Both AC5 and AC6 mRNAs appear decreased in dogs with pacing-induced Congestive Heart Failure (CHF) (Ishikawa et al., 1994); while in a swine model of tachypacing and severe heart failure, AC6 but not AC5 is downregulated (Ping et al., 1997). The gene discussed is ADCY6; the disease is congestive heart failure.