Analysis of the interpolation phenomenon in man evaluated by premature atrial stimulation.

After early premature atrial stimulations, returning cycles shorter than the basic cycle were observed in 25 patients. In 4 of them sinus echoes were seen to occur after premature atrial stimulation coupling intervals shorter than those able to induce completely interpolated beats. Such a sequence is unexpected if we suggest a sino-atrial entrance block for explaining the interpolation phenomenon. An alternative explanation can be postulated assuming that all these early premature beats are sinus node re-entries and that the completely interpolated beat is only a sinus re-entry fortuitously occurring at an appropriate interval.

Analysis of sino-atrial conduction in man using premature atrial stimulation.

Sino-atrial conduction was investigated using premature atrial depolarization in 25 patients seven of whom had sino-atrial block. The results obtained in this investigation were evaluated plotting the test cycle (expressed as difference between the basic sinus cycle and the test cycle as a percentage of the basic sinus cycle) as a function of the return cycle (expressed as difference between the return cycle and the basic cycle as a percentage of the basic sinus cycle). In normal subjects, premature atrial depolarizations elicited in the last 10-20% of the spontaneous sinus cycle, produced a progressive prolongation of the return cycle and the points correlating the return cycle index to the test cycle index fell above the diagonal of the plotting system. After earlier premature atrial depolarizations, the return cycle remained of the same length, and the points correlating the return cycle index to the test cycle index fell along a line parallel to the y-axis ('plateau'). The mean value of the returning cycles (as expressed above) corresponding to the test cycles (as evaluated above) included in the first 5% of the 'plateau' can be defined as 'the sino-atrial conduction index'. This index, the sum of conduction into and out of the sinus node, was found to range from 79 to 185 ms. By assuming similar anterograde and retrograde conduction, the sino-atrial conduction time ranged from 39.5 to 97.5 ms (mean value=70 ms). In the patients with sino-atrial block, fully compensatory pauses were observed for atrial premature depolarizations elicited up to the last 25-35% of the atrial cycle, and a slow and progressive divergence from the diagonal of the plotting system was seen instead of the 'plateau'. In these patients the sino-atrial conduction index ranged from 151 to 297 ms (mean 253 ms). By assuming similar antegrade and retrograde conduction, the sino-atrial conduction time ranged from 75.5 to 148.5 ms (mean value=126.5 ms) with a statistically significant difference with respect to normal subjects (P=0.001).

Pyelovesicostomy: an alternative to ureteropelvic junction-plasty in pelvic ectopic kidneys.

Pyelovesicostomy was performed in 2 cases of hydronephrosis in pelvic kidneys secondary to ureteropelvic junction obstruction. In the first patient, who presented with a solitary kidney, the procedure was done after failure of a dismembered pyeloplasty, while in the second patient the procedure was performed electively. Both patients had sterile urines and stable renal function, although some dilatation persisted in the first case. The indications and the functional aspects of this surgical solution are discussed.

Experience with ureterocalyceal anastomosis.

Experience with 10 cases of ureterocalyceal anastomosis is reported. Most cases involved scleroatrophic scarring of the pelvis after repeated stone surgery, and 1 case each for failed pyeloplasty, tuberculous stricture of the pelvis, transitional cell carcinoma of the pelvis and calyces, and ureteropelvic junction obstruction associated with renal malformation. Three patients had a solitary kidney. End-to-end ureterocalyceal anastomosis was performed in 5 patients; laterolateral in 1 case, and ureteropyelocalyceal anastomosis in the remaining 4. In 3 cases omentoplasty was also performed.

The antibody response in chronic pyelonephritis.

Serum antibodies specific for the bacteria isolated from the urines of 41 patients with chronic pyelonephritis and 14 with asymptomatic bacteriuria were assayed. Even though it is clear that infections which involve the kidney evoke higher antibody responses than do purely bladder infections, it is difficult to establish a cut-off level for distinguishing the two by this method. There is a greater probability that there will be an upper urinary tract infection without an antibody response than that there will be a good antibody response in cases with lower tract infections. In our case list, 49% of the patients with chronic pyelonephritis had titers equal to or greater than 1:400, and another 44% had titers between 1:50 and 1:100. Therefore it appears that the magnitude of the antibody response depends not only on the location of the infection but also on other factors, such as the intrinsic immunogenicity of the different bacterial strains and the properties of the immunological system of the patient.

Efficacy of mexiletine in chronic ventricular arrhythmias: a multicentre double-blind medium-term trial.

In a multicentre double-blind, inpatient, placebo-controlled trial the effects on premature ventricular beats (PVBs) of mexiletine in a standard, submaximal dose were studied by Holter monitoring in 144 outpatients. After wash-out, mexiletine was administered for 14 days. The effects were re-tested, after one week of a placebo, in a second 14-day period of mexiletine administration. Of the patients 73% in the first period and 82.5% in the second period responded to mexiletine (a reduction of 75% or more of PVBs/24 h--p less than 0.001 compared with the placebo for both periods). Mexiletine also significantly reduced the Lown class of PVBs and the frequence of paired PBVs, ventricular tachycardia, multiform beats and R on T wave phenomenon. Mexiletine showed an equivalent effectiveness in the four main aetiological groups of arrhythmias. Fifty nine patients complained of adverse effects (gastrointestinal or neurological) the intensity of which led to the stopping of the treatment in 16 of them. These results show that mexiletine is highly effective, even in submaximal doses, in preventing ventricular arrhythmias of whatever origin.

[Cardiac pacing in sinus node disease (author's transl)]. / L'elettrostimolazione nella malattia del nodo del seno.

In sinus node disease, cardiac pacing is used as a diagnostic and therapeutic tool. The assessment of sinus node recovery time by means of rapid atrial pacing and sino-atrial conduction time by means of premature atrial stimulation, are the methods usually utilized in the diagnosis of sino-atrial dysfunctions. Theoretical and practical limitations however induce to careful evaluation of the results. Heart pacing is also useful for the treatment of sino-atrial dysfunctions. However, criteria for pacemaker implantation in these conditions are still lacking and the type of pacemaker indicated is not defined yet. At present, the accurate clinical investigation of the patient still remains the best guide to therapeutical approach.

[Hyperkinetic ventricular arrhythmia induced by atropine administration]. / Aritmia ventricolare ipercinetica indotta dalla somministrazione di atropina.

We report the case of a patient with ventricular tachyarrhythmia, which occurred after atropine was given intravenously for diagnostic purposes. The arrhythmia was accompanied with precordial pain and nitroglycerin promptly reduced both events. On the ECG an elevated ST segment in leads I, aVL, V4, V5, V6 was observed for few hours after the end of the arrhythmia, followed by a pattern of myocardial ischemia. Serum enzymes were repeatedly normal. Spontaneous anginal attacks, usually accompanied with ECG signs of myocardial ischemia and 2nd degree AV block, were often observed by means of 24 hours ECG monitoring (Holter) in the following weeks, in spite of appropriate treatment. Either myocardial ischemia, induced by the increased heart rate following atropine administration, or direct electrophysiologic effects of the drug upon the ventricle muscle (possibly in association with ischemia) could have caused the ventricular arrhythmia.

[Atrial tachyarrhythmias in sinus node disease: diagnostic and therapeutic problems]. / Tachiaritmie atriali nella malattia del nodo del seno: problemi diagnostici e terapeutici.

It is known that sinus node dysfunctions can, in some instances, be accompanied by paroxysmal supraventricular arrhythmias. It is however not completely understood if, in these patients, it is present a situation of electrical atrial vulnerability or an electrophysiological condition which may represent the substrate for these arrhythmias. With the aim to solve this issue, 23 patients with sinus node dysfunction (8 of whom with atrial tachyarrhythmias) underwent a complete electrophysiological study, according to the protocol of the Italian Group of Cardiac Electrophysiology. The results of the electrophysiologic study allowed to demonstrate that in 75% of patients with atrial tachyarrhythmias it was possible to reproduce the arrhythmia by means of a low aggressive protocol. Also, in these patients, an inter- and intra-atrial conduction disturbance was demonstrated and, with respect to those patients without arrhythmias, the atrial refractory period was shorter in basal conditions and during induced atrial rhythm with cycle length of 600 ms, it was longer in left atrium than in high right atrium, and it shortened to a lesser extent with the shortening of the cardiac cycle.

[Atrial stimulation and intranodal migration of sinus pacemaker in man (author's transl)]. / Elettrostimolazione atriale e migrazione intranodale del segnapassi sinusale nell'uomo.

In order to demonstrate, in man, sinus node pacemaker shift following atrial stimulation, we compared, in 26 patients, the curve of sinus node function obtained with Strauss' method with that resulting by the scanning with premature atrial stimulation of the first returning cycle following either a single premature atrial induced beat (140 ms shorter than the basic cycle) (group A), or a train of 8 consecutive atrial beats induced with a rate slightly faster (10 beats/m) than the control sinus rhythm (group B). Assuming that no changes in sinus pacemaker automaticity or in sinoatrial conduction occur owing to atrial stimulation, curves with the same shape should be observed if the site of the dominant pacemaker remains unchanged: whereas, different lengths of the compensatory phase (zone I) should be expected if an intranodal pacemaker shift occurs. For evaluating the length of the compensatory zone (zone I), we calculate, on the curve of the sinus node function, the mean value of the relation points included in the first third of the reset zone (zone II). According to our results, the length of the compensatory phase (zone I) evaluated on the curve resulting by the scanning of the first returning cycle following either a single premature atrial induced beat (group A), or eight consecutive atrial beats (group B) was shorter than that observed with the original Strauss' method (10% and 18% respectively). However, only in the group B, this difference was statistically significant. In addition, a significant inverse relationship between the shortening of the compensatory zone and the sinoatrial conduction index was also observed. Considering that our results have been corrected in such way as to repeal eventual changes in sinus pacemaker automaticity or sinoatrial conduction following atrial stimulation, the shortening of the compensatory zone, we have observed in our patients, strongly suggests an intranodal sinus pacemaker shift. If we assume that this result could represent an indirect evidence of this phenomenon, some clinical implications may follow: 1) another limitation, in addition to others known (intraatrial conduction delay, sinus arrhythmia, changes in sinus node automaticity, difference between retrograde and antegrade conduction time) could decrease the accuracy of atrial stimulation techniques in the estimation of the sinoatrial conduction time; 2) sinus pacemaker shift following atrial stimulation, may induce an understimulation of the true sinoatrial conduction time; however, according to our results, the error is generally small, so that it does no preclude the usefulness of atrial stimulation techniques in the evaluation of sinoatrial conduction; 3) the more evident and significant shortenings of the compensatory phase occurred with atrial pacing technique: this finding could explain why shorter sinoatrial conduction times are generally observed with Narula's method in comparison with Strauss' method.

[Diagnostic value of the continuous electrocardiographic monitoring (Holter) and of the electrophysiologic testings in patients with sino-atrial node dysfunction (author's transl)]. / Valore diagnostico dell'elettrocardiografia dinamica e delle indagini elettrofisiologiche nelle disfunzioni del nodo seno-atriale.

A twenty-four hours electrocardiographic recording and an electrophysiological study were performed in 48 patients with sinus bradycardia, 21 of them with symptoms suggesting a sino-atrial dysfunction. Both methods, and independently one each other, were not diagnostic in all symptomatic patients; on the contrary, they showed sinus dysfunction in patients without symptoms related to sino-atrial node dysfunction. These results induce to conclude that the two methods are complementary and that their results must be ever critically accepted, especially when a permanent cardiac pacing is indicated. Because of their not high sensitivity, some patients with sinus dysfunction are not recognised; there-after, the diagnosis is only possible, in these cases, on the base of clinical-signs.

[Pyelocaliceal diverticula. Diagnostic problems: wash-out technique investigation and dynamic study (author's transl)]. / In tema di diverticoli pielici. Problemi diagnostici: esame con la tecnica della diuresi indotta e studio dinamico.

The authors evaluated the pyelocaliceal diverticula by means of high dosis contrast urography with nephrotomography and following wash-out and dynamic examination. Most of cases showed stasis in the diverticulum. In no case dynamic activity of diverticulum walls was founded.

[Tachycardia-bradycardia syndrome. An electrophysiological and pharmacological study (author's transl)]. / La sindrome bradicardia-tachicardia. Studio elettrofisiologico e farmacologico

In nine patients with the tachycardia-bradycardia syndrome, a dysfunction of sinusal automatism was observed, shown by a prolonged recovery time of sinus node for six of the patients, and by an insufficient response to atropine in all nine. In two of the five patients, where a study of seno-atrial conduction was possible a conduction defect at this level was noticed. In three patients (33%), asystole was observed: in one patient in the course of a tachycardial crisis; during the passage of an atrial fibrillation in sinusal rhythm in another, and following premature isolated atrial pulsations in the third. The observations of asystole pause in the third patient following premature isolated beats which were longer than those induced electrically, led to the conclusion that, more than a sinusal automatism or sino-atrial conduction defect, asystole can be due to repetitive re-entries that are not reproduced at the level of the sino-atrial junction. The atrial response obtained in another patient with atrial stimulation slightly superior to the threshold, seems to exclude an atrial inexcitability hypothesis. The paroxysmal tachycardia and the atrial fibrillation were the most frequently noted arrhythmias; atrial flutter was only rarely observed. A rotation of rhythm disturbances was recorded in four of the nine patients, both on diverse occasions and during one crisis. The atrial electrostimulation performed on a patient during asystole pauses occurred spontaneously during the course of a tachy cardial crisis, allowed conduction of the atria only for 1-2 stimuli, and did not impede the recovery of the tachycardial paroxysm. It is probable that the conduction disturbances and/or the atrial excitability, which have the same determining cause of sinusal dysfunction, can be responsible for atrial arrhythmias, with the characteristic symptom of the tachycardia-bradycardia syndrome.

[Programmed atrial stimulation in the study of sinoatrial conduction in normal subjects (author's transl)]. / La stimolazione atriale programmata nello studio della conduzione seno-atriale nel soggetto normale

Sinoatrial conduction was investigated in 18 normal subjects, using premature atrial depolarizations. The results obtained in this investigation were evaluated plotting the test cycle (expressed as difference between the basic sinus cycle and the test cycle as a percentage of the basic sinus cycle) as a function of the return cycle (expressed as difference between the return cycle and the basic cycle as a percentage of the basic sinus cycle). In normal subjects, premature atrial depolarizations elicited in the last 10-20% of the spontaneous sinus cycle, produced a progressive prolongation of the return cycle and the points correlating the return cycle index to the test cycle index fell above the diagonal of the plotting system. After earlier premature atrial stimulations, the return cycle stayed the same length, and the points correlating the return cycle index to the test cycle index fell along a line parallel to "y" axis (plateau). The mean value of the returning cycle (expressed as above) corresponding to the test cycles (evaluated as above) included in the first 5% of the "plateau" can be defined as the "sinoatrial conduction index". This index, the sum of conduction into and out of the sinus node, ranged from 79 msec to 187 msec. By assuming similar anterograde and retrograde conduction, the sinoatrial conduction time ranged from 39.5 msec to 97.5 msec (mean value 70 msec).