Predictors of nonpulmonary vein triggers for atrial fibrillation: A clinical risk score.

BACKGROUND: Targeting non-pulmonary vein triggers (NPVTs) after pulmonary vein isolation may reduce atrial fibrillation (AF) recurrence. Isoproterenol infusion and cardioversion of spontaneous or induced AF can provoke NPVTs but typically require vasopressor support and increased procedural time. OBJECTIVE: The purpose of this study was to identify risk factors for the presence of NPVTs and create a risk score to identify higher-risk subgroups. METHODS: Using the AF ablation registry at the Hospital of the University of Pennsylvania, we included consecutive patients who underwent AF ablation between January 2021 and December 2022. We excluded patients who did not receive NPVT provocation testing after failing to demonstrate spontaneous NPVTs. NPVTs were defined as non-pulmonary vein ectopic beats triggering AF or focal atrial tachycardia. We used risk factors associated with NPVTs with P <.1 in multivariable logistic regression model to create a risk score in a randomly split derivation set (80%) and tested its predictive accuracy in the validation set (20%). RESULTS: In 1530 AF ablations included, NPVTs were observed in 235 (15.4%). In the derivation set, female sex (odds ratio [OR] 1.40; 95% confidence interval [CI] 0.96-2.03; P = .080), sinus node dysfunction (OR 1.67; 95% CI 0.98-2.87; P = .060), previous AF ablation (OR 2.50; 95% CI 1.70-3.65; P <.001), and left atrial scar (OR 2.90; 95% CI 1.94-4.36; P <.001) were risk factors associated with NPVTs. The risk score created from these risk factors (PRE2SSS2 score; [PRE]vious ablation: 2 points, female [S]ex: 1 point, [S]inus node dysfunction: 1 point, left atrial [S]car: 2 points) had good predictive accuracy in the validation cohort (area under the receiver operating characteristic curve 0.728; 95% CI 0.648-0.807). CONCLUSION: A risk score incorporating predictors for NPVTs may allow provocation of triggers to be performed in patients with greatest expected yield.

Identifying Origin of Nonpulmonary Vein Triggers Using 2 Stationary Linear Decapolar Catheters: A Novel Algorithm.

BACKGROUND: Targeting nonpulmonary vein triggers (NPVTs) of atrial fibrillation (AF) after pulmonary vein isolation can be challenging. NPVTs are often single ectopic beats with a surface P-wave obscured by a QRS or T-wave. OBJECTIVES: The goal of this study was to construct an algorithm to regionalize the site of origin of NPVTs using only intracardiac bipolar electrograms from 2 linear decapolar catheters positioned in the posterolateral right atrium (along the crista terminalis with the distal bipole pair in the superior vena cava) and in the proximal coronary sinus (CS). METHODS: After pulmonary vein isolation in 42 patients with AF, pacing from 15 typical anatomic NPVT sites was conducted. For each pacing site, the electrogram activation sequence was analyzed from the CS catheter (simultaneous/chevron/inverse chevron/distal-proximal/proximal-distal) and activation time (ie, CSCTAT) between the earliest electrograms from the 2 decapolar catheters was measured referencing the earliest CS electrogram; a negative CSCTAT value indicates the crista terminalis catheter electrogram was earlier, and a positive CSCTAT value indicates the CS catheter electrogram was earlier. A regionalization algorithm with high predictive value was defined and tested in a validation cohort with AF NPVTs localized with electroanatomic mapping. RESULTS: In the study patient cohort (71% male; 43% with persistent AF, 52% with left atrial dilation), the algorithm grouped with high precision (positive predictive value 81%-99%, specificity 94%-100%, and sensitivity 30%-94%) the 15 distinct pacing sites into 9 clinically useful regions. Algorithm testing in a 98 patient validation cohort showed predictive accuracy of 91%. CONCLUSIONS: An algorithm defined by the activation sequence and timing of electrograms from 2 linear multipolar catheters provided accurate regionalization of AF NPVTs to guide focused detailed mapping.

Septal Substrate Ablation Guided by Delayed Transmural Conduction Times: A Novel Ablation Approach to Target Intramural Substrates.

BACKGROUND: Intraprocedural identification of intramural septal substrate for ventricular tachycardia (ISS-VT) in nonischemic cardiomyopathy (NICM) is challenging. Delayed (>40 ms) transmural conduction time (DCT) with right ventricular basal septal pacing has been previously shown to identify ISS-VT. OBJECTIVES: This study sought to determine whether substrate catheter ablation incorporating areas of DCT may improve acute and long-term outcomes. METHODS: We included patients with NICM and ISS-VT referred for catheter ablation between 2016 and 2020. ISS-VT was defined by the following: 1) confluent septal areas of low unipolar voltage (<8.3 mV) in the presence of normal or minimal bipolar abnormalities; and 2) presence of abnormal electrograms in the septum. Substrate ablation was guided by the following: 1) activation and/or entrainment mapping for tolerated VT and pace mapping with ablation of abnormal septal electrograms for unmappable VTs (n = 57, Group 1); and 2) empirically extended to target areas of DCT during right ventricular basal septal pacing regardless of their participation in inducible VT(s) but sparing the conduction system when possible (n = 24, Group 2). RESULTS: There were no significant baseline differences between Groups 1 and 2. Noninducibility of any VT programmed stimulation at the end of ablation was higher in Group 2 compared with Group 1 (80% vs 53%; P = 0.03). At 12-month follow-up, single-procedure VT-free survival was significantly higher (79% vs 46%; P = 0.006) and the time to VT recurrence was longer (mean 10 ± 3 months vs 7 ± 4 months; P = 0.02) in Group 2 compared with Group 1. CONCLUSIONS: In patients with NICM and ISS-VT, a substrate ablation strategy that incorporates areas of DCT appears to improve freedom from recurrent VT.

Sinus rhythm electrocardiographic abnormalities, sites of origin, and ablation outcomes of ventricular premature depolarizations initiating ventricular fibrillation.

BACKGROUND: Ventricular fibrillation (VF) can be initiated by ventricular premature depolarizations (VPDs) in the absence of obvious structural abnormalities. OBJECTIVE: The purpose of this study was to determine the prevalence of 12-lead electrocardiographic (ECG) sinus rhythm reduced QRS amplitude, QRS fractionation (QRSf), and early repolarization (ER) pattern, and the outcome of catheter ablation and VPD anatomic distribution in patients with VPDs initiating VF. METHODS: We compared a cohort with no apparent structural heart disease and VPDs initiating VF (group 1; n = 42) to a reference cohort (group 2; n = 61) of patients with no structural heart disease and symptomatic unifocal VPDs. RESULTS: A reduced QRS amplitude (<0.55 mV) in aVF (59% vs 10%; P <.001), QRSf in ≥2 contiguous leads (50% vs 16%; P <.001), and ER pattern (21.4% vs 1.6%; P = .01) were more common in group 1 than in group 2. At least 1 abnormal ECG finding was present in 34 group 1 patients (81%) vs 17 group 2 patients (28%) (P <.001). VPD origin included right ventricular and left ventricular distal Purkinje system and moderator band/papillary muscles in 83% of group 1 patients vs 18% of group 2 patients (P <.001). VF was eliminated with a single ablation procedure in 77% of group 1 patients with at least 2 years of follow-up. CONCLUSION: A reduced QRS amplitude (<0.55 mV) in aVF, QRSf in ≥2 contiguous leads, and/or an ER pattern are frequently observed in patients with VPDs initiating VF. VPDs initiating VF typically originate from the distal Purkinje system and papillary muscles and can be successfully eliminated with catheter ablation.

Sinus rhythm QRS amplitude and fractionation in patients with nonischemic cardiomyopathy to identify ventricular tachycardia substrate and location.

BACKGROUND: Ventricular tachycardia (VT) substrate in left ventricular (LV) nonischemic cardiomyopathy (NICM) consists of fibrosis with surviving myocardium. OBJECTIVE: The purpose of this study was to determine whether, in patients with LV NICM and sustained VT, reduced QRS amplitude and QRSf during sinus rhythm can identify the presence and location of abnormal septal (S-NICM) and/or free-wall (FW-NICM) VT substrate. METHODS: We compared patients with NICM and VT (group 1) with electroanatomic mapping septal (S-NICM; n = 21) or free-wall (FW-NICM; n = 20) VT substrate to a 38-patient reference cohort (group 2) with cardiac magnetic resonance imaging (cMRI) and NICM but no VT referred for primary prevention implantable cardioverter-defibrillator (26 [68.4%] with late gadolinium enhancement). RESULTS: Group 1 had lower QRS amplitude in leads II (0.60 ± 0.22 vs 0.86 ± 0.35, P <.001), aVR (0.60 ± 0.24 vs 0.75 ± 0.31, P = .002), aVF (0.48 ± 0.20 vs 0.70 ± 0.28, P <.001), and V2 (1.09 ± 0.52 vs 1.38 ± 0.55, P = .001) than group 2. QRS <0.55 mV in lead aVF identified VT and accompanying substrate with sensitivity 70% and specificity 71%. Most group 1 and group 2 patients had 12-lead ECG QRS fractionation (QRSf) in ≥2 contiguous leads (78% vs 63.2%, P = .14). Sensitivity and specificity for ≥2 QRSf leads identifying respective regional electroanatomic or cMRI abnormalities were 76% and 50% for inferior, 44% and 87% for lateral, and 21% and 89% for anterior leads. CONCLUSION: In LV NICM, low frontal plane QRS (<0.55 mV in aVF) is associated with VT substrate. Although multilead QRS fractionation is associated with the presence and location of VT substrate, it is frequently identified in patients without VT with cMRI abnormalities.

HeartMate 3: new challenges in ventricular tachycardia ablation.

AIM: To describe clinical characteristics, procedural details, specific challenges, and outcomes in patients with HeartMate3™ (HM3), a left ventricular assist device system with a magnetically levitated pump, undergoing ventricular tachycardia ablation (VTA). METHODS AND RESULTS: Data were collected from patients with an HM3 system who underwent VTA in seven tertiary centres. Data included baseline patient characteristics, procedural data, mortality, and arrhythmia-free survival. The study cohort included 19 patients with cardiomyopathy presenting with ventricular tachycardia (VT) (53% with VT storm). Ventricular tachycardias were induced in 89% of patients and a total of 41 VTs were observed. Severe electromagnetic interference was present on the surface electrocardiogram. Hence, VT localization required analysis of intra-cardiac signals or the use of filter in the 40-20 Hz range. The large house pump HM3 design obscured the cannula inflow and therefore multi imaging modalities were necessary to avoid catheter entrapment in the cannula. A total of 32 VTs were mapped and were successfully ablated (31% to the anterior wall, 38% to the septum and only 9% to the inflow cannula region). Non-inducibility of any VT was reached in 11 patients (58%). Over a follow-up of 429 (interquartile range 101-692) days, 5 (26%) patients underwent a redo VT ablation due to recurrent VTA and 2 (11%) patients died. CONCLUSIONS: Ventricular tachycardia ablation in patients with HM3 is feasible and safe when done in the appropriate setup. Long-term arrhythmia-free survival is acceptable but not well predicted by non-inducibility at the end of the procedure.

Substrate Characterization and Outcome of Catheter Ablation of Ventricular Tachycardia in Patients With Nonischemic Cardiomyopathy and Isolated Epicardial Scar.

BACKGROUND: The substrate for ventricular tachycardia (VT) in left ventricular (LV) nonischemic cardiomyopathy may be epicardial. We assessed the prevalence, location, endocardial electrograms, and VT ablation outcomes in LV nonischemic cardiomyopathy with isolated epicardial substrate. METHODS: Forty-seven of 531 (9%) patients with LV nonischemic cardiomyopathy and VT demonstrated normal endocardial (>1.5 mV)/abnormal epicardial bipolar low-voltage area (LVA, <1.0 mV and signal abnormality). Abnormal endocardial unipolar LVA (≤8.3 mV) and endocardial bipolar split electrograms and predictors of ablation success were assessed. RESULTS: Epicardial bipolar LVA (27.3 cm2 [interquartile range, 15.8-50.0]) localized to basal (40), mid (8), and apical (3) LV with basal inferolateral LV most common (28/47, 60%). Of 44 endocardial maps available, 40 (91%) had endocardial unipolar LVA (24.5 cm2 [interquartile range, 9.4-68.5]) and 29 (67%) had characteristic normal amplitude endocardial split electrograms opposite the epicardial LVA. At mean of 34 months, the VT-free survival was 55% after one and 72% after multiple procedures. Greater endocardial unipolar LVA than epicardial bipolar LVA (hazard ratio, 10.66 [CI, 2.63-43.12], P=0.001) and number of inducible VTs (hazard ratio, 1.96 [CI, 1.27-3.00], P=0.002) were associated with VT recurrence. CONCLUSIONS: In patients with LV nonischemic cardiomyopathy and VT, the substrate may be confined to epicardial and commonly basal inferolateral. LV endocardial unipolar LVA and normal amplitude bipolar split electrograms identify epicardial LVA. Ablation targeting epicardial VT and substrate achieves good long-term VT-free survival. Greater endocardial unipolar than epicardial bipolar LVA and more inducible VTs predict VT recurrence.

Epicardial Connections Involving Pulmonary Veins: The Prevalence, Predictors, and Implications for Ablation Outcome.

BACKGROUND: The presence of epicardial connections (ECs) between pulmonary veins (PVs) and other anatomic structures may hinder PV isolation. In this study, we analyzed their prevalence, location, associated factors, and clinical implications. METHODS: Five hundred thirty-four consecutive patients with atrial fibrillation undergoing radiofrequency ablation were included. We considered that an EC was present if: (1) the first pass around the PV antrum did not produce PV isolation and (2) subsequent atrial activation during PV pacing showed that the earliest site was located away from the ablation line and later activation sites were observed near the ablation line. Clinical and electrophysiological variables were collected from all patients. Patients were followed during 12.9±9.4 months, and any documented atrial tachyarrhythmia after the 3-month blanking period was classified as a recurrence. RESULTS: Out of the 534 patients included, 72 (13.5%) were found to have 81 ECs. There was a significant association between the presence of ECs and structural heart disease (15.3% in patients without ECs versus 36.5% in patient with ECs; P<0.001) and patent foramen ovale (4.6% versus 13.5%; P=0.002). The presence of a left common trunk was significantly associated with the absence of ECs (29.6% in patients without ECs versus 16.2% in patients with ECs; P=0.014). Patients with ECs had lower acute success in PV isolation compared with patients without ECs (99.1% versus 86.1%; P<0.001). After adjusting for age, sex, type of atrial fibrillation, left atrium area, hypertension, structural heart disease, presence of left common trunk, patent foramen ovale, and time for atrial fibrillation diagnosis to the ablation, we found a significantly higher risk of atrial tachyarrhythmia recurrences in patients with ECs compared with patients without ECs (hazard ratio, 1.7 [95% CI, 1.1-2.9]; P=0.04). CONCLUSIONS: ECs between PVs and other adjacent structures are frequent in patient with atrial fibrillation (prevalence: 13.5%). Structural heart disease and a patent foramen ovale are strongly associated with the presence of ECs. ECs reduce the acute and chronic success of PV isolation.

Electrogram voltage and pacing threshold before ablation, measured by mini-electrodes, predict parameters indicative of transmural lesions in the human atrium.

PURPOSE: An important attenuation of the atrial signal recorded with mini-electrodes (ME) embedded in an 8-mm tip was associated with a transmural radiofrequency lesion. Our aim was to assess if parameters obtained from ME or conventional bipoles before applications predict successful atrial lesions. METHODS: We prospectively included 33 consecutive patients undergoing cavotricuspid isthmus (CTI) ablation. Electrogram voltages and pacing thresholds were measured with ME and conventional bipoles before and after radiofrequency (RF) applications. The time before the loss of capture during applications was recorded. Lesions were considered successful, in accordance with preclinical data, if ME voltage decreased > 54%. RESULTS: Of 207 applications, 107 could be analyzed. During applications, voltages decreased more in the ME than in the conventional bipoles (66.8 ± 26.1% vs 37.5 ± 42.5%, P = 0.001). Likewise, pacing threshold increased significantly more using the ME (86.3 ± 22.9% ME, 52.6 ± 35.6% conventional, P = 0.001). ME pre-ablation voltages were significantly higher and pacing thresholds significantly lower in successful lesions (voltage 0.88 ± 0.71 vs 0.26 ± 0.18 mV, P = 0.0001; threshold 1.6 ± 1.7 vs 2.8 ± 3.0, P = 0.04). Neither of these parameters with conventional bipoles nor time to loss of capture showed differences. A ME voltage > 0.33 mV and a pacing threshold < 1.5 mA predicted a successful lesion with 0.78 and 0.6 sensitivity and 0.78 and 0.59 specificity. CONCLUSIONS: Certain pre-ablation parameters derived from ME such as electrogram voltage and pacing threshold differ from those obtained by a conventional configuration and can predict a successful atrial lesion.

A constant postpacing interval in response to overdrive pacing with variable number of beats: An aid in the identification of entrainment for a particular pacing train during macroreentrant atrial tachycardias.

BACKGROUND: When pacing trains with a constant cycle length (CL) but increasing number of beats are introduced during a macroreentrant atrial tachycardia (MAT), the postpacing interval (PPI) is expected to increase if entrainment does not occur but could be stable if entrainment occurs. We tested the ability of PPI analysis to detect entrainment. METHODS: Synchronized pacing trains with increasing number of beats (1-20) were delivered from the coronary sinus (CS) and lateral right atrium (RA) at a CL 20 ms shorter than the MAT CL. Pacing trains were grouped in pairs differing by one-paced beat, and the ∆PPI measured. RESULTS: In an initial prospective cohort of 21 patients (48% had left atrial flutter) the mean ∆PPI was 21.3 ± 5.6 ms for pairs of pacing trains in which neither entrained the MAT and 2.8 ± 1.4 ms for those in which both entrained the MAT (P < .0001). Results were similar for common vs atypical flutter, PPI-TCL ≤30 ms vs PPI-TCL >30 ms, presence vs absence of antiarrhythmic drugs and faster vs slower MAT. When an index pacing train was compared to one with two-paced beats less, a PPI difference of <19 ms identified entrainment with 95% sensitivity and 98% specificity. In a validation cohort of 16 patients, this cut-off value resulted in sensitivity and specificity of 90% and 94%. CONCLUSIONS: A relatively constant ∆PPI in response to overdrive pacing with identical CL but different number of beats allows accurate discrimination between trains that entrained vs those which did not entrain a MAT.

Atrial mapping during pulmonary vein pacing to detect conduction gaps in a second pulmonary vein isolation procedure.

BACKGROUND: Finding the conduction gaps in redo PV isolation procedures is challenging, and several maneuvers have been described. In the present study, we analyze the pace and map (P&M) maneuver [atrial mapping during pulmonary vein (PV) pacing] to locate the gaps in redo PV isolation procedures. METHODS: Consecutive patients undergoing a second PV isolation procedure at a single institution over a 4-year period were included. For the last 2 years, all the patients (n = 38) studied underwent PV isolation based on the P&M maneuver and were compared to the previous patients (n = 45). The atrial side of the ablation line was mapped with the ablation catheter during PV pacing, and the earliest site was considered a gap site. RESULTS: Shorter radiofrequency time was required to obtain PV isolation in the P&M group (485 ± 374 vs. 864 ± 544 s; p < 0.001), which remained significant after adjusting for the number of reconnected PVs (p = 0.01). We did not find significant differences in the procedure duration (106 ± 46 vs. 112 ± 53 min; p = 0.57) and arrhythmia recurrence during 1-year follow-up (26.6 vs. 28.9%; p = 0.82) after adjusting for several confounding factors (HR 1.32; 95% CI 0.5-3.4; p = 0.57). CONCLUSIONS: P&M is a simple maneuver to identify the gaps in ablation lines around the PV. It remains efficacious in redo procedures despite the difficulties in localizing the ablation lines performed in the first procedure. The P&M maneuver reduced the radiofrequency time required to isolate the PV without compromising the efficacy.

Electrical isolation of the superior vena cava by laser balloon ablation in patients with atrial fibrillation.

PURPOSE: The aim of the present study is to evaluate the feasibility and safety of SVC electrical isolation by LB ablation in patients with atrial fibrillation (AF) referred for pulmonary vein isolation (PVI). METHODS: Electrical disconnection of the SVC was attempted by LB in 13 consecutive patients (59 ± 10.5 years, 11 male) with AF following PVI. PVI was successfully achieved by standard LB in all before attempting SVC isolation. RESULTS: A laser beam was delivered with 6.3 ± 2.3 W and 8.4 ± 2.7 W (P = 0.001) during 5.38 ± 2.4 min and 9.75 ± 1.6 min (P = 0.024) to achieve SVC and PV, respectively. Isolation of the SVC by LB was accomplished in 8 patients (61%) without complications. Phrenic nerve palsy developed in 3 patients (23%), which resulted in early procedure termination before isolation. Technical problems or interposition of a pacemaker lead to prevented SVC isolation in the remaining 2 patients. After a mean follow-up of 19 ± 3 months, no patient recovered from phrenic nerve palsy. CONCLUSIONS: SVC isolation by LB is feasible but associated with a high risk of phrenic nerve palsy. Limitation of laser delivery time and power appears insufficient to prevent this complication.

Administración simultánea de rivaroxabán y dronedarona en pacientes con fibrilación auricular no valvular / Concomitant rivaroxaban and dronedarone administration in patients with nonvalvular atrial fibrillation

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Estado actual de la ablación de la fibrilación auricular / Current status on atrial fibrillation ablation

La fibrilación auricular es la arritmia más común en la práctica clínica. La ablación se considera el tratamiento de elección (indicación clase I) en los pacientes sintomáticos con recurrencias a pesar del tratamiento con fármacos antiarrítmicos. El presente artículo revisa tanto los mecanismos propuestos de esta arritmia como las diferentes metodologías de ablación con catéter y sus indicaciones.

Summary Atrial fibrillation is the most common arrhythmia in clinical practice. Catheter ablation is the treatment of choice (Class I indication) for symptomatic patients with recurrences despite antiarrhythmic drugs. The present article reviews the proposed mechanisms of this arrhythmia and the different ablation methods and indications.

What is behind radiofrequency delivery at the cavo-tricuspid isthmus?

Catheter-based ablation of isthmus-dependent common atrial flutter results in very high success rates and almost no complications. However, bidirectional conduction block through the isthmus may be challenging in a small percentage of patients regarding the use of high power and high temperature settings during radiofrequency delivery. Anatomical and physiological circumstances may be the reason for such difficulties to achieve bidirectional block at the cavo-tricuspid isthmus. However, in the present case we show edema formation after multiple shots of radiofrequency delivery at the cavo-tricuspid isthmus, which complicates the achievement of bidirectional conduction block.

What is behind radiofrequency delivery at the cavo-tricuspid isthmus? / ¿Qué sucede en el istmo cavo-tricuspídeo durante la ablación con radiofrecuencia?

Catheter-based ablation of isthmus-dependent common atrial flutter results in very high success rates and almost no complications. However, bidirectional conduction block through the isthmus may be challenging in a small percentage of patients regarding the use of high power and high temperature settings during radiofrequency delivery. Anatomical and physiological circumstances may be the reason for such difficulties to achieve bidirectional block at the cavo-tricuspid isthmus. However, in the present case we show edema formation after multiple shots of radiofrequency delivery at the cavo-tricuspid isthmus, which complicates the achievement of bidirectional conduction block.

La ablación con catéter del flutter de tipo común dependiente del istmo es un procedimiento con elevada tasa de éxito y rara vez complicaciones. Sin embargo, en un pequeño porcentaje de casos puede resultar complicado conseguir el objetivo de bloquear bidireccionalmente el istmo durante el procedimiento de ablación a pesar de incrementar la potencia y temperatura del catéter de radiofrecuencia. Las características anatómicas y fisiológicas del istmo cavo-tricuspídeo pueden ocasionar dificultades en la consecución del bloqueo bidireccional. Sin embargo, en el presente caso mostramos cómo la propia aplicación de radiofrecuencia puede ocasionar edema importante tras múltiples aplicaciones con las consiguientes dificultades para conseguir el bloqueo bidireccional del istmo.

Análisis retrospectivo de una población de pacientes con síndrome de Brugada y cardiodesfibrilador automático implantable / Retrospective Analysis of Patients with Brugada Syndrome and Implantable Cardioverter Defibrillator

Introducción El síndrome de Brugada es una anomalía eléctrica hereditaria con riesgo incrementado de muerte súbita. El cardiodesfibrilador automático implantable es el único tratamiento efectivo para la prevención de la muerte súbita, mientras que la conducta terapéutica en los pacientes asintomáticos continúa siendo controversial. Objetivos Evaluar la incidencia y las causas de choques apropiados e inapropiados y las complicaciones relacionadas con el dispositivo. Identificar la relación de variables clínicas y del estudio electrofisiológico con la ocurrencia de choques apropiados. Material y métodos Registro unicéntrico, retrospectivo de pacientes con síndrome de Brugada, con patrón electrocardiográfico tipo I espontáneo o inducido con infusión de ajmalina, a quienes se les colocó un cardiodesfibrilador automático implantable. Resultados Se incluyeron 21 pacientes, 18 hombres, con una mediana de edad de 40 años. El dispositivo fue indicado por síntomas -respiración agónica nocturna, síncope y paro cardíaco resucitado- o por un estudio electrofisiológico positivo en pacientes asintomáticos. En un seguimiento de 88 meses no hubo muertes; la tasa anual de choques apropiados fue del 1,9%, inferior a la de choques inapropiados (7,5%). Diez pacientes tuvieron complicaciones, que incluyeron infección del dispositivo y trastornos psiquiátricos. La única variable relacionada significativamente con la presencia de choques apropiados fue el antecedente de fibrilación y aleteo auricular. Conclusiones Se observó una tasa anual baja de choques apropiados. Las dificultades en la estratificación del riesgo, la alta incidencia de choques inapropiados y la elevada frecuencia de complicaciones hacen recomendable una selección cuidadosa para el implante de estos dispositivos hasta encontrar predictores más confiables de riesgo arrítmico.(AU)

Introduction The Brugada syndrome is an inherited, electrical anomaly, with increased risk of sudden cardiac death. Automatic cardioverter defibrillators are the only effective treatment to prevent sudden cardiac death, while therapy management in asymptomatic patients is still controversial. Objectives The aims of the study were to evaluate the incidence and causes of appropriate and inappropriate shocks and the complications related to the device, and to identify the relation of clinical and electrophysiological study variables with the incidence of appropriate shocks. Methods This was a single-center, retrospective registry of patients with Brugada syndrome, with type-1 electrocardiographic pattern, either spontaneous or induced by ajmaline infusion, who were recipients of automatic implantable cardioverter defibrillator. Results Twenty-one patients were included in the study; 18 were males, and average age was 40 years. The device was indicated due to the following symptoms: nocturnal agonal respiration, syncope and aborted cardiac arrest, or positive electrophysiology study in asymptomatic patients. There were no deaths during follow-up of 88 months, and the yearly rate of appropriate shocks was 1.9%, below that of inappropriate shocks (7.5%). Ten patients presented complications including device infection and psychiatric disorders. The only variable significantly related with the presence of appropriate shocks was history of fibrillation and atrial flutter. Conclusions A low yearly rate of appropriate shocks was observed. The difficulties in risk stratification, the high incidence of inappropriate shocks and the high frequency of complications indicate need of careful patient selection for the implantation of these devices until more reliable predictors of arrhythmic risk are found.(AU)

Análisis retrospectivo de una población de pacientes con síndrome de Brugada y cardiodesfibrilador automático implantable / Retrospective Analysis of Patients with Brugada Syndrome and Implantable Cardioverter Defibrillator

Introducción El síndrome de Brugada es una anomalía eléctrica hereditaria con riesgo incrementado de muerte súbita. El cardiodesfibrilador automático implantable es el único tratamiento efectivo para la prevención de la muerte súbita, mientras que la conducta terapéutica en los pacientes asintomáticos continúa siendo controversial. Objetivos Evaluar la incidencia y las causas de choques apropiados e inapropiados y las complicaciones relacionadas con el dispositivo. Identificar la relación de variables clínicas y del estudio electrofisiológico con la ocurrencia de choques apropiados. Material y métodos Registro unicéntrico, retrospectivo de pacientes con síndrome de Brugada, con patrón electrocardiográfico tipo I espontáneo o inducido con infusión de ajmalina, a quienes se les colocó un cardiodesfibrilador automático implantable. Resultados Se incluyeron 21 pacientes, 18 hombres, con una mediana de edad de 40 años. El dispositivo fue indicado por síntomas -respiración agónica nocturna, síncope y paro cardíaco resucitado- o por un estudio electrofisiológico positivo en pacientes asintomáticos. En un seguimiento de 88 meses no hubo muertes; la tasa anual de choques apropiados fue del 1,9%, inferior a la de choques inapropiados (7,5%). Diez pacientes tuvieron complicaciones, que incluyeron infección del dispositivo y trastornos psiquiátricos. La única variable relacionada significativamente con la presencia de choques apropiados fue el antecedente de fibrilación y aleteo auricular. Conclusiones Se observó una tasa anual baja de choques apropiados. Las dificultades en la estratificación del riesgo, la alta incidencia de choques inapropiados y la elevada frecuencia de complicaciones hacen recomendable una selección cuidadosa para el implante de estos dispositivos hasta encontrar predictores más confiables de riesgo arrítmico.

Introduction The Brugada syndrome is an inherited, electrical anomaly, with increased risk of sudden cardiac death. Automatic cardioverter defibrillators are the only effective treatment to prevent sudden cardiac death, while therapy management in asymptomatic patients is still controversial. Objectives The aims of the study were to evaluate the incidence and causes of appropriate and inappropriate shocks and the complications related to the device, and to identify the relation of clinical and electrophysiological study variables with the incidence of appropriate shocks. Methods This was a single-center, retrospective registry of patients with Brugada syndrome, with type-1 electrocardiographic pattern, either spontaneous or induced by ajmaline infusion, who were recipients of automatic implantable cardioverter defibrillator. Results Twenty-one patients were included in the study; 18 were males, and average age was 40 years. The device was indicated due to the following symptoms: nocturnal agonal respiration, syncope and aborted cardiac arrest, or positive electrophysiology study in asymptomatic patients. There were no deaths during follow-up of 88 months, and the yearly rate of appropriate shocks was 1.9%, below that of inappropriate shocks (7.5%). Ten patients presented complications including device infection and psychiatric disorders. The only variable significantly related with the presence of appropriate shocks was history of fibrillation and atrial flutter. Conclusions A low yearly rate of appropriate shocks was observed. The difficulties in risk stratification, the high incidence of inappropriate shocks and the high frequency of complications indicate need of careful patient selection for the implantation of these devices until more reliable predictors of arrhythmic risk are found.