction and failure in the OR and ICU.