Catheter Induced Mechanical Suppression of Outflow-tract Arrhythmias: Incidence, Characteristics, and Significance.

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.

Ablation-Induced Change in the Course of Fascicular Tachycardia.

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.

Arrhythmic Events in Brugada Syndrome: A Nationwide Israeli Survey of the Clinical Characteristics, Treatment; and Long-Term Follow-up (ISRABRU-VF).

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.

Use of New Imaging CARTO® Segmentation Module Software to Facilitate Ablation of Ventricular Arrhythmias.

INTRODUCTION: A new imaging software (CARTO® Segmentation Module, Biosense Webster) allows preprocedural 3-D reconstruction of all heart chambers based on cardiac CT. We describe our initial experience with the new module during ablation of ventricular arrhythmias. METHODS AND RESULTS: Eighteen consecutive patients with idiopathic ventricular arrhythmias or ischemic ventricular tachycardia (VT) were studied. In the latter group, a combined endocardial and epicardial ablation was performed. Of the 14 patients with idiopathic arrhythmias, 12 were ablated in the outflow tract (OT), 1 in the midseptal left ventricle, and 1 at the left posterior fascicular area; acute successful ablation was achieved in 11 (78.6%) patients. The procedure was discontinued due to close proximity of the arrhythmia origin to the coronary arteries (CA) in 2 patients. Acute successful uncomplicated ablation was achieved in all 4 patients with ischemic VT. During ablation in the coronary cusps commissures, the CARTO® Segmentation Module accurately defined the cusps anatomy. The precise anatomic location provided by the module assisted in successfully ablating when information from activation mapping was not optimal, by ablating at the opposite side of the cusps. In addition, by demonstrating the precise location of the CA, it allowed safe ablation of arrhythmias that originated in close proximity to the CA both in the OT area and the epicardium, eliminating the need for repeat angiography. CONCLUSIONS: The CARTO® Segmentation Module is useful for accurate definition of the exact anatomic location of ventricular arrhythmias and for safely ablating them especially in close proximity to the CA.

Atrial Tachycardia Originating in the Vicinity of the Noncoronary Sinus of Valsalva: Report of a Series Including the First Case of Ablation-Related Complete Atrioventricular Block.

BACKGROUND: A few series of focal atrial tachycardia (AT) originating from the noncoronary sinus of Valsalva (NCSV) have been reported in the literature during the last decade. METHODS AND RESULTS: Of 147 patients with AT referred for radiofrequency ablation (RFA), we identified nine (6%) originating in the vicinity of the NCSV. Clinical AT was induced during electrophysiological study in all patients without (n = 6) and with (n = 3) isoproterenol infusion. Mean cycle length of the induced tachycardia was 399 ± 85 ms. Mapping of the right atrium and of the left atrium (LA) was initially performed in all nine patients and in four patients, respectively. Earliest tachycardia activation occurred at the His bundle area in all cases. Earliest activations in the LA were at the low paraseptal regions. In two patients with antegrade dual atrioventricular (AV) node physiology that rendered difficult accurate distinction between atrial and ventricular activation, slow pathway ablation was necessary. A retrograde aortic approach was used for mapping the aortic cusps. The earliest local atrial activation in the NCSV preceded the atrial activation in the His area in all patients by 27 ± 8 ms. RFA was performed in all nine patients and was acutely successful in eight. Two patients required radiofrequency (RF) energy outputs of 50 W in order to terminate the arrhythmia. In one patient, successful AT ablation was associated with complete AV block requiring implantation of permanent pacemaker. CONCLUSIONS: Focal AT can be successfully mapped and ablated in the NCSV. Higher than usual RF energy levels are sometimes required. Complete AV block is a possible complication.

Left Ventricular Outflow Tract Arrhythmias: Clinical Characteristics and Site of Origin.

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.

Atrioventricular block during radiofrequency catheter ablation of atrial flutter: incidence, mechanism, and clinical implications.

AIMS: To evaluate the incidence, mechanism, and clinical implications of atrioventricular (AV) block during catheter radiofrequency (RF) ablation of the cavotricuspid isthmus (CTI). Although RF ablation of atrial flutter is the most frequently performed ablation procedure, data on the incidence and significance of an AV block occurring during the procedure are scarce. METHODS AND RESULTS: Consecutive patients (n=845, 73.5% male) undergoing CTI ablation (913 procedures) between 1998 and 2010 were studied. Data on the occurrence of complete AV block (lasting≥3 s) during the procedure were prospectively collected. Sixteen (1.9%) patients experienced AV block, 12 during delivery of RF pulses (Group 1) and 4 (Group 2) during manipulation of catheters in the cardiac chambers. The AV block was short lived (<1 min), located in the AV node, and associated with septal isthmus RF lines in 11 Group 1 patients. It was long-lasting and led to pacemaker implantation in one Group 1 patient. Atrioventricular blocks had an infranodal location in four Group 2 patients, all of whom had a pre-existing complete left bundle branch block (LBBB). One Group 2 patient had an AV block during his two ablation procedures. Permanent pacemakers were implanted in five (0.6%) patients (one from Group 1 and four from Group 2). CONCLUSIONS: Atrioventricular blocks requiring pacemaker implantation following administration of RF pulses at the CTI are rare (0.12%). The occurrence rate of AV block related to the procedure and requiring pacemaker implantation is, however, not negligible (0.6%) and mostly affects patients with a pre-existing complete LBBB.

Escape rhythm from a partially disconnected pulmonary vein.

We present a 34-year-old patient with recurrent episodes of drug refractory paroxysmal atrial fibrillation referred for pulmonary vein (PV) isolation at our institution. During isolation of the right superior PV, a dissociated escape rhythm was observed on a portion of the PV that was disconnected, while the rest of the PV showed clear left atrium to PV conduction. This report demonstrates the rare possibility of escape PV rhythm from only partially disconnected PV, highlighting that dissociated PV rhythm does not necessarily reflect complete PV isolation.

Excellent long-term reproducibility of the electrophysiologic efficacy of quinidine in patients with idiopathic ventricular fibrillation and Brugada syndrome.

BACKGROUND: Quinidine is very effective in preventing the reinduction of sustained ventricular fibrillation (VF) during electrophysiologic study (EPS) in patients with idiopathic VF and Brugada syndrome. However, there are no data on the long-term reproducibility of this EP efficacy. METHODS AND RESULTS: Nine patients (seven males and two females, aged 21-72 years), who suffered from aborted cardiac arrest (n = 8) or recurrent syncope (n = 1) due to Brugada syndrome (n = 5) or idiopathic VF (n = 4), comprised the study. All patients had inducible sustained VF at baseline that was prevented by quinidine therapy and underwent another EPS on medication after 1.7-23.6 (9.8 +/- 6.8) years (>5 years in eight patients). Two patients underwent two late EPS on quinidine. The goal of repeat EPS on quinidine was to ensure persistent long-term drug efficacy (n = 6) or to elucidate the reason of syncopal episodes during therapy (n = 3). The EPS protocol significantly evolved over the years as it became more aggressive (more pacing sites and/or more ventricular extrastimuli). All nine patients tolerated the medication well and had no recurrent documented arrhythmic events during long-term follow-up (mean 15 +/- 7 years). No sustained ventricular tachyarrhythmias could be induced in any patient during repeat late EPS. In six patients, a more aggressive stimulation protocol could be tested at repeat EPS. CONCLUSION: The long-term reproducibility of the EP efficacy of quinidine in patients with idiopathic VF and Brugada syndrome is excellent. EP-guided quinidine therapy represents a valuable long-term alternative to ICD therapy in these patients.

An "aggressive" protocol of programmed ventricular stimulation for selecting post-myocardial infarction patients with a low ejection fraction who may not require implantation of an automatic defibrillator.

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 identifies post-infarction patients with low ejection fraction (EF < or = 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 (< or = 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 (EPS+/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 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.

Outcome after implantation of cardioverter defibrillator [corrected] in patients with Brugada syndrome: a multicenter Israeli study (ISRABRU).

BACKGROUND: Many electrophysiologists recommend implantable cardioverter defibrillators for patients with Brugada syndrome who are cardiac arrest survivors or presumed at high risk of sudden death (patients with syncope or a familial history of sudden death or those with inducible ventricular fibrillation at electrophysiologic study). OBJECTIVES: To assess the efficacy and complications of ICD therapy in patients with Brugada syndrome. METHODS: The indications, efficacy and complications of ICD therapy in all patients with Brugada syndrome who underwent ICD implantation in 12 Israeli centers between 1994 and 2007 were analyzed. RESULTS: There were 59 patients (53 males, 89.8%) with a mean age of 44.1 years. At diagnosis 42 patients (71.2%) were symptomatic while 17 (28.8%) were asymptomatic. The indications for ICD implantation were: a history of cardiac arrest (n = 11, 18.6%), syncope (n = 31, 52.5%), inducible VF in asymptomatic patients (n = 14, 23.7%), and a family history of sudden death (n = 3, 0.5%). The overall inducibility rates of VF were 89.2% and 93.3% among the symptomatic and asymptomatic patients, respectively (P = NS). During a follow-up of 4-160 (45 +/- 35) months, all patients (except one who died from cancer) are alive. Five patients (8.4%), all with a history of cardiac arrest, had appropriate ICD discharge. Conversely, none of the patients without prior cardiac arrest had appropriate device therapy during a 39 +/- 30 month follow-up. Complications were encountered in 19 patients (32%). Inappropriate shocks occurred in 16 (27.1%) due to lead failure/dislodgment (n = 5), T wave oversensing (n = 2), device failure (n = 1), sinus tachycardia (n = 4), and supraventricular tachycardia (n = 4). One patient suffered a pneumothorax and another a brachial plexus injury during the implant procedure. One patient suffered a late (2 months) perforation of the right ventricle by the implanted lead. Eleven patients (18.6%) required a reintervention either for infection (n = 1) or lead problems (n = 10). Eight patients (13.5%) required psychiatric assistance due to complications related to the ICD (mostly inappropriate shocks in 7 patients). CONCLUSIONS: In this Israeli population with Brugada syndrome treated with ICD, appropriate device therapy was limited to cardiac arrest survivors while none of the other patients including those with syncope and/or inducible VF suffered an arrhythmic event. The overall complication rate was high.

Radiofrequency ablation of accessory pathways: a 14 year experience at the Tel Aviv Medical Center in 508 patients.

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 of APs 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.

Familial Occurrence of Atrioventricular Nodal Reentrant Tachycardia.

BACKGROUND: Atrioventricular nodal reentrant tachycardia (AVNRT) is considered a sporadic disease occurring in ≈22.5 cases per 10 000 in the general population. We define the prevalence and characteristics of familial AVNRT among patients who underwent radiofrequency ablation. METHODS AND RESULTS: Ablation reports of all patients with familial AVNRT (at least 2 first-degree family members) who underwent radiofrequency ablation in our institution and in another hospital were reviewed. There were 1587 patients from our institution, of whom 20 had ≥1 first-degree relatives with AVNRT. This indicates a familial AVNRT prevalence of 127 cases per 10 000 (95% confidence interval, 82-196/10 000). First-degree relatives of patients with AVNRT presented a hazard ratio of at least 3.6 for exhibiting AVNRT compared with the general population. After inclusion of 4 families with familial AVNRT who underwent ablation at another hospital our population study comprised a total of 24 families (50 patients) with AVNRT. Patients at ablation were younger in the familial AVNRT group when compared with the sporadic AVNRT group (44.2±19 versus 54.8±18 years old, P=0.0001). The male/female ratio was similar, with female predominance. The supraventricular tachycardia mechanism was typical slow/fast reentry in most cases in both groups. The most common familial relationship in our 24 families included a parent and a child in 67% of cases and less often 2 siblings (29%). CONCLUSIONS: Familial AVNRT prevalence is higher than previously believed suggesting that this arrhythmia may have a genetic component. Autosomal dominance with incomplete penetrance is the most likely mode of inheritance.

The value of electrophysiologic study in decision-making regarding the need for pacemaker implantation after TAVI.

PURPOSE: The purpose of this study was to evaluate electrophysiologic study (EPS) in risk stratification of relative indications for pacemaker implantation (PMI) after transcatheter aortic valve implantation (TAVI). METHODS: We reviewed files of all patients who had a left bundle branch block (LBBB) and underwent EPS after TAVI between 3/2009 and 5/2015. The indications for EPS were new-onset LBBB and the presence of an old or a new-onset LBBB associated with either PR prolongation after TAVI (∆PR >20 ms) or with "slow" atrial fibrillation (<100/min). Pacemakers were implanted when significant infranodal disease was demonstrated. The control group comprised of 55 consecutive patients who underwent TAVI and had an indication for an EPS per our definitions. These patients were discharged without further intervention. All patients were followed during 1 year for the composite endpoint of mortality or PMI after hospital discharge. RESULTS: Indications for EPS were new LBBB (n = 8, 30.8%), new LBBB + ∆PR >20 ms (n = 9, 34.6%), baseline LBBB + ∆PR >20 ms (n = 7, 26.9%) and new LBBB + slow AF <100 bpm (n = 2, 7.7%). Multilevel conduction disturbances involving the AV node (n = 19, 73.1%), the His (n = 3, 11.5%), and the infra-His system (n = 4, 15.4%) were found. Post discharge, there were 5 (9%) deaths and 3 (5.5%) PMI in the control group compared to none in the EPS group corresponding to event-free survival of 85 and 100%, respectively (p = 0.04). CONCLUSIONS: Patients with LBBB with or without ∆PR >20 ms are at a higher risk of mortality and late PMI at 1-year follow-up. EPS can be used to safely identify patients in whom a PMI is needed.

Differentiating the QRS Morphology of Posterior Fascicular Ventricular Tachycardia From Right Bundle Branch Block and Left Anterior Hemiblock Aberrancy.

BACKGROUND: Left posterior fascicular ventricular tachycardia (LPF-VT) is frequently misdiagnosed as supraventricular tachycardia with aberrant right bundle branch block (RBBB) and left anterior hemiblock (LAHB). The purpose of the present study was to define the morphological ECG characteristics of LPF-VT and attempt to differentiate it from RBBB and LAHB aberrancy. METHODS AND RESULTS: A systematic Medline search was used to identify or locate ECG tracings from patients with LPF-VTs. ECGs with LPF-VT were also collected from patients who underwent ablation of this arrhythmia at the Tel Aviv and Sheba Medical Centers. These ECGs were compared with ECGs of consecutive patients with RBBB and LAHB and no obvious cardiac pathology by echocardiography. Overall, 183 ECGs of LPF-VT were compared with 61 ECGs showing RBBB and LAHB. Univariate analysis demonstrated differences in QRS axis, limb (I, aVr), and precordial (V1, V2, V6) ECG leads. On multivariate logistic regression analysis, LPF-VT was more often associated with atypical RBBB-like V1 morphology (odds ratio, 5.1; P=0.004), positive QRS in aVr (odds ratio, 19.2; P<0.001), V6 R/S ratio ≤1 (odds ratio, 6.7; P=0.01), and QRS ≤140 ms (odds ratio, 7.7; P<0.001). Using these 4 variables, a prediction model was developed that predicted LPF-VT with sensitivity and specificity of 82.1% and 78.3%, respectively. Patients with 3 of 4 positive variables had high probability of having LPF-VT, whereas patients with ≤1 positive variable always had RBBB plus LAHB. CONCLUSIONS: The morphological ECG characteristics of LPF-VT were defined, and a high accurate tool for correctly differentiating LPF-VT from RBBB and LAHB aberrancy was developed.

Neurohormonal and inflammatory markers as predictors of short-term outcome in patients with heart failure and cardiac resynchronization therapy.

BACKGROUND: Cardiac resynchronization therapy is a modality with proven morbidity and mortality benefit in advanced systolic heart failure. Nevertheless, not all patients respond favorably to CRT. Natriuretic peptides and inflammatory markers are elevated in congestive heart failure and reflect disease severity. 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 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. 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 but not hsCRP were significantly 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 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. Baseline New York Heart Association and CSBNP 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 clinical response and may guide patient management.

Radiofrequency ablation of atrioventricular nodal reentry tachycardia: a 14 year experience with 901 patients at the Tel Aviv Sourasky Medical Center.

BACKGROUND: Atrioventricular nodal reentry tachycardia is the most frequent cause of regular, paroxysmal supraventricular tachycardia. Radiofrequency ablation of the slow pathway has been recommended as first-line therapy for curing AVNRT. OBJECTIVES: To report a 14 year experience of RFA 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 WI 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.

Efficacy of quinidine in high-risk patients with Brugada syndrome.

BACKGROUND: Automatic implantable cardioverter-defibrillator therapy is considered the only effective treatment for high-risk patients with Brugada syndrome. Quinidine depresses I(to) current, which may play an important role in the arrhythmogenesis of this disease. METHODS AND RESULTS: The effects of quinidine bisulfate (mean dose, 1483+/-240 mg) on the prevention of inducible and spontaneous ventricular fibrillation (VF) were prospectively evaluated in 25 patients (24 men, 1 woman; age, 19 to 80 years) with Brugada syndrome. There were 15 symptomatic patients (including 7 cardiac arrest survivors and 7 patients with unexplained syncope) and 10 asymptomatic patients. All 25 patients had inducible VF at baseline electrophysiological study. Quinidine prevented VF induction in 22 of the 25 patients (88%). After a follow-up period of 6 months to 22.2 years, all patients are alive. Nineteen patients were treated with quinidine for 6 to 219 months (mean+/-SD, 56+/-67 months). None had an arrhythmic event, although 2 had non-arrhythmia-related syncope. Administration of quinidine was associated with a 36% incidence of side effects that resolved after drug discontinuation. CONCLUSIONS: Quinidine effectively prevents VF induction in patients with Brugada syndrome. Our data suggest that quinidine also suppresses spontaneous arrhythmias and could prove to be a safe alternative to automatic implantable cardioverter-defibrillator therapy for a substantial proportion of patients with Brugada syndrome. Randomized studies comparing these two therapies seem warranted.

Management of Brugada Syndrome: Thirty-Three-Year Experience Using Electrophysiologically Guided Therapy With Class 1A Antiarrhythmic Drugs.

BACKGROUND: Information on long-term clinical outcome of patients with Brugada syndrome treated with electrophysiologically guided class 1A antiarrhythmic drugs (AAD) is limited. METHODS AND RESULTS: An aggressive protocol of programmed ventricular stimulation was performed in 96 patients with Brugada syndrome (88% males; mean age, 39.8±15.9 years). Ten patients were cardiac arrest survivors, 27 had presented with syncope, and 59 were asymptomatic. Ventricular fibrillation was induced in 66 patients, including 100%, 74%, and 61% of patients with cardiac arrest, syncope, and no symptoms, respectively. All but 6 of the 66 patients with inducible ventricular fibrillation underwent electrophysiological testing on quinidine (n=54), disopyramide (n=2), or both (n=4). Fifty-four (90%) patients were electrophysiological responders to >1 AAD with similar efficacy rates (≈90%) in all patients groups. Patients with no inducible ventricular fibrillation at baseline were left on no therapy. After a mean follow-up of 113.3±71.5 months, 92 patients were alive, whereas 4 died from noncardiac causes. No arrhythmic event occurred during class 1A AAD therapy in any of electrophysiological drug responders and in patients with no baseline inducible ventricular fibrillation. Arrhythmic events occurred in only 2 cardiac arrest survivors treated with implantable cardioverter-defibrillator alone but did not recur on quinidine. All cases of recurrent syncope (n=12) were attributed to a vasovagal (n=10) or nonarrhythmic mechanism (n=2). Class 1A AAD therapy resulted in 38% incidence of side effects that resolved after drug discontinuation. CONCLUSIONS: Our data suggest that electrophysiologically guided class 1A AAD treatment has a place in our therapeutic armamentarium for all types of patients with Brugada syndrome.

Ethnic differences among implantable cardioverter defibrillators recipients in Israel.

Heart failure is an increasingly common condition arising from a variety of different pathophysiological processes. Little is known about the unique features of Israeli Arabs who present with heart failure and who undergo cardiac device implantation. The study population comprised of 4,671 patients who were enrolled in the national Israeli Implantable Cardioverter Defibrillator registry. We compared demographic, clinical, and echocardiographic characteristics; device-related indications; and outcomes between Israeli Arabs (n = 733) and Jews (n = 3,938), who were enrolled in the registry from July 2010 through December 2013. Israeli Arabs constituted 15.7% of the study population. They were younger at presentation compared with Jews (57 ± 15 vs 66 ± 12 years, respectively; p <0.001), with a greater burden of co-morbidities, including diabetes mellitus and chronic obstructive lung disease and smoking. In addition, Arab patients had a greater frequency of non-ischemic cardiomyopathy (40.2% vs 24.6%, respectively; p <0.001), which was associated with a greater frequency of familial history of sudden cardiac death. During 15 ± 9 month follow-up, the mortality rates and appropriate device therapy were similar in both ethnic groups. In conclusion, Israeli Arab patients implanted with implantable cardioverter defibrillators display unique clinical features with greater prevalence of non-ischemic cardiomyopathy characterized by an early-onset and rapid deterioration.