Subcutaneous ICD Implantation and Catheter Ablation: A Step-Planned Approach for Ventricular Tachycardia Management in ARVC.

Secondary prevention of sudden cardiac death in the young patient with arrhythmogenic right ventricular cardiomyopathy and hemodynamically tolerated ventricular tachycardia is still a challenging field. We present a combined approach, including subcutaneous implantable cardioverter-defibrillator (ICD) and catheter ablation, as a promising treatment to prevent both ventricular tachycardia recurrences and ICD shocks. ().

Cardiac autonomic regulation in patients undergoing pulmonary vein isolation for atrial fibrillation.

Aims: Ablation procedures for the treatment of atrial fibrillation lead to changes in autonomic heart control; however, there are insufficient data on the possible association of these changes with atrial fibrillation recurrence. The study aim was to assess the effects of pulmonary vein isolation (PVI) on cardiac autonomic modulation and atrial fibrillation recurrence.

Methods: We screened 52 patients with atrial fibrillation referred for PVI, of whom 20 patients met inclusion and exclusion criteria, and were enrolled in the study and followed over 6 months.

Radiofrequency catheter ablation of atypical atrial flutter in dogs.

Five dogs were presented to our institution for fatigue caused by an incessant supraventricular tachycardia. In all dogs, an ECG on admission showed a narrow QRS complex tachycardia with a median ventricular cycle length of 220 ms (range 180-360 ms), and a positive atrial depolarization identifiable in the ST segment following the previous QRS complex. There was a 1:1 atrioventricular conduction ratio in all but one dog, which presented with 2:1 atrioventricular block.

Persistence of baroreceptor control of cerebral blood flow velocity at a simulated altitude of 5000 m.

Objective: To assess the effects of acute exposure to simulated high altitude on baroreflex control of mean cerebral blood flow velocity (MCFV).

Patients And Methods: We compared beat-to-beat changes in RR interval, arterial blood pressure, mean MCFV (by transcranial Doppler velocimetry in the middle cerebral artery), end-tidal CO2, oxygen saturation and respiration in 19 healthy subjects at baseline (Albuquerque, 1779 m), after acute exposure to simulated high altitude in a hypobaric chamber (barometric pressure as at 5000 m) and during oxygen administration (to achieve 100% oxygen saturation) at the same barometric pressure (HOX). Baroreflex control on each signal was assessed by univariate and bivariate power spectral analysis performed on time series obtained during controlled (15 breaths/min) breathing, before and during baroreflex modulation induced by 0.

Reduced hypoxic ventilatory response with preserved blood oxygenation in yoga trainees and Himalayan Buddhist monks at altitude: evidence of a different adaptive strategy?

Yoga induces long-term changes in respiratory function and control. We tested whether it represents a successful strategy for high-altitude adaptation. We compared ventilatory, cardiovascular and hematological parameters in: 12 Caucasian yoga trainees and 12 control sea-level residents, at baseline and after 2-week exposure to high altitude (Pyramid Laboratory, Nepal, 5,050 m), 38 active lifestyle high-altitude natives (Sherpas) and 13 contemplative lifestyle high-altitude natives with practice of yoga-like respiratory exercises (Buddhist monks) studied at 5,050 m.

Radiofrequency catheter ablation of concealed accessory pathways in two dogs with symptomatic atrioventricular reciprocating tachycardia.

Background: Radiofrequency catheter ablation (RFCA) is widely used as a curative therapeutic strategy in human beings with paroxysmal supraventricular tachycardia (SVT), but rarely applied in animals. This report describes successful RFCA of atrioventricular accessory pathways (AP) in two dogs with episodic weakness caused by frequent paroxysms of supraventricular tachycardia.

Methods And Results: Invasive electrophysiological studies (EPS) identified two APs in the 1st dog (right postero-septal, right posterior), and one in the 2nd dog (right posterior).

Frequency-dependent baroreflex control of blood pressure and heart rate during physical exercise.

Background: It is widely recognised that during exercise vagal heart rate control is markedly impaired but blood pressure control may or may not be retained. We hypothesised that this uncertainty arose from the differing responses of the vagus (fast) and sympathetic (slow) arms of the autonomic effectors, and to differing sympatho-vagal balance at different exercise intensities.

Methods And Results: We studied 12 normals at rest, during moderate (50% maximal heart rate) and submaximal (80% maximal heart rate) exercise.

Simultaneous dual fast and slow pathway conduction upon induction of typical atrioventricular nodal reentrant tachycardia: electrophysiologic characteristics in a series of patients.

Introduction: Simultaneous dual atrioventricular nodal conduction (SDNC) through slow (SP) and fast pathway (FP) is a rare phenomenon observed upon the induction of atrioventricular nodal reciprocating tachycardia (AVNRT). The aim of this study is to report the electrophysiological features of patients showing typical AVNRT induced through SDNC.

Methods And Results: Among 461 consecutive patients with typical AVNRT submitted to radiofrequency catheter ablation (RFCA), seven patients (1.

Adenosine restores atrio-venous conduction after apparently successful ostial isolation of the pulmonary veins.

Aims: Pulmonary vein (PV) isolation is a curative treatment for patients with atrial fibrillation. The aim of this study was to evaluate prospectively the effects of adenosine administration on the PV activity and atrio-venous conduction after PV isolation.

Methods And Results: Twenty-nine patients (21 m; age: 55+/-8 years) were submitted to ostial PV isolation guided by basket catheter recordings.

Successful selective ablation of fast atrioventricular node pathway by cryothermal energy application.

This paper reports the experience of successful cryoablation of fast atrioventricular nodal pathway in a patient with recurrent atrioventricular nodal reentrant tachycardia after previous unsuccessful attempts of slow pathway ablation. Slow formation of a permanent lesion by cryothermal energy application allowed precise modulation of atrioventricular nodal conduction until the endpoints of complete fast pathway ablation were met with long-term cure of the arrhythmia.

Computerized high-density mapping of the pulmonary veins: new insights into their electrical activation in patients with atrial fibrillation.

Aim: To report the method and findings of computerized high-density mapping of pulmonary veins (PVs) in patients undergoing their electrical isolation for atrial fibrillation (AF).

Methods And Results: In 17 consecutive patients (8 M, age 55+/-11 years), a 64 electrode basket catheter was placed in the target PVs and 56 bipolar electrograms were recorded, analyzed and isochronal maps were generated. PVs were mapped during sinus rhythm, left-sided pacing and ectopic activity.

Radiofrequency ablation in a patient with atrioventricular reentrant tachycardia and atrioventricular nodal reentrant tachycardia with 2:1 atrioventricular block.

The authors report the case of 15-year-old girl with a history of palpitations and shortness of breath during exercise. The electrocardiogram showed ventricular preexcitation suggesting a Wolff-Parkinson-White syndrome with a posteroseptal accessory pathway. During the electrophysiological study a left posterospetal accessory pathway was identified and an orthodromic atrioventricular reentry tachycardia was reproducibly induced (cycle length 400 ms).

Successful treatment of anteroseptal accessory pathways by transvenous cryomapping and cryoablation.

Radiofrequency is the most commonly used energy source for the treatment of cardiac arrhythmias. Despite its high success rate, radiofrequency energy may sometimes present limitations, especially in case of anteroseptal atrioventricular accessory pathways. In these patients, inadvertent atrioventricular block may occur during or after the procedure and a high recurrence rate of conduction over the accessory pathway is observed.

Electroanatomic analysis of sinus impulse propagation in normal human atria.

Introduction: Better understanding of atrial propagation during sinus rhythm (SR) in normal hearts under the most normal physiologic conditions may be propaedeutic to pathophysiologic studies of complex atrial arrhythmias. In this study, qualitative and quantitative analyses of sinus impulse propagation in both atria were performed by electroanatomic mapping in patients with no organic heart disease who were undergoing an electrophysiologic procedure.

Methods And Results: Seven patients (5 men and 2 women; age 37 +/- 11 years) undergoing ablation of a left-sided accessory pathway were considered.

Slow breathing increases arterial baroreflex sensitivity in patients with chronic heart failure.

Background: It is well established that a depressed baroreflex sensitivity may adversely influence the prognosis in patients with chronic heart failure (CHF) and in those with previous myocardial infarction.

Methods And Results: We tested whether a slow breathing rate (6 breaths/min) could modify the baroreflex sensitivity in 81 patients with stable (2 weeks) CHF (age, 58+/-1 years; NYHA classes I [6 patients], II [33], III [27], and IV [15]) and in 21 controls. Slow breathing induced highly significant increases in baroreflex sensitivity, both in controls (from 9.