Facilitation of atrioventricular reentrant tachycardia by iatrogenic right bundle branch block.

The present case report describes the diagnosis of a concealed bypass tract in the right lateral wall revealed by electrophysiologic evaluation performed in a patient with rare palpitations. A iatrogenic right bundle branch block (RBBB) caused the occurrence of an incessant atrioventricular reentrant tachycardia. The disappearance of the RBBB determined a very difficult induction of the tachycardia that, when induced, showed a shorter cycle length and ventriculoatrial interval than those observed during RBBB tachycardia. The presence of a RBBB ipsilateral to the right free wall accessory pathway provided a critical delay within the circuit thus allowing the bypass tract to recover excitability. This relevant delay also allows the sinus beat to initiate and stabilize the tachycardia thus rendering it incessant.

Radiofrequency catheter ablation of idiopathic left ventricular outflow tract tachycardia: utility of intracardiac echocardiography.

INTRODUCTION: The site of origin of idiopathic ventricular tachycardia (VT) arising from the left ventricular outflow tract (LVOT) may be closely related to the aortic valve leaflets, and radiofrequency (RF) delivery potentially can damage them. Intracardiac echocardiography (ICE) can identify accurately the ablation electrode and anatomic landmarks, and contact with the endocardium can be easily assessed. The aim of this study was to define the utility and the accuracy of ICE in guiding RF ablation of idiopathic VT of the LVOT. METHODS AND RESULTS: Five consecutive patients (all men; mean age 20.4 years, range 16 to 25) symptomatic for idiopathic VT underwent RF ablation. A 9-French, in-sheath catheter with a 9-MHz ultrasound transducer was inserted through the femoral vein and positioned in the His-bundle region or right ventricular outflow tract to provide a clear view of the aortic root. Local earliest ventricular activation during tachycardia and pace mapping were used to identify the ablation site. Idiopathic VT was ablated successfully in all patients using a median of two RF pulses, delivered during tachycardia. High-resolution images of the aortic valve and ablation electrode were achievable in all cases. Direct vision of ablation electrode-endocardial contact in the outflow tract was assessed easily in all patients. CONCLUSION: Idiopathic VT of the LVOT can be treated successfully with RF ablation. ICE can accurately guide catheter ablation and identify anatomic landmarks, endocardial contact, and ablation electrode movement.

Electrophysiology of atrial fibrillation: evolving insights.

In the last few years many studies have been performed to better understand the pathophysiological nature of atrial fibrillation (AF). These recent observations provide new insights into the initiation and perpetuation of AF, underlying the importance of the pulmonary veins as major sources of atrial triggers and introducing new concepts such as atrial electrical remodeling and spatial heterogeneity of the electrophysiologic characteristics of this arrhythmia. The purpose of this review was to provide current knowledge about AF electrophysiology in an effort to unite old models and new concepts.

Catheter ablation of paroxysmal atrial fibrillation using a 3D mapping system.

BACKGROUND: We treated paroxysmal recurrent atrial fibrillation (AF) with radiofrequency (RF) catheter ablation by creating long linear lesions in the atria. To achieve line continuity, a 3D electroanatomic nonfluoroscopic mapping system was used. METHODS AND RESULTS: In 27 patients with recurrent AF, a catheter incorporating a passive magnetic field sensor was navigated in both atria to construct a 3D activation map. RF energy was delivered to create continuous linear lesions: 3 lines (intercaval, isthmic, and anteroseptal) in the right atrium and a long line encircling the pulmonary veins in the left atrium. After RF application, the atria were remapped to validate completeness of the block lines, demonstrated by late activation of the areas circumscribed by the lines. The mean procedure duration was 312+/-103 minutes (range, 187 to 495), with mean fluoroscopy time of 107+/-44 minutes (range, 32 to 185 minutes). No acute complications occurred, but 1 patient experienced early prolonged sinus pauses and received a pacemaker. During the first day, 17 patients (63%) had AF episodes, but at discharge, 25 patients were in sinus rhythm. After a follow-up of 6. 0 to 15.3 months (average, 10.5+/-3.0 months), 16 patients are asymptomatic, 3 have an almost complete disappearance of symptoms, 1 patient is improved, and 7 patients have their AF attacks unchanged. CONCLUSIONS: Paroxysmal recurrent drug-refractory AF can be treated by RF catheter ablation. Creation of long continuous linear lesions necessary to compartmentalize the atria is facilitated by a nonfluoroscopic electroanatomic mapping system.

[The correlation between the clinical characteristics and psychological status in syndrome X patients]. / Correlazione tra caratteristiche cliniche e stato psicologico in pazienti con sindrome X.

Patients with anginal symptoms and normal coronary arteries have been found to present with high levels of neuroticism i.e. anxiety, depression and somatic concerns. Whether neuroticism plays a role in precipitating coronary hypoperfusion and symptoms is still a matter of investigation. The present study was undertaken to assess the relation between psychological status and clinical symptoms in 22 patients with syndrome X (angina and ST depression with angiographically normal coronary arteries and reversible myocardial perfusion abnormalities). Neuroticism was evaluated by Beck Depression Inventory, Hamilton Anxiety Rating Scale (HAM-A), State-Trait Anxiety Inventory, Sheehan Patient Rated Anxiety Scale, State-Trait Anger Expression Inventory (STAXI), Brief Psychiatric Rating Scale and Clinical Global Impression. Data were compared with those obtained in 30 patients with stable angina as well as coronary artery disease. All patients underwent an exercise stress testing and a 24-hour ambulatory Holter monitoring. Patients with syndrome X scored significantly higher than stable angina (p < 0.05 each) on all psychological tests but STAXI. No significant differences, between syndrome X and stable angina were found in exercise stress testing parameters and during Holter monitoring. Twelve out of 22 syndrome X patients had a score > 28 in HAM-A (Group 1, with frank psychiatric abnormalities). The remaining 10 patients were labelled as Group 2. No significant differences between Group 1 and Group 2 were found in exercise capacity (time to 0.1 m V ST depression: 397 +/- 73 and 419 +/- 137 s, respectively; NS) or in the number of anginal episodes per day (0.9 +/- 1.3/24 hours and 0.6 +/- 0.8/24 hours respectively; NS). In contrast, Holter monitoring showed a significantly higher number of ischemic episodes in Group 1 than in Group 2 (1.6 +/- 1.7 vs 0.1 +/- 0.3/24 hours; p < 0.02) and a greater duration of ischemia (23.8 +/- 32 vs 0.3 +/- 1 min/24 hours; p < 0.03). We conclude that: patients with syndrome X evidence elevated neuroticism scores; a high degree of anxiety correlates with increased transient myocardial ischemia during daily life; neuroticism may itself cause changes in coronary microvascular function in syndrome X. Alternatively it may simply modulate the threshold for ischemia in the presence of underlying dysfunction.

[An analysis of the variability of the heart rate and its significance in the risk stratification of patients with unstable angina]. / Analisi della variabilità della frequenza cardiaca e suo significato nella stratificazione di rischio dei pazienti con angina instabile.

Decreased heart rate variability (HRV) correlates with increased sympathetic or decreased vagal tone. This could contribute to increase local coronary hyperreactivity caused by atherosclerotic plaque disruption, thus facilitating progression from unstable angina to acute myocardial infarction (AMI). To test this hypothesis we studied 92 patients admitted to the coronary care unit for episodes of chest pain at rest associated with transient ST shifts (> 0.15 mV). Patients who developed AMI in the first 24 hours, as well as those with previous AMI, concomitant valvular or myocardial diseases or diabetes mellitus were not enrolled in the study. Thirty age-matched subjects without any evidence of coronary artery disease were chosen as controls. All patients underwent a 2 to 5 day continuous Holter monitoring during full medical treatment (including beta-blockers, heparin and aspirin). Angiography was performed within 1 week in 88 of the 92 patients. During follow-up (mean duration of 16 +/- 5 days), 26 patients (Group I) had a major coronary event (6 deaths, 7 non fatal AMI, 13 urgent revascularizations). The remaining 66 patients (Group II) had a good clinical outcome. ECG recordings during ST shifts were excluded from Holter monitoring analysis. Time domain measurements of HRV predicted mortality and total events. The most powerful predictors was the standard deviation of the means of the 5 min R-R intervals (SDANN index) which was significantly (p < 0.001) lower in Group I than Group II (55 +/- 18 versus 87 +/- 29).(ABSTRACT TRUNCATED AT 250 WORDS)

[Ablation of paroxysmal tachycardia in Wolff-Parkinson-White syndrome]. / Ablazione del circuito delle tachicardie parossistiche nella sindrome di Wolff-Parkinson-White.

Surgical or catheter ablation of accessory pathways by means of high energy shock has been substantial associated with morbidity and mortality. On the contrary radiofrequency current, an alternative energy source for ablation, has a low incidence of complications and a very high success rate. Aim of this study was to relate about the results using catheter ablation of accessory pathways by radiofrequency current in our Electrophysiologic laboratory. Radiofrequency current (20-40 W) was delivered between a large-tip catheter electrode positioned against the mitral or tricuspid anulus and a standard adhesive electrosurgical dispersive pad applied to the left chest wall. When possible radiofrequency delivery was guided by catheter recordings of accessory pathway activation. Ablation was attempted in 181 patients with 191 accessory pathways. We obtained successful ablation of 187/191 accessory pathways and accessory pathway conduction was eliminated in 177/181 patients. During a mean follow-up of 14 +/- 10 months preexcitation returned in 7 patients (3.9%). All underwent a second successful ablation. In 1 patient, during the procedure, we observed a transient ischemic attack, with no complications. In accordance to other reports we conclude that radiofrequency ablation is highly effective in ablating accessory pathways, with low morbidity and no mortality.

[A methodological approach to the transcatheter radiofrequency ablation of anomalous Kent-type pathways]. / Approccio metodologico all'ablazione transcatetere mediante radiofrequenza di vie anomale tipo Kent.

Aim of this study is to suggest our methodological approach for transcatheter ablation of Kent bundles by radiofrequency energy as to the potential ablation sites, the need in unipolar or bipolar recording mode, single catheter or multiple catheters mapping of anomalous pathways, the vascular approach for both left sited and right sited anomalous pathways, and finally the duration and power to supply. The recording of Kent potential and/or a Va-QRS interval > or = 0 ms have been considered significant predictors of success (respectively p < 0.001 and p < 0.05). The unipolar recording mode has been considered critical in the choice of ablation site in 47 (29.9%) patients. A 6-catheter approach for both diagnostic electrophysiologic studies and mapping allowed us to easily localize accessory pathways and to record either a probable or possible Kent potential in a high percentage of patients and to reduce the permanence of the ablation catheter in the left ventricle. By transaortic retrograde approach in ablating left sited anomalous pathways, we obtained a high success rate, while right sited accessory pathway were approached from the inferior vena cava. In right sited anomalous pathway we delivered radiofrequency energy for a longer time in order to avoid a relapse soon after the procedure. We performed ablation of 174/178 (97.7%) anomalous pathways in 165/169 (97.6%) patients. We observed a 3.8% relapse during a mean follow up of 13 +/- 9 months.