Teisuke Anzai

Phosphorus-31 magnetic resonance spectroscopy of forearm flexor muscles in student rowers using an exercise protocol adjusted for differences in cross-sectional muscle area

SummaryTo assess exercise energy metabolism of forearm flexor muscles in rowers, six male student rowers and six control subjects matched for age and sex were studied using phosphorus-31 magnetic resonance spectroscopy (31P-MRS). Firstly, to adjust for the effect of differences in cross-sectional muscle area, the maximal cross-sectional area (CSAmax) of the forearm flexor muscles was estimated in each individual using magnetic resonance imaging. Multistage exercise was then carried out with an initial energy production of 1 J · cm−2 CSAmax for 1 min and an increment of 1 J · cm−2 CSAmax every minute to the point of muscle exhaustion. A series of measurements of31P-MRS were performed every minute. The CSAmax was significantly greater in the student rowers than in the control subjects [19.8 (SD 2.2) vs 17.1 (SD 1.2) cm2,P<0.05]. The absolute maximal exercise intensity (J · min−1) was greater in the rowers than in the control subjects. However, the maximal exercise intensity per unit of muscle cross sectional area (J · min−1 · cm−2) was not significantly different between the two groups. During mild to moderate exercise intensities, a decrease in phosphocreatine and an increase in inorganic phosphate before the onset of acidosis were significantly less in the rowers, indicating a requirement of less adenosine 5′-diphosphate to drive adenosine 5′-triphosphate production. The onset of acidosis was also significantly delayed in the rowers. No difference was observed in forearm blood flow between the two groups at the same exercise intensity (J · min−1 · cm−2). These results demonstrated that the findings of the maintenance of a higher level of phosphocreatine and a lower level of inorganic phosphate with less acidosis observed in the rowers were the results of the intrinsic characteristics of energy metabolism of their muscles and that these characteristics were independent of their greater cross-sectional muscle area.

Left ventricular noncompaction with intractable heart failure responsive to empagliflozin

Despite several reports on the mechanism of the effect of empagliflozin, which has the potential for improved prognosis in heart failure, it is still not fully understood. We experienced a case of left ventricular noncompaction that caused fluid retention in a patient who showed resistance to existing diuretics. By using empagliflozin, we successfully treated this case of acute heart failure and observed stabilized symptoms with no renal dysfunction and deterioration of patient condition. Although the potential for improved prognosis with this drug in a high-risk group for cardiovascular events has been reported, based on EMPA-REG OUTCOME trial results, there are few reports on its effect of treatment and mechanism in treating acute heart failure. The effect of this drug in treating heart failure from the acute phase to the chronic phase can be expected. <Learning objective: Empagliflozin is a drug that works from the acute phase and is effective from the acute phase to the chronic phase, in treating intractable heart failures that demonstrate resistance to existing drug treatments.>.