Inducible Sustained Ventricular Tachycardia Research Articles

PO-04-194 PROGNOSTIC SIGNIFICANCE OF ELECTROPHYSIOLOGIC TESTING FOR VENTRICULAR ARRHYTHMIAS IN PATIENTS WITH MITRAL ANNULAR DISJUNCTION

Mitral annular disjunction (MAD), with or without mitral valve prolapse (MVP), is associated with a higher risk of ventricular arrhythmias (VA) and sudden cardiac death. The prognostic significance of VA inducibility during electrophysiological studies (EPS) in patients with MAD is unclear. To assess the prognostic significance of VA inducibility in patients with MAD undergoing EPS. We included 21 patients with MAD and no history of sustained VAs who underwent EPS for risk stratification. Patients who underwent ablation of any VA during the same procedure were excluded. EPS protocol included programmed ventricular stimulation with up to triple extrastimuli and with burst pacing from 2 ventricular sites. Post-EPS events including sustained VAs, appropriate implantable-cardioverter defibrillator (ICD) shocks, and sudden death, were assessed according to the EPS results. Mean age at the time of EPS was 46±16 years, and 15 (71.4%) patients were female. Mean MAD length was 10±4 mm. 18 (85.7%) patients had MVP (bileaflet MVP in 15 patients and posterior MVP in 3 patients). Non-sustained ventricular tachycardia (NSVT) was induced in 2 (9.5%) patients, sustained monomorphic ventricular tachycardia (VT) in 4 (19%) patients, and ventricular fibrillation (VF) in 9 (42.9%) patients, while six (28.6%) patients had no inducible VAs. 10 (47.6%) patients underwent ICD implantation due to inducible sustained VT (n=4) or VF (n=6), while 5 (23.8%) patients received an implantable loop recorder (ILR). After a median follow-up of 18.9 months, 4 (19%) patients had incident sustained VT or VF, all among patients with an ICD. These events occurred in 2 of the 4 patients with inducible VT and 2 of the 9 with inducible VF, while no events occurred in those with inducible NSVT or no inducible VAs. Inducible sustained VT or VF at EPS did not demonstrate a statistically significant association with incident sustained VAs (p=0.13). No deaths occurred in any patients in this series. More than half of patients with MAD referred for risk stratification EPS had inducible sustained VT or VF. Inducibility of VT/VF was not statistically associated with incident sustained VAs though this analysis is limited by the small sample size. Larger prospective studies are needed to clarify the role of EPS with standardized protocols in the risk stratification of patients with MAD, including investigation of the value of right and left ventricular stimulation.

Programmed ventricular stimulation for risk stratification in patients with myocardial scarring and an ejection fraction above or equal to 40%

Abstract Funding Acknowledgements Type of funding sources: None. Background Sudden cardiac death (SCD) is one of the leading causes of death, particularly among patients with myocardial scars. Implantable cardioverter defibrillators (ICD) are recommended in patients with a left ventricular ejection fraction (LVEF) ≤ 35%. Another recognised indication is the induction of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) during programmed ventricular stimulation (PVS) in post-myocardial infarction patients with non-sustained VT and a LVEF between 35% and 40%. However, no recommendation exists to guide the use of prophylactic ICD implantation in patients with less altered LVEF, even though they represent the majority of SCDs. Purpose We aimed to evaluate the prognostic value of PVS in patients with myocardial scars and a relatively preserved LVEF (≥ 40%). Methods Patients with evidence of a chronic myocardial scar and a LVEF ≥ 40%, who underwent PVS at two hospital centers were considered for inclusion. Ischemic and non-ischemic myocardial scars were included. The primary endpoint was the occurrence of a Major Arrhythmic Event (MAE), namely SCD, clinical VT/ventricular fibrillation, or appropriate ICD therapy. Results 134 patients were included (mean age 62.4 ± 12.5 years, LVEF 54.7 ± 8.6 %). Indication for PVS was mostly non-sustained VT and/or syncope (84%). Post-myocardial infarction patients represented about half of the cases (53%). Inducibility during PVS was observed in 17 patients (13%). There was a nonsignificant trend towards higher inducibility rates in ischemic versus nonischemic scars (17% and 8%, respectively; p-value = 0.1). Of these patients, 15 received an ICD (88%). Over a mean follow-up of 49 (±42) months, a MAE occurred in 7 patients (41.2%) with positive PVS, versus 4 patients (3.4%) with negative PVS. MAE-free survival at 10 years was 91% and 43% in PVS-negative and PVS-positive patients, respectively (p-value < 0.001). One SCD occurred in a PVS-positive patient who denied prophylactic ICD implantation. Inducibility during PVS provided a 64% sensitivity and a 97% negative predictive value (PV) to predict the occurrence of MAE (specificity 92%, positive PV 41%). Conclusion PVS is a useful tool to discriminate patients with myocardial scars and LVEF ≥ 40% at increased arrhythmic risk. Effective utilisation of ICD may be anticipated in case of positive PVS, while non-inducible patients are at lower MAE risk.

Ventricular Arrhythmias and Sudden Death Following Percutaneous Pulmonary Valve Implantation in Pediatric Patients

Reports have suggested a transient increase in ventricular ectopy early after percutaneous pulmonary valve implantation (PPVI). Little is known about the potential for more serious ventricular arrhythmias (VA) in children who undergo PPVI. We sought to evaluate the incidence of severe VA following PPVI in a pediatric population and to explore potential predictive factors. A retrospective cohort study was conducted of patients who underwent PPVI under 20 years of age in our institution from January 2007 to December 2019. The primary outcome of severe VA was defined as sustained and/or hemodynamically unstable ventricular tachycardia (VT), inducible sustained VT, or sudden death of presumed arrhythmic etiology. A total of 21 patients (mean age 16.2 ± 2.1 years; 66.7% male) underwent PPVI. The majority of patients (N = 15; 71.4%) had tetralogy of Fallot (TOF) or TOF-like physiology, with the most common indication being pulmonary insufficiency (N = 10; 47.6%). During a median follow-up of 29.6 months (IQR 10.9–44.0), severe VA occurred in 3 (14.3%) patients aged 15.6 (IQR 14.7–16.1) a median of 12.3 months (IQR 11.2–22.3) after PPVI. All events occurred in patients with TOF-like physiology following Melody valve implant. In conclusion, severe VA can occur long after PPVI in a pediatric population, particularly in those with TOF-like physiology. Further studies are required to elucidate underlying mechanisms and assess strategies to mitigate risks.

Heterogeneity of right ventricular refractory period: a novel prognostic predictor in type-1 Brugada

Abstract Funding Acknowledgements Type of funding sources: None. Risk stratification in Brugada syndrome (BrS) is needed especially for the choice of an Implantable Cardiac Defibrillator (ICD). To date the predictive value of either clinical or conventional electrophysiological indexes in type 1 electrocardiographic pattern BrS is rather low. We aimed to evaluate the eventual prognostic significance of refractoriness heterogeneity of right ventricular outflow tract, an emergent relevant pathophysiological substrate, at electrophysiological study (EPS) in patients with BrS. From 5 centers 348 patients were retrospectively selected (age 44 ± 15 years, males 68%). Eighty-five (24%) patients had an ICD. EPS was proposed in patients with spontaneous type-1 ECG pattern regardless of symptoms, or in patients with drug-induced type-1 ECG pattern with symptoms (n = 174). The difference in the refractory period between the right ventricular outflow tract and the apex (ΔRPRVOT-apex) at EPS was evaluated as a prognostic factor. The optimal ΔRPRVOT-apex cutpoint for prognosis prediction was calculated through a P-spline hazard ratio analysis. Thus, ΔRPRVOT-apex was compared through different statistical analyses to other other clinical or conventional electrophysiological prognostic indexes previosly described in literature. During a 36-month median follow-up (range 6-228) 3 SCD and 10 appropriate ICD shocks (aborted SCD, aSCD) occurred. Fifty patients (29%) had a positive EPS (induction of sustained ventricular tachycardia, VT, or ventricular fibrillation, VF, during the procedure). At multivariable logistic analysis, only ΔRPRVOT-apex and late potentials remained independent predictors of a positive EPS. At Cox Proportional Hazard analysis, family history of SCD, history of syncope, VT/VF inducibility and a ΔRPRVOT-apex >60 ms were all univariate predictors of SCD/aSCD. At bivariate analysis, a ΔRPRVOT-apex >60 ms remained an independent predictor of SCD/aSCD even when adjusted the other univariate predictors. At C-Statistic analysis, the strongest predictive model was the one using ΔRPRVOT-apex >60 ms as covariate with a C-statistics (95% CI) of 0.72 (0.51-0.93). At Kaplan-Meyer curves, ΔRPRVOT-apex >60 ms was confirmed a strong predictor of SCD/aSCD and another very interesting observation was possible: patients with positive EPS, but a ΔRPRVOT-apex < 60 ms, had a similar risk to SCD/aSCD compared to patients with a negative EPS, while those with a positive EPS and a ΔRPRVOT-apex > 60 ms were found to be at a higher risk of events. Refractory period heterogeneity of the right ventricle defined as ΔRPRVOT-apex > 60 ms at EPS is a strong and independent predictor of SCD/aSCD in patients with BrS, beyond VT/VF inducibility at EPS and common clinical predictors. Abstract Figure.

675Non-sustained ventricular tachycardia in nonischemic dilated cardiomyopathy: results from a nonischemic cardiomyopathy study

Abstract Background The underlying substrates and mechanisms of non-sustained ventricular tachycardia (NSVT) in nonischemic dilated cardiomyopathy (DCM) are unclear and may be different than those of sustained VT. Purpose To characterize NSVT in DCM and analyze its association with late gadolinium enhancement (LGE) on CMR, inducibility of sustained VT during EP study, and ventricular arrhythmias during follow-up. Methods In the prospective Leiden Nonischemic Cardiomyopathy Study (ClinicalTrials.gov Identifier: NCT01940081) patients with DCM underwent a comprehensive evaluation. For the present study, 24h-Holters were assessed for the presence of NSVT (defined as ≥3 consecutive beats arising below the atrioventricular node with a rate ≥120 bpm and lasting <30 s) and its features (number of episodes, rate, rate variability >10%, duration, coupling interval and morphology). CMRs were assessed for the presence of LGE and EP studies for inducibility of sustained monomorphic VT. Patients were followed and ICDs were programmed with therapy >188-200 bpm or adjusted to clinically documented VT. Results Of all 148 patients, 95 underwent a 24-hour Holter at the Leiden University Medical Center and were included in the present study (age 59 ± 13 years, 76% male, history of sustained VT in 26 [27%], out-of-hospital cardiac arrest in 7 [9%]). NSVT was observed during Holter in 52 patients (55%) and was typically short (median 4 beats, IQR 3-5 beats), relatively slow (median 144 bpm, IQR 134-156 bpm), irregular (median 67%, IQR 43-100% of all episodes per patient) and monomorphic (median 87%, IQR 12-100%). NSVT was not associated with LGE on CMR (p = 0.49) or VT inducibility during EP study (p = 0.96), nor were its features (all p > 0.05). During 4.0 ± 1.7 years follow-up, sustained VT occurred in 25 patients (26%), polymorphic VT/VF in 8 (8%), and any sustained ventricular arrhythmia in 30 (32%). NSVT was associated with a higher rate of sustained VT during follow-up (HR 5.45, p = 0.002) and any sustained ventricular arrhythmia (HR 4.17, p = 0.002), but not with polymorphic VT/VF (p = 0.69). Similarly, inducibility of sustained VT during EP study was also associated with sustained VT during follow-up (HR 5.78, p < 0.001) and any sustained ventricular arrhythmia (HR 4.88, p < 0.001), but not with polymorphic VT/VF (p = 0.13). The findings remained similar when only primary prevention patients were included. In multivariate analysis, NSVT on Holter and inducibility of sustained VT during EP study both remained independently associated with sustained VT and any sustained ventricular arrhythmia during follow-up (all p ≤ 0.001), but not with polymorphic VT/VF. Conclusion In DCM, NSVT on Holter and inducible sustained VT during EP study are not directly interrelated, but both predict the occurrence of sustained VT during follow-up. These data suggest that non-sustained and sustained VT may have different underlying mechanisms and provide complementary information in DCM. Abstract Figure. Sustained VT during follow-up

Prognostic value of noninvasive programmed stimulation in patients with implantable cardioverter defibrillator.

Implantable cardioverter defibrillator (ICD) offers an opportunity to examine vulnerability to ventricular tachycardia (VT) or ventricular fibrillation (VF) by performing noninvasive programmed ventricular stimulation (NIPS). Whether NIPS can predict VT/VF recurrences has not yet been established. To examine the predictive value of NIPS for identification of patients with VT/VF recurrences. The study group consisted of consecutive 105 ICD recipients included in the prospective NIPS-ICD study (ClinicalTrials ID: NCT02373306) (88 males, age 65±11years). The patientsunderwent NIPS using the protocol up to three premature extrastimuli at 600-500- and 400-ms drive cycle lengths. The endpoint of NIPS was induction of sustained VT or VF or completion of the protocol. VT/VF was induced in 29 (27.6%) patients. During a 12-month follow-up NIPS-inducible patients had significantly more frequently appropriate ICD therapy than noninducible patients (17%vs 4%, P=0.023). NIPS-induced VT/VF had a sensitivity of 63%, specificity of 75%, positive predictive value of 17%, and negative predictive value of 96% for identification of patients with future VT/VF. Apart from NIPS, age ≥65years, QRS duration, treatment with angiotensin-converting enzyme, history of coronary artery bypass grafting, history of VT/VF prior to NIPS, and prior appropriate ICD therapy were also associated with VT/VF recurrences. Multivariate analysis showed that, together with QRS duration, NIPS result was an independent predictor of future VT/VF. Predictive value of NIPS was significantly higher in ischemic than nonischemic patients. NIPS result is associated with future VT/VF. Noninducibility at NIPS identifies those patients with high accuracy who will have uneventful follow-up.

Abstract 267: Safety and Efficacy of a Combinatorial CCN5/SERCA2a Gene Delivery Approach for Arrhythmia Suppression in a Chronic Model of Angiotensin II (ANG) Induced Cardiac Hypertrophy and Failure

Background: Structural & electromechanical remodeling promotes the incidence of ventricular tachycardia (VT) during progression from compensated hypertrophy to heart failure. The multifactorial nature of VT during disease progression presents a major challenge for conventional anti-arrhythmic approaches. Objective: To determine the safety & efficacy of the antifibrotic matricellular protein CCN5 and a novel combinatorial vector carrying CCN5 and SERCA2a (CCN5/S2a) for prevention of VT. Methods: Adult mice (N=15) underwent chronic ANG infusion (3mg/kg/d) for 2 wk. Mice were subsequently randomized for treatment with AAV9 vectors carrying CCN5, CCN5/S2a, or an empty vector and were maintained for another 2 wk. Age matched mice served as controls (Ctrl). Cardiac function was serially assessed by echocardiography. Optical mapping was performed in perfused hearts before & after challenge with isoproterenol and rapid pacing. VT threshold (VT-t) was defined as the pacing frequency required for induction of sustained VT. Results: ANG infusion resulted in a biphasic change in fractional shortening (FS) consistent with an early phase of compensated hypertrophy followed by decompensation. Late decompensation was associated with adverse electrophysiological (EP) remodeling, including action potential prolongation (21.3±2.4ms in ANG vs 17.5±1.9ms in Ctrl), conduction slowing (0.43±0.04m/s in ANG vs 0.57±0.08m/s in Ctrl) and susceptibility for pacing induced VT (VT-t 21.3±1.2Hz in ANG vs 25.8±1.4Hz in Ctrl). At a cut-off frequency of 22Hz, 5/5 ANG vs 0/7 Ctrl heart were prone to VT. Treatment of ANG mice with CCN5 and the combinatorial CCN5/S2a vector suppressed VT susceptibility by increasing VT-t (25.9±2.9Hz for CCN5, 28.4±2.6Hz for CCN5/S2a). Mechanistically, CCN5/S2a delivery reversed EP and structural remodeling, which in turn prevented the formation of the critical lines of block that maintained VT circuits. In addition, CCN5/S2a fully abrogated the late decrease in FS. Conclusion: Delivery of a combinatorial AAV9 vector carrying CCN5/S2a during the early phase of compensated hypertrophy prevents the progression of electrical and structural remodeling, thereby suppressing the incidence of VT while preserving mechanical function.

Fragmentation of QRS complex during ventricular pacing is associated with ventricular arrhythmic events in patients with left ventricular dysfunction.

QRS fragmentation (fQRS) during baseline ventricular conduction, a myocardial fibrosis marker, is associated with increased risk of ventricular tachyarrhythmias but may not manifest unless ventricular activation change is provoked. We examined the association of fQRS during right ventricular (RV) pacing with death and ventricular tachyarrhythmia in patients with left ventricular (LV) dysfunction undergoing electrophysiology study (EPS). Study participants had LV dysfunction (ejection fraction<50%) undergoing EPS from January 2002 to May 2014 at Mayo Clinic in Rochester, Minnesota. fQRS during RV stimulation involved>2 notches on R/S waves identified in ≥2 contiguous standard electrocardiographic leads representing anterior, inferior, or lateral ventricular segments. Primary outcomes were ventricular tachyarrhythmias that were symptomatic or required intervention and total and cardiac deaths. In all, 528 patients participated (mean age, 65 years; male sex, 80%). Of them, 312 (59%) had ischemic cardiomyopathy and mean (SD) left ventricular ejection fraction (LVEF) of 33.2% (9.5%); 457 (87%) had implantable cardiac devices (implanted defibrillator, n=380). Mean (SD) follow-up was 3.2 (3.0) years. fQRS during RV pacing was observed in 292 patients (60%) in any ventricular segment. Patients with fQRS during RV pacing had 2.5 higher rate of ventricular tachyarrhythmia events than patients with no fQRS (hazard ratio [95% CI], 2.45 [1.5-4.2]; P<0.01), after correcting for baseline ventricular conduction defect and QRS duration, LVEF, inducible sustained ventricular tachycardia, diabetes mellitus, chronic kidney disease, and ischemic cardiomyopathy. RV stimulation can unmask fQRS, and it is associated with increased risk of ventricular tachyarrhythmia in LV dysfunction.

Perioperative electrophysiology study in patients with tetralogy of Fallot undergoing pulmonary valve replacement will identify those at high risk of subsequent ventricular tachycardia

Ventricular tachyarrhythmias are the most common cause of death in patients with repaired tetralogy of Fallot (TOF), but predicting those at risk remains a challenge. An electrophysiology study (EPS) has been proposed to risk stratify patients with TOF. We sought to evaluate a perioperative EPS-guided approach to risk stratify patients with TOF undergoing pulmonary valve replacement (PVR) and guide concomitant cryoablation. A prospective cohort study of patients with TOF undergoing an EPS at the time of PVR from 2006 to 2017 was conducted at 2 centers. Patients inducible at the time of pre-PVR had undergone concomitant cryoablation in addition to PVR. A repeat post-PVR EPS was performed in those initially inducible to guide implantable cardioverter-defibrillator (ICD) implantation. Of 70 patients who underwent a pre-PVR EPS, 34 (49%) had inducible sustained ventricular tachycardia (VT): 25 monomorphic VT and 9 polymorphic VT. Among patients undergoing cryoablation, 14 (45%) had inducible VT and underwent ICD implantation. During a mean follow-up period of 6.1 ± 3.2 years, 3patients (21%) had appropriate ICD shocks for symptomatic VT. There was an average of 2.3 shocks (range 1-4 shocks), and the mean time to first shock post-device implantation was 3.6 years (range 2.9-4.3 years). Among patients with negative pre- or post-PVR EPS results, 2 had VT requiring radiofrequency ablation and/or subsequent ICD implantation. There were no arrhythmic deaths. A pre-PVR EPS identified patients with higher-risk TOF undergoing PVR. Despite empirical VT cryoablation at the time of PVR, a high percentage of patients remained inducible for VT. In this high-risk cohort, post-PVR EPS evaluation is important to identify patients at risk of VT despite cryoablation.

Syncope Diagnosed by Inducible Sustained Ventricular Tachycardia

Syncope Diagnosed by Inducible Sustained Ventricular Tachycardia

In vivo Electrophysiological Study of Induced Ventricular Tachycardia in Intact Rat Model of Chronic Ischemic Heart Failure.

The objective of this study was to define the clinical relevance of in vivo electrophysiologic (EP) studies in a rat model of chronic ischemic heart failure (CHF). Electrical activation sequences, voltage amplitudes, and monophasic action potentials (MAPs) were recorded from adult male Sprague-Dawley rats six weeks after left coronary artery ligation. Programmed electrical stimulation (PES) sequences were developed to induce sustained ventricular tachycardia (VT). The inducibility of sustained VT was defined by PES and the recorded tissue MAPs. Rats in CHF were defined ( 0.05) by elevated left ventricular (LV) end-diastolic pressure (5 ± 1 versus 18 ± 2 mmHg), decreased LV + d P/dt (7496 ± 225 versus 5502 [Formula: see text] s), LV - dP/dt (7723 ± 208 versus 3819 [Formula: see text]), LV ejection fraction (79 ± 3 versus [Formula: see text]), peak developed pressure (176 ± 4 versus 145 ± 9 mmHg), and prolonged time constant of LV relaxation Tau (18 ± 1 versus 29 ± 2 ms). The EP data showed decreased ( 0.05) electrogram amplitude in border and infarct zones (Healthy zone (H): 8.7 ± 2.1 mV, Border zone (B): 5.3 ± 1.6 mV, and Infarct zone (I): 2.3 ± 1.2 mV), decreased MAP amplitude in the border zone (H: [Formula: see text] 1.0 mV, B: 9.7 ± 0.5 mV), and increased repolarization heterogeneity in the border zone (H: 8.1 ± 1.5 ms, B: 20.2 ± 3.1 ms). With PES we induced sustained VT (>15 consecutive PVCs) in rats with CHF (10/14) versus Sham (0/8). These EP studies establish a clinically relevant protocol for studying genesis of VT in CHF. The in vivo rat model of CHF combined with EP analysis could be used to determine the arrhythmogenic potential of new treatments for CHF.

16-35: Catheter Ablation of Ventricular Tachycardia in Arrhythmogenic Right Ventricular Cardiomyopathy – Experience of a Tertiary Care Center

Introduction: Sustained Ventricular Tachycardia (VT) is common in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC/D), and associated with frequent ICD interventions, hospitalizations, and reduced quality of life. Antiarrhythmic drugs are not always effective in suppressing ventricular arrhythmias in this cardiomyopathy, and frequently associated with side effects. Aim: We assessed short-term outcomes of radiofrequency catheter ablation (RFA) for VT in a single-center cohort of patients with ARVC/D. Methods: All RFA procedures addressing VT performed in our tertiary-care center between 1998 and 2015 in 40 patients (49.2 ± 15.8 years of age; 83% male) with definite (n = 32) or borderline (n = 8) ARVC/D were analyzed. Procedural data and short-term success were determined. Results: 71 RFA procedures using a three-dimensional mapping system were performed (mean 1.8 per patient), of these 55% (n = 39) using an endocardial approach, 34% (n = 24) using a combined endo-epicardial approach, and 11% (n = 8) using an epicardial approach. VT was inducible in 86% of patients referred for RFA of VT. In 44% of ablations, >1 sustained VT was inducible, and multiple VT morphologies (mean 1.5 ± 1.0) were common (38%). The mean cycle length of induced VT was 351 ± 78ms. Most VT had a LBBB morphology and superior axis, correlating with the subtricuspid area as the most frequent VT exit site. Although fibro-fatty infiltration typically begins subepicardially, an endocardial substrate with low voltage (bipolar <1.5 mV) and fragmented/late potentials was found in the majority of patients (55%). Procedural data are shown in the table. RFA was successful (defined as abolishment of all inducible sustained VTs) in 86%, and partially successful (defined as abolishment of all clinical VTs) in 10%. 3 procedures on two different patients were not successful. The reason was the close proximity of the target substrate and ICD lead (combined endo-/epicardial approach) in the first case, and hemodynamically not tolerable VT in the second patient. VT ablation was generally safe with 1 (1.4%) pericardial tamponade occurring after epicardial puncture, and 9 minor complications (pericardial effusion n = 2, mild pericarditis n = 4, mild femoral hematoma n = 3). The majority of patients had an ICD (76%). The number of sustained VT significantly decreased after RFA compared to before RFA (27 ± 38 vs. 4 ± 12, p < 0.05). The percentage of patients on antiarrhythmic drugs did not significantly change before and after RFA (93% vs. 90%, p = ns). Conclusions: RFA is an effective strategy to reduce the sustained VT burden in patients with ARVC/D. Although the pathologic process begins in the subepicardium, the majority of patients referred for VT ablation has rather advanced disease stages, and thus presents with an endocardial substrate amenable to endocardial RFA. Endocardial RFA has a high acute success rate, potentially obviating the need for a more invasive epicardial approach in some of these patients.

Catheter Ablation of Ischemic Ventricular Tachycardia With Remote Magnetic Navigation: STOP-VT Multicenter Trial.

Catheter ablation is an effective treatment of scar-related ventricular tachycardia (VT), but the overall complexity of the procedure has precluded its widespread use. Remote magnetic navigation (RMN) has been shown to facilitate cardiac mapping and ablation of VT in a retrospective series. STOP-VT is the first multicenter, prospective, single-arm and single-procedure study evaluating RMN-based mapping and ablation of post-infarction VT. Patients with documented VT and prior MI, in whom an ICD was implanted either for primary or secondary prevention, were recruited from four EU and US centers. Either a transseptal (48 patients) or transaortic (5 patients) approach was employed to gain access for ventricular endocardial mapping/ablation during VT (entrainment mapping, activation mapping) and/or substrate mapping in sinus rhythm (elimination of fractionated/late potentials, variable extent of substrate modification) with RMN and irrigated RF ablation. The primary endpoints were as follows: (i) non-inducibility of the target VT or any other sustained VT; (ii) elimination of sustained VT/VF during ICD follow-up of up to 12 months. The cohort included 53 consecutive patients (median age 67 years, 49 men, median LVEF 31%). One hemodynamically unstable patient was excluded at the onset of mapping. Inducibility of sustained VT was achieved an average of 2.2 times per patient (1-8), with mean tachycardia cycle length (TCL) 374 milliseconds (179-510). Mean total procedure and fluoroscopy times were 223 minutes and 8.7 minutes, respectively; mean cumulative fluoroscopy time during mapping and ablation was 0.95 minutes; maximum power averaged 42.3 W with nominal saline 30 cc/min irrigation; mean cumulative RF time was 38 minutes. Non-inducibility of the target VT was achieved in 49/52 patients (94.2%) and non-inducibility of any VT was achieved in 38/52 patients (73.1%). A combination of RMN and manual ablation was performed in two patients, rendering one non-inducible. During the 12-month ICD follow-up period, freedom from any sustained VT/VF was observed in 30 patients (62%), of which 19 (63%) were off antiarrhythmic medications. Five patients expired during follow-up: one presented with a VT storm, but for the others, death was not related to VT/VF (MI-cardiogenic shock, pulmonary embolism, bronchogenic carcinoma, end stage heart failure). No procedural complications were reported. This first prospective, single-procedure, multicenter study indicates that remote magnetic navigation is a safe and effective method for catheter ablation of post-infarction VT.

Induction of Sustained Ventricular Tachycardia by Programmed Stimulation through Permanent Pacemaker Generator

Induction of Sustained Ventricular Tachycardia by Programmed Stimulation through Permanent Pacemaker Generator

Induction of Sustained Ventricular Tachycardia by Programmed Stimulation through Permanent Pacemaker Generator

Induction of Sustained Ventricular Tachycardia by Programmed Stimulation through Permanent Pacemaker Generator

Clinical predictors of inducible sustained ventricular tachycardia during electrophysiologic study in patients with chronic Chagas' heart disease

BackgroundClinical independent predictors of inducible sustained ventricular tachycardia (VT) during electrophysiologic study (EPS) are not known in patients with chronic Chagas' heart disease. The purpose of this investigation was to fill this gap. MethodsThe medical charts of 47 patients with a positive serology for Chagas' disease who had undergone EPS between September 2006 and July 2012 at our institution were reviewed. Reasons for the EPS were the presence of unexplained syncope, non-sustained ventricular tachycardia (NSVT) on either resting ECG or 24h-Holter monitoring as well as a LVEF<55% and >35% at echocardiography. A stepwise logistic regression analysis was performed to identify noninvasive predictors of inducible sustained VT/ventricular fibrillation during EPS. ResultsOn univariate analysis, syncopal episodes (p=0.04), amiodarone therapy (p<0.005), diastolic blood pressure (p=0.03), creatinine serum levels (p<0.001), potassium serum levels (p<0.001), and lengthening of the QRS complex (p=0.03) were associated with inducible sustained VT during EPS. In the multivariate model, amiodarone therapy (p=0.03; hazard ratio=10; Wald coefficient=4.5; 95% confidence interval 1.2 to 85.2) was the only variable retained as independent predictor of inducible sustained VT during EPS. ConclusionAmiodarone therapy was the only independent variable associated with sustained VT inducibility during EPS in patients with chronic Chagas' heart disease.

Long‐Term Outcome of Patients With Idiopathic Ventricular Fibrillation: A Meta‐Analysis

The long-term outcome of the patients with idiopathic ventricular fibrillation (IVF) is not well known. Relevant studies published through May 21, 2014 were searched and identified in the MEDLINE, PsycINFO, Cochrane Library, CINAHL, and EMBASE databases and a hand search of article references was also performed. Random-effect models were used for pooling proportions of mortality and recurrent events. Twenty-three studies were included with a total of 639 patients (449 males) with a mean age ranging from 33 to 51 years. Eighty percent of patients had received ICD implantation. Over an average of 5.3 years follow-up, 167 patients (31%) experienced a recurrence of ventricular arrhythmic events (proportion, 0.29 [95% CI 0.21-0.38]). Moreover, 17 patients (3.1%) died among all studies (proportion, 0.01 [95% CI 0.00-0.04]). No association was found between the induction of sustained ventricular tachycardia or ventricular fibrillation at baseline electrophysiological study and risk of recurrent ventricular arrhythmias (risk difference: 0.12 [95% CI, 0.08-0.32]). In patients with IVF, this meta-analysis revealed an estimated recurrent event rate of 31% and a pooled mortality rate of 3.1% during an average of 5 years follow-up. The results of baseline electrophysiological studies are not predictive of future ventricular arrhythmias.

Catheter ablation of ventricular tachycardia and mortality in patients with nonischemic dilated cardiomyopathy: can noninducibility after ablation be a predictor for reduced mortality?

Data on outcomes after catheter ablation of ventricular tachycardia (VT) in patients with nonischemic dilated cardiomyopathy (NIDCM) are insufficient. We aimed to investigate the effects of successful catheter ablation of VT on cardiac mortality in patients with NIDCM. One hundred two patients with NIDCM (86 men; mean age, 58.8±15.2 years; mean ejection fraction, 33.3±11.9%) underwent VT ablation. After catheter ablation, a programmed ventricular stimulation to test for success was performed. Complete VT noninducibility was achieved in 62 (61%) patients and partial success or failure in 32 (31%) patients. During 2 years of follow-up, VT recurrence was observed in 33 patients (53%) without inducible VTs and in 24 patients (75%) with inducible VT inducible (P=0.041). VT inducibility was associated with higher VT recurrence (adjusted hazard ratio, 1.84; 95% confidence interval, 1.08-3.13; P=0.025). The primary end point of all-cause mortality was reached in 9 patients (15%) with noninducible VTs versus 11 patients (34%) with inducible sustained VTs (P=0.026). VT inducibility was associated with all-cause mortality (adjusted hazard ratio, 2.73; 95% confidence interval, 1.003-7.43; P=0.049). In patients with NIDCM and recurrent sustained VTs, a complete ablation of all inducible VTs may be achieved in 60% of the cases. The complete noninducibility may be a preferable end point of ablation because it was associated with better long-term success. Importantly, if possible to achieve through ablation, a complete VT noninducibility was associated with reduction of the likelihood for all-cause mortality in patients with NIDCM.

Utility of electrophysiological studies to predict arrhythmic events.

To evaluate the prognostic value of electrophysiological stimulation (EPS) in the risk stratification for tachyarrhythmic events and sudden cardiac death (SCD). We conducted a prospective cohort study and analyzed the long-term follow-up of 265 consecutive patients who underwent programmed ventricular stimulation at the Luzerner Kantonsspital (Lucerne, Switzerland) between October 2003 and April 2012. Patients underwent EPS for SCD risk evaluation because of structural or functional heart disease and/or electrical conduction abnormality and/or after syncope/cardiac arrest. EPS was considered abnormal, if a sustained ventricular tachycardia (VT) was inducible. The primary endpoint of the study was SCD or, in implanted patients, adequate ICD-activation. During EPS, sustained VT was induced in 125 patients (47.2%) and non-sustained VT in 60 patients (22.6%); in 80 patients (30.2%) no arrhythmia could be induced. In our cohort, 153 patients (57.7%) underwent ICD implantation after the EPS. During follow-up (mean duration 4.8 ± 2.3 years), a primary endpoint event occurred in 49 patients (18.5%). The area under the receiver operating characteristic curve (AUROC) was 0.593 (95%CI: 0.515-0.670) for a left ventricular ejection fraction (LVEF) < 35% and 0.636 (95%CI: 0.563-0.709) for inducible sustained VT during EPS. The AUROC of EPS was higher in the subgroup of patients with LVEF ≥ 35% (0.681, 95%CI: 0.578-0.785). Cox regression analysis showed that both, sustained VT during EPS (HR: 2.26, 95%CI: 1.22-4.19, P = 0.009) and LVEF < 35% (HR: 2.00, 95%CI: 1.13-3.54, P = 0.018) were independent predictors of primary endpoint events. EPS provides a benefit in risk stratification for future tachyarrhythmic events and SCD and should especially be considered in patients with LVEF ≥ 35%.

Abstract 606: Soluble Guanylate Cyclase (sGC) Stimulator Reduces The Cardiac And Renal Damage In Angiotensin II (Ang II)-induced Diastolic Heart Failure

Diastolic heart failure (DHF) is estimated to account for approximately 40% of heart failure cases. Due to the high prevalence and high mortality rates, diastolic heart failure represents a major challenge in cardiovascular medicine. The novel therapeutic alternative with NO-independent direct stimulators of sGC has recently been approved for the treatment of pulmonary hypertension. We analyzed the role of the sGC stimulator BAY 41-8543 in a transgenic rat model of hypertension-induced diastolic heart failure. We used 4 week-old male double transgenic rats harboring both human renin and angiotensinogen genes (dTGRs). At age 7 weeks, dTGR show striking cardiac hypertrophy with fibrosis, severe diastolic dysfunction but preserved systolic function, albuminuria, and renal failure. We compared vehicle-treated dTGR receiving 10% transcutol, 20% cremophor, 70% water, dTGR receiving 3 mg/kg/d BAY 41-8543, and vehicle-treated SD control rats (single oral dose per day for 3 weeks). Systolic blood pressure increased progressively in vehicle-treated dTGRs compared with SD rats. BAY 41-8543 significantly reduced the blood pressure (197 ± 11 mmHg vehicle vs 133 ± 4 mmHg BAY 41-8543). Treatment with sGC stimulator ameliorated albuminuria (0.3 ± 0.06 mg/8h at week 7) compared with vehicle-treated dTGRs (12.4 ± 2.6 mg/8h at week 7). In addition BAY 41-8543 prevented fibrosis and inflammation in kidney and heart. Cardiac hypertrophy or myocyte size were not reduced by BAY 41-8543 treatment. Cardiac echocardiography and hemodynamic investigations showed that BAY 41-8543 increased ejection fraction and improved diastolic function including speckle tracking and tissue doppler imaging. Programmed electrical stimulation showed a high non-sustained and sustained ventricular tachycardia induction rate in vehicle-treated dTGRs (46%), which was significantly reduced in BAY 41-8543-treated dTGR (11%). Finally, BAY 41-8543 treatment resulted in 100% survival at week 7, whereas 76% of vehicle-treated dTGRs died. Our data demonstrate that sGC stimulators ameliorate cardiac and renal end-organ damage including electrical remodeling in a transgenic rat model of hypertension-induced DHF. Treatment of DHF with sGC stimulators offers a novel therapeutic potential.