Israel Medical Association Journal

Background: Catheter ablation (CA) is a well-established therapeutic option for patients with recurrent symptomatic atrial fibrillation (AF). Data on gender-related differences are limited with regard to baseline characteristics and long-term success rates of catheter ablation for AF.

Methods: We analyzed a cohort of 251 consecutive patients who underwent a first catheter ablation for AF in our institute during the period 2008 through 2015. All patients were followed by regular annual clinic visits, electrocardiograms, periodic 24–48 hour Holter monitoring, and loop recorders. The primary endpoint was first recurrence of AF during 1 year of follow-up.

Results: The cohort comprised 26% women (n=65), who were older (62.1 ± 9.6 vs. 54.4 ± 11.3 years, P < 0.01) and had a higher proportion of diabetes mellitus (23.1 vs. 5.4%, P < 0.001) than male patients. No other significant differences were evident. At 1 year follow-up, the cumulative survival free of AF was significantly higher in women compared with men (83% vs. 66%, respectively, log rank P value = 0.021). Subgroup analysis showed an interaction between female and small indexed left atrial diameter (LADi < 23 mm/m²).

Conclusions: Our findings suggest that women experience a significantly lower rate of AF recurrence post-CA compared with men. This gender-related advantage appears to be restricted to women without significant left atrial enlargement. It further implies that left atrial enlargement has a stronger negative impact on post-CA AF recurrence in females than in males. Due to the relatively small sample number of females further research is warranted to validate our conclusions.

Background: The incidence, characteristics, and clinical significance of catheter-induced mechanical suppression (trauma) of ventricular arrhythmias originating in the outflow tract (OT) area have not been thoroughly evaluated.

Objectives: To determine these variables among our patient cohort.

Methods: All consecutive patients with right ventricular OT (RVOT) and left ventricular OT (LVOT) arrhythmias ablated at two medical centers from 1998 to 2014 were included. Patients were observed for catheter-induced trauma during ablation procedures. Procedural characteristics, as well as response to catheter-induced trauma and long term follow-up, were recorded.

Results: During 288 ablations of OT arrhythmias in 273 patients (RVOT n=238, LVOT n=50), we identified 8 RVOT cases (3.3%) and 1 LVOT (2%) case with catheter-induced trauma. Four cases of trauma were managed by immediate radiofrequency ablation (RFA), three were ablated after arrhythmia recurrence within a few minutes, and two were ablated after > 30 minutes without arrhythmia recurrence. Patients with catheter-induced trauma had higher rates of repeat ablations compared to patients without: 3/9 (33%) vs. 12/264 (0.45%), P = 0.009. The three patients with arrhythmia recurrence were managed differently during the first ablation procedure (immediate RFA, RFA following early recurrence, and delayed RFA). During the repeat procedure of these three patients, no catheter trauma occurred in two, and in one no arrhythmia was observed.

Conclusions: Significant catheter-induced trauma occurred in 3.1% of OT arrhythmias ablations, both at the RVOT and LVOT. Arrhythmia suppression may last > 30 minutes and may interfere with procedural success. The optimal mode of management following trauma is undetermined.

Background: Multiform fascicular tachycardia (FT) was recently described as a ventricular tachycardia (VT) that has a reentrant mechanism using multiple fascicular branches and produces alternate fascicular VT forms. Ablating the respective fascicle may cause a change in the reentrant circuit resulting in a change in morphology. Ablation of the septal fascicle is crucial for successful treatment.

Objectives: To describe four cases of FT in which ablation induced a change in QRS morphologies and aggravated clinical course.

Methods: Four out of 57 consecutive FT cases at three institutions were retrospectively analyzed and found to involve multiform FT. These cases underwent electrophysiological study, fascicular potential mapping, and electroanatomical mapping. All patients initially had FT with right bundle branch block (RBBB) and superior axis morphology.

Results: Radiofrequency catheter ablation (RFCA) targeting the distal left posterior fascicle (LPF) resulted in a second VT with an RBBB-inferior axis morphology that sometimes became faster and/or incessant and/or verapamil-refractory in characteristics. RFCA in the upper septum abolished the second VT with no complications and uneventful long-term follow-up.

Conclusions: The change in FT morphology during ablation may be associated with a change in clinical course when shifting from one route to another and may aggravate symptoms. Targeting of the proximal conduction system (such as bifurcation, LPF, left anterior fascicle, high septal/auxiliary pathway) may serve to solve this problem.

Background: Left ventricular outflow tract (LVOT) arrhythmias are increasingly recognized. Data regarding the distribution of the sites of origin (SOO) of the arrhythmias are sparse.

Objectives: To describe the clinical characteristics of patients with LVOT arrhythmias and the distribution of their SOO. 

Methods: All 42 consecutive patients with LVOT arrhythmias who underwent radiofrequency (RF) ablation during the period 2000–2014 were included. SOO identification was based on mapping activation, pace mapping and a 3D mapping system in eight patients. 

Results: The study group comprised 28 males (66.7%) and 14 females, the mean age was 55 ±15.4 years. Most patients (76%) were symptomatic. All suffered from high grade ventricular arrhythmias. Left ventricular (LV) dysfunction (ejection fraction ≤ 50%) was observed in 15 patients (35.7%), of whom 14 (93.3%) were males. The left coronary cusp (LCC) was the most common arrhythmia SOO (64.3%). Other locations were the right coronary cusp (RCC), the junction of the RCC-LCC commissure, aortic-mitral continuity, endocardial-LVOT, and a coronary sinus branch. Acute successful ablation was achieved in 29 patients (69%) and transient arrhythmia abolition in 40 (95.2%). There was a trend for a higher success rate using cooled tip ablation catheters as compared to standard catheters. The ablation procedure significantly improved LV function in all patients with tachycardiomyopathy. 

Conclusions: LVOT arrhythmias mostly originate from the LCC and are associated with LV dysfunction in 36% of patients. Knowledge regarding the prevalence of the anatomic origin of the LVOT arrhythmias may help achieve successful ablation. The use of cooled tip ablation catheters might have beneficial effects on the success rate of the procedure.

 

Objectives: To demonstrate the efficacy of rhTSH in radioiodine thyroid ablation in patients with differentiated thyroid cancer.

Methods: We conducted a retrospective study of patients who underwent total thyroidectomy for well-differentiated thyroid cancer with different levels of risk, treated with rhTSH prior to remnant ablation with radioiodine.  

Results: Seventeen patients with thyroid cancer were studied and followed for a median of 25 months (range 8–49 months). Ablation (defined as stimulated thyroglobulin < 1 mg/ml, negative neck ultrasonography, and radioiodine scan) was successful in 15 patients (88.2%). One of the patients was lost to follow-up.

Conclusions: The use of rhTSH with postoperative radioiodine ablation may be an efficient tool for sufficient thyroid remnant ablation, avoiding hypothyroidal state in the management of thyroid cancer patients.

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: Left ventricular outflow gradient is associated with increased morbidity and mortality in hypertrophic cardiomyopathy. Alcohol septal ablation is the alternative to surgery in cases refractory to drug therapy. The implication of LVOG[1] measured 1 week post-ASA[2] for prediction of outcome is unknown.

Objective: To observe the pattern of LVOG course and prediction of long-term clinical and hemodynamic outcome of ASA.

Methods: Baseline clinical and echocardiographic parameters were prospectively recorded in 14 consecutive patients with a first ASA, at the time of ASA, 3 and 7 days after ASA (in-hospital) and 3 and ≥ 12 months after ASA (last follow-up).

Results: There was improvement in NYHA class, exercise parameters and LVOG in 11 of 14 patients (P < 0.005 in all). Maximal creatine kinase level was lower than 500 U/L in those without such improvement and 850 U/L or higher in successful cases. LVOG dropped from 79 ± 30 to 19 ± 6 mmHg after the ASA. LVOG was 50 ± 21 mmHg on day 3, 39 ± 26 on day 7, 32 ± 26 at 3 months and 24 ± 20 mmHg at last follow-up. LVOG identified 27% sustained procedural successes on day 3 and 73% on day 7. The overall predictive accuracy of the test for sustained success and failure was 36% on day 3 and 71% on day 7. Combination of maximal CK[3] and LVOG on day 7 showed four distinct outcome patterns: "early success" with low LVOG and high CK (73% of successful cases), "late success" with high LVOG and high CK, and "early failure" and "late failure" with both low CK and high or low LVOG, respectively
Conclusion: LVOG measurement 7 days post-ASA combined with maximal CK levels predicts late procedural outcome in the majority of patients

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.