[Effect of propafenone on left ventricular function in patients with myocardial infarct].
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Aged↗
Biomedical subjects
F Luzza
Publications and source records attributed to F Luzza.
[The retriggerable refractory period: a rare cause of apparent sensing malfunctioning in various types of VVI pacemakers].
The retriggerable Refractory Period (RP) is an anti-interference device that causes prolongation of the RP in the presence of rapid false signals. The device starts functioning when a suprathreshold impulse manifests during the second half of the RP of the pacemaker; in such a case the RP itself is retriggered, i.e., re-starts from the moment in which the retrigger occurs. As a consequence, the time during which the pacer cannot be recycled is prolonged. We report a case of unusual pseudo-malfunction caused by the retriggerable RP observed in a patient paced with a Lit 222 Sorin VVI pacemaker. Spontaneous QRS complexes coupled up to 480 ms appeared as not senses, i.e. did not reset the pacemaker, whereas complexes occurring at 510 ms or more from the spike provoked a normal recycling, and complexes coupled at 490-500 ms resulted in partial recycling. This pattern has been interpreted assuming that a spurious signal (probably an afterpotential) occurs shortly after the paced stimulus. Such a signal falls in the retriggerable RP, resulting in prolongation of the RP. Spontaneous QRS, thus, cannot be sensed until 480 ms from the paced impulse. The chest wall stimulation has clarified the principles governing the functioning of the retriggerable RP. When the RP is retriggered three times in the course of a single pacemaker cycle, the pacer varies its mode of functioning, being the pacing rate increased to a value identical to the magnet rate. Furthermore, the RP is extremely prolonged, occupying the 90% of the pacing interval; only impulses occurring during the last 80 ms, thus, are able to reset the PM.(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
[Reduction of the threshold of myocardial excitability after an extremely long asystolic pause: late phase of "supernormal excitability?].
A patient with a malfunctioning pacemaker due to lead insulation defect is reported. High voltage stimuli were always effective, while when the pulse amplitude was reduced to 3.8 volt stimuli were uneffective except when occurring after extremely long asystolic pauses. An advanced exit block (up to 7:1) thus occurred. Late lowering of the myocardial threshold of excitability could be explained by slow spontaneous diastolic depolarization occurring in myocardial fibers surrounding the tip of the electrode.
Aged↗
[Ventricular extrasystole of re-entry originating in the myocardium surrounding a parasystolic focus: a mechanism responsible for the irregularity of the interectopic intervals during parasystole].
We have observed a case of ventricular parasystole in which the ectopic beats occurred often in couplets. The analysis of the interectopic intervals suggests that the first beat of the couplet is parasystolic in origin, whereas the second one is due to a re-entry which takes place in the myocardium surrounding the parasystolic focus. Moreover, our observations lead us to speculate that an occasional supraventricular beat could cause an exit block of the parasystolic focus through a concealed re-entry.
Aged↗
[Modulated parasystole. An arrhythmia waiting for diagnostic criteria. Deductive analysis of a case].
We report a case of ventricular parasystole in which the long interectopic intervals are always less than a multiple of the short interectopic intervals. Assuming a regular ectopic discharge, the above said phenomenon could theoretically be due to relative prolongation of the short interectopic intervals caused by delayed ectopic-ventricular conduction of the second consecutive conducted impulse (a Wenckebach-like phenomenon). Nevertheless, this hypothesis may be ruled out in this case by the analysis of a long tracing. The unusual relationship between the interectopic intervals may be explained assuming the modulation of the parasystolic activity by sinus beats. Experimental work has shown that despite the protection (or entrance) block, the sinus or dominant rhythm may affect the automaticity of a parasystolic focus by means of electrotonic influence. It has been pointed out that sinus impulses falling in the first part of the ectopic cycle delay the next ectopic discharge, while relatively late sinus beats (falling in the last 30-40% of the ectopic cycle) are able to anticipate the delivery of the parasystolic impulse. The phenomenon of modulation is marked by a characteristic biphasic phase-response curve. In the reported case a phase-response curve has been obtained, which explains the parasystolic cycle variations according to the phase of the cycle in which the sinus beats fall. The obtained curve is quite similar to those observed experimentally, therefore the diagnosis of modulated parasystole appears to be very likely.(ABSTRACT TRUNCATED AT 250 WORDS)
Arrhythmias, Cardiac↗
[Occult ventricular bigeminy. Description of a case with extrasystole variable coupling separated by sinus beats in even or odd numbers].
We have analyzed an electrocardiogram showing many unifocal ventricular extrasystoles with wide variations of the coupling intervals. Ventricular bigeminy was frequent but in many instances more than one sinus beat occurred between two consecutive extrasystoles. In such a case the intervening sinus beats occurred indifferently both in odd and even numbers. Moreover, extrasystoles preceded by an even number of sinus beats had a relatively long coupling interval whereas extrasystoles that followed and odd number of sinus beats showed shorter coupling intervals. An opposite pattern of the coupling interval was observed with the extrasystoles that followed an interpolated premature ventricular depolarization. In such a case the coupling interval was long after an odd number of sinus beats and vice versa. This mechanism may be interpreted as due to concealed ventricular bigeminy caused by a ventricular ectopic focus which is surrounded by two different zones of block: a proximal zone of 2:1 block, and a distal one in which the block occurs irregularly. Unlike what appears in typical concealed bigeminy, characterized by only odd numbers of sinus beats between consecutive extrasystoles the intervening sinus complexes are indifferently in odd and even numbers. The constant relationship between the coupling interval and the number (odd or even) of sinus beats by which the extrasystole is preceded, allows us to recognize the presence of an atypical form of concealed bigeminy.
Aged↗
[Ventricular parasystole with duplicated level of exit block].
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Aged↗
["Supernormal" A-V conduction during chaotic atrial rhythm. A case report].
We describe the electrocardiogram of a patient who had a chaotic atrial rhythm with partial A-V block. Only the late P waves (R-P greater than 1 sec.), and the early ones (with one R-P interval between 44 and 52 hundredths of a second) were conducted to the ventricle. On the contrary, no P waves with coupling intervals between 52 and 100 hundredths of a second reached the ventricles. Careful analysis of the tracing showed that the conduction of the early P waves could not depend upon the atrial pacemaker site, or upon concealed conduction of preceding atrial impulses. The existence of a "gap" phenomenon although unlikely, could not be excluded. Supernormal A-V conduction, or early diastolic decrease of the vagal tone due to hemodynamic mechanism could be responsible for the early ventricular captures observed in this patient.
Aged↗
[Myocardial excitation by late coupling impulses in a patient with a malfunctioning pacemaker due to high threshold: supernormality or Wedensky effect?].
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Cardiac Pacing, Artificial↗
Bundle branch block in alternate beats: the role of supernormal and concealed bundle branch conduction.
This article reports an example of right bundle branch block occurring on alternate beats in the presence of atrial tachycardia with 2:1 atrioventricular conduction. Analysis of the tracing suggests that the alternate disappearance of right bundle branch block is a manifestation of supernormal bundle branch conduction. The phenomenon is assumed to be caused by retrograde concealed conduction within the bundle branch that is blocked in anterograde direction (the "linking" mechanism).
Aged↗
Expression of proinflammatory and Th1 but not Th2 cytokines is enhanced in gastric mucosa of Helicobacter pylori infected children.
BACKGROUND: Helicobacter pylori-induced gastric inflammation is thought to be largely regulated by cytokines. PATIENTS AND METHODS: The expression of interferon-gamma, interleukin-12, interleukin-4, interleukin-10, interleukin-8, and interleukin-17 mRNA was examined on gastric mucosal samples from 24 children by semiquantitative reverse transcription polymerase chain reaction and southern blotting. Biopsy-based tests, serology, and urea 13C breath test were used to assess Helicobacter pylori status. Gastric biopsies were also evaluated for bacterial density, chronic inflammation, and acute inflammatory activity. RESULTS: Interferon-gamma, interleukin-12, interleukin-8 and interleukin-17 expression was higher in Helicobacter pylori-infected (n=13) than uninfected (n=11) children. Conversely, interleukin-4 and interleukin-10 expression did not differ between Helicobacter pylori-infected and uninfected children. In Helicobacter pylori-infected children, interferon-gamma, interleukin-12, interleukin-8 and interleukin-17 expression correlated with bacterial density, and Interferon-gamma and interleukin-12 expression with chronic inflammation score. CONCLUSIONS: The findings of this study indicate that, in children, Helicobacter pylori-induced inflammatory response would favour production of proinflammatory cytokines and development of cell-mediated immunity, namely Th1 response.
Adolescent↗
Prevalence of atrial septal aneurysm in patients with migraine: an echocardiographic study.
OBJECTIVE: To evaluate the prevalence of atrial septal aneurysm in patients with migraine. BACKGROUND: Migraine has long been considered a risk factor for stroke. Atrial septal aneurysm is often observed in young patients with ischemic stroke and is frequently associated with other conditions potentially leading to embolism. METHODS: We performed a transthoracic echocardiogram in 90 consecutive patients (65 women and 25 men; mean age, 35.3 years [standard deviation, 9]) with migraine but free from cerebral and cardiovascular disease and in 53 control subjects (37 women and 16 men; mean age, 34 years [standard deviation, 10]). The diagnosis of atrial septal aneurysm was performed according to Olivares-Reyes criteria. A transesophageal echocardiogram also was performed in 75 patients with migraine (83.3%). RESULTS: The prevalence of isolated atrial septal aneurysm was higher in patients with migraine with aura (28.5%) than in patients with migraine without aura (3.6%) (P <.005) or in control subjects (1.9%) (P <.005). CONCLUSIONS: Our data suggest a role of atrial septal aneurysm in the genesis of aura in patients with migraine.
Adult↗
Antibacterial drugs in Crohn's disease.
The evidence of a beneficial role of antibacterial drugs in Crohn's disease is largely empirical. Data accumulate to show that these drugs may well be used as an adjunctive therapy to oral anti-inflammatory drugs. Circumstantial evidence has also been provided that antibacterial drugs are effective in relieving symptoms related to bacterial overgrowth and when used for specific indications such as perianal lesions.
Anti-Bacterial Agents↗
[Intestinal bleeding from an ulcerated diverticulum of the small intestine. A clinical case].
A case of occult bleeding of the upper intestinal tract in a patient with secondary polycythaemia and aortic valve stenosis is described. Routine tests failed to disclose the origin of the bleeding and the patient's condition continued to deteriorate. On the 23rd day after admission, laparotomy was performed, and an ulcerated diverticulum diagnosed. Resection of the diverticulum was done immediately. The patient had an uneventful post-operative recovery and was dismissed from the hospital 15 days later. Our experience underscores the necessity for early laparotomy in cases of gastrointestinal bleeding of obscure origin.
Aged↗
Evidence against colonic mucosa colonisation by Helicobacter pylori. Lack of a specific antibody response in homogenates of rectal endoscopic biopsies.
Aim of this study is to provide indirect evidence that human colonic mucosa harbour Helicobacter pylori. The antibody response of IgG and IgA class against Helicobacter pylori was examined in autologous homogenate of gastric and rectal endoscopic biopsies from 26 patients and in rectal samples of a further 36. All had a documented (histology and/or serology) Helicobacter pylori status. Helicobacter pylori specific IgG and IgA were measured by an in-house ELISA. In Helicobacter pylori positive patients having both gastric and rectal homogenate, mean level of Helicobacter pylori IgG and IgA was higher in gastric than in rectal samples (0.810 +/- 0.668 optical density vs 0.329 +/- 0.509 optical density for IgG, p = 0.007 and 0.660 +/- 0.477 vs 0.116 +/- 0.229 for IgA, p < 0.001, respectively). In each patient, level of the two isotypes was clearly higher in gastric than in autologous rectal sample. In the overall study population, mean level of Helicobacter pylori IgG in rectal homogenate was not significantly (p = 0.16) different between Helicobacter pylori positive (48/62, 77%, 0.243 +/- 0.388 optical density) and negative (14/62, 23%; 0.095 +/- 0.088) patients. In same material, levels of Helicobacter pylori IgA were very low and undetectable either in Helicobacter pylori positive or negative patients. Although Helicobacter pylori IgG are detectable in rectal homogenates of Helicobacter pylori positive patients, present data suggest that these antibodies may not be local in origin but rather reflect circulating response. These observations do not support the view that large bowel mucosa is colonised by Helicobacter pylori.
Adult↗