Transesophageal echocardiographic evaluation of the morphologic and hemodynamic cardiac changes during ventricular fibrillation.

To analyze cardiac motion during ventricular fibrillation (VF), we used transesophageal echocardiography to study nine male subjects, aged 44 +/- 7 years, affected by heart disease who have poor left ventricular function, during implantation of an Implantable Cardioverter Defibrillator, when VF is induced several times to determine the defibrillation threshold. Wall and valvular motion, transmitral and transaortic blood flow, and blood echoreflectivity were evaluated in all patients. Moreover, in basal conditions, during VF, 1 and 5 minutes after restoration of basal rhythm, we calculated the left ventricular end-diastolic volume (EDLVV) and area (EDLVA), the left ventricular end-systolic volume and area, the ejection fraction, and the fractional area change with a four-chamber echocardiographic view. At the onset of VF, the myocardium and valves exhibited a chaotic motion. About 10 seconds later the oscillatory movement of the heart walls became more ample and regular; the mitral valve showed a cyclic closure and opening with a forward flow, and the aortic valve exhibited similar behavior, although at a lower intensity. A spontaneous echo contrast appeared inside the atrial and ventricular cavities, gradually becoming an incrt homogeneous mass that was completely flushed away with the restoration of the basal rhythm. When VF started, EDLVV (286 +/- 98 ml) and EDLVA (50 +/- 16.5 cm2) decreased abruptly (EDLVV = 182 +/- 65 ml, p < 0.02; EDLVA = 38 +/- 9.2 cm2,p < 0.05); so did ejection fraction (31.8% +/- 15% versus 11% +/- 5%; p < 0.003) and fractional area change (25.8% +/- 6.5% versus 7% +/- 3.4%; p < 0.001). When the basal rhythm was restored, the heart extended again and EDLVV, EDLVA, ejection fraction, and fractional area change after 1 and 5 minutes were similar to those calculated before induction of VF. This behavior was observed during both the first and last induced VF. Thus during VF, great variations of heart morphology and dynamics, as well as blood echoreflectivity, occur; the heart seems to make attempts to organize its dynamics during the arrhythmia. Repeated episodes of VF and defibrillation with low energies do not seem to worsen left ventricular dynamics even in impaired hearts.

Cardiovascular adaptations to endurance training and detraining in young and older athletes.

In order to evaluate the influence of aging on cardiovascular adaptations to endurance training and detraining, 12 young (range 19-25 years) and 12 older (range 50-65 years) male cyclists were examined during the training and after 2 months of detraining. Twelve young and 12 older healthy sedentary males matched for age and body surface area were used as control groups. Each subject underwent a maximal exercise test using a cycle-ergometer in order to measure maximum oxygen consumption, an M-mode and 2D echocardiography in order to assess left ventricle morphology and systolic function, and a Doppler echocardiography for evaluating the diastolic filling pattern. During the training period both groups of athletes showed higher values of maximum oxygen consumption, left ventricular wall thicknesses, end-diastolic diameter and volume, as well as left ventricular mass, than their control subjects; in the older subjects the adaptation of the heart to aerobic training seems to be obtained mainly through a higher increase in left ventricular diastolic filling. In both groups no significant modifications in the ejection fraction and diastolic function parameters were recorded. After the detraining period the wall thicknesses decreased only in young athletes, while left ventricular mass and end-diastolic diameter and volume reduced only in older athletes. In conclusion, training and detraining induced nearly similar left ventricular morphological modifications in the two age groups, even though greater in the older athletes with respect to the ventricular mass and volume. No relevant differences were observed in the Doppler filling pattern between athletes and sedentary controls.

[Post-traumatic constrictive pericarditis with fast course]. / Péricardite constrictive posttraumatique à évolution rapide.

A case is reported of a 46-year-old male patient who sustained a blunt thoracic injury with an anterior flail chest, and right haemopneumothorax. He was intubated and ventilated because of acute respiratory failure. There were initially no signs suggesting any myocardial injury. It was not before day 20 that the electrocardiogram showed a QS wave in leads V2 and V3. The hypothesis of an antero-septal myocardial infarct was not confirmed by echocardiography, which only revealed slight thickening of the posterior pericardium. From day 50 on, the patient had tachycardia, raised jugular venous pressure, and effort dyspnoea. Echocardiography (day 59) showed an anterior and posterior pericardial effusion (about 500 ml), marked pericardial thickening, and inferior vena caval collapse during inspiration, with normal myocardial wall movements. Drainage pericardiocentesis was therefore carried out, followed by, four days later, a pericardiectomy. A small ecchymosis was found on the anterior aspect of the right ventricle. The pericardium was thickened, fibrous, hyperhaemic, Case is y stuck to the epicardium. Eight months later, echocardiography showed that the posterior pericardium remained thickened, and there was a very small residual effusion. Movements of the septum had returned to normal.

[Hypokinetic cardiomyopathy. A possible result of myocardial contusion]. / Cardiomiopatia ipocinetica. Possibile esito della contusione miocardica.

Myocardial contusion is a frequent complication of blunt chest trauma. Ventricular involvement is generally segmental and exhibits a favourable evolution. We describe the case of a 44-year-old male who suffered an acute blunt thoracic injury with a consequent stable worsening of his functional class. His first electrocardiographic examination 30 days after the trauma showed negative T wave in V3-V6 leads while one and two-dimensional echocardiography exhibited a diffuse damage of the morphology of the left ventricle and a lowering of the fractional shortening (FS) of its end-diastolic diameter (EDD): FS = 23%, EDD = 6.9 cm, diastolic eccentricity index = 65%, systolic eccentricity index = 70%. During a follow-up period of thirteen months ECG became normal after a short time while the echocardiogram maintained its initial abnormalities and the patient maintained his compromised functional class. We report this peculiar pattern of myocardial contusion evolution which has not previously been described.

Anabolic steroid use in body builders: an echocardiographic study of left ventricle morphology and function.

To ascertain the effect of anabolic steroids (AS) on left ventricle size and function, M-mode and 2D echocardiographic evaluation was carried out in 14 body builders at the end of a phase of AS self-administration (8 +/- 3 weeks, mean +/- S.D.) and after a period (9 +/- 2 weeks, mean +/- S.D.) of drug withdrawal, as well as in 14 other body builders who had never made use of AS, and in 14 sedentary individuals. All the subjects were also examined anthropometrically. Ventricular septal thickness index was slightly greater in athletes using AS, compared to the other two groups (p less than 0.05), while left ventricle mass, the end-diastolic volume indexes and isovolumetric relaxation time, (a parameter of left ventricle diastolic function) were significantly increased (p less than 0.001) as well as the fat free mass (FFM), a marker of skeletal muscle mass. The non-users showed no differences in echocardiographic parameters, compared to sedentary controls. During the off treatment phase, the percentage of adipose mass increased and FFM decreased, while echocardiographic parameters did not vary significantly from on treatment values. The findings indicate that AS can induce an unfavourable enlargement and thickening of the left ventricle, which loses its diastolic properties with the mass increase. These modifications tend to persist following a short period of drug withdrawal.

[Hypertrophic cardiomyopathy. Correlation between the morphologic-quantitative data of the 2-dimensional echocardiogram and electro-vectorcardiographic aspects]. / Cardiomiopatia ipertrofica. Correlazione tra i dati morfologico-quantitativi dell'ecocardiogramma bidimensionale e gli aspetti elettro-vettorcardiografici.

39 patients affected with hypertrophic cardiomyopathy (ICM) have been studied by M-mode and two-dimensional echocardiography (1 and 2D Echo), standard electrocardiogram (ECG) and vectorcardiogram (VCG). For each patient we have outlined the anatomical shape of the left ventricle and we have tried to measure the myocardial hypertrophy by a score system that determines its size and extent. For this reason we have followed the echocardiographic segmental analysis procedure suggested by Edward (1981) but we have modified it dividing the left ventricle into 11 segments and measuring the value of the apex three times. We have given each patient a hypertrophy score by assigning a value 0 to any segment with a thickness less than or equal to 12 mm, a value 1 if the thickness was greater than 12 less than or equal to 17 mm, a value 2 if it was greater than 17 less than or equal to 22 mm, a value 3 if greater than 22 mm. We have also calculated the distribution index of the hypertrophy dividing the number of the hypertrophied segments by the number of the ventricular segments. We have identified five patterns of hypertrophic cardiomyopathy: 7 cases with a partial involvement of the interventricular septum (IVS) (pattern 1), 7 cases with a full involvement of the IVS (pattern 2), 22 cases with involvement of the free wall of the left ventricle (pattern 3), 2 cases with involvement of the distal IVS and the apex (pattern 4), 1 case with involvement of the inferior and lateral wall (pattern 5). The highest hypertrophy score and distribution index was noticed in the third anatomical pattern (p less than 0.001). Comparing the three more frequent anatomical patterns with their Ecg-Vcg aspects, we have found a higher prevalence of the left anterior hemiblock in pattern 1, of the pathological Q waves in pattern 2, of the left ventricular hypertrophy in pattern 3. However this correlation was not significant while the correlation between the Ecg-Vcg aspects and the myocardial hypertrophy score and distribution index was extremely significant (p less than 0.001). Consequently the size and distribution of the myocardial hypertrophy could differentiate the Ecg-Vcg aspects better than the anatomical shape of the left ventricle; when hypertrophy was moderate the left anterior hemiblock and the pathological Q waves were more frequent. On the contrary when hypertrophy was high and widespread the prevailing Ecg-Vcg aspect was the left ventricle hypertrophy.

[Evolutive study of the vectorcardiogram from the 14th day to the 6th month of life on the normal infant]. / Studio evolutivo del vettorcardiogramma dal 14 giorno al 6 mesi di vita del bambino normale.

With the purpose of a better evaluation of the changes of cardiac potentials during the early hemodynamic arrangement of the normal heart, the authors analyze the VCG of 10 normal children periodically recorded from the 14th day to the 6th month from birth. Rotation of QRS, T and P loops in the three planes, direction and voltage of principal planar and spatial vectors were analyzed. The QRS loop showed a balanced distribution between right and left ventricular forces in the second week and developed a leftward orientation from the 4th week to the 3rd month, as demonstrated both by the loss of clockwise rotation of horizontal QRS loop and by the progressive leftward and backward direction of intermediate vectors. The initial vectors were sketched or absent in the 14th day and increased successively until the typical Q loop. The voltage of terminal vectors did not change in the course of time, but the S loop in the horizontal plane lost its original clockwise rotation and shifted to middle posterior line. The T loop progressively shifted backward so that it was always posterior after the 30th day. The P loop in the frontal plane was similar to the adult's one while in the horizontal plane it often presented a figure-of-eight. The semeiological aspects and the electrogenic considerations of these changes were discussed.

[Evolutive study of the VCG in the first week of the normal newborn infant (author's transl)]. / Studio evolutivo del vettorcardiogramma nella prima settimana di vita del bambino normale

The vectorial and morphological variations of the VCG (Frank method) during the first seven days of life of sixteen normal newborn infants were analyzed. A byphasic distribution of the QRS vectors in the horizontal plane was found at birth. Successive observations showed a rising of initial forces of left septal activation and a slight increase of left parietal forces. The T loop variations were more remarkable, being probably correlated with rapid postnatal hemodynamic modifications. After a few days the T loop was oriented posteriorly and to the left, not changing this direction for many year. The P loop did not differ from the adult's in the majority of cases. Sometimes it showed a figure-or-eight rotation in the horizontal plane, probably due, according to the authors, to a different pathway of atrial activation.

[The vectorcardiogram of the normal child, 2-12 years of age (author's transl)]. / Il vettorcardiogramma del bambino normale dia 2 ai 12 anni di eta'

Morphological aspects and the most important vectorial parameters of the VCG (Frank method) of normal children, aged 2 to 12 years, were analyzed. The total group consisted of 110 subjects (10 for each )ear) subdivided into three subgroups of progressive age. Semeiologic evaluation of the QRS in the frontal and sagittal planes was not significant because of the stereotypes of the figures. In the horizontal plane the majority of cases showed typical triphasic development of the vectorial groups, while biphasic morphology was found in the minority. The triphasic loop presented 1) a balance between anterior and posterior forces which was more frequent in the youngest children, 2) a posterior orientation which was more frequent in the oldest children or 3) an anterior orientation which was infrequent. Since the anterior orientation of triphasic QRS was not related to the age -- it may also be seen in normal adults -- it was attributed to a variation of ventricular activation. The biphasic loop was attributed to immaturity of ventricular conduction. The evaluation of quantitative parameters was in agreement with the results of other studies. The changes of initial and intermediate vectors were probably due to the more important development of the left ventricle. The QRS duration increased with age. The T loop was posterior in the majority of the youngest children and progressively advanced with age, although it remained posterior in an important number of cases of children aged twelve.

Transthoracic and transesophageal echocardiographic indices predictive of sinus rhythm maintenance after cardioversion of atrial fibrillation: an echocardiographic study during direct current shock.

BACKGROUND: Up to 57% of atrial fibrillation (AF) recurrences after cardioversion take place during the first 30 days following direct current shock (DCS) delivery. Previous echocardiographic studies on sinus rhythm (SR) maintenance after cardioversion have focused mainly on parameters recorded before DCS, while other studies have reported on the indices recorded soon after delivery of the shock. METHODS: Therefore, we investigated 18 patients with nonrheumatic AF, selected to undergo DCS, by both transthoracic (TTE) and transesophageal (TEE) echocardiography performed within 10 minutes before and after the electrical shock delivery. TTE was utilized for the evaluation of left atrium and left ventricle shape as well as for mitral Doppler flow sampling, while TEE was used to evaluate left atrial appendage (LAA) morphology and function, to score the LAA spontaneous echo contrast, and to evaluate the flow of left superior pulmonary vein; the transesophageal probe was left in situ during the electrical procedure. Thirty days after cardioversion, 10 (55%) patients maintained SR (Group 1) while 8 (45%) reverted to AF (Group 2). We compared the mean values of the parameters recorded in the two groups both before and after DCS. RESULTS: Although many parameters of pre- and postcardioversion analysis proved to be significantly different between the two groups, the most marked differences were exhibited by the following postcardioversion indices: Peak Doppler flow velocity of the end-diastolic mitral flow (30.10 +/- 5.24 vs. 20.50 +/- 6.32 cm/sec, P = 0.003); sum of peak velocities of the end-diastolic contraction (A) and relaxation (A(1)) of LAA (A + A(1) = 58.20 +/- 17.02 vs. 31.25 +/- 9.27 cm/sec, P = 0.001); duration of A + A(1) (162.70 +/- 27.01 vs. 133.75 +/- 5.31 msec, P = 0.002); and sum of durations of the early diastolic forward (E) and reverse (E(1)) flow of LAA (101.90 +/- 35.15 vs. 53.33 +/- 16.33 msec, P = 0.006). CONCLUSIONS: Using a single echocardiographic examination during DCS and after induction of anesthesia, without further discomfort to patients, we were able to identify useful parameters for the prediction of future electrical activity of the heart before as well as soon after DCS. Postcardioversion indices, derived by both TTE and TEE, were even more predictive of SR maintenance after 1 month than precardioversion parameters.

[Electrocardiographic changes and echocardiography variations in ventricular morphology in left ventricular overload]. / Alterazioni elettrocardiografiche e variazioni ecocardiografiche della morfologia ventricolare nei sovraccarichi ventricolari sinistri.

In order to compare the ECG patterns to several echocardiographic morphological indexes in different left ventricular overloadings, 15 cases of systolic left ventricular overloading (SLVO) and 17 cases of diastolic left ventricular overloading (DLVO) were analyzed. The current ECG changes of left ventricular hypertrophy and some original parameters of ventricular repolarization have been correlated with volumes, ejection fraction and mass of the left ventricle (calculated by Reichek's formula) and with left ventricular diastolic and systolic eccentricity indexes, derived by the application of Fishl's formula to the 2D echocardiographic four or two chamber apical view. In both SLVO and DLVO we found a correlation between the left ventricular mass and Romhilt-Estes point score system (p = 0.02) as well as the degree of ventricular repolarization abnormalities (p = 0.01). In SLVO we found a direct correlation between negative P wave deflection on lead V1 and diastolic as well as systolic eccentricity index: that is, the more negative P wave the more elongated left ventricular geometry. Moreover, in SLVO we found an interesting apposite correlation, compared with DLVO, between the systolic eccentricity index and the degree of ventricular repolarization abnormalities: in SLVO ST depression or T wave inversion on left limb or left precordial leads was associated with the maintenance of an elongated shape of left ventricle, while in DLVO the same ventricular repolarization abnormalities were associated with the loss of the elongated geometry of left ventricle which became spheric. Thus ECG correlates with echocardiographic left ventricular mass if poliparametric voltage indexes are considered.(ABSTRACT TRUNCATED AT 250 WORDS)

[The usefulness of transesophageal echocardiography in the diagnosis of arrhythmogenic cardiomyopathy of the right ventricle]. / Utilità dell'ecocardiografia transesofagea nella diagnosi di cardiomiopatia aritmogena del ventricolo destro.

OBJECTIVES: The aim of this study was to evaluate the usefulness of transesophageal echocardiography (TEE) for the diagnosis of arrhythmogenic right ventricle cardiomyopathy (ARVC). PATIENTS: Using TEE and the standard transthoracic echocardiography (TTE), we studied 19 patients affected with hyperkinetic ventricular arrhythmias with a LBBB pattern, as well as 10 normal control subjects (C). METHODS: We calculated the following parameters: the fractional area change (FAC) of the end-diastolic right ventricule (RV) area; the global wall motion score (WMS) by the algebraic sum of the score of each of the 9 wall segments including the inflow, outflow and apex of RV; the asynergy index (AI) by the percentage of the 9 segments with a score > or = 2; the average thickness of moderator band and papillar muscles (ATMP); the echo reflectivity score (ERS) and the structural abnormalities score (SAS) of RV. The diagnosis of ARVC was proposed when RV segmental wall motion abnormalities were visualized, or when a decrease of the ventricular FAC and dysmorphic aspects were contemporaneously present. The results of the two echocardiographic approaches were compared, and in arrhythmic patients (A) echocardiographic results were compared with those obtained by cineventriculography (CVG), which we had adopted as the reference diagnostic method. RESULTS: The comparison between A and C showed significant differences for all parameters if calculated by the TEE (p < 0.003-0.0001), except for ATMP if calculated by TTE (p < 0.003-0.0001). The comparison between TEE and TTE approaches did not show any difference in the C group while in the A group only FAC and ERS resulted similar; the values of the remaining parameters were significantly greater if calculated by TEE than by TTE (WMS = 7.3 +/- 4.1 vs 4.3 +/- 2.3: p < 0.01; AI = 22.6 +/- 18.5 vs 11.6 +/- 10.3: p < 0.05; ATMP = 6.1 +/- 0.9 vs 5 +/- 1.2 mm: p < 0.04; SAS = 2.2 +/- 0.8 vs 1.4 +/- 0.7: p < 0.002). In 17 of the 19 patients who were clinically suspected to be affected with ARVC the diagnosis was confirmed by CVG; 12 of them (70%) were correctly identified by TTE and 17 (100%) by TEE. One of the two negative patients was erroneously considered positive both by TTE and TEE. CONCLUSIONS: TEE is a usefull diagnostic tool for ARVC and is more accurate than TTE for the identification of the concealed or dubitative forms of the disease.

[Diabetic cardiomyopathy: preclinical pathology disclosed by the increase in ventricular afterload]. / Cardiomiopatia diabetica: patologia preclinica evidenziabile con l'incremento dell'afterload ventricolare.

In order to test the importance of the association of diabetes mellitus and arterial hypertension in generating morphological and functional changes of the left ventricle (LV) consistent with a cardiomyopathy, 37 patients, aged 27 +/- 6.7 years, were studied by standard and digitized M-Mode echo: eighteen of them were affected by diabetes mellitus, 11 by arterial hypertension, 8 by diabetes and hypertension. Each group was compared to the others and with a group of 14 normal subjects. In order to verify the importance of increased ventricular after-load in modifying ventricular performance of diabetic patients, changes of the peak rate of systolic and diastolic variation of LV diameter and changes of the peak rate of interventricular septum and posterior wall excursion (IVSE, PWE) were evaluated after methoxamine hydrochloride infusion in 8 diabetic and 6 normal subjects. In diabetics the ratio between ventricular thickness and diameter (h/r) was greater than normal subjects (p less than 0.02); this ratio resulted higher in patients with diabetic rhinopathy who also exhibited an isovolumic diastolic period longer than normal (p less than 0.02). Both h/r ratio and isovolumic diastolic period (IDP) were higher in diabetic-hypertensive group as compared to normals (p less than 0.001), strictly diabetic (p less than 0.01 and p less than 0.001) or hypertensive subjects (p less than 0.01). Diabetic-hypertensive group, exhibited a lowering of the systolic and diastolic peak rate of IVSE (p less than 0.01) as well as of systolic peak rate of PWE as compared to the other three groups (p less than 0.05).

The anterior displacement of the QRS loop as a right ventricular conduction disturbance. Electrophysiologic and vectorcardiographic study in man.

Anterior displacement (AD) of the QRS horizontal loop (Frank VCG method) was induced by programmed right atrial stimulation (PRAS) in 15 cases. When AD occurred we noticed changes of the terminal QRS vectors and of the T loop similar to those observed in incomplete right bundle branch block (RBBB). The increasingly anticipated extrastimuli induced progressively the AD and then progressive degrees of RBBB. The anterior shifting of the efferent limb never appeared after the induction of RBBB. A left conduction disturbance never appeared after the AD. In cases of supposed incomplete left bundle branch block (i.e. left ventricular hypertrophy) the QRS duration decreased when the AD was induced. Therefore, the AD induced by PRAS and probably those observed in some clinical cases are due to a right ventricular conduction disturbance.

Effects of transdermal nitroglycerin on left ventricular function after acute myocardial infarction.

Progressive left ventricular dysfunction in acute myocardial infarction patients is associated with a poor prognosis. It has been shown that some therapeutic measures which have the potential for limiting the infarct size and preserving ventricular function, are also able to reduce the incidence of congestive heart and improve survival. The aim of this protocol was to assess the effects of transdermal nitroglycerin administered within 72 hours after the onset of acute myocardial infarction and for the following 6 months, on left ventricular function. A total of 98 consecutive acute myocardial infarction patients were randomly allocated, within 72 hours of onset of symptoms, to a double-blind 6-month-therapy with either 10 mg/24 hour transdermal nitroglycerin or placebo. Patients underwent two-dimensional echocardiography at entry, after 2 weeks, 3 months and 6 months. In the nitroglycerin group, end-diastolic volume increased during the follow-up (+6.7%, p < 0.05) while end-systolic volume remained nearly unchanged; ejection fraction and stroke volume increased progressively (+6.3%, p < 0.05, +14.2%, p < 0.05, respectively) and a important reduction of percent of dyssynergic segments was present (-19.2%, p < 0.005). In the placebo group end-diastolic volume and end-systolic volume slightly increased during the follow-up (+2% and +4.9% respectively); ejection fraction and stroke volume remained nearly unchanged during the study; percent of dyssynergic segments showed an important decrease after 2 weeks and 6 months (-21.3%, p < 0.005). A clinically relevant increase (> 20%) in ejection fraction was present more frequently in the nitroglycerin than in the placebo group (p < 0.001). In conclusion, the early (within 72 hours) and prolonged (6 months) administration of transdermal nitroglycerin in acute myocardial infarction improves ejection fraction and stroke volume but does not modify ventricular remodeling.

Electrogenesis of the S1S2S3 electrocardiographic pattern. A study in humans based on body surface potential and right ventricular endocardial mapping.

To study the electrogenesis of the S1S2S3 pattern, seven patients had body surface potential mapping and endocardial mapping of inflow tract, outflow tract, and apex of the right ventricle. QRS duration was longer in S1S2S3 versus controls (94 +/- 14 vs. 84 +/- 14 msec). Surface mapping was similar in S1S2S3 patients and in controls during the first 30-40 msec of QRS, but S1S2S3 patients subsequently presented the following differences: (1) earlier time of onset (34 +/- 3 vs. 44 +/- 6 msec) and a lower voltage (1,242 +/- 468 vs. 1,649 +/- 31 mV) of peak positive anterior maximum; (2) earlier dorsal migration (45 +/- 3 vs. 55 +/- 7 msec) of the maximum; (3) a second peak positive maximum at 58 +/- 3 msec, located on the dorsal spine; (4) the appearance of a right subclavicular positive area at 51 +/- 6 msec, which in controls was absent or appeared later (66 +/- 7 msec). At the end of QRS, the maximum was located in all but two S1S2S3 cases on the upper sternum. Right ventricular endocardial mapping showed a similar activation time of the apex in S1S2S3 patients and controls, but in the former a significant inflow (56 +/- 21 vs. 36 +/- 9 msec) and outflow tract (79 +/- 13 vs. 39 +/- 8 msec) activation delay was documented. The data obtained using body surface potential mapping suggest that an anomalous wavefront rightward and superiorly oriented is present in the S1S2S3 pattern, which is able to oppose the electrical forces of ventricular free walls.(ABSTRACT TRUNCATED AT 250 WORDS)