(A) Mice (C57 BL6/J) were subjected to transverse aortic constriction (TAC) surgery and were studied for a period of 12 weeks following TAC. The H2S donor, Diallyl trisulfide (DATS), was initiated at a dose of 200 μg/kg (daily i.p. injection) at 24 hours following TAC surgery. Vehicle-treated mice were administered 1% DMSO. Baseline echocardiography was performed 1-week prior to TAC and thereafter at 1, 3, 6, 9, and 12 weeks following TAC. Additional mice were sacrificed at 6 weeks post TAC. Heart and lung tissue were collected for assessment of cardiac and lung weights, cardiac histology, and myocardial molecular determinations. In addition, blood samples were also collected for measurement of nitric oxide intermediates. Representative gas chromatograph peaks and summary data for (B-D) serum and (E-G) myocardial levels of free H2S and sulfane sulfur after 1 week of TAC in groups of mice injected daily with vehicle or DATS. Results are expressed as mean ± SEM. Numbers in bars represent sample size.