P. Vergara | Università Vita-Salute San Raffaele (original) (raw)

Papers by P. Vergara

BACKGROUND The impact of catheter ablation of ventricular tachycardia (VT) on all-cause mortality... more BACKGROUND The impact of catheter ablation of ventricular tachycardia (VT) on all-cause mortality remains unknown. OBJECTIVE The purpose of this study was to examine the association between VT recurrence after ablation and survival in patients with scar-related VT. METHODS Analysis of 2061 patients with structural heart disease referred for catheter ablation of scar-related VT from 12 international centers was performed. Data on clinical and procedural variables, VT recurrence, and mortality were analyzed. Kaplan–Meier analysis was used to estimate freedom from recurrent VT, transplant, and death. Cox proportional hazards frailty models were used to analyze the effect of risk factors on VT recurrence and mortality. RESULTS One-year freedom from VT recurrence was 70% (72% in ischemic and 68% in nonischemic cardiomyopathy). Fifty-seven patients (3%) underwent cardiac transplantation, and 216 (10%) died during follow-up. At 1 year, the estimated rate of transplant and/or mortality was 15% (same for ischemic and nonischemic cardiomyopathy). Transplant-free survival was significantly higher in patients without VT recurrence than in those with recurrence (90% vs 71%, P o .001). In multivariable analysis, recurrence of VT after ablation showed the highest risk for transplant and/or mortality [hazard ratio 6.9 (95% CI 5.3-9.0), P o .001]. In patients with ejection fraction o30% and across all New York Heart Association functional classes, improved transplant-free survival was seen in those without VT recurrence. CONCLUSION Catheter ablation of VT in patients with structural heart disease results in 70% freedom from VT recurrence, with an overall transplant and/or mortality rate of 15% at 1 year. Freedom from VT recurrence is associated with improved transplant-free survival, independent of heart failure severity.

BACKGROUND A recent meta-analysis demonstrated a survival benefit in post-infarction patients who... more BACKGROUND A recent meta-analysis demonstrated a survival benefit in post-infarction patients whose ventricular

IRA-CTO and VT Ablation. Introduction: In patients with a prior myocardial infarction (MI), angio... more IRA-CTO and VT Ablation. Introduction: In patients with a prior myocardial infarction (MI), angiographic predictors of ventricular tachycardia (VT) recurrence after ablation are lacking. Recently, a proarrhythmic effect of a chronic total occlusion (CTO) in a coronary artery has been suggested. Methods and Results: A total of 191 patients with prior MI were referred to our Hospital between 2010 and June 2013 for a first ablation of VT. Of these, 84 patients (44%) with stable coronary artery disease that underwent a coronary angiography during the index hospitalization were included in this study. A CTO in an infarct-related artery (IRA-CTO) was present in 47 patients (56%). Patients with and without IRA-CTO did not differ in terms of comorbidities, severity of heart failure, presentation of VT or acute outcome of ablation, that was completely successful in 93% of cases. At electroanatomic mapping, IRA-CTO was associated with greater scar and especially with greater area of border zone (34 cm 2 vs. 19 cm 2 , P = 0.001). Median follow-up was 19 months (IQR 18). At follow-up, patients with IRA-CTO had a significantly higher rate of VT recurrence (47% vs. 16%, P = 0.003). At multivariate analysis, IRA-CTO resulted to be an independent predictor of VT recurrence after ablation (HR 4.05, P = 0.004). Conclusions: IRA-CTO is an independent predictor of VT recurrence after ablation and identifies a subgroup of patients with high recurrence rate despite a successful procedure. IRA-CTO is associated with greater scars and border zone area; however, this association does not completely justify its proarrhythmic effect. (J Cardiovasc Electrophysiol, Vol. pp. 1-8) catheter ablation, coronary artery occlusion, ischemic cardiomyopathy, myocardial infarction, ventricular tachycardia

Background-Ripple mapping (RM) displays each electrogram at its 3-dimensional coordinate as a bar... more Background-Ripple mapping (RM) displays each electrogram at its 3-dimensional coordinate as a bar changing in length according to its voltage-time relationship with a fiduciary reference. We applied RM to left ventricular ischemic scar for evidence of slow-conducting channels that may act as ventricular tachycardia (VT) substrate. Methods and Results-CARTO-3© (Biosense Webster Inc, Diamond Bar, CA) maps in patient undergoing VT ablation were analyzed on an offline MatLab RM system. Scar was assessed for sequential movement of ripple bars, during sinus rhythm or pacing, which were distinct from surrounding tissue and termed RM conduction channels (RMCC). Conduction velocity was measured within RMCCs and compared with the healthy myocardium (>1.5 mV). In 21 maps, 77 RMCCs were identified. Conduction velocity in RMCCs was slower when compared with normal left ventricular myocardium (median, 54 [interquartile range, 40-86] versus 150 [interquartile range, 120-160] cm/s; P<0.001). All 7 sites meeting conventional criteria for diastolic pathways coincided with an RMCC. Seven patients had ablation colocating to all identified RMCCs with no VT recurrence during follow-up (median, 480 [interquartile range, 438-841] days). Fourteen patients had ≥1 RMCC with no ablation lesions. Five had recurrence during follow-up (median, 466 [interquartile range, 395-694] days). One of the 2 patients with no RMCC locations ablated had VT recurrence at 605 days post procedure. RMCCs were sensitive (100%; negative predictive value, 100%) for VT recurrence but the specificity (43%; positive predictive value, 35.7%) may be limited by blind alleys channels. Conclusions-RM identifies slow conduction channels within ischemic scar and needs further prospective investigation to understand the role of RMCCs in determining the VT substrate. (Circ Arrhythm Electrophysiol. 2015;8:76-86.

All F1000Prime Reports articles are distributed under the terms of the Creative Commons Attributi... more All F1000Prime Reports articles are distributed under the terms of the Creative Commons Attribution-Non Commercial License (http://creativecommons.org/licenses/by-nc/3.0/legalcode), which permits non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. The electronic version of this article is the complete one and can be found at: Abstract Atrial fibrillation (AF) is associated with increases in the risk of mortality, congestive heart failure, and stroke. Medical treatment is aimed at preventing thrombo-embolic complications and reducing symptoms and consequences related to the arrhythmia. In the first section of this review, we discuss the principles of mainstream oral anticoagulant therapy and the possible advantages of the new oral anticoagulants. In the second section, we review the catheter ablation approaches to paroxysmal and persistent/long-standing AF, their results, and the current application of new catheters.

To assess the efficacy of non-contact mapping for outflow tract premature ventricular contraction... more To assess the efficacy of non-contact mapping for outflow tract premature ventricular contraction (PVC) and ventricular tachycardia (VT) ablation in patients without structural heart disease and a precordial transition at V3 or later and to determine the diagnostic accuracy of new virtual unipolar electrogram criteria for distinguishing left from right-sided foci using a multi-electrode array positioned within the right ventricular outflow tract.

T he implantable cardioverter defibrillator (ICD) is indicated for primary and secondary preventi... more T he implantable cardioverter defibrillator (ICD) is indicated for primary and secondary prevention of sudden cardiac death because of ventricular arrhythmias in patients with a prior myocardial infarction (MI) and reduced left ventricular (LV) function. 1,2 In patients implanted with ICDs for primary prevention, regardless of cause, the risk of death is significantly increased by both appropriate and inappropriate shock therapy. 3 ICD-unresponsive sudden cardiac death remains in ≈5% of recipients. 4 Pre-emptive substrate-based ablation has been shown to reduce the risk of ventricular tachycardia (VT) recurrence and ICD therapy, including shocks, without affecting mortality in patients with documented VT undergoing ICD implantation. 5,6 We recently reported that successful late potential (LP) abolition reduces the risk of VT recurrence and that achieving postprocedural VT noninducibility reduces both VT recurrence and cardiac death in patients undergoing cath-eter ablation for VT because of multiple causes in the setting of a dedicated VT unit (VTU). 7,8 Despite the prognostic value of programmed ventricular stimulation (PVS), limitations for its use as a sole procedural end point include deficient baseline inducibility, poor reproducibility, and a low negative predic-tive value for VT recurrence (26%–44%) among noninducible patients. 8–11 In a large series of patients with post-MI VT, we assessed the benefit of a strategy based on both VT and sinus rhythm (SR) electrogram-guided mapping and ablation, specifically targeting LPs, and whether achieving the novel combined procedural end point of VT noninducibility and LP abolition could further reduce VT recurrence and cardiac mortality. Background—Successful late potential (LP) abolition and postprocedural ventricular tachycardia (VT) noninducibility constitute significant end points after catheter ablation for VT. We investigated the prognostic impact of a combined procedural end point of VT noninducibility and LP abolition in a large series of post–myocardial infarction patients with VT. Methods and Results—A total of 160 (154 men, 94% with implantable cardioverter defibrillators) consecutive post– myocardial infarction patients undergoing first-time ablation procedures from 2010 to 2012 were included. Of the 159 patients surviving the procedure, 137 (86%) were either inducible or in VT at baseline and 103 (65%) had baseline LP presence, of which 79 (77%) underwent successful LP abolition. The combined end point was assessable in 155 (97%) patients. There were 50 (32%) patients with VT recurrences and 17 (11%) cardiac deaths during follow-up. Patients who fulfilled the combined end point of VT noninducibility and LP abolition compared with inducible patients exhibited a significantly lower incidence of VT recurrence (16.4% versus 47.4%; log-rank P<0.001) and cardiac death (4.1% versus 42.1%; log-rank P<0.001). Among noninducible patients, those with additional LP abolition also had a lower incidence of VT recurrence (16.4% versus 46.0%; log-rank P<0.001). After multivariate analysis, the combined end point of VT noninducibility and LP abolition (hazard ratio, 0.205, P<0.001) was independently associated with VT recurrence and cardiac death (hazard ratio, 0.106; P=0.001). Conclusions—Achieving a combined catheter ablation procedural end point of VT noninducibility and LP abolition reduces VT recurrence rates to low levels (16%). The overall strategy was associated with a significant impact on cardiac survival. (Circ Arrhythm Electrophysiol. 2014;7:424-435.)

We present clinical, electroanatomical mapping (EAM), imaging, and catheter ablation (CA) strateg... more We present clinical, electroanatomical mapping (EAM), imaging, and catheter ablation (CA) strategies in patients with myocarditis-related ventricular tachycardia (VT).

Catheter ablation of ventricular tachycardia (VT) currently has an important role in the treatmen... more Catheter ablation of ventricular tachycardia (VT) currently has an important role in the treatment of incessant ventricular tachycardia and reduction of the number of episodes of recurrent ventricular tachycardia. Conventional mapping techniques require ongoing tachycardia and haemodynamic stability during the procedure. However, in many patients with scar-related ventricular tachycardia, non-inducibility of clinical tachycardia, poor induction reproducibility, haemodynamic instability , and multiple ventricular tachycardias with frequent spontaneous changes of morphology, preclude tachycardia mapping. To overcome these limitations, new strategies for mapping and ablation in sinus rhythm (SR)-substrate mapping strategies-have been developed and are currently used by many centres. This review summarizes the progresses recently achieved in the ablative treatment of ventri-cular tachycardia using a substrate mapping approach in patients with structural heart disease. Técnicas de mapeo y ablación del sustrato arrítmico en pacientes con taquicardia ventricular Resumen La ablación de la taquicardia ventricular está adquiriendo gran importancia en el tratamiento de la taquicardia ventricular incesante así como en la reducción y prevención de episodios en pacientes con taquicardia ventricular monomorfa sostenida. El abordaje convencional requiere la inducción de la taquicardia ventricular y la tolerancia de la misma durante el procedimento. Sin embargo, en muchos pacientes con taquicardia ven-tricular, en contexto de un infarto previo, no es factible la inducción de la taquicardia clínica, la inducción presenta baja reproducibilidad, la taquicardia se acompaña de inestabilidad hemodi-námica o se presentan múltiples morfologías con variaciones espontáneas de una morfología a otra que dificultan el mapeo durante la taquicardia. Para superar a estas limitaciones, se han

A 67-year-old male with previous inferior myocardial infarction and surgical mitral stenosis repa... more A 67-year-old male with previous inferior myocardial infarction and surgical mitral stenosis repair, underwent VT ablation. Electroana-tomical mapping showed earliest endocardial activation in the mid inferior ventricular wall, with diastolic potentials preceding surface QRS by 10 ms. Repeated radiofrequency pulses (Navistar-Thermocool, 50 W) only transiently interrupted the tachycardia. Due to extensive pericardial adhesion, epicardial access was obtained by subxyphoid surgical window. Repeated radiofrequency (RF) pulses (50 W) on diastolic potentials preceding surface QRS by 30 ms in an area facing the failed endocardial ablation, resulted in only transient VT interruption. A surgical cryo-probe was connected to a standard quadripolar diagnostic catheter by a sterile adhesive tape, allowing visualization of the probe on the electroanatomical map. Cooling of the area of previous failed epicardial RF ablation (2708C) resulted in VT interruption and stable sinus rhythm. No VT was further inducible at programmed ventricular stimulation. After 13 months follow-up the patient had no arrhythmia recurrences. Failure of both endocardial and epicardial RF ablations and the absence of clear signs of endocardial or epicardial origin of the arrhythmia supported an intra-myocardial substrate for VT circuit. Availability of alternative energy sources, such as cryoenergy or bipolar RF, can be effective in the treatment of intra-myocardial VTs. The full-length version of this report can be viewed at: http://www.escardio.org/communities/EHRA/publications/ep-case-reports/ Documents/radiofrequency-and-cryoenergy.pdf

Brugada syndrome is an inherited arrhythmogenic disorder leading to sudden death predominantly in... more Brugada syndrome is an inherited arrhythmogenic disorder leading to sudden death predominantly in the 3–4 decade. To date the only reliable treatment is the implantation of a cardioverter defibrillator; however, better criteria for risk stratification are needed, especially for asymptomatic subjects. Brugada syndrome genetic bases have been only partially understood, accounting for o30% of patients, and have been poorly correlated with prognosis, preventing inclusion of genetic data in current guidelines. We designed an observational study to identify genetic markers for risk stratification of Brugada patients by exploratory statistical analysis. The presence of genetic variants, identified by SCN5A gene analysis and genotyping of 73 candidate polymorphisms, was correlated with the occurrence of major arrhythmic events in a cohort of 92 Brugada patients by allelic association and survival analysis. In all, 18 mutations were identified in the SCN5A gene, including 5 novel, and statistical analysis indicated that mutation carriers had a significantly increased risk of major arrhythmic events (P ¼ 0.024). In addition, we established association of five polymorphisms with major arrhythmic events occurrence and consequently elaborated a pilot risk stratification algorithm by calculating a weighted genetic risk score, including the associated polymorphisms and the presence of SCN5A mutation as function of their odds ratio. This study correlates for the first time the presence of genetic variants with increased arrhythmic risk in Brugada patients, representing a first step towards the design of a new risk stratification model. INTRODUCTION Brugada syndrome (BrS) is a cardiac disorder with estimated prevalence of 1:5000 in western countries, characterized by electrical ventricular instability leading to sudden cardiac death (SCD) predominantly in the 3–4 decade, although cases of infant death have also been reported. 1 Diagnosis is based on the presence of type I ECG, characterized by right bundle branch block and ST elevation in right precordial leads. 2,3 To date the only reliable treatment is defibrillator (ICD) implantation. 4 Current guidelines select higher risk patients based mainly on the presence of syncope and spontaneous ECG. 5 However, predisposition of BrS patients to develop ventricular arrhythmias still cannot be easily predicted and new criteria for prognostic risk stratification are needed, especially for asymptomatic subjects. BrS is genetically heterogeneous, SCN5A gene mutations accounting for o25%. 6 Accordingly, the emerging concept of arrhythmia genomics supports the idea of a complex disorder, where the co-segregation of different mutations and common genetic variants can contribute to the clinical phenotype. 7 The aim of our study was to evaluate the contribution of candidate genetic variants to the predisposition to malignant arrhythmias in a cohort of BrS patients. We identified disease-modifying variants

Contact Force for Ventricular Tachycardia Ablation. Background: Although the importance of contac... more Contact Force for Ventricular Tachycardia Ablation. Background: Although the importance of contact force monitoring during mapping and ablation procedures is widely recognized, only indirect measurements have been validated. Methods: Real-time force values were measured using the force-sensing catheter and electroanatomical mapping system from 27 chambers (13 LVs, 6 RVs, and 8 epicardial space) in 17 patients affected by ventricular tachycardia. Left ventricular mapping was performed by the transaortic approach in all patients and in 5 patients also by a transseptal approach with the aid of a deflectable sheath. All points were divided into 2 groups according to the presence of positive contact force during diastole: good and poor contact. The frequency of good contact and its impact on electrophysiological parameters such as signal amplitude, local impedance, and frequency of late potentials was evaluated. The best cutoff value to discriminate the 2 groups was calculated by a generalized linear mixed-effects model. Results: Among all 5,926 points, 1,566 (26%) points were taken with poor contact. In healthy tissue, categorical increase of contact force caused the increase of unipolar and bipolar signal potential amplitude followed by plateau. The frequency of late potentials in the poor contact group was significantly lower when compared to the good contact group (11.9 vs 23.2%; P < 0.0001). The best cutoff force value to predict good contact during left ventricular endocardial and epicardial mappings was 9 g. Conclusions: A combined transaortic and transseptal approach allows better endocardial contact during left ventricular mapping. Ventricular mapping with sufficient contact force produces better substrate characterization within pathological areas.

Background: Lead extraction (LE) techniques have evolved from simple traction to extraction with ... more Background: Lead extraction (LE) techniques have evolved from simple traction to extraction with dilators and powered sheaths with very high success rates. On the basis of the systematic implementation of a stepwise approach, we aimed to identify those characteristics that can predict the need for advanced LE techniques. Methods: Between April 2005 and March 2012, 208 consecutive LE procedures were performed and 456 leads were extracted using an initial superior approach. Advanced techniques for LE (step 4 according to our stepwise approach) were used in 122 patients (58.7%). Results: Younger patient age (odds ratio [OR] = 0.963, P = 0.002), longer duration of the initial implantation (OR = 1.013, P = 0.002), the number of extracted leads (OR = 2.184, P < 0.001), and the presence of right ventricular defibrillator leads (OR = 2.144, P = 0.049) independently predicted the necessity of using step 4 in multivariate analysis. A prediction tool was created taking into account four categorical variables derived even from Receiver Operating Curve analysis of quantitative characteristics (age < 70.7 years, implant duration > 37 months, extraction of at least two leads, one of them being a defibrillator lead). The absence of all the four characteristics was accompanied by 0% positive predictive value for the requirement of step 4 for LE, whereas the coexistence of all four risk factors is characterized by 87% requirement of advanced LE. Conclusion: In most of the patients with indication for LE, use of a powered sheath extraction is necessary in order to obtain clinical success. We have identified four patient and lead characteristics that may help the operator plan the means of extraction. (PACE 2013; 36:837–844) lead extraction, implanted cardioverter defibrillators, pacemakers

The evolution mechanical dilator sheath has been reported to be an effective tool for chronic lea... more The evolution mechanical dilator sheath has been reported to be an effective tool for chronic lead extraction (LE). We examined safety and efficacy of evolution system as compared with laser system.

Editorial Comment The development of the subcutaneous (S-) implantable cardioverter defibrillator... more Editorial Comment The development of the subcutaneous (S-) implantable cardioverter defibrillator (ICD) provided the availability of a new interesting and clinically relevant technology for the treatment of lethal ventricular arrhythmias. The transvenous ICD has proven a very powerful weapon in our fight against sudden arrhythmic death; now, due to the extremely high number of implants, we are becoming aware of the significant complications related to this form of therapy. At the time of the implant, abnormalities of the vascu-lar anatomy may cause pneumothorax, hemothorax, or failure at advancing the leads to the desired position; over the years, degradation of the physical properties of the leads, or even their fracture, occurs at a substantial rate and requires complex interventions to restore proper function of the system. Most importantly, infections of the cardiovascu-lar implantable electronic devices are occurring at increasing rate, in spite of technological advancements and of the awareness of the problem. Removal of the ICD and extraction of the leads are frequently indicated in this setting, but these maneuvers are not devoid of morbidity and mortality. In those situations, the availability of a fully subcuta-neous lead system may represent a valid alternative to the current transvenous devices. Possible advantages and limitations have been extensively discussed. 1 In their article published in this issue of JCE, Cappato and colleagues 2 describe the initial experimental work on the energy requirements and the electrode configuration leading to the development of a fully implantable S-ICD. The data have been obtained in 19 healthy dogs with a mean weight of 29 kilograms. Several leads with different configuration and surface area were tested, proving that the lowest defibrillation thresholds were achieved with a flexible rod electrode with an area of 25 cm; 2 the final assembly—identical to that used in current clinical practice—includes an 8-cm-long electrode placed in the left parasternal space and an active can pulse generator positioned subcutaneously in the left lateral thorax, between the 4th and the 6th intercostal space: this configuration, tested in a second set of experiments, proved effective defibrillation with a 65 J submaximal energy shock in 17 of 19 (90%) ventricular fibrillation (VF) episodes; no further attempts at VF termination were performed with the maximal output (80 J), this representing, in our view, some concern. The current recommendation for the implant of the S-ICD requires that the induced arrhythmia is terminated by a 65 J shock to allow a 15 J safety margin. Following implantation, the device output (nonprogrammable) is 80 J. To date, there are no cases reported of failed defibrillation in the published clinical experience. A second set of experiments, performed on 5 animals, proved appropriate detection of all induced VF episodes (mean R wave voltage during VF 0.5 mV, vs. 1.02 during sinus rhythm). Furthermore, during the follow-up (7–24 months), there were no inappropriate shocks delivered as a consequence of inappropriate sensing of supraventricular arrhythmias or sinus tachycardia. The issue of arrhythmia detection appears a quite sensitive one for the S-ICD, because of the peculiar arrangement of the sensing electrodes. The far-field signal recorded is more similar to that obtained by the surface electrocardiogram, and this might theoretically enhance classic algorithms for the correct discrimination of ventricular from supraventricular arrhythmias. Multiple features are implemented to ensure tachyarrhythmia detection and arrhythmia discrimination: 1) To avoid oversensing, the sensing algorithm adapts to the R wave complex and decays overtime; and 2) analysis of the waveform to measure the degree of similarity between the analyzed beat and the stored morphology of the sinus QRS. The performance of the arrhythmia discrimination algorithms of the S-ICD was analyzed and compared to that implemented in 3 models of commercially available transve-nous ICD in the START study. 3 Although the ventricular arrhythmia detection appeared excellent for all the ICD systems , the power of the discrimination criteria for supraven-tricular arrhythmia of the S-ICD proved superior than that achieved by the transvenous system. Furthermore, the authors stated that by programming the high value of the conditional zone at 240 bpm, the sensitivity of arrhythmia detection was not compromised.

Sustained monomorphic ventricular tachycardia (VT) in patients with a previous myocardial infarct... more Sustained monomorphic ventricular tachycardia (VT) in patients with a previous myocardial infarction is due to re-entry mechanism in areas of slow conduction. The recognition of the pathogenic mechanism and the characterization of the activation pathway are usually obtained by indirect measures with entrainment mapping and pacing manoeuvres. We studied a 61-years-old patient with a history of previous inferior myocardial infarction and we provided the in vivo direct visualization of the critical components of re-entry circuit by non-contact mapping. VT circuit entrance, central pathway, and exit were characterized during the same beat by virtual electrodes and visualized on a three-dimensional map both during sinus rhythm, ongoing VT, and pacemapping. The analysis demonstrated an activation of the conductive channel in opposite directions during the sinus rhythm and ventricular tachycardia. Late potentials during sinus rhythm turned into mid-diastolic activity during VT; non-contact mapping allowed the ablation procedure to be performed in sinus rhythm, targeting the central pathway of the conducting channel and the abolition of VT inducibility.