[Atrial desynchronization induced by Valsalva's maneuver in a patient with reciprocating supraventricular tachycardia and Wolff-Parkinson-White syndrome]

A 22 years old man with ventricular preexcitation syndrome due to a left accessory pathway, was admitted because of orthodromic reciprocating tachycardia, 205 bpm in frequency. The patient was invited to perform a Valsalva Maneuvre, and at its ending, the tachycardia degenerated into atrial fibrillation (AF) associated with high ventricular rate, reverted to sinus rhythm by D.C. shock. The electrophysiologic study documented a left lateral by pass tract, with an anterograde refractory period of 230 msec. AF was inducible and had a minimal RR interval of 220 msec. Vagal stimulation, induced at the end of Valsalva maneuvre, probably caused dispersion of atrial refractorines and intraatrial reentry, converting the orthodromic tachycardia into atrial fibrillation.

A polymorphic form of familial arrhythmogenic right ventricular dysplasia

Thirty-two members of a family were studied. Three of them died in their youth and had evidence of arrhythmogenic right ventricular (RV) dysplasia. The other 29 members underwent clinical examination, electrocardiography, chest x-ray and M-mode and 2-dimensional echocardiography. Fourteen patients found to have structural abnormalities of the right ventricle underwent 24-hour ambulatory electrocardiographic recording and symptom-limited bicycle stress testing. Hemodynamic and angiographic studies were performed in 6 of these patients. In this family the arrhythmogenic RV dysplasia showed a wide variation of abnormalities, ranging from mild, local alterations to generalized involvement of the right ventricle. The patients were separated into 3 groups on the basis of both the clinical profile and noninvasive/invasive studies: 3 subjects who died suddenly; 3 subjects who had severe ventricular arrhythmias; and 8 subjects in whom RV impairment was not associated with any significant arrhythmias. There was no close relation between the severity of the RV abnormality and presence of ventricular arrhythmias. The variability of the RV abnormality and the high prevalence of this condition in this family is consistent with a genetic pattern of autosomal dominance with incomplete penetrance.

[Electro-vectorcardiographic analysis of the negative, diphasic and bifid T wave in right precordial leads in young subjects]

Morphology, genesis and incidence of isolated T wave abnormalities on right precordial leads of healthy young individuals were studied in this work. ECG were obtained from 1510 healthy subjects aged 14 to 40 years consecutively submitted to a cardiological evaluation in order to assess their fitness for sport. In 510 of them a VCG was made too. The results showed that T waves were rarely negative beyond V1 (0.46%) and even more rarely negative from V1 to V3 (0.13%); diphasic T waves were present in 2.38% and bifid T waves in 6.15% of our cases. The T loop of VCG tended to be more posteriorly displaced and evolved from a counterclockwise to a clockwise rotation as the presence of negative T waves spread toward left on precordial leads. The "+-" type of diphasic T wave corresponded to a counterclockwise rotation of the T loop, the "-+" type to a clockwise rotation. Bifid T waves were associated with figure of eight or "arched" T loops of VCG. The T loops of those subjects who underwent a second evaluation after several years tended to be displaced more anteriorly, with counterclockwise rotation. The causes of these T wave abnormalities have not been clearly explained yet, even if a slight delay in the right final vectors was present in the majority of our cases.

[Tachycardia and ventricular fibrillation in the arrhythmogenic right ventricle (arrhythmogenic dysplasia of the right ventricle). Clinical and electrocardiographic spectrum]

In this paper we report the arrhythmias recorded on basal ECG, on Holter monitoring or on exercise test, in 32 pts affected by arrhythmogenic right ventricle (ARV). A sustained ventricular tachycardia (VT) was present in 11 pts a non sustained VT in 15 pts, a slow VT in 2 pts, a ventricular fibrillation (VF) in 3 pts and both sustained VT and VF in 1 pt. All but 1 case of sustained VT showed a LBBB like pattern. The heart rate during VT ranged between 170 and 280 beats/min. The frontal axis of the VT showed a wide range of deviation. Among non sustained VT, 9 cases had LBBB like pattern and 6 cases had polymorphic configuration. The 2 cases of slow VT showed LBBB like pattern with right axis deviation. A comparison between ventricular arrhythmias and RV impairment was made. The data obtained suggest that the effort plays an important role in the induction of VT in pts with localized RV impairment. In conclusion a wide spectrum of ventricular tachyarrhythmias is present in the ARV. Probably the RV "arrhythmogenic" zones and the electrophysiological mechanism causing the arrhythmias are various.

Rhythm and conduction disturbances in isolated, congenitally corrected transposition of the great arteries

The incidence and types of rhythm and conduction disturbances in 11 male and 6 female patients with congenitally corrected transposition of the great arteries and no other intrinsic complicating anomalies were studied. Patient age ranged from 5 to 54 years; follow-up ranged from 5 to 37 years. Surface electrocardiograms were recorded in each patient; 15 also underwent 24-hour Holter monitoring and 10 underwent electrophysiologic study. The conduction system of a 54-year-old woman who died suddenly, with complete atrioventricular (AV) block since age 30 years, was studied by serial histologic sections. Fifteen patients were asymptomatic and 2 reported repeated episodes of palpitation since childhood. Ten patients presented with a normal PR interval and 2 with first-degree AV block (12%). Five patients had complete AV block (29%), but none had had it at birth; first- and second-degree AV block preceded complete AV block in 2 patients. The morphologic pattern and duration of QRS suggested a junctional rhythm in 4 patients and an idioventricular pacemaker in 1 patient. Electrophysiologic studies confirmed that the complete AV block site was supra-Hisian in 2 patients and proximal to the His bundle bifurcation in 1 patient. However, histologic investigation disclosed fibrosis and disruption of the proximal nonbifurcating His bundle in the patient who died suddenly. In 2 patients with recurrent supraventricular tachycardia, electrophysiologic studies suggested reentry through James fibers (or dual AV nodal pathway) in 1 and the presence of a left lateral accessory AV pathway in the other. Holter monitoring showed a high incidence of ventricular arrhythmias.

Fatal paroxysmal supraventricular tachycardia in an infant

A 37-day-old infant, without associated congenital anomalies, died following a 48-hour episode of supraventricular tachycardia. The histopathologic findings of nodoventricular and fasciculoventricular Mahaim's fibers in a setting of persistent fetal dispersion were consistent with an anatomic substrate for a reentry circuit at the specialized A-V junction.

[Vectorcardiographic analysis of late potentials]

We analyzed by high amplification vectorcardiography the morphology of the QRS ending loop and the ST segment of patients with previously recorded Lown 4A, 4B ventricular arrhythmias and the healthy subject. Eight patients were affected by ischemic heart disease and 7 by arrhythmogenic right ventricular dysplasia. All had some irregularities at the end of the QRS or in the ST segment, on the standard ECG. The VCG showed one or more of these three morphologies: complete or incomplete ring, rapidly inscripted isodi-triphasic potentials, sinusoidal irregularities. In the 20 healthy subjects, the loop corresponding to the last 30 msec of the QRS, till the end of the afferent portion of T, was regular, without any particular morphology. We think that these aspects could be related to delayed fragmentation of the ventricular depolarization.

[Superior axial deviation in the young adult. An electro-vectorcardiographic study]

We analyzed the VCGs of 100 young subjects without apparent cardiac disease showing an ECG superior Axis Deviation, i.e. AQRS greater than - 30 degrees, and a rS aspect in V1. Our findings demonstrated that, in these subjects, the superior axis deviation is due to a distal right bundle branch block with posterior displacement of the terminal forces in 78% of the cases. The other cases being left anterior hemiblocks, either isolated (12%) or associated with a block of the anterior subdivision of the right bundle branch (10%). The differential diagnosis, easy on VCG, is sometimes very difficult on ECG. The most reliable ECG criteria to discriminate this kind of right bundle branch block from left anterior hemiblock are: intrinsic deflection in a VL-V6 greater than or equal to 0.015" (sensitivity 100%; specificity 57%), RV6/Ra VL ratio greater than 1 (sensibility 100%; specificity 50%) and the presence of a notched R wave in L2, L3 and a VF (sensitivity 90%; specificity 100%).

[Electro-vectorcardiographic behavior of right bundle branch block in endocardial cushion defects. Its probable relation to the so-called left anterior fascicular hemiblock]

We have investigated the possible ECG signs of incomplete Left Anterior Hemiblock (LAH). As an experimental model we chose the endocardial cushion defect, which is proved to have a ventricular activation correspondent to different degrees of LAH due to the particular disposition of the AV node and the His bundle. The VCG of 50 patients with endocardial cushion defect were divided into 5 groups according to the entity of the left and superior deviation of the maximum left vector. Comparison with the ECG signs shows that: a) minimal degrees of LAH occur with simple counterclockwise rotation of the frontal loop without a significant left axis deviation; b) there is no linear correlation between the importance of the left axis deviation and the signs of left ventricular activation asincronism. We conclude that, with the exception of this particular congenital heart disease, minimal LAH degrees can only be suspected on the basis of a counterclockwise VCG frontal loop, because the ECG diagnosis is possible only when the left axis deviation becomes important.

Dysplasia of the atrioventricular valves associated with conduction system anomalies

Clinical, vectorcardiographic, and echocardiographic data from two siblings with atrial septal defects and dysplasia of the mitral and tricuspid valves are reported. Vectorcardiograms showed that both siblings had abnormal ventricular activation with initial electrical forces directed posteriorly. One sibling died after surgery, and necropsy showed incomplete differentiation of the leaflets and tensor apparatus producing anomalies resembling "mitral arcade." Serial histological examination of the conducting tissue showed that the atrioventricular node was located on the left side of the atrial septum, that the central fibrous body and the membranous septum were hypoplastic, and that an accessory nodoventricular pathway originating in the compact node joined the left side of the ventricular septum. This accessory pathway was probably the cause of the unusual ventricular activation. Dysplasia of the mitral and tricuspid valves together with hypoplasia of the central fibrous body and the presence of accessory pathways are probably part of a malformative complex caused by incomplete differentiation of both the cardiac atrioventricular valves and the junctional area.

Programmed chest-wall stimulation to evaluate the progress of A-V block after pacemaker insertion in patients with trifascicular disease

Twenty six patients (aged 46-80, mean age 64) with bifascicular block in the presence of prolonged H-V interval (trifascicular block), were followed for an average of 31 months after inserting an R-wave inhibited pacemaker (PM) because of syncope and/or dizzy attacks. The underlying rhythm was evaluated at 4-6-month intervals by three different techniques: 1) 12-lead ECG when intrinsic patient rate was faster than PM rate; 2) abrupt PM inhibition (APMI) by the rapid chest-wall stimulation technique, and 3) progressive PM inhibition (PPMI) using a programmed chest-wall stimulation technique capable of decreasing the PM rate gradually to 30 beats/min before complete PM inhibition. In addition, the PPMI allowed the underlying rhythm to be induced and sustained and properly evaluated without any discomfort to the patient. Following PM insertion, 4 patients (15%) developed complete heart block after a mean follow-up of 43 months, and one patient (4%) developed 2nd degree 2:1 A-V block (VX) after 83 months. The P-R interval increased in 5 patients (19%) and decreased in 2 (8%). No change of A-V conduction was found in 9 patients (34%). Three patients developed low atrial rhythm, atrial flutter and atrial fibrillation, respectively (12%). After PM insertion 2 patients still complained of dizziness. None reported syncope. Two patients died during follow-up, both of congestive heart failure (8%). By detection of intrinsic rhythm it was recognized that a long symptomatic paroxysmal phase may precede the development of chronic complete A-V block. Therefore, the insertion of a permanent PM is recommended in patients with unexplained neurologic symptoms and trifascicular disease, without waiting for documented episodes of complete A-V block.

A pharmacological approach to the study of AV conduction in man

Smooth and interrupted curves of AV conduction, generated with an atrial extrastimulus technique, are seen in man, suggesting the involvement of two physiological AV pathways named "alpha" and "beta" and leading to a final common pathway (FCP). In view of this knowledge, the effects of some representative antiarrhytmic agents (Atropine, Verapamil, Ajmaline) were studied in eight patients in order to elucidate the physiological role of the various components of AV junction. Verapamil decreased conduction velocity of both "alpha" and "beta" pathways and increased their refractoriness; Atropine decreased "alpha" and "beta" pathways' refractory periods and increased their conduction velocity; further studies are required to clarify the effects of Ajmaline on AV conduction.

The conduction system in corrected transposition with situs inversus

The location and course of the conduction system were investigated by serial section in two hearts with corrected transposition of the great arteries in situs inversus. In the first case, characterized by dextrocardia, the interventricular septum was intact, while in the second case with levocardia, a high ventricular septal defect was associated with pulmonary atresia. In both hearts, a regular posterior connecting AV node was present, left-sided in one case and right-sided in the other. The bundle branches were distributed in the morphologically appropriate ventricles. Extensive hemorrhage and coagulation necrosis of the common bundle and bundle branches were observed in the first case, being consequent upon surgical replacement of the right-sided tricuspid valve. The common bundle ran below the membranous septum in this case. In the heart with ventricular septal defect it was related to the postero-inferior rim of the defect. In both cases, an accessory AV node was located anteriorly in the interatrial septum but did not connect with the ventricular musculature. The different position of the atrioventricular conducting tissue in corrected transposition, between cases in situs solitus and situs inversus, is emphasized.

Multiple lesions of the conduction system in a case of cardiac rhabdomyosarcoma with complex arrhythmias. An anatomic and clinical study

Anatomic and electrocardiographic correlations in a case of primary cardiac rhabdomyosarcoma are examined. Interatrial and atrioventricular conduction disturbances were associated with multiple lesions involving the alleged internodal pathways, together with atrial-atrioventricular nodal connections. The clinicopathologic findings seem to be consistent with the hypotheses of the functional and morphologic value of Bachmann's fascicle, and of the inherent pathways of interatrial and internodal conduction in health and disease.

[Anorectal fistulous abscesses. Long-term follow-up of the 1st operation, in 287 cases]

A review of a series of 287 operations for peri-anal fistulous abscess in patients admitted for the first time, to the 1st Surgical Division of the Fatebenefratelli Hospital, Milan, is reported. Surgical management adapted as far as possible to the anatomy of the anal canal and to the aetiopathogenesis of the fistula, resulted in a recurrence rate of only 13%. There were no instances of faecal incontinence. Two cases of partial gas incontinence were observed.