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Biomedical subjects

E M Greco

Publications and source records attributed to E M Greco.

7 recordsLinked to original sources
PubMed1992

A new acceleration driven pacemaker: rate modulation versus normal sinus rhythm--comparison during treadmill exercise.

The pacing rate response of a new acceleration driven pulse generator (SWING 100, SORIN BIOMEDICA) was compared with simultaneous normal sinus rhythm (NSR) during two different treadmill exercises. This pacemaker has a gravitational acceleration sensor able to discriminate between physical activities and vibrations. Six healthy volunteers (three male, three female; aged 21.7 +/- 4.3 years), with the pacemaker strapped to their right infraclavicular area, performed each test three times with different rise response curve (RRC) each time: fast, normal, and slow. The fall response curve used was the same as the rising one during each test. Pacing rates were recorded using the VEGA analyzer (SORIN BIOMEDICA) and compared with simultaneous NSR recorded by a 7-channel ECG recorder (MINGOGRAF 7, SIEMENS). During all tests immediate (within seconds) rapid increase in pacemaker rate was seen up to about 60 seconds, then a slower increase followed thereafter. The mean correlation between pacing rates and NSR during the Bruce tests were 0.7941 +/- 0.10, 0.8562 +/- 0.14, and 0.8292 +/- 0.07; during the discontinuous tests 0.7292 +/- 0.16, 0.7233 +/- 0.10, and 0.7480 +/- 0.11 for fast, normal, and slow RRC, respectively. Each 30 seconds, nonsignificant differences were present between pacing rate and NSR during all the discontinuous tests; similar responses were observed only during the first two stages of Bruce tests after which NSR was significantly higher than pacemaker rates. The speed of rise to upper rate was the main difference between the different programs (fast, normal, and slow). The discontinuous tests showed that the pacemaker responds more to speed than to grade.(ABSTRACT TRUNCATED AT 250 WORDS)

Acceleration↗
PubMed1992

[Ventricular stimulation triggered by esophageal atriogram: a new technique of temporary physiologic stimulation in the course of acute myocardial infarct complicated by atrioventricular block and low cardiac output].

Advanced atrio-ventricular (AV) block during acute myocardial infarction (AMI) is considered a complicating dysrhythmia as the well as mechanism responsible for occurrence of life-threatening hemodynamic changes. Often, simple VVI pacing can result insufficient in improving the decreased cardiac output. VDD pacing, which preserves atrial contribution, should represent the most effective electrical approach; therefore, it requires intracavitary placement of 2 catheters. In 10 pts (6M, 4F, mean age of 63.8 +/- 6.6 years) with advanced AV block due to AMI (4 inferior, 6 anterior) and without sinus node dysfunction, we performed stable VDD stimulation (mean 16.6 +/- 20.6 hours) using only one catheter positioned in the right ventricle while the atrial impulse, filtered (50-70 Hz) and amplified through a special device, was derived from the esophagus. Such technique is rapid and reliable, avoiding problems associated with atrial sensing and catheterization.

Aged↗
PubMed1978

[Clinical and electrophysiological indications for permanent electrostimulation in sick sinus syndrome (author's transl)].

In 49 patients with sick sinus syndrome the following electrophysiological parameters were studied: sinus node recovery time and conduction time, atrial and AV nodal refractory periods, atrioventricular and intraventricular conduction. Moreover, pharmacological, vagal and sympathicomimetic stimulation were performed. These data were related to the clinical picture to establish any possible correlation leading to a more specific therapeutical choice. Patients were divided in two groups: group 1, with a prevalence of tachyarrhythmic symptoms and a lesser incidence of syncope, in which cases the sinus node function appeared to be only slightly affected. In group 2 small incidence of tachyarrhythmias and a clear prevalence of syncope with severe impairment of sinusal automaticity and/or sinoatrial conduction were present; AV and IV conduction disturbances were equally distributed in both groups. In more than 1/3 of the cases of the group I arrhythmias were succesfully treated with pharmacological therapy only, with Group 1 A antiarrhythmic agents in most cases. In the other cases of this Group and in all cases of Group II permanent electrical stimulation alone or together with drug therapy was necessary. Long term results with different therapeutical choices and, specifically, with the type of stimulation chosen in individual cases (sequential, rate-programmable ventricular, demand ventricular) are presented.

Adult↗
PubMed1975

[His electrogram recordings in disturbances of atrio-ventricular conduction in acute ryocardial infarction (author's transl)].

48 His bundle recordings were performed on 30 patients with acute mycardial infarction and various degrees of atrioventricular block. Studies were undertaken at the time of transvenous pacemaker insertion and/or removal from the right ventricle, without pharmacological or electrical stimulation tests. The connections between site of the infarcted area and localization of the a-v block were investigated, to identify uncommon relations. Several atypical cases were observed: among 12 cases of patients with anterior infarction, 6 had prolonged P-H interval, with prolonged H-V interval in 4 cases, and normal H-V interval in the remaining 2 cases. Among the 18 cases of inferior infarction, 5 had prolonged H-V interval, 2 of which had a normal P-H interval and 3 with prolonged P-H interval. In the latter cases, the identification of a two-step a-v block by His bundle recordings was shown to be important from the clinical and prognostic viewpoint. Nevertheless, it is evident that the His bundle recording is insufficient by itself to provide any evidence of the inner pathogenetical mechanism of these phenomena, and only various hypotheses can be advanced.

Acute Disease↗