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Biomedical subjects

F Luzza

Publications and source records attributed to F Luzza.

At least 37 records · Page 2Linked to original sources
PubMed1988

"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.

Adolescent↗
PubMed1988

Concealed ventricular bigeminy with exceptions due to time-dependent modulation of an ectopic rhythm.

This presentation reflects a case of atypical concealed bigeminy, where some interectopic intervals contain even numbers of sinus beats. Exceptions to the rule of concealed bigeminy only occur during slowing of the sinus node. The pattern is explained on the basis of modulated parasystole, by drawing a phase-response curve which explains all the interectopic intervals on the basis of the modulating effect exerted by the sinus impulses upon a parasystolic focus.

Aged↗
PubMed1987

Non-sustained ventricular tachycardia with Wenckebach exit block.

A case of non-sustained, recurrent ventricular tachycardia, manifesting with irregular R-R intervals, is described. Analysis of a long electrocardiographic recording reveals that the arrhythmia is generated by a regularly discharging ectopic ventricular focus, the R-R interval variations being due to a Wenckebach form of exit block.

Adult↗
PubMed1987

Concealed ventricular quadrigeminy linked to atrial quadrigeminy: a manifestation of modulated parasystole.

Analysis of a long electrocardiographic recording including many atrial and ventricular extrasystoles shows that when atrial extrasystoles are in a quadrigeminal distribution, the ventricular extrasystoles also manifest a quadrigeminal distribution or reflect a distributional pattern of concealed quadrigeminy. Conversely, when atrial extrasystoles are other than in a quadrigeminal distribution, the ventricular extrasystoles do not occur in a quadrigeminal or concealed quadrigeminal distribution. This pattern is explained on the basis of modulated parasystole. A biphasic phase-response curve explains the observed phenomena on the basis of variations of the parasystolic cycle length due to the modulating effect of supraventricular beats.

Aged↗
PubMed1987

Changes in morphology of the paced QRS complex related to atrial contraction.

A patient with 2:1 AV block underwent temporary ventricular pacing. All the paced stimuli resulted in ventricular capture, but a marked variability in morphology of the paced QRS complexes occurred. Two different types of paced QRS complex (labeled A and B) were recognized. Type B complexes were manifest only when the pacing stimulus was preceded by a sinus P wave within a time interval ranging from 0.15 to 0.52 sec. The P wave-induced changes in morphology of the paced QRS complexes were interpreted as due to displacement of the pacing ventricular lead caused by atrial systole.

Aged↗
PubMed1987

[Effects of propafenone on arrhythmias induced by exertion in patients with ischemic cardiopathy].

The efficacy of Propafenone to prevent exercise-induced ventricular arrhythmias (EIVA) has been studied in eleven patients affected by ischemic heart disease. None of the patients manifested any arrhythmia at rest, but ventricular arrhythmias occurred in every case during a treadmill test. EIVA disappeared after Propafenone in nine patients, while a reduction by 90% was achieved in the remaining two patients. A further treadmill test carried out five days after withdrawal of the drug induced again the same ventricular arrhythmias in all the patients. Thus, Propafenone appears effective to prevent EIVA in patients with ischemic heart disease.

Aged↗
PubMed1986

Modulated ventricular parasystole as a mechanism for concealed bigeminy.

Concealed extrasystolic ventricular bigeminy reflects a distributional pattern of ventricular extrasystoles where intervening sinus beats are always in odd numbers. This has been explained on bigeminal rhythm associated with exit block. This presentation reflects a modification of this concept in that the distributional pattern may be explained on the basis of complex concealed modulation of ventricular parasystole, the concealment being due to impulses falling within the refractory period rather than suffering true exit block.

Adult↗
PubMed1986

Supernormal modulation of ventricular parasystole: the triphasic phase-response curve.

Modulation of ventricular parasystole by sinus beats has been shown both in vitro and in vivo to result in a classic biphasic phase-response curve. The first clinical presentation of 3 cases of supernormal modulation of ventricular parasystole resulting in a triphasic phase response curve is reported. Supernormal modulation reflects an unexpected early enhancement expedition of the ectopic ventricular impulses. An alternative explantation for the triphasic phase-response curve is the discharge and resetting of the parasystolic focus by critically timed sinus impulses.

Adult↗
PubMed1986

Wedensky facilitation. Electrotonic potentiation during complete A-V block.

The electrocardiogram recorded from a patient with third degree A-V block reflected almost regular A-V junctional escape rhythm. Some of the R-R cycles were slightly shorter than the basic escape cycle. A QRS complex ending such a relatively short R-R interval was always preceded by a sinus P wave, and had a QRS configuration which was minimally different from that of the escape complexes. The His bundle recording demonstrated that these minimally premature complexes were associated with an H-V interval which was shorter than that of the escape complexes. This indicates that the premature QRS complex could not be a capture beat. The relationship between the slightly premature QRS complex and the preceding sinus P-waves is explained on the basis of electrotonic potentiation or modulation to due Wedensky facilitation.

Aged↗
PubMed1985

Candida albicans infection of gastric ulcer frequency and correlation with medical treatment. Results of a multicenter study.

This paper reports the results of a multicenter prospective study of 188 consecutive patients affected by gastric ulcer, verified by endoscopy, in whom the frequency of a mycotic infection of the lesion was evaluated as well as the eventual influence of such pathology on the efficiency of medical treatment, the healing rate, and the healing time. A mycotic infection, defined as penetration of the periulcerous mucosa by the fungi, was found in only 13 patients (6.9%). No significant differences were found in the healing rate and healing time among these patients treated with H2-receptor antagonists and a control group of 43 matched gastric ulcer patients treated in the same period with the same therapy. It would appear from the data that mycotic infections of the gastric ulcer do not modify the efficiency of medical treatment.

Candida↗