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Biomedical subjects

F Arrigo

Publications and source records attributed to F Arrigo.

At least 37 records · Page 2Linked to original sources

[An analysis of the circadian frequency in the onset of acute myocardial infarct].

The purpose of this study was to evaluate if the occurrence of acute myocardial infarction (AMI) follows a regular pattern during the day and, if so, to assess any difference according to sex and patients' age. To determine 24-hour trend of AMI onset, clinical recordings of patients admitted to the CCU for AMI over a period of 8 years were reviewed: 427 patients (310 men and 117 women, aged 24-95 years), with a first AMI and in whom the time of onset of cardiac pain due to MI could be accurately established by history, were selected. Analysis of hourly distribution of the event was performed using a mathematical model based on Whittaker's method for periodic phenomena. It showed the occurrence is cyclic with 2 waves with periods of 6 and 12 hours in all age groups in men an women. No statistical differences were found between observed figures of periods and values calculated by Fourier analysis. The overall occurrence of MI showed a regular pattern with 4 peaks at 4.00 am, 10.00 am, 4.00 am and 10.00 pm. This periodic behaviour is nearly the same both in men and in women. The occurrence of MI is maximal in the morning (34.2% in men, and 35.9% in women); the minimum was recorded during the evening in male patients over 70 years and during the night in the other age groups; it was recorded during the afternoon and the night in women.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

Trifascicular block with asynchronous intraventricular recovery and "supernormal" AV conduction.

The authors present a case of trifascicular block: complete right bundle branch block, tachycardia-dependent left anterior hemiblock, and bradycardia-dependent left posterior hemiblock. There is, in addition, a complicating independent AV junctional rhythm that is in most instances not affected by the conducted sinus impulses. Occasionally, however, this focus is discharged by very early sinus impulses that are unexpectedly conducted to the ventricles (a manifestation of "supernormal" conduction). A complex electrocardiographic pattern results from the interplay of the aforementioned mechanisms.

Atrioventricular Node↗

[Correlation between the sites of mitral annular calcification and conduction disturbances: echocardiographic evaluation].

A clinical, electrocardiographic and echocardiographic (M-Mode, 2D) study was performed to explain the causal relationship between mitral annular calcification and cardiac conduction disturbances. Forty-seven patients, 28 women and 19 men (mean age 69) with mitral annular calcification were studied. In 18 patients A-V and/or intraventricular conduction disturbances were present. In this study we have found: a greater incidence of posterior than anterior mitral annular calcification; the anterior mitral annular calcification is often associated with aortic valve calcification and ultimately the common association between anterior mitral annular calcification and conduction disturbances.

Aged↗

[Treatment of recent atrial fibrillation with intravenous propafenone].

Intravenous propafenone (1 mg/Kg in 3 min) has been administered to 14 patients with recent atrial fibrillation. The sinus rhythm was restored in 7 patients within 30 min after the injection. The left atrial size, evaluated by M-mode echocardiography, was no different in the group of responders, with respect to the non-responders. No adverse effect has been observed. One single patient manifested a long asystolic pause (3860 ms), at the restoration of sinus rhythm. Propafenone appears to be useful in the treatment of recent atrial fibrillation.

Atrial Fibrillation↗

"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↗

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↗

Abnormalities in pituitary thyroid axis function tests in patients with paroxysmal supraventricular arrhythmias.

The study was carried out on 60 consecutive patients (23 males and 37 females) aged between 20 and 83 years (means +/- SD, 40.7 +/- 16) who arrived at our Cardiologic Unit with paroxysmal supraventricular arrhythmias (PSVA) including junctional paroxysmal tachycardia (n = 32), atrial fibrillation (n = 13), atrial flutter (n = 1), premature beats (n = 13) and with no obvious cardiovascular causes. Serum thyroxine and triiodothyronine were normal in all patients and thyroid scintiscan revealed normal shape and size thyroids without autonomously functioning nodule(s). Thyrotropin (TSH) response to thyrotropin releasing hormone (TRH) was normal in 44 subjects in whom normal serum free T4 (FT4) and free T3 (FT3) levels were measured. Six patients with normal FT4 and FT3 levels did not respond to TRH. Abnormalities in thyrotropin response to TRH were observed in 10 patients all exhibiting increased FT4 or also FT3 levels. Among these, 5 patients did not respond to TRH, whereas the remaining 5 exhibited a blunted TSH response to TRH. These results suggest that only in a small proportion (5/60) of consecutive patients with PSVA it is possible to recognize a status of "occult thyrotoxicosis" on the basis of the combined evaluation of free thyroid hormones and TSH response to TRH.

Adult↗

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↗

[Echocardiographic aspects of false intraventricular tendons].

A series of 4260 consecutive echocardiographic examinations, performed in 5 Cardiological Centers was examined, identifying 125 intraventricular false tendons (FTs) in 100 cases (55 normals and 45 with heart disease) of whom 31 were female and 69 male, aged 3 to 82 years. An anatomo-morphological study was possible in 9 cases, dead for stroke or heart failure, on autopsy, and in 7, on heart surgery. A phonocardiogram was performed in all normals and in 20 patients. On echocardiography, FTs appeared as an echo-producing string-like structure, straight between the septum and the ventricular free wall, mobile during the cardiac cycle, without systolic thickening and any relation with the atrioventricular valvular apparatus. The prevalence of FTs was 2.3%; it was 3.2% to 5.3% in younger people. FTs were located in the right ventricle (4 cases), left ventricle (95 cases) or in both (1 case). Their site was left apical (45 FTs), right apical (2 FTs), right (3 FTs) and left (20 FTs), upper septum-to-free wall (55 cases). In 1 case hypertrophy of trabeculae of the left ventricle was detected. FTs were single (79 cases), double (19 cases), multiple (2 cases), short (42 cases), long (58 cases), thick (45 cases) and thin (55 cases). They showed a membrane-like motion (thick FTs-45 cases) and a valve-like motion (thin FTs-55 cases). Innocent murmur was detected in 50 of 55 normals and related to thin FTs. Of 16 cases examined anatomically and histologically, FTs were fibrous in their distal portion and fibro-muscular in the proximal one in 12 cases, whereas they were entirely fibrous-muscular in 4 cases. The site and location of FTs detected by echo were confirmed by anatomy in all cases. In 4 cases other 9 FTs, not detected on echocardiography, were found. These data suggest that echocardiography is a useful tool to detect intraventricular FTs and differentiate them from other echo-producing structures. Although a relationship between FTs and heart disease has not been found, their presence could be responsible of innocent murmur in many normal subjects.

Adolescent↗

[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↗

[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↗