Chez Eddy is a Houston restaurant that serves a kind of nouvelle American Southwestern fare, as high-flying as marinated wild boar with plum-port wine sauce, as au courant as radicchio/arugula/jicama/fresh-corn salad with beet vinaigrette-- but with one difference you're unlikely to notice without being told (and that's a plus): Conceived by heart-specialist Gotto, the restaurant makes every dish conform to American Heart Association guidelines for fat, cholesterol, sodium, and calories. Obviously, the recipes here are a far cry from the ones in those dreary AHA cookbooks. Though many diet cookbooks make the promise, these dishes--among them escallops of veal with apricot coulis, broiled swordfish with red pepper salsa, tamarind sauce with an unexpected dollop of Marsala wine, vitello tonnato with reduced-calorie mayonnaise cut further with nonfat yogurt, and two cheesecakes (one of ricotta, one nonfat yogurt, both using liqueurs)--really have the pizazz and sumptuous qualities that make a heart-healthy diet easy to maintain. (Of course, calorie-watchers still have to sacrifice in the serving-size department.) And they're not especially demanding of the cook.