Food and Drug Administration approval of a cardiovascular laser system made by Santa Ana-based Trimedyne helped the company achieve a profit of $440,000 for the fiscal year ended Sept. 30, contrasted with a loss of $773,000 a year earlier. Sales climbed to $12.3 million from $5.5 million. During the fourth quarter, Trimedyne posted earnings of $468,000, contrasted with a loss of $224,000 for the comparable period in 1986. Sales totaled $4.2 million, more than double 1986 fourth-quarter sales of $1.8 million. Trimedyne is a manufacturer of medical devices, including fiber-optic catheters, laser catheters, medical laser systems and optical fibers.