Israel Medical Association Journal

Background: Limited information exists about detailed clinical characteristics and management of the small subset of Brugada syndrome (BrS) patients who had an arrhythmic event (AE).

Objectives: To conduct the first nationwide survey focused on BrS patients with documented AE.

Methods: Israeli electrophysiology units participated if they had treated BrS patients who had cardiac arrest (CA) (lethal/aborted; group 1) or experienced appropriate therapy for tachyarrhythmias after prophylactic implantable cardioverter defibrillator (ICD) implantation (group 2).

Results: The cohort comprised 31 patients: 25 in group 1, 6 in group 2. Group 1: 96% male, mean CA age 38 years (range 13–84). Nine patients (36%) presented with arrhythmic storm and three had a lethal outcome; 17 (68%) had spontaneous type 1 Brugada electrocardiography (ECG). An electrophysiology study (EPS) was performed on 11 patients with inducible ventricular fibrillation (VF) in 10, which was prevented by quinidine in 9/10 patients. During follow-up (143 ± 119 months) eight patients experienced appropriate shocks, none while on quinidine. Group 2: all male, age 30–53 years; 4/6 patients had familial history of sudden death age < 50 years. Five patients had spontaneous type 1 Brugada ECG and four were asymptomatic at ICD implantation. EPS was performed in four patients with inducible VF in three. During long-term follow-up, five patients received ≥ 1 appropriate shocks, one had ATP for sustained VT (none taking quinidine). No AE recurred in patients subsequently treated with quinidine.

Conclusions: CA from BrS is apparently a rare occurrence on a national scale and no AE occurred in any patient treated with quinidine.

Background: For patients with ventricular tachyarrhythmias, implantable cardioverter defibrillators are a mainstay of therapy to prevent sudden death. However, ICD[1] shocks are painful, can result in clinical depression, and do not offer complete protection against death from arrhythmia. Radiofrequency catheter ablation of ventricular tachycardia in the setting of ischemic cardiomyopathy has emerged recently as a useful adjunctive therapy to ICD.

Objectives: To assess the feasibility, safety and efficacy of our initial experience in ablation of scar-related VT[2].

Methods: Eleven patients (all males, mean age 71 ± 8 years) with drug-refractory ischemic VT were referred to our center for scar mapping and ablation procedures using the CARTO navigation system.

Results: Eleven clinical VTs (mean cycle length 436 ± 93 ms) were induced in all patients. An endocardial circuit, identified by activation, entrainment and/or pace mapping, was found in eight patients with stable VT. These patients were mapped and ablated during VT. Three patients had predominantly unstable VT and linear ablation lesions were performed during sinus rhythm. Acute success, defined as termination of VT and or non-inducibility during programmed electrical stimulation, was found in 9 patients (82%). During follow-up, a significant reduction in tachyarrythmia burden was observed in all patients who had successful initial ablation, except for one who had recurrence of VT 2 days after the procedure and died 2 weeks later.

Conclusions: Ablation of ischemic VT using electroanatomic scar mapping is feasible, has an acceptable success rate and should be offered for ischemic patients with recurrent uncontrolled VT.

Background: Catheter ablation is assuming a larger role in the management of patients with cardiac arrhythmias. Conventional fluoroscopic catheter mapping has limited spatial resolution and involves prolonged fluoroscopy. The non-fluoroscopic electroanatomic mapping technique (CARTO) has been developed to overcome these drawbacks.

Objectives: To report the early and late outcome in patients with different arrhythmias treated with radiofrequency ablation combined with the CARTO mapping and navigation system.

Methods: The study cohort comprised 125 consecutive patients with different cardiac arrhythmia referred to our center from January 1999 to July 2005 for mapping and/or ablation procedures using the CARTO system. Forty patients (32%) had previous failed conventional ablation or mapping procedures and were referred by other centers. The arrhythmia included atrial fibrillation (n=13), atrial flutter (n=38), atrial tachycardia (n=25), ventricular tachycardia (n=24), arrhythmogenic right ventricular dysplasia (n=9), and supraventricular tachycardia (n=16).

Results: During the study period, a total of 125 patients (mean age 49 ± 19 years, 59% males) underwent electrophysiological study and electroanatomic mapping of the heart chambers. Supraventricular arrhythmias were identified in 92 patients (73 %) and ventricular arrhythmias in 33 (27%). Acute and late success rates, defined as termination of the arrhythmia without anti-arrhythmic drugs, were 87% and 76% respectively. One patient (0.8%) developed a clinically significant complication.

Conclusions: The CARTO system advances our understanding of arrhythmias, and increases the safety, efficacy and efficiency of radiofrequency ablation.

Background: Magnetic resonance imaging is a diagnostic tool of growing importance. Since its introduction, certain medical implants, e.g., pacemakers, were considered an absolute contraindication, mainly due to the presence of ferromagnetic components and the potential for electromagnetic interference. Patients with such implants were therefore prevented from entering MRI systems and not studied by this modality. These devices are now smaller and have improved electromechanical interference protection. Recently in vitro and in vivo data showed that these devices may be scanned safely in the MRI.

Objectives: To report our initial experience with three patients with pacemakers who underwent cerebral MRI studies.

Methods: The study included patients with clear clinical indications for MRI examination and who had implanted devices shown to be safe by in vitro and in vivo animal testing. In each patient the pacemaker was programmed to pacing-off. During the scan, continuous electrocardiographic telemetry, breathing rate, pulse oximetry and symptoms were monitored. Specific absorption rate was limited to 4.0 W/kg for all sequences. Device parameters were assessed before, immediately after MRI, and 1 week later.

Results: None of the patients was pacemaker dependent. During the MRI study, no device movement was felt by the patients and no episodes of inappropriate inhibition or rapid activation of pacing were observed during the scan. At device interrogation here were no significant differences in device parameters pre-, post-, and 1 week after MRI. Image quality was unremarkable in all imaging sequences used and was not influenced by the presence of the pacemaker.

Conclusion: Given appropriate precautions, MRI can be safely performed in patients with a selected permanent pacemaker. This may have significant implications for current MRI contraindications.