Search PubMed⌕ Search

Biomedical subjects

G Oreto

Publications and source records attributed to G Oreto.

At least 73 records · Page 4Linked to original sources
PubMed1991

[Electrocardiographic diagnosis of ventricular tachycardia in patients with previous myocardial infarct: frequency and significance of diverse diagnostic criteria].

Electrocardiographic tracings of ventricular tachycardia were recorded from 34 patients with old myocardial infarction. The diagnostic criteria of ventricular tachycardia were carefully assessed in each tracing. The most commonly observed signs were: 1) QRS duration greater than 140 msec; 2) a prevalent negative deflection in Lead V6; 3) an interval from the beginning of the QRS complex to the S wave nadir greater than 100 msec in at least one precordial lead. The cases were subdivided into two groups on the basis of a predominant positive or negative deflection in Lead V1 (Group 1 and 2, respectively). The most common signs in Group 1 were a monophasic R wave configuration of the QRS complex in Lead V1, and a QS configuration in Lead V6. On the other hand, the most frequent criteria in Group 2 were an interval between the beginning of the QRS complex and the S wave nadir greater than 60 msec in Lead V1, and a QS configuration in Lead V6. Furthermore, none of the cases reflected a normal frontal plane QRS axis, but an axis deviation was evident in all 29 cases where axis could be calculated.

Diagnosis, Differential↗
PubMed1990

Longitudinal dissociation within the reentry pathway of ventricular tachycardia.

Two cases of nonsustained, repetitive ventricular tachycardia are analyzed. In both, the episodes of tachycardia do not contain random numbers of beats, but the complexes in each phase of tachycardia are either always in even numbers (case 1) or always in odd numbers (case 2). This indicates longitudinal dissociation within the reentry circuit: i.e., there are two functionally separate pathways in some part of the reentry circuit, and the reciprocating impulse runs alternatively through the two pathways. Tachycardia ends due to block of the impulse always in the same pathway, thus, the number of beats in each episode of tachycardia is always either in odd or even numbers.

Aged↗
PubMed1989

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↗
PubMed1989

Concealed ventricular hexageminy.

The authors report a case of concealed ventricular hexageminy in which, with a few exceptions, extrasystoles were separated by sinus beats conforming to the formula 6n - 1. Whenever an exception to this formula occurs, the intervening beats are not all of sinus origin, but include also a ventricular extrasystole that is different from those occurring in hexageminal distribution. The pattern is explained by a parasystolic rhythm modulated by sinus impulses, assuming a 3:1 ratio between the parasystolic cycle and the sinus cycle. Such a ratio would have to be associated with a trigeminal or concealed trigeminal distribution. There is, however, a 2:1 ectopic-ventricular block, leading to a change of the ectopic distributional pattern from the expected concealed trigeminy to that of the concealed hesageminy.

Aged↗
PubMed1989

Modulated parasystole complicating permanent ventricular pacing: the different influence of spontaneous and paced impulses upon the parasystolic rhythm.

A case of modulated ventricular parasystole observed in a patient with a VVIM pacemaker is reported. Analysis reveals that the electronic influence (modulation) effected upon the parasystolic focus by the sinus impulses is different from that exerted by the paced impulses. Furthermore, fusion beats reflect an intermediate modulating effect according to the prevalence of the sinus or the paced wavefront.

Aged↗
PubMed1989

Atrioventricular junctional parasystole with ventricular fusion beats due to complicating Wolff-Parkinson-White syndrome.

We present a case of atrioventricular (AV) junctional parasystole manifesting with ventricular fusion beats due to the presence of an accessory AV conduction pathway. Ventricular fusion beats are usually impossible in AV junctional parasystole. In the reported case the ventricular fusion occurs because the ectopic AV junctional impulse is conducted through the His bundle, whereas the sinus impulse is conducted to the ventricles through the Kent bundle.

Adult↗
PubMed1989

[A-V conduction in atrial flutter. Electrocardiographic study].

One hundred and twenty-nine cases of atrial flutter were analyzed to assess the A-V conduction. The R-R intervals, the A-V conduction ratio, and the F-R intervals were measured in each case. Conduction in atrial flutter was defined either as constant or as variable depending on whether the A-V conduction ratio was fixed or variable. Furthermore, atrial flutter was defined as regular whenever the R-R intervals were mathematically related to each other, any interval being a multiple of the F-F cycle. On the other hand, atrial flutter was defined as irregular when the R-R cycles did not reflect a precise mathematical relationship. The R-R intervals in irregular atrial flutter were not exactly multiples of the F-F cycle. This was because the F-R intervals were variable. Sixty-five cases of atrial flutter had constant A-V conduction, whereas 64 cases were associated with variable A-V conduction. Eighty-eight per cent of cases with constant conduction were regular. On the contrary, 91% of cases with variable A-V conduction were irregular. These data reflect a relationship between the constancy of the A-V conduction ratio and the regularity of the R-R intervals. Several mechanisms were identified as being responsible for atrial flutter irregularity. Alternation of the F-R intervals was the most frequent mechanism leading to irregularity of atrial flutter with constant A-V conduction. Alternating Wenckebach periodicity was the most common cause of irregularity in atrial flutter with variable conduction ratio. Concealed conduction of blocked impulses was also frequently involved in determining atrial flutter irregularity.

Atrial Flutter↗
PubMed1989

[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↗
PubMed1988

Mobitz type II delay.

Mobitz type II second-degree block manifests with several consecutive impulses conducted with a constant conduction time that are followed by block. This study reflects an entirely new concept of the Mobitz type II phenomenon, wherein consecutive impulses have constant conduction times, but instead of being followed by a block of conduction, are in fact followed by a conduction delay. The diagnosis of this manifestation at the atrioventricular (AV) junction is made by the appearance of an unexpected prolonged PR interval followed by a shorter PR interval. The recognition of this manifestation at the sinoatrial junction is suggested when, during regular sinus rhythm with manifest episodes of Mobitz type II sinoatrial block, the sinus rhythm is at times also complicated by a sudden unexpected prolongation of a P-P interval, which is followed by an shortened P-P interval. This new phenomenon is termed by Mobitz type II delay.

Electrocardiography↗
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↗