Israel Medical Association Journal

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: 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: 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.

 

Background: The predictive value of electrophysiologic studies depends on the aggressiveness of the programmed ventricular stimulation protocol.

Objectives: To assess if non-inducibility with an "aggressive" protocol of PVS[1] identifies post-infarction patients with low ejection fraction (EF[2] ≤ 30%) who may safely be treated without implantable cardioverter defibrillator.

Methods: We studied 154 patients during a 9 year period. Our aggressive PVS protocol included: a) stimulus current five times the diastolic threshold (≤ 3 mA) and b) repetition of double and triple extrastimulation at the shortest coupling intervals that capture the ventricle.

Results: Sustained ventricular tachyarrhythmias were induced in 116 patients (75.4%) and 112 (97%) of them received an ICD[3] (EPS[4]+/ICD+ group). Of the 38 non-inducible patients, 34 (89.5%) did not receive an ICD (EPS-/ICD- group). In comparison to the EPS+/ICD+ group, EPS-/ICD- group patients were older (69 ± 10 vs. 65 ± 10 years, P < 0.05), had a lower EF (23 ± 5% vs. 25 ± 5%,  P < 0.05) and a higher prevalence of left bundle branch block (45.5% vs. 20.2%, P < 0.005). Follow-up was longer for EPS+/ICD+ patients (40 ± 26 months) than for EPS-/ICD- patients (27 ± 22 months) (P = 0.011). Twelve EPS+/ICD+ patients (10.7%) and 5 EPS-/ICD- patients (14.7%) died during follow-up (P = 0.525). Kaplan-Meier survival curves did not show a significant difference between the two groups (P = 0.18).
Conclusions: The mortality rate in patients without inducible VTAs[5] using an aggressive PVS protocol and who did not undergo subsequent ICD implantation is not different from that of patients with inducible arrhythmias who received an ICD. Using this protocol, as many as one-fourth of primary prevention ICD implants could be spared without compromising patient prognosis

Background: Radiofrequency ablation has been suggested as first-line therapy in the management of accessory pathways. There are limited data on the results of ablation over years of experience.

Objectives: To assess the results and complications following RFA[1] of APs[2] performed in our institution over a 14 year period.

Methods: RFA was performed using deflectable electrode catheters positioned at the mitral or tricuspid annulus. The site of the AP was localized by electrophysiological study and radiofrequency energy was applied via the tip of the catheter

Results: The study cohort comprised 508 consecutive patients (64.2% males, mean age 33.6 ± 15.1 years) who underwent 572 RFA procedures for ablating 534 APs. A single AP was found in 485 (95.5%) patients while multiple APs were noted in 23 patients (4.5%). The APs were manifest, concealed or intermittent in 46.8%, 44.4% and 8.8% of cases, respectively. AP distribution was as follows: left free wall (56.6%), posteroseptal (23%), right anteroseptal (7.9%), right free wall (6.2%), midseptal (3.4%) and right atriofascicular (3.0%). Acute successful rates for a first or multiple ablation attempts were 93.1% and 95.3%, respectively. At a first ablation attempt, acute success and failure rates were the highest for midseptal (100%) and right atriofascicular (12.5%) APs respectively. Right anteroseptal APs were associated with the highest rate (23.9%) of discontinued or non-attempted procedures. Recurrent conduction in an AP after an initial successful ablation was observed in 9.9% of cases; it was the highest (24.2%) for right free wall APs and the lowest (5.0%) for left free wall APs. During follow-up (85 ± 43 months), definite cure of the AP was achieved in 94.9% of cases following a single or multiple procedures: midseptal (100%), left free wall (98%), right free wall (97%), posteroseptal (92.7%), right atriofascicular (87.5%) and right anteroseptal (78.5%). A non-fatal complication occurred in 18 patients (3.5%), more frequently in females (6.6%) than in males (1.8%) (P < 0.01). The two major complications (pericardial effusion and myocardial ischemic events) mainly occurred during RFA of a left free wall AP using a retrograde aortic approach. Catheter-induced mechanical trauma to APs was observed in 56 cases (10.5%). Mechanical trauma mainly involved right atriofascicular (43.8%) and right anteroseptal (38.1%) APs and contributed to the low success rate of RFA at these AP locations. During the 14 year period, our learning curve was achieved quickly in terms of success rate, although the most significant complications were observed at the beginning of our experience.

Conclusions: The results of this study confirm the efficacy and safety of RFA and suggest that it is a reasonable first-line therapy for the management of APs at any location.

Objectives: To report a 14 year experience of RFA[2] of the slow pathway in patients with AVNRT treated in our laboratory.

Methods: A total of 901 consecutive patients (aged 9–92, mean 50.8 ± 18.2 years) underwent RFA of the slow pathway. All patients had sustained AVNRT induced with or without intravenous administration of isoproterenol. A standard electrophysiologic method with three diagnostic and one ablation catheter was used in 317 patients (35.2%); in the remaining 584 patients (64.8%), only two electrode catheters (one diagnostic, one ablation) were used ("two-catheter approach").

Results: Catheter ablation of the slow pathway abolished AVNRT induction in 877 patients (97.3%). In 14 patients (1.6%) the procedure was discontinued while in 10 (1.1%) the procedure failed. In 864 patients (95.9%) there were no complications. Transient or permanent AV block occurred during the procedure in 31 patients (3.4%), of whom 8 (0.9%) eventually required pacemaker insertion (n=7) or upgrade of a previously implanted VVI pacemaker (n=1) during the month following the procedure. The number of catheters used did not significantly affect the rate of results or complications of the ablation procedure. The success and complication rates remained stable over the years, although a significant trend for increased age and associated heart disease was observed during the study period.

Conclusions: The results of this single-center large study, which included patients with a wide age range, showed results similar to those of previous studies. The use of a "two-catheter approach" (one diagnostic and one ablation) was as effective and safe as a multi-catheter approach.

Objectives: To test whether an early change in neurohormonal and inflammatory markers after implantation can predict the clinical response to CRT.

Methods: The study group included 32 patients with advanced symptomatic systolic heart failure and a prolonged QRS complex and who were assigned to undergo CRT. Baseline plasma levels of B-type natriuretic peptide and high sensitivity C-reactive protein were determined in the peripheral venous blood and coronary sinus. Post-implantation levels were determined 2 weeks post-procedure in the PVB[2]. Baseline levels and their change in 2 weeks were correlated with all-cause mortality and hospitalization for congestive heart failure.

Results: At baseline, coronary sinus levels of BNP[3] but not hsCRP[4] were significanly elevated compared to the PVB. Compared to baseline levels, BNP and hsCRP decreased significantly within 2 weeks after the implantation (BNP mean difference 229.1 ± 102.5 pg/ml, 95% confidence interval 24.2–434, P < 0.0001; hsCRP mean difference 5.2 ± 2.4 mg/dl, 95% CI[5] 0.3–10.1, P = 0.001). During a mean follow-up of 17.7 ± 8.2 months 6 patients died (18.7%) and 12 (37.5%) were hospitalized due to exacerbation of CHF[6]. Baseline New York Heart Association and CS[7] BNP levels predicted CHF-related hospitalizations. HsCRP levels or their change over 2 weeks did not predict all-cause mortality or hospitalizations.

Conclusions: BNP levels in the CS and peripheral venous blood during biventricular implantation and 2 weeks afterwards predict cilinical response and may guide patient management.

Background: Idiopathic left ventricular tachycardia with a right bundle branch block configuration and left axis deviation, first described by Belhassen et al., is a rare electrocardiographic-electrophysiologic entity. Radiofrequency catheter ablation has been proposed as a good therapeutic option, but the best criteria for determining the optimal site of ablation are still under debate.

Objectives: To report the clinical features, electrophysiologic characteristics, results of RFA[1], and long-term outcome in 18 patients with "Belhassen's VT” treated in our laboratory during the last 10 years, stressing the best electrophysiologic criteria for determining the optimal site of ablation.

Methods: Eighteen consecutive patients with this specific VT[2] underwent RFA in our laboratory during the last 10 years. RFA was acutely successful in 17 patients after one or two procedures (15 and 2 patients, respectively) using 4.1 ± 2.2 RF pulses. The putative ablation sites were defined by good pace-mapping (3 patients), earliest recorded Purkinje spike prior to the QRS onset during VT or sinus rhythm (6 patients), earliest endocardial activation during VT (1 patient), and diastolic potential preceding the Purkinje spike during VT and/or late diastolic potential in sinus rhythm (7 patients). In the patients with a definite successful ablation, the ratio of successful to unsuccessful radiofrequency pulse delivery to the diastolic potential site was compared to that of other methods. The ratio of successful RFA at the diastolic potential site (5:8) was higher than in the other methods (8:31), and the difference was statistically significant (P = 0.05). Successful ablation sites were more basal when the diastolic potential site was chosen.

Conclusion: The results of the present study confirm the high success rate and safety of RFA using conventional techniques in the management of “Belhassen VT,” suggesting that this procedure can be proposed as a first-line therapy. Ablating at a site demonstrating a late diastolic potential is at least as effective as ablating at a ventricular exit site, although the use of combined electrophysiologic criteria may be the optimal approach.