ACE and hydrops fetalis: Considering observations that myocardial production of Ang II can persist despite treatment with captopril [237] due to incomplete blockade of Ang II production during ACE inhibition, and production of it independent of ACE via chymase [238], the OPTIMAAL trial was conducted to compare the effects of ACE inhibitors and AT1 receptor antagonist son mortality and morbidity in patients suffering from MI with evidence of HF or LV dysfunction.