Noninvasive positive pressure ventilation has been found to be efficacious in the setting of acute respiratory failure, specifically in chronic obstructive pulmonary disease exacerbations. Its use in congestive heart failure (CHF) is less well established. Additionally, it has been reported that there is an increase in acute myocardial infarction (AMI) rate with the use of bilevel positive pressure ventilation (BiPAP) in CHF patients. This study examined whether BiPAP decreases the intubation rate or improves cardiopulmonary parameters in severe CHF patients compared to high flow O(2) by mask (MASK), and whether there is an increase in AMI rate with the use of BiPAP. A prospective, randomized clinical trial at a county hospital teaching Emergency Department was conducted by enrolling 38 patients who were in severe CHF. Patients were randomized to receive either BiPAP or MASK in addition to adjunct therapy. Age and gender were not different between the groups. Heart rate, systolic blood pressure, diastolic blood pressure, respiratory rate, and pulse oximetry all showed no significant difference in change over time between groups, but there was a significant change over time within groups. Arterial pH, pCO(2), and pO(2) also showed no significant difference in change over time between groups, but there was a significant change over time within groups. The intubation rate for BiPAP was 23.8% (5) vs. MASK at 41.2% (7). The AMI rate was 19% (4) in the BiPAP group and 29.4% (5) in the MASK group. No true differences were detected between groups for increased oxygenation or a reduction in intubation rate. An increase in AMI rate with BiPAP was not found in this study as previously reported. This study provides support for a larger clinical trial assessing the safety and efficacy of BiPAP in acute CHF.