title: Threshold energy dose for enzyme release after direct-current countershock.
abstract: Serial measurement of serum total creatine kinase and creatine kinase MB isoenzyme was prospectively performed by photometric assay in 82 consecutive patients (55 male and 27 female; mean age 62 +/- 11 years) after elective DC countershock for atrial flutter or fibrillation. Enzyme release is commonly observed to follow DC shock; the related energy threshold for enzyme release, however, a parameter with potential clinical usefulness, has not yet been determined. The energy dose was individually titrated but the anterolateral paddle-electrode location was used in all cases. The mean +/- S.D. (range) of shock number, peak energy level and cumulative energy dose normalized to body weight were respectively: 1.7 +/- 0.9 (1-5), 228.6 +/- 87.6 (75-400) J and 5.26 +/- 3.74 (1.0-19.7) J/kg. All these parameters had highly significant positive correlation with enzyme release (P < 0.0001), which peaked 16 h after countershock. Only creatine kinase levels changed significantly vs. baseline (P < 0.0001). As evidenced by dose vs. effect scattergram, the energy threshold value for enzyme release was around 4 J/kg for creatine kinase and 6 J/kg for creatine kinase MB isoenzyme. These energy dose figures may provide clinical usefulness to avoid unnecessary muscle damage; moreover, they may be used as a reference when enzyme elevations interfere with the diagnosis of a concomitant ischemic acute myocardial infarction.
authors.affiliation: Department of Cardiology, Bassano General Hospital, Vicenza, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Gheno
authors.forename: R
authors.initials: R
authors.lastname: Zeppellini
authors.forename: R
authors.initials: R
authors.lastname: De Domenico
authors.forename: F
authors.initials: F
authors.lastname: Cucchini
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers; D003402:Creatine Kinase / Q000097:blood / Q000378:metabolism*; D004554:Electric Countershock / Q000009:adverse effects; D005260:Female; D006801:Humans; D007527:Isoenzymes; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D013610:Tachycardia / Q000628:therapy*; D013997:Time Factors
chemical_list: D015415:Biomarkers; D007527:Isoenzymes; D003402:Creatine Kinase