Coexisting preexcitation syndrome and intermittent heart block presenting as neonatal seizures.

An infant presented with neonatal syncope and seizures. An ECG showed a preexcitation pattern, most compatible with Wolff-Parkinson-White (WPW) syndrome. Rhythm monitoring during an event demonstrated prolonged periods of complete AV block with no ventricular escape mechanism. We postulated that ventricular asystole was initiated by mechanical or autonomic influences on the accessory pathway and sustained by electrophysiologic interactions between the accessory pathway and the junctional escape focus. This is the first case report of a newborn having coexisting congenital AV block and WPW syndrome.

Variabilidad de la frecuencia cardíaca en pacientes con síncope neurocardiogénico / Heart rate variability in patients with neurocardiogenic syncope

Se evaluó el perfil autonómico basal a través de la variabilidad de la frecuencia cardíaca en 19 pacientes con síncope neurocardiogénico (10 con Tilt test positivo y 9 con Tilt test negativo) y en voluntarios sanos. La variabilidad de la frecuencia cardíaca fue analizada en registros de corta duración en dominio de tiempo y en dominio de frecuencia. No se encontraron diferencias significativas en ninguno de los parámetros analizados, tanto al comparar entre sí ambos grupos con síncope como contra el grupo control. En estado basal, los parámetros analizados con este método no resultaron predictivos de la respuesta al Tilt test ni mostraron diferencias en el perfil autonómico en pacientes con síncope, en comparación con la población control. El método mostró ser reproducible en este subgrupo de pacientes

Variabilidad de la frecuencia cardíaca en pacientes con síncope neurocardiogénico / Heart rate variability in patients with neurocardiogenic syncope

Se evaluó el perfil autonómico basal a través de la variabilidad de la frecuencia cardíaca en 19 pacientes con síncope neurocardiogénico (10 con Tilt test positivo y 9 con Tilt test negativo) y en voluntarios sanos. La variabilidad de la frecuencia cardíaca fue analizada en registros de corta duración en dominio de tiempo y en dominio de frecuencia. No se encontraron diferencias significativas en ninguno de los parámetros analizados, tanto al comparar entre sí ambos grupos con síncope como contra el grupo control. En estado basal, los parámetros analizados con este método no resultaron predictivos de la respuesta al Tilt test ni mostraron diferencias en el perfil autonómico en pacientes con síncope, en comparación con la población control. El método mostró ser reproducible en este subgrupo de pacientes (AU)

Unmasking the trifascicular left intraventricular conduction system by ablation of the right bundle branch.

Twenty-five patients underwent transcatheter right bundle ablation either for bundle branch reentrant tachycardias or inadvertent or deliberate right bundle ablation during atrioventricular junctional ablation for rate control. Electrophysiologic data and 12-lead electrocardiograms before and after right bundle ablation were available in all patients. Eleven of the patients had no significant intraventricular conduction abnormalities by surface electrocardiograms (group I), whereas 14 patients had underlying intraventricular conduction delays (group II). All group I patients had typical electrocardiographic changes of right bundle branch block after right bundle ablation, with minimal changes in initial or mean QRS axis. In group II, 5 patients had an initial 40 ms QRS axis shift of > 45 degrees, in 7 patients the mean QRS axis changed significantly (leftward in 4 and rightward in 3), and a qR pattern in V1 was seen in 12 of 14 patients including 2 with structurally normal hearts. These changes, namely new Q waves, and rightward and leftward axis shifts are most likely the result of septal fascicular, left posterior fascicular, and left anterior fascicular delay/block, which were exposed by exclusive conduction via a diseased left bundle and its fascicles. The trifascicular nature of left intraventricular conduction is more apparent when diseased and unmasked by concomitant block in the right bundle branch.

Reproducibility of head-up tilt test in patients with syncope.

As the head-up tilt test (HUT) is employed to verify the efficacy of undertaking a treatment, we prospectively evaluated the reproducibility of positive and negative results, as well as that of the response type in 64 consecutive patients (mean age 34.6 +/- 22.9 years) with syncope of unknown cause. Two HUTs (60 min, 75 degrees), separated by an interval of 9.77 +/- 8.21 days, were performed on each patient. Positive responses were reproduced in the second HUT in 54.5% of the patients. A greater reproducibility (84.3%) was observed for negative responses. Of the 31 patients with a negative first test, 5 had a positive response during the second HUT. Using a multivariate analysis, no clinical variable correlated with the reproducibility of positive or negative results. Likewise, neither arterial pressure nor heart rate observed during the test were correlated with reproducibility. Of 18 patients who reproduced positive responses, 12 (66.6%) did so with the same response modality. In three patients with documented monomorphic sustained ventricular tachycardia, which was hemodynamically well tolerated, and in one patient with temporal spike wave activity in the electroencephalogram, HUT was also positive. It was concluded that the low reproducibility of HUT limits its usefulness as a tool for evaluating treatment efficacy. The variability of the type of response suggests a common mechanism leading to cardioinhibitory and vasodepressor reactions. A positive result in only the second study shows the rationale of performing two tests when the first one is negative.

Functional bundle branch block as a delayed manifestation of retrograde concealment in the His-Purkinje system.

INTRODUCTION: The mechanism of functional bundle branch block induced at the onset of supraventricular tachycardia (SVT) is well established. However, no data exist to address the underlying mechanism of functional bundle branch block occurring in the second beat of SVT, when the first beat is conducted with a narrow QRS morphology and preceded by ventricular stimulation. METHODS AND RESULTS: Two patients showing such a phenomenon form the basis of this report. Patient 1 with AV nodal reentrant tachycardia of the common variety persistently demonstrated functional right bundle branch block in the second SVT complex when a short train of ventricular pacing was introduced during SVT. This occurred without any discernible change in the SVT cycle length. Patient 2 had a manifest posteroseptal accessory pathway and inducible orthodromic reentrant tachycardia. Functional bundle branch block during propagation of the second SVT complex invariably occurred either in the left bundle when SVT was induced by a bundle branch reentrant complex during premature ventricular stimulation, or in the right bundle when SVT was induced with a short train of ventricular pacing. The development of functional bundle branch block was preceded by minimal or no cycle length variations in the His-bundle inputs. CONCLUSION: These observations suggest that the type of functional bundle branch block occurring in the second SVT complex as a de novo phenomenon may be related to the relative timing of the retrograde penetration of the right versus left bundle during ventricular pacing or bundle branch reentrant complex. Therefore, due to its longest cycle length of activation and refractoriness, the earliest site of retrograde penetration is the most likely site of functional block during propagation of the second SVT complex. This delayed manifestation of retrograde concealment may provide new information regarding the electrophysiologic behavior of the His-Purkinje system.

Evolution of patients with clinical neurocardiogenic (vasovagal) syncope not subjected to specific treatment.

The purpose of this prospective study was to analyze the natural history of patients with clinical neurocardiogenic syncope. The results obtained with some therapeutic strategies in the prevention of neurocardiogenic syncope are encouraging. However, the benefit they represent when compared with the natural history of syncope has not been clearly established. Fifty-six consecutive patients with either (1) one or more episodes of syncope and a positive head-up tilt test or (2) typical history of vasovagal syncope despite a negative tilt test were monitored during a mean period of 16.1 +/- 10.2 months. Patients were discharged without any specific medication. There were no deaths during the follow-up period. Recurrences were found in 5 (8.9%) patients. The risk of recurrence was 7% after 1 year and 15% after 21 months. The prognosis of patients with clinical neurocardiogenic syncope is excellent as far as survival is concerned. Recurrences of episodes without specific treatment were uncommon after diagnosis had taken place. This finding strengthens the need to evaluate the effect of drugs with placebo control groups and to select the highest-risk group for treatment.

[Use-dependence of propafenone. Clinical demonstration of the hypothesis of modulated receptors]. / Uso-dependencia con propafenona. Demonstración clínica de la hipótesis de los receptores modulados.

UNLABELLED: The aim of this study was to assess use-dependence in patients with ventricular premature contractions (VPC's) treated with propafenone, by means of the increase in heart rate using transesophageal atrial pacing. It was also analyzed whether this phenomenon was related to the antiarrhythmic effect. Fifteen patients with more than 30 symptomatic VPC's/sour were evaluated. Esophageal pacing was performed with cycles of 600 and 400 msec during periods of 1 min and with simultaneous recording of 2 or 3 EKG leads with a paper speed of 100 mm/sec. Holter monitoring (HM) was carried out in all patients. Propafenone was administered in doses of 450 and 900 mg/day, during 5-7 days, at which moment another HM and esophageal stimulation were repeated. The QRS duration (pre-treatment) was 82.6 +/- 13.5 msec (basal) and 82.4 +/- 13 msec during pacing with 600 msec cycle length (p: NS). The QRS duration with P (900 mg/day) was 96.6 +/- 20 msec (basal) (p:NS vs. pre-treatment) but during atrial pacing with 600 msec cycle length it increased to 109.3 +/- 23 msec (p < 0.0004). This use-dependence was also observed with pacing at 600 msec in patients receiving doses of 450 mg/day: 95.3 +/- 13 msec (p < 0.0001 vs. baseline QRS) (Table 1). IN CONCLUSION: 1) there was no significant increase in the QRS duration with P without pacing; 2) propafenone showed use-dependence during atrial stimulation, even with cycle length of 600 msec and with the lower doses.

Uso-dependencia con propafenona. Demonstración clínica de la hipótesis de los receptores modulados. / [Use-dependence of propafenone. Clinical demonstration of the hypothesis of modulated receptors]

The aim of this study was to assess use-dependence in patients with ventricular premature contractions (VPCs) treated with propafenone, by means of the increase in heart rate using transesophageal atrial pacing. It was also analyzed whether this phenomenon was related to the antiarrhythmic effect. Fifteen patients with more than 30 symptomatic VPCs/sour were evaluated. Esophageal pacing was performed with cycles of 600 and 400 msec during periods of 1 min and with simultaneous recording of 2 or 3 EKG leads with a paper speed of 100 mm/sec. Holter monitoring (HM) was carried out in all patients. Propafenone was administered in doses of 450 and 900 mg/day, during 5-7 days, at which moment another HM and esophageal stimulation were repeated. The QRS duration (pre-treatment) was 82.6 +/- 13.5 msec (basal) and 82.4 +/- 13 msec during pacing with 600 msec cycle length (p: NS). The QRS duration with P (900 mg/day) was 96.6 +/- 20 msec (basal) (p:NS vs. pre-treatment) but during atrial pacing with 600 msec cycle length it increased to 109.3 +/- 23 msec (p < 0.0004). This use-dependence was also observed with pacing at 600 msec in patients receiving doses of 450 mg/day: 95.3 +/- 13 msec (p < 0.0001 vs. baseline QRS) (Table 1). In conclusion: 1) there was no significant increase in the QRS duration with P without pacing; 2) propafenone showed use-dependence during atrial stimulation, even with cycle length of 600 msec and with the lower doses.

[Treatment of paroxysmal supraventricular tachycardia with a single oral doses of diltiazem and propranolol]. / Tratamiento de la taquicardia paroxística supraventricular con doses única oral de diltiazem y propranolol.

Chronic antiarrhythmic therapy for the prevention of episodes of paroxysmal supraventricular tachycardia is limited by its elevated cost, the development of side effects and lack of patients' collaboration. In this study the efficacy and safety of a single oral dose of diltiazem (180 mg) and propranolol (80 mg) were assessed. Eighteen episodes of supraventricular tachycardia were treated in 17 patients, 9 female and 8 male, aged between 19 and 60 years old (mean 45.3 +/- 11.4). The episodes had begun 3 months to 40 years before. They were divided in 3 groups: group I (placebo), 6 episodes; group II (diltiazem-propranolol), 12 episodes; and group III (patients from the placebo group without spontaneous recovery of sinus rhythm who were given active drug), 6 episodes. There were no spontaneous conversions in group I (placebo) within 80 minutes. In group II, ten out of 12 episodes responded to the combination after 38.8 +/- 20.8 minutes (seven episodes were converted to sinus rhythm within the first 45 minutes). In group III (non-responders to placebo who were subsequently given active drugs), four out of 6 episodes were suppressed after 50.7 +/- 16.7 minutes. The cycle of the tachycardia lengthened before conversion to sinus rhythm both in groups II and III. Neither systolic nor diastolic blood pressure changed significantly in any group. Seven out of 14 patients who successfully converted to sinus rhythm in groups II and III, suffered mild to moderate sweat between 3 and 5 minutes before the end of the episodes.(ABSTRACT TRUNCATED AT 250 WORDS)

Tratamiento de la taquicardia paroxistica supra ventricular con dosis unica oral de diltiazem y propranolol / Treatment of paroxysmal supraventricular tachycardia with a single oral dosis of diltiazem and propranolol

El tratamiento crónico para prevenir la recurrencia de episodios de taquicardia supraventricular presenta el incoveniente del elevado costo, aparición de efectos adversos y escasa adherencia de los pacientes. En el presente estudio se evaluó la seguridad y eficacia de la combinación de ditiazem (180 mg) y propranolol (80 mg) en dosis única oral. Fueron incluidos 18 episodios de taquicardia supraventricular en 17 pacientes. La población fue dividida en 3 grupos I (placebo), 6 episodios; grupo II (droga activa), 12 episodios y grupo III (pacientes del grupo placebo en quienes, al no existir reversión a ritmo sinusal, se indicó diltiazem-propranolol), 6 episodios. No hubo ceses epontáneos de la arritmia en el grupo I (placebo) dentro de los 80 minutos. En el grupo II, 10 e 12 episodios fueron convertidos a ritmo sinusal a los 38,8 ñ 20,8 minutos post-droga. En el grupo III, 4 de 6 episodios fueron convertidos a ritmo sinusal a los 50,7 ñ 16,7 minutos post-droga activa. Dos pacientes tuvieron hipotensión arterial que no requirió tratamento específico. Es decir que 14 de 18 episodios revirtieron a ritmo sinusal con la combinación oral. Se concluye que el tratamiento episódico puede ser de utilidad en pacientes sin cardiopatía severa y con aceptable tolerancia hemodinámica durante las crisis

Tratamiento de la taquicardia paroxística supraventricular con doses única oral de diltiazem y propranolol. / [Treatment of paroxysmal supraventricular tachycardia with a single oral doses of diltiazem and propranolol]

Chronic antiarrhythmic therapy for the prevention of episodes of paroxysmal supraventricular tachycardia is limited by its elevated cost, the development of side effects and lack of patients collaboration. In this study the efficacy and safety of a single oral dose of diltiazem (180 mg) and propranolol (80 mg) were assessed. Eighteen episodes of supraventricular tachycardia were treated in 17 patients, 9 female and 8 male, aged between 19 and 60 years old (mean 45.3 +/- 11.4). The episodes had begun 3 months to 40 years before. They were divided in 3 groups: group I (placebo), 6 episodes; group II (diltiazem-propranolol), 12 episodes; and group III (patients from the placebo group without spontaneous recovery of sinus rhythm who were given active drug), 6 episodes. There were no spontaneous conversions in group I (placebo) within 80 minutes. In group II, ten out of 12 episodes responded to the combination after 38.8 +/- 20.8 minutes (seven episodes were converted to sinus rhythm within the first 45 minutes). In group III (non-responders to placebo who were subsequently given active drugs), four out of 6 episodes were suppressed after 50.7 +/- 16.7 minutes. The cycle of the tachycardia lengthened before conversion to sinus rhythm both in groups II and III. Neither systolic nor diastolic blood pressure changed significantly in any group. Seven out of 14 patients who successfully converted to sinus rhythm in groups II and III, suffered mild to moderate sweat between 3 and 5 minutes before the end of the episodes.(ABSTRACT TRUNCATED AT 250 WORDS)

Tratamiento de la taquicardia paroxistica supra ventricular con dosis unica oral de diltiazem y propranolol / Treatment of paroxysmal supraventricular tachycardia with a single oral dosis of diltiazem and propranolol

El tratamiento crónico para prevenir la recurrencia de episodios de taquicardia supraventricular presenta el incoveniente del elevado costo, aparición de efectos adversos y escasa adherencia de los pacientes. En el presente estudio se evaluó la seguridad y eficacia de la combinación de ditiazem (180 mg) y propranolol (80 mg) en dosis única oral. Fueron incluidos 18 episodios de taquicardia supraventricular en 17 pacientes. La población fue dividida en 3 grupos I (placebo), 6 episodios; grupo II (droga activa), 12 episodios y grupo III (pacientes del grupo placebo en quienes, al no existir reversión a ritmo sinusal, se indicó diltiazem-propranolol), 6 episodios. No hubo ceses epontáneos de la arritmia en el grupo I (placebo) dentro de los 80 minutos. En el grupo II, 10 e 12 episodios fueron convertidos a ritmo sinusal a los 38,8 ñ 20,8 minutos post-droga. En el grupo III, 4 de 6 episodios fueron convertidos a ritmo sinusal a los 50,7 ñ 16,7 minutos post-droga activa. Dos pacientes tuvieron hipotensión arterial que no requirió tratamento específico. Es decir que 14 de 18 episodios revirtieron a ritmo sinusal con la combinación oral. Se concluye que el tratamiento episódico puede ser de utilidad en pacientes sin cardiopatía severa y con aceptable tolerancia hemodinámica durante las crisis (AU)

[Comparative multicenter clinical study of flecainide and amiodarone in the treatment of ventricular arrhythmias associated with chronic Chagas cardiopathy]. / Estudio clínico multicéntrico comparativeo de la flecainida y la amiodarona en el tratamiento de las arritmias ventriculares asociadas a la cardiopatía chagásica cronica.

Eighty one patients with ventricular arrhythmias associated with chronic Chagas disease participated in this multi-clinic study. Treatment with Amiodarone and Flecainide were compared using an open, parallel, randomized experimental design. Inclusion criteria required the selected patients to have 1,200 premature ventricular contractions per 24 hours and/or repetitive ventricular arrhythmias. Patients received 60 days of treatment with either Flecainide at 200 to 400 mg per day or Amiodarone 800 to 400 mg per day. This dosage was adjusted to the therapeutic response. Clinical and laboratory evaluations, electrocardiogram and 24 hour Holters were performed at study days: -7, -1, 8/9, 15/16 and 59/60. The percentage reduction of premature ventricular contractions at days 9, 16 and 60 were: 73.1%, 82.9% and 92.4% with Flecainide and 77.6%, 90.1% and 90.7% with Amiodarone. At the end of the study, Flecainide had induced a 92.5% reduction in couplets and 96.5% reduction in ventricular tachycardia. For the same parameters the percentages following Amiodarone were 95.2% and 92.6% respectively. Treatment was discontinued in three patients in the Flecainide group (two because of prolonged sinus node bradycardia and one because of sustained ventricular tachycardia). In the Amiodarone group, treatment was discontinued also in three patients (one because of sustained ventricular tachycardia and two because of severe photosensitive dermatosis). Although there were some differences in the results form center to center, the conclusions from the overall data indicate a similar, therapeutic effect with both drugs.