Cerebral protection with filter devices during carotid artery stenting.

BACKGROUND: Distal embolization of debris during percutaneous carotid artery stenting may result in neurological deficit. Filter devices for cerebral protection potentially reduce the risk of embolization. METHODS AND RESULTS: Elective carotid stent implantation using 3 different types of distal filter protection devices was attempted in 88 consecutive lesions (84 patients) in the internal carotid artery that had >70% diameter stenosis (mean, 78.7+/-10.7%). Procedures were performed in 3 different centers. The mean age of the patients was 69+/-8 years, 75% were men, and 35.7% had neurological symptoms. In 86 lesions, a stent was successfully implanted (97.7%). In 83 of these 86 procedures (96.5%), it was possible to position a filter device. In 53% of filters, there was macroscopic evidence of debris. Collected material consisted of lipid-rich macrophages, fibrin material, and cholesterol clefts. Neurological complications during the procedure, in the hospital, and at 30 days of clinical follow-up occurred in only one patient (1.2%). This patient suffered a minor stroke that resolved within 1 week. Two major adverse cardiac events (2.3%) occurred during the 30 days of follow-up. CONCLUSIONS: Filter protection during carotid artery stenting seems feasible and safe. In the present series, the incidence of neurological complications was low.

Efficacy of intravenous propafenone in termination of atrial flutter by overdrive transesophageal pacing previously ineffective.

Fifty patients with symptomatic type I atrial flutter in whom termination of the arrhythmia with transesophageal stimulation was unsuccessful were randomized to undergo a repeat procedure after intravenous propafenone (n = 25) or placebo (n = 25). Immediate sinus rhythm recovery rate was 36% in the propafenone group and 4% in the placebo group (p = 0.005), indicating that intravenous propafenone increases the rate of successful transesophageal stimulation and can be used when a first attempt at conversion is ineffective.

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.

[Venous infusion of nerapamil in the treatment of refractory angina pectoris and arrhythmia due to associated electric instability]. / Il verapamil per infusione venosa nel trattamento dell'angor refrattario e delle aritmie da instabilità elettrica associate

The therapeutic effect of Verapamil in 45 patients with angina that had failed to respond to other drugs is described. Angina was distinguished in terms of its clinical and ECG features. Verapamil was administered i.v., usually in infusions of 10-250 mg/day over periods of hours or days; alternatively, direct injections of 2,5-5 mg were employed. The effect on arterial pressure is particularly stressed. In the great majority of cases, there was a marked improvement in the symptomatology and in arrhythmic changes arising during angina. The importance of the therapeutic effects of the drug is examined and its possible mechanisms of action are discussed.

[Evaluation of the efficacy and tolerability of sustained-release nifedipine in arterial hypertension. Continuous monitoring of arterial pressure]. / Valutazione dell'efficacia e tollerabilità della nifedipina ritardo nell'ipertensione arteriosa. Studio con monitoraggio continuo incruento della pressione arteriosa.

UNLABELLED: The anti-hypertensive efficacy of slow-release nifedipine 20 mg twice a day was investigated in 20 consecutive patients (13 females and 7 males, mean age 50.3 +/- 9.9 years) with mild to moderate hypertension (mean casual BP 162.2 +/- 7.5/103.1 +/- 4.7 mmHg) continuous blood pressure monitoring and routine laboratory tests were performed before and after three months of continuous therapy, whereas casual blood pressure was assessed after one and three months of therapy. RESULTS: In 4 patients, all female, adverse effects (headache) led to discontinuation of therapy. In the other 16 patients casual blood pressure decreased to 149.8 +/- 12.7/95.3 +/- 6.6 after one month and to 148.7 +/- 11.7/91.4 +/- 7.1 after three months (p less than 0.05 and became normal after three months in 11 patients (68%). Continuous blood pressure monitoring showed a significant fall in systolic and diastolic day time blood pressure (from 132.8 +/- 6.0/87.9 +/- 5.1 - p less than 0.02) and in systolic night time blood pressure (from 117.1 +/- 6.6 to 107.1 +/- 5.1 - p less than 0.02) without changing the shape of the circadian profiles. No significant changes in systolic blood pressure variability were observed. There was no correlation between pretreatment blood pressure levels and the extent of blood pressure fall during therapy. Heart rate, body weight and all biochemical parameters remains unchanged. CONCLUSION: Our findings confirm the antihypertensive efficacy of slow release nifedipine. This study does not concord with other reports regarding the tolerability of this drug in women. However the small number of patients does not allow any firm conclusions to be drawn.

Cardioversion of persistent atrial flutter in non-anticoagulated patients at low risk for thromboembolism.

BACKGROUND: The true risk of thromboembolic events after cardioversion of atrial flutter was not addressed carefully. Nevertheless, thromboembolic events were thought to be rare and less likely to occur after cardioversion of atrial fibrillation. The aim of this study was to prospectively evaluate if the interruption of persistent typical atrial flutter could be safely performed without anticoagulation in a group of patients at low risk for thromboembolic events. METHODS: We studied 64 subjects selected among 138 consecutive patients with persistent typical atrial flutter (minimal duration 72 hours) in whom a transesophageal atrial pacing was performed in our electrophysiology laboratory from October 1994 to May 1999. Exclusion criteria included: anticoagulation therapy during the previous 4 weeks; previous history of atrial fibrillation; recent (< 1 month) myocardial infarction; history of thromboembolic events; left ventricular ejection fraction < 40%; presence of moderate or severe mitral regurgitation or stenosis; induction of sustained (> 6 hours) atrial fibrillation during transesophageal atrial pacing. Patients in whom atrial flutter persisted in spite of transesophageal atrial pacing underwent external direct current cardioversion or right atrial overdrive pacing within 24 hours. Thromboembolic events were checked for 4 weeks after the restoration of sinus rhythm. RESULTS: Sinus rhythm was restored in 54 patients by transesophageal atrial pacing, in 8 patients by electrical cardioversion, and in 2 by right atrial pacing. The mean duration of atrial flutter was 18 +/- 19 days, the mean left atrial size 41.3 +/- 6.2 mm, and the mean left ventricular ejection fraction 54.8 +/- 7.3%. During the study period no episodes of thromboembolism were recorded. CONCLUSIONS: Cardioversion of persistent typical atrial flutter in non-anticoagulated patients at low risk for thromboembolic events appears safe.

The duration of atrial fibrillation influences the long-term efficacy of low-energy internal cardioversion.

BACKGROUND: It is commonly held that long-lasting atrial fibrillation (AF), especially if associated with marked enlargement of the left atrium, is a negative predictive factor for both the recovery and the maintenance of sinus rhythm. The aim of the present study was to identify the clinical features of patients who have a greater likelihood of success both in the acute phase and, especially, in the medium-long term. METHODS: Since June 1997, we have performed low-energy internal cardioversion to 93 patients (66 males, 27 females, mean age 62 +/- 9 years, range 26-80 years) with a mean duration of AF of 922 +/- 1032 days. Seventy-four patients had heart disease and 19 isolated AF. External cardioversion had been previously performed in 79 patients to no avail. All patients underwent antiarrhythmic therapy and were followed for a period of 13 +/- 7 months. RESULTS: Low-energy internal cardioversion proved efficacious, restoring sinus rhythm, in 92% of patients (86/93) and inefficacious in 8% (7/93). In 24% (21/86) the procedure, although efficacious, was followed by early recurrence of AF which proved to be intractable in 52% (11/21). At the end of the session, 81% (75/93) of the patients maintained sinus rhythm. At the end of follow-up, 40% (38/93) maintained sinus rhythm. Of all the parameters considered in the two groups, the duration of AF was the only one which differed significantly between the group in sinus rhythm and that in AF, with regard to both the efficacy of the procedure in the acute phase (755 +/- 868 vs 1618 +/- 1359 days, p < 0.001) and the long-term outcome (655 +/- 5.8 vs 1107 +/- 1098 days, p < 0.05). CONCLUSIONS: AF lasting more than 2 years constitutes a negative predictive factor for both the recovery and the long-term maintenance of sinus rhythm.

Right bundle branch block, intermittent ST segment elevation and inducible ventricular tachycardia in an asymptomatic patient: an unusual presentation of the Brugada syndrome?

We describe the case of an asymptomatic 54-year-old female who underwent a routine electrocardiogram (ECG) in July 1997, which showed incomplete right bundle branch block and an important ST segment elevation with a coved fashion and the inversion of T waves in leads V1-V2. Her family and personal history was free of any cardiovascular pathology. She previously underwent a routine ECG in 1991 and 1995, showing an incomplete right bundle branch block with a moderate ST segment elevation in leads V1-V2. Exercise test, 24-hour Holter ECG, echocardiogram and QT dispersion analysis were all normal. The heart-rate variability in the frequency domain revealed low vagal tone. The signal-averaged ECG was positive due to the presence of three criteria. The patient underwent an electrophysiologic study. The baseline ECG resembled the ones performed in 1991 and 1995. Sinoatrial node and atrioventricular node were normal. The HV interval resulted of 62 ms. A syncopal polymorphic ventricular tachycardia (cycle length 220 ms) interrupted by electrical defibrillation (200 J) was induced with double extrastimulus during pacing at a cycle length of 600 ms from the apex of the right ventricle. At the end of the study, one minute after a bolus of ajmaline 1 mg/kg, an important ST segment elevation in lead V1 and a left axis deviation appeared. The patient began therapy with sotalol 80 mg t.i.d. and the electrophysiologic study was repeated three days later. A non-sustained polymorphic ventricular tachycardia (cycle length 200 ms) was induced with triple extrastimulus during pacing at a cycle length of 370 ms from the outflow tract of the right ventricle. On the basis of these results and as also suggested by recent reports, we decided to implant an Automatic Implantable Cardioverter Defibrillator.

[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.

[The mechanism of the chronic supraventricular tachycardia: an intracavitary electrophysiological study (author's transl)]. / Meccanismo della tachicardia sopraventricolare cronica. Studio elettrofisiologico intracavitario.

Chronic Supraventricular Tachycardia (CST) or Chronic Atrial Tachycardia is a relatively rare arrhythmia. Because of very poor number of cases studied with electrophysiologic techniques its mechanism is still debated. Three cases of CST, one of persistent type and two of repetitive type, are reported. His bundle electrogram, high and low right atrial electrograms and atrial stimulation were performed in every case, ventricular stimulation in only one case. The Amiodarone, Pindolol, Verapamil and vagal manoeuvres effects were evaluated in all cases. The site of origin of tachycardia, atrial in cases 1 and 3 and junctional in case 2, was estabished by atrial map. The electrophysiologic findings suggested the presence of an ectopic focus in cases 1 and 3 and of an AV nodal re-entry circuit in case 2. Our results and those of the literature indicate that the site and the mechanism of CST, as in paroxysmal supraventricular tachycardia, is not univocal. Their electrophysiologic evaluation by means of endocavitary techniques can allow a more satisfactory therapeutic approach.

Transient complete atrioventricular block during transcatheter ablation of a left inferoparaseptal anomalous pathway in a patient with a history of previous surgical repair of ventricular septal defect.

This case describes a young woman with a manifest left inferoparaseptal accessory pathway and previous history of surgical repair of a defect of the ventricular inlet septum in whom a transient complete AV block occurred during radiofrequency ablation performed from the coronary sinus. The presence of a preexisting surgery related AV block unmasked by anomalous pathway ablation is the more reliable explanation for this case.

[The ST/HR slope and coronary stenoses]. / ST/HR slope e stenosi coronariche.

BACKGROUND: The heart rate adjustment of ST depression (ST/HR Slope) has been shown by some authors to markedly improve the accuracy of treadmill exercise electrocardiogram for identifying and quantifying coronary artery disease. However, other authors have obtained different results. In the present study the results of our exercise electrocardiography laboratory are compared with the data obtained from the literature. METHODS: Fifty patients (46 males and 4 females, age range 60 +/- 7 years) with suspect or certain coronary artery disease were referred for a routine treadmill exercise electrocardiogram, and subsequently underwent cardiac catheterization and selective coronary cineangiography to assess the severity of coronary obstruction. All patients exercised according to a recently reported modification of the standard Bruce protocol, proposed by Kligfield et al, for a more accurate evaluation of the ST/HR Slope, which was calculated in real time by a computerized system. Patients with coexisting valvular heart disease, cardiomyopathy, left bundle-branch block on the resting ECG, myocardial infarction within 8 weeks, diabetes mellitus, hypertensive response during exercise testing (diastolic blood pressure > 95 mm Hg and/or systolic blood pressure > 190 mm Hg), abnormalities or variations of the coronary arteries, were excluded from this study. RESULTS: This method correctly identified 13 of 14 patients with multivessel coronary artery disease and 35 of 36 with less severe disease: one patient was false negative and another one false positive. Thus, in our exercise electrocardiography laboratory this approach shows a sensitivity of 93%, a specificity of 97%, a positive predictive value of 93% and a negative predictive value of 97% for the detection of severe coronary disease. CONCLUSIONS: These findings suggest that, in patients selected as in this study, the ST/HR slope is a good method which improves the clinical usefulness of the treadmill exercise electrocardiogram in coronary artery disease.

Electrophysiological properties of the atrioventricular node and ageing: evidence of a lower incidence of dual nodal pathways in the elderly.

AIMS: The purpose of this study was to investigate the relationship between the incidence of dual atrioventricular (AV) nodal pathways and age. Age-related changes in the AV node electrophysiological properties have rarely been investigated. AV nodal re-entrant tachycardia is more frequent in the young than in the elderly. METHODS AND RESULTS: From 1988 to 1998, premature atrial stimulation was performed in 1,435 patients referred to our institution for transoesophageal electrophysiological study. 1,276 patients (89%) with a diagnosis of ventricular pre-excitation, supraventricular arrhythmia or AV block were excluded. The study cohort consisted of the remaining 159 patients (11%) of the whole group) referred for syncope (8.2% of the subgroup), suspected ventricular pre-excitation (10.7%), suspected sinus node dysfunction (52.8%) or undetermined palpitations (28.3%). The 159 study patients were divided into 3 groups according to age: group A (11-30 years, 50 patients), group B (30-60 years, 35 patients) and group C (>60 years, 74 patients). A dual AV nodal pathway was found in 16 patients of group A (32.0%), 6 patients of group B (17.1%) and 8 patients of group C (10.8%), the difference between group A and group C being significant (P<0.05). CONCLUSION: The incidence of dual AV nodal pathways decreases with ageing, suggesting that the AV node undergoes age-related electrophysiological changes. This finding could explain the uncommon onset of AV nodal re-entrant tachycardia in the elderly.

Effects of oral calcium-antagonists in spontaneous angina. Verapamil and nifedipine in a double-blind cross-over trial.

Verapamil and nifedipine, two calcium-antagonist drugs, were evaluated in a double-blind cross-over trial. The study was performed in 15 patients admitted to our Coronary Care Unit for spontaneous angina. Before and after a 24 hours placebo period, oral verapamil 480 mg daily and oral nifedipine 60 mg daily were administered alternatively. Symptomatic as well as asymptomatic ischemic episodes with ST segment elevation or depression and ventricular and supraventricular ectopic beats were documented by continuous electrocardiographic Holter monitoring. The average number of attacks during the placebo periods was 243; the number of attacks decreased to 129 during verapamil treatment (P less than 0.05) and to 57 during nifedipine treatment (P less than 0.01). Ventricular ectopic beats decreased with both drugs while supraventricular ectopic beats decreased only during verapamil treatment. The difference was not statistically significant because of a small number of observations. In conclusion the two drugs appear to be effective in the management of patients with unstable angina at rest, especially in the variant form.

[Morphological aspects and electrophysiological evaluation of the vectorcardiogram in inferior myocardial infarction (author's transl)]. / Aspetti morfologici e considerazioni elettrofisiologiche sul vettorcardiogramma dell'infarto miocardico inferiore

The purpose of the paper is to evaluate the vectorcardiographic characteristics of the QRS in inferior myocardial infarction, now extended and modified in the light of recent advances in electrophysiology. The VCGs (Frank system) of 70 patients with old inferior myocardial infarction were analyzed. The most important parameters previously considered by others and the behaviour of the different vectorial groups were considered. The results of the analysis of these parameters were concordant with those obtained by others. The morphologic evaluation of the QRS on different planes allowed our cases to be divided into five vectorcardiographic groups. The evaluation of the morphological aspects of the QRS for a more sure diagnosis of myocardial infarction, specially considering false positive cases, was considered from the semeiological point of view. Moreover, it was shown that some alterations of VCG cannot be apparent electrocardiographically. The electrogenetic meaning of vectorcardiographic alterations, probably related with depth and width of necrosis and with conduction disturbances in the subdivisions of left bundle branch, were evaluated.

Success of serial external electrical cardioversion of persistent atrial fibrillation in maintaining sinus rhythm; a randomized study.

AIMS: The aim of this prospective, randomized study was to determine the efficacy of a serial external electrical cardioversion strategy in maintaining sinus rhythm after 12 months in patients with recurrent persistent atrial fibrillation. METHODS AND RESULTS: Ninety patients with persistent atrial fibrillation lasting more than 72 h but less than 1 year were randomized in a one to one fashion to repetition of up to two electrical cardioversions in the event of relapse of atrial fibrillation detected within 1 month of the previous electrical cardioversion (Group AGG), or to non-treatment of atrial fibrillation relapse (Group CTL). ECGs were scheduled at 6 h, 7 days, and 1 month. Clinical examination and ECGs were repeated during the 6-month and 12-month follow-up examinations. Echocardiography was repeated during the 6-month follow-up examination. Clinical and echocardiographic characteristics were similar in the two groups. All patients were treated with antiarrhythmic drugs before electrical cardioversion and throughout follow-up. After 12 months, sinus rhythm was maintained in 53% of Group AGG patients and in 29% of Group CTL patients (P<0.03). After 6 months, left ventricular ejection fraction had recovered significantly only in Group AGG (56.8 +/- 9.0% at enrollment vs 60.4 +/- 9.4% at 6 months,P <0.001). CONCLUSION: These results demonstrate that an aggressive policy towards persistent atrial fibrillation by means of repetition of electrical cardioversion after early atrial fibrillation recurrence is useful in maintaining sinus rhythm after 12 months.

Diagnostic value of stored electrograms in single-lead VDD systems.

UNLABELLED: Evaluation of the quality of atrial sensing is indispensable to monitor the performance of VDD single-lead systems. In addition to counters, a new VDD system offers storage of intracardiac electrograms (EGMs). The clinical contribution of stored EGMs in a VDD pacemaker was prospectively examined in a multicenter study, and the reliability of its counters was evaluated on the basis of EGM information. METHODS: A VDD system (Pulsar 870, Guidant Co.) was implanted in 46 patients with atrioventricular block. EGM storage was activated upon detection of ventricular tachycardia (VT), recurrent premature ventricular complexes (PVCs), and mode switch ("atrial tachy reaction," ATR). Stored EGMs were retrieved before discharge of the patients from the hospital, and at 6-week, 3-month, and 6-month follow-up. RESULTS: A total of 440 stored EGMs were retrieved and analyzed. Of 30 VT episodes detected, 2 (7%) were confirmed, and all others were attributable to ventricular oversensing. One postmortem interrogation documented VT as the cause of sudden death. Of 175 EGMs stored upon detection of PVCs, 43 episodes (25%) were confirmed and 124 (70%) showed intermittent atrial undersensing with spontaneous AV conduction; in 8 episodes (5%) no abnormality was observed. Of 235 episodes stored upon ATR, 82 (35%) were confirmed and 153 were due to atrial oversensing. CONCLUSIONS: (1). Stored EGMs indicated a high percentage (69%) of event misdiagnosis by the pacemaker. Thus, pacemaker counter information without the availability of stored EGMs should be interpreted with caution. (2). Misclassified events are of high clinical importance since they unmask otherwise unsuspected intermittent under- or oversensing.

Mid-diastolic intraventricular functional block. A new mechanism for intermittent intraventricular blocks?

Experimental and clinical studies have demonstrated the existence of phase 3 and phase 4 functional blocks. In this report six cases are presented in which the electrophysiological study demonstrated the existence of a functional intraventricular block different from phase 3 and phase 4 blocks. In these cases the occurrence of the block was related to the presence in mid-diastole of a zone of block preceded and followed by intervals of unimpaired conduction. In two of 6 cases the functional block (infrahisian block) was not present in the basal tracing; it occurred during programmed atrial stimulation in a range of critical H1H2 coupling intervals delivered late in diastole, and did not appear after earlier stimuli. In the remaining four cases the conduction disturbance (2 RBBB, 2 infrahisian blocks) was present in the basal tracing, but disappeared both during early and late supraventricular extrastimuli, the first having short H1H2 intervals, the latter having H1H2 intervals longer than H1H1 basal cycle length. The width of the mid-diastolic zone of block varied from a few msec to hundreds of sec, and increased as heart rate increased. Two hypotheses are put forward in order to explain the electrophysiological mechanism responsible for the phenomenon: 1) a longitudinal dissociation in the conducting system, generating two different ways, one having a long refractory period, the other having a phase 4 spontaneous depolarization; they would be responsible of phase 3 and phase 4 blocks respectively. The early and late zones of conduction could be explained by an alternate conduction in one of the two ways, while the mid-diastolic zone of block could be due to a simultaneous block in both ways; 2) the existence of a diastolic oscillatory potential (late after-depolarization). In the latter case we can suppose that the mid-diastolic block was due to the stimulation of the cells of the conducting system before the restoration of the normal diastolic potential. Our electrophysiological data offer a new contribution to the understanding of intermittent intraventricular blocks. However further experimental and clinical studies are needed to confirm our electrophysiological hypotheses.

The role of left ventricular conduction in the electrogenesis of left ventricular hypertrophy. An electrophysiologic study in man.

Various electrocardiographic and vectorcardiographic (ECG-VCG) patterns of ventricular conduction disturbances are inducible by premature right atrial stimulation (PRAS). These patterns are a consequence of different degrees of refractoriness in the specialized ventricular conduction system. We observed that the intermediate phase of left bundle branch block (LBBB) induced by PRAS in 20 subjects with normal basal QRS (complexes) were similar to those of left ventricular hypertrophy (LVH). In 18 patients with basal ECG-VCG signs of LVH, right bundle branch block (RBBB) induced by PRAS produced a progressive disappearance of these signs and the "normalization" of the tracings. The initial maximum QRS vector decreased, disappeared or remained absent in the patients with LBBB induced by PRAS, and appeared (when absent in the basal VCG) and remained unchanged (when present) in patients with RBBB induced by PRAS. In this paper we discuss the electrogenetic implications of these data. The ECG-VCG sings of LVH are probably dependent on a slowed conduction in the left bundle branch system, while anatomical hypertrophy per se probably plays a less important role.