[Non-invasive assessment of coronary reperfusion]. / Valutazione incruenta della riperfusione coronarica.

The patency of the infarct-related coronary artery seems to be an important prognostic factor after an acute myocardial infarction. Coronary angiography has been used until now to assess coronary patency. However, as it is an invasive procedure and its optimal timing after fibrinolytic treatment has not been established, a noninvasive marker is most desirable. There are a number of methods currently used to document coronary reperfusion non-invasively. This review discusses the advantages and disadvantages of the classic non-invasive methods, like resolution of chest pain, reperfusion arrhythmias, normalization of ST segment elevation, and enzymatic determinations. The imaging methods, especially echocardiography but also magnetic resonance imaging, offer interesting possibilities for the future.

"Irregular" ventricular parasystole: the influence of sinus rhythm on a parasystolic focus.

Fifteen cases of ventricular parasystole were analyzed to determine whether the interectopic intervals were regular, as expressed by long intervals being exact multiples of the short ones, or not. The regularity of the interectopic intervals was assessed by means of the variation index: the ratio of the maximal difference between various measurements of the parasystolic cycle length and the mean parasystolic cycle length. Three out of 15 cases had a variation index less than 5, and were classified as "regular parasystole." Twelve cases were associated with a variation index greater than 7.5, and were classified as "irregular parasystole." The cases of irregular parasystole were then analyzed to determine whether the variability of the interectopic intervals was casual or dependent on action of the sinus beats. A parasystolic resetting by critically timed sinus impulses (a form of intermittent parasystole) was evident in three cases. The irregularity in the remaining nine cases was due to modulation (viz., due to electrotonic influence exerted by the sinus beats on the parasystolic focus). In every case of modulated parasystole a phase-response curve was constructed, which enabled an analysis of all the interectopic intervals on the basis of a time-dependent effect exerted by the sinus impulses on an otherwise rhythmic parasystolic focus.

[Evaluation of the kinetics of MB creatine kinase in patients undergoing systemic thrombolytic therapy]. / Valutazione della cinetica della CK-MB in pazienti sottoposti a terapia trombolitica sistemica.

This study was aimed to evaluate if the time-course of creatinkinase MB in acute myocardial infarction (AMI) is influenced by therapy and which index, derived from the enzymatic curve, is the most reliable marker of successful coronary artery recanalization. We studied the enzymatic curves in 38 patients with transmural myocardial infarction, 19 treated with streptokinase (SK) and 19 with tissue plasminogen activator (rtPA). Blood samples were obtained every 2 hours for the first 12 hours and every 6 hours until the level of serum CK returned to baseline. Three indexes were calculated: peak serum enzyme level, time to peak enzyme level and maximal enzyme rise velocity. Time to peak did not differ significantly between SK and rtPA groups. Peak levels were significantly higher (414 +/- 40 vs 249 +/- 33; p = 0.004) in rtPA groups, as well as maximal enzyme rise velocity (1.7 +/- 0.4 vs 0.8 +/- 0.1; p = 0.02). However, infarct size evaluated by the total release of CK-MB in 28 patients was greater in rtPA group (10949 +/- 1097 vs 6346 +/- 869; p = 0.002). These findings suggest that differences in peak level and in maximal velocity of rise observed between SK and rtPA are due to differences in infarct size and not to a different recanalization rate. Thus, enzymatic estimate of infarct size significantly correlates to peak enzyme (r = 0.894, p less than 0.001), and to maximal rise velocity (r = 0.518, p = 0.007) but not to time to peak (r = 0.208, NS).(ABSTRACT TRUNCATED AT 250 WORDS)