Biomedical subjects
Publications and source records attributed to S Priori.
This paper describes a compact, low-profile patch radiator which is the base element for efficient, small-size applicators suitable for superficial hyperthermia. The design criteria and the technological processes involved are presented. The electromagnetic characteristics of the patch element are outlined, and possible application of the radiator are discussed.
Recently it has been stated that in dogs absence of arrhythmias during coronary artery occlusion identifies a subgroup at almost no risk for developing ventricular fibrillation (VF) during reperfusion. A potential implication would be that prevention of ischemic arrhythmias may also prevent the most severe reperfusion arrhythmias. This concept is at variance with available clinical evidence. In order to reexamine this problem the left anterior descending coronary artery was occluded for 20 minutes in 41 anesthetized cats; the incidence and type of arrhythmias during occlusion and during the first minute of reperfusion were analyzed. Five animals had VF during occlusion and were not resuscitated. Twenty animals had ischemic arrhythmias, and among them the incidence of reperfusion VF was 50%. Sixteen animals did not have ischemic arrhythmias, but they did have a very similar incidence of reperfusion VF (44%). Thus, in this feline preparation, absence of ischemic arrhythmias did not help to predict a favorable outcome at the moment of reperfusion. This disparity with previous studies does not depend on the protocol used, but it may be partly due to species difference. These results demonstrate a lack of correlation between reperfusion VF and ischemic arrhythmias and provide further support for the concept of different mechanisms involved in occlusion and reperfusion arrhythmias.
The efficacy of the new class Ic anti-arrhythmic (aa) drug, Flecainide, has been evaluated in patients (pts) affected by frequent and/or severe chronic ventricular arrhythmias (VA), as assessed by 24 hours Holter monitoring and maximal exercise stress testing. The protocol consisted in a preliminary screening with multiple aa drugs (average 6.0 per pt) using the acute oral drug testing. The most effective drug was then given for 72 hours and 24 hours Holter monitoring and exercise stress testing repeated; if the efficacy was confirmed, chronic treatment was initiated and control visits were repeated after 3, 6 and 12 months. The study population consisted of 27 pts; 22 (81%) were in Lown class 4A (18%) or 4B (63%). Eight pts (30%) had a previous (greater than 1 year) myocardial infarction, while in 14 (52%) no evidence of cardiac disease was found. During acute oral drug testing a positive response (reduction of PVC's greater than 90% and abolition of grades 4A and 4B) was obtained with Flecainide, 200 mg, in 20 pts (74%). In 6 pts (22%) no effect was observed, while a possible proarrhythmic effect was observed in 1 pt (4%). Eighteen pts entered the second phase of the study with an average dose of Flecainide of 175 mg b.i.d. In 83% of the pts there was a positive concordance between the acute oral testing and the 72 hours treatment, as in 15 out of 18 pts grades 4A and 4B were totally abolished and the mean frequency of PVC's was reduced by 99%. In 3 pts (17%) no response was observed. Flecainide increased significantly PR (37 msec), QRS (20 msec) and QTc (28 msec). The plasma levels attained with chronic therapy (846 ng/ml) were higher than those achieved with the acute oral testing (372 ng/ml). Mild side effects (dizziness, tremor and headache) were observed in 33% of the pts and were all eliminated by a 100 mg reduction in Flecainide dose. Fifteen pts entered the third phase (long term treatment): in this group there was a 93.3% correlation with phase two, as in 14 out of 15 pts there was a complete abolition of grade 4B arrhythmias, a 98.8% reduction of couplets and a reduction in the number of PVC's greater than 85%. This study shows that Flecainide is a quite powerful aa drug with modest side effects. Its efficacy against chronic VA is high, also when compared to the most effective and available aa drugs.(ABSTRACT TRUNCATED AT 400 WORDS)