Direct determination of distribution volume and disappearance rate of native creatine kinase in humans.

Distribution volume (DV) and disappearance rate (Kd) of native creatine kinase (CK), parameters needed for enzymatic estimation of infarct size, have not been characterized in humans. Values for these parameters have been determined in experimental models and extrapolated for use in humans. During hemodynamic monitoring, 100 to 150 ml of enzyme-rich plasma was collected from 10 patients with acute myocardial infarction, stored at -30 degrees C for a maximum of 6 days, and then rapidly reinfused back to the same patient after return of CK serum activity to baseline levels. After reinfusion, blood samples were obtained at 5- to 15-minute intervals for 2 hours and at 30- to 60-minute intervals for an additional 10 hours. In each specimen, total CK activity and MM-CK and MB-CK concentrations were determined by spectrophotometry and radioimmunoassay. Data were analyzed by either nonlinear least-squares approximation or the noncompartmental approach after baseline subtraction. Concentration of immunologically active molecules appeared to decline in parallel to enzymatic activity. In three patients a double exponential decay was demonstrated. All others exhibited single exponential decay, with a Kd of 0.0023 +/- 0.00057 (SD) min-1. DV averaged 3284 +/- 693 (SD) ml, 5% of body weight. There was no correlation between Kd estimated from terminal portions of CK time-activity curves following infarction and Kd calculated after reinfused plasma. It was concluded that a one-compartment model using values for Kd and a DV compatible with plasma volume is suitable for clinical application, and that true Kd cannot be determined from the terminal portion of CK time-activity curves after acute infarction.

[Long term electrophysiological study on patients with acute myocardial infarction and complete heart block. Is cardiac pacing always necessary? (author's transl)]. / Studio elettrofisiologico a distanza in pazienti con infarto miocardico acuto complicato da blocco atrioventricolare completo parossistico. E sempre indicata l'elettrostimolazione cardiaca permanente?

UNLABELLED: Of 335 consecutive patients (pts) admitted to the coronary care unit (CCU) for acute myocardial infarction (AMI), 34 (10%) evidenced complete heart block (HB). The overall inhospital mortality was 14% (47 pts) versus 39% of the HB group (13 pts). No previous conduction disturbances were documented in 58% of pts before appearance of complete HB. Complete HB was preceded in 52% of pts by first or second degree HB or bundle branch block. Of 21 pts with HB discharged from the hospital, 5 (23%) died between 5 and 24 months (mean 12): no patients had sudden death; 16 pts (76%) are still alive after 13 to 45 months (mean 30). His bundle electrophysiologic (HBE) study was performed in 10 pts of the HB group after 4 to 40 months: 4 pts with anterior versus 6 with inferior AMI. Conduction disturbances were no longer present in all but one pt who had H-V 60 msec. Ajmaline (50 + 50 mg iv) prolonged A-H over 130 msec in 4 pts; H-V was not significantly increased in 8 of the 10 pts, while in two pts was 100 msec. One pt in the acute phase and one pt 12 months later, required pacemaker (PM) implant (both had inferior MI). IN CONCLUSION: no sudden death was documented during the follow-up period. The late HBE study, before and after ajmaline, did not allow to recognize critical conduction abnormalities suggessting prophylactic PM implantation.

[Precordial mapping and enzymatic analysis for estimating infarct size in man. A comparative study (author's transl)]. / Mappaggio precordiale ed analisi enzimatica nella valutazione quantitativa della necrosi miocardica

To investigate the relationships between electrocardiographic and enzymatic indexes of infarct size (I.S.), a group of 19 patients with anterior infarction was studied by serial precordial mapping and CPK curves analysis. The time course of ST and QRS changes was examined and a sharp, spontaneous fall of sigmaST was shown to occur within 10-12 hours after onset of symptoms, followed by a gradual rise. sigmaST on admission appears to be a poor predictor of subsequent enzymatic I.S. (r=0.49). Good correlations with I.S. were observed, for sigmaST at 48-96 hours (r=0.82) and, especially, for the percent decrease of sigmaR, with respect to the initial values (deltaR%), (r=0.94).