Improvement in electrocardiographic parameters of repolarization related to sudden death in patients with ventricular dysfunction and left bundle branch block after cardiac resynchronization through His bundle pacing.

BACKGROUND: Cardiac resynchronization therapy (CRT) through permanent His bundle pacing (p-HBP) normalizes interventricular conduction disorders and QRS. Similarly, there are immediate and long-term changes in repolarization, which could be prognostic of a lower risk of sudden death (SD) at follow-up. We aimed to compare the changes in different electrocardiographic (ECG) repolarization parameters related to the risk of SD before and after CRT through p-HBP. METHODS: In this prospective, descriptive single-center study (May 2019 to December 2021), we compared the ECG parameters of repolarization related to SD in patients with non-ischemic dilated cardiomyopathy, left bundle branch block (LBBB), and CRT indications, at baseline and after CRT through p-HBP. RESULTS: Forty-three patients were included. Compared to baseline, after CRT through p-HBP, there were immediate significant changes in the QT interval (ms): 445 [407.5-480] vs 410 [385-440] (p = 0.006), QT dispersion (ms): 80 [60-100] vs 40 [40-65] (p < 0.001), Tp-Te (ms): 90 [80-110] vs 80 [60-95] (p < 0.001), Tp-Te/QT ratio: 0.22 [0.19-0.23] vs 0.19 [0.16-0.21] (p < 0.001), T wave amplitude (mm): 6.25 [4.88-10] vs - 2.5 [- 7-2.25] (p < 0.001), and T wave duration (ms): 190 [157.5-200] vs 140 [120-160] (p = 0.001). In the cases of the corrected QT (Bazzett and Friederichia) and the Tp-Te dispersion, changes only became significant at 1 month post-implant (468.5 [428.8-501.5] vs 440 [410-475.25] (p = 0.015); 462.5 [420.8-488.8] vs 440 [400-452.5] (p = 0.004), and 40 [30-52.5] vs 30 [20-40] (p < 0.001), respectively) (Table 1). Finally, two parameters did not improve until 6 months post-implant: the rdT/JT index, 0.25 [0.21-0.28] baseline vs 0.20 [0.19-0.23] 6 months post-implant (p = 0.011), and the JT interval, 300 [240-340] baseline vs 280 [257-302] 6 months post-implant (p = 0.027). Additionally, most of the parameters continued improving as compared with immediate post-implantation. CONCLUSIONS: After CRT through His bundle pacing and LBBB correction, there was an improvement in all parameters of repolarization related to increased SD reported in the literature.

His bundle pacing success and electrical parameter stability regardless of three-dimensional transthoracic echocardiography lead localization.

BACKGROUND OR PURPOSE: His bundle pacing (HBP) is the most physiological form of ventricular pacing. Few prospective studies have analyzed lead localization using imaging techniques and its relationship with electrical parameters and capture patterns. The objective of this study is to examine the correlation between electrical parameters and lead localization using three-dimensional transthoracic echocardiography (3D TTE). METHODS: This single-center, prospective, nonrandomized clinical research study (January 2018 to June 2020) included patients with an indication of permanent pacing, in whom 3D TTE was performed to define lead localization as supravalvular or subvalvular. RESULTS: A total of 92 patients were included: 56.5% of leads were supravalvular, and 43.5% were subvalvular, which resembles previous anatomic descriptions of autopsied hearts of His bundle localization within the triangle of Koch (ToK). R-wave sensing was higher when the His lead was localized subvalvular instead of supravalvular. His lead localization was not associated with HBP threshold or impedance differences, nor with the two different HBP patterns of capture, or with the ability of HBP to correct baseline BBB. The thresholds remained stable during follow-up visits, regardless of His lead localization. Higher R-wave sensing was observed during follow-up than at baseline, mainly in the subvalvular His leads. However, lead impedances in both positions decreased during follow-up. CONCLUSIONS: Lead localization in relation to the tricuspid valve did not influence the electrical performance of HBPs. Wide anatomical variations of the His bundle within the ToK explain our findings, reinforcing the idea that the technique for HBP should be fundamentally guided by electrophysiological and not anatomical parameters.

Cardiac resynchronization therapy in non-ischemic cardiomyopathy: a comparative non-randomized study of His Bundle pacing versus biventricular pacing.

BACKGROUND: Cardiac resynchronization therapy (CRT) via permanent His bundle pacing (pHBP) has gained acceptance globally, but robust studies comparing pHBP-CRT with classic CRT are lacking. In this study, we aimed to compare the improvement in left ventricular ejection fraction (LVEF) after pHBP-CRT versus classic CRT. METHODS: This was a single-center study comparing a prospective series of pHBP-CRT with a historical series of CRT via classic biventricular pacing (BVP). Patients with non-ischemic cardiomyopathy, baseline LVEF < 35%, left bundle branch block (LBBB), and CRT indications were selected. RESULTS: Fifty-one patients underwent classic CRT and 52 patients underwent pHBP-CRT. In the classic CRT group, the median (interquartile range) basal LVEF was 30% (IQR, 29-35%) before implantation and 40% (35-48%) at follow-up. In the pHBP-CRT group, the median basal LVEF was 30% (28-34%) before implantation and 55% (45-60%) at follow-up, with significant differences between both modalities at follow-up (p = 0.001). The median long term His recruitment threshold with LBBB correction was 1.25 (1-2.5) V at 0.4 ms in cases of pHBP-CRT, compared to a left ventricular coronary sinus threshold of 1.25 (1-1.75) V in cases of classic CRT (p = 0.48). After CRT, the median paced QRS was 135 (120-145) ms for pHBP-CRT versus 140 (130-150) ms for BVP-CRT (p = 0.586). CONCLUSIONS: The improvement in LVEF was superior with pHBP-CRT than with classic CRT. The thresholds at follow-up were similar in both groups.

Validation of multiparametric approaches for the prediction of sudden cardiac death in patients with Brugada syndrome and electrophysiological study.

INTRODUCTION AND OBJECTIVES: Multiparametric scores have been designed for better risk stratification in Brugada syndrome (BrS). We aimed to validate 3 multiparametric approaches (the Delise score, Sieira score and the Shanghai BrS Score) in a cohort with Brugada syndrome and electrophysiological study (EPS). METHODS: We included patients diagnosed with BrS and previous EPS between 1998 and 2019 in 23 hospitals. C-statistic analysis and Cox proportional hazard regression models were used. RESULTS: A total of 831 patients were included (mean age, 42.8±13.1; 623 [75%] men; 386 [46.5%] had a type 1 electrocardiogram (ECG) pattern, 677 [81.5%] were asymptomatic, and 319 [38.4%] had an implantable cardioverter-defibrillator). During a follow-up of 10.2±4.7 years, 47 (5.7%) experienced a cardiovascular event. In the global cohort, a type 1 ECG and syncope were predictive of arrhythmic events. All risk scores were significantly associated with events. The discriminatory abilities of the 3 scores were modest (particularly when these scores were evaluated in asymptomatic patients). Evaluation of the Delise and Sieira scores with different numbers of extra stimuli (1 or 2 vs 3) did not substantially improve the event prediction c-index. CONCLUSIONS: In BrS, classic risk factors such as ECG pattern and previous syncope predict arrhythmic events. The predictive capabilities of the EPS are affected by the number of extra stimuli required to induce ventricular arrhythmias. Scores combining clinical risk factors with EPS help to identify the populations at highest risk, although their predictive abilities remain modest in the general BrS population and in asymptomatic patients.

Effectiveness and safety of AV node ablation after His bundle pacing in patients with uncontrolled atrial arrhythmias.

INTRODUCTION: In patients with uncontrolled atrial fibrillation, atrioventricular (AV) node ablation after permanent His bundle pacing (p-HBP) could be a therapeutic option for heart rate (HR) control. We aimed to demonstrate the advantages of AV node ablation with p-HBP, and to describe its effectiveness and safety. METHODS: This descriptive observational study included patients with uncontrolled permanent atrial arrhythmias who were candidates for HR control (January 2019 to July 2020) and underwent p-HBP and AV node ablation. RESULTS: A total of 39 patients were included. The median left ventricular ejection fraction (LVEF) was 55% (45-60); 46.1% in NYHA class II and 43.6% in NYHA class III. p-HBP was achieved in 92.3% (n = 36), and AV node ablation was successfully performed in all patients. The LVEF improved in patients with reduced LVEF (baseline, 35% [23.8-45.3%]; follow-up, 40% [35-56.5%], p < 0.05); the NYHA class also showed improvement (baseline, 71.4% patients in class III and 7.1% in class II, and at follow-up, 78.6% patients in class II and 14.3% in class I). In patients with previously normal LVEF, LVEF remained stable; nevertheless, a significant NYHA class improvement was observed (baseline, 63.6% class II and 31.8% class III patients; follow-up, 54.5% class I and 45.5% class II patients). The His thresholds and lead parameter values did not significantly change during the follow-up and remained stable. CONCLUSIONS: In patients with uncontrolled atrial arrhythmias who underwent AV node ablation after p-HBP, the NYHA class improved and the LVEF increased in those with reduced baseline LVEF. The values of pacing parameters were acceptable and remained stable during the follow-up.

Long-term prognosis of women with Brugada syndrome and electrophysiological study.

BACKGROUND: A male predominance in Brugada syndrome (BrS) has been widely reported, but scarce information on female patients with BrS is available. OBJECTIVE: The purpose of this study was to investigate the clinical characteristics and long-term prognosis of women with BrS. METHODS: A multicenter retrospective study of patients diagnosed with BrS and previous electrophysiological study (EPS) was performed. RESULTS: Among 770 patients, 177 (23%) were female. At presentation, 150 (84.7%) were asymptomatic. Females presented less frequently with a type 1 electrocardiographic pattern (30.5% vs 55.0%; P <.001), had a higher rate of family history of sudden cardiac death (49.7% vs 29.8%; P <.001), and had less sustained ventricular arrhythmias (VAs) on EPS (8.5% vs 15.1%; P = .009). Genetic testing was performed in 79 females (45% of the sample) and was positive in 34 (19%). An implantable cardioverter-defibrillator was inserted in 48 females (27.1%). During mean (± SD) follow-up of 122.17 ± 57.28 months, 5 females (2.8%) experienced a cardiovascular event compared to 42 males (7.1%; P = .04). On multivariable analysis, a positive genetic test (18.71; 95% confidence interval [CI] 1.82-192.53; P = .01) and atrial fibrillation (odds ratio 21.12; 95% CI 1.27-350.85; P = .03) were predictive of arrhythmic events, whereas VAs on EPS (neither with 1 or 2 extrastimuli nor 3 extrastimuli) were not. CONCLUSION: Women with BrS represent a minor fraction among patients with BrS, and although their rate of events is low, they do not constitute a risk-free group. Neither clinical risk factors nor EPS predicts future arrhythmic events. Only atrial fibrillation and positive genetic test were identified as risk factors for future arrhythmic events.

Electrocardiographic patterns predictive of left bundle branch block correction with His bundle pacing.

INTRODUCTION: Permanent His bundle pacing (p-HBP) could be an alternative for traditional cardiac resynchronization therapy (CRT), but an important limitation is that p-HBP cannot always correct the left bundle branch block (LBBB). The purpose of this article is to assess electrocardiographic patterns of LBBB that can predict electrocardiographic response (QRS narrowing) to His bundle pacing. METHODS: We designed a prospective descriptive study of patients with LBBB and CRT indication proposed for CRT by p-HBP. We analyzed the correlation between the different electrocardiographic patterns and the correction of conduction disturbance (LBBB). RESULTS: We included 70 patients. Pacing at the location where His bundle electrogram was recorded narrowed the QRS in 81.4% (n = 57). Basically, we identified two electrocardiographic patterns in lead V1: QS or rS. The QS pattern was a sensitivity of 56%, a specificity of 84.6%, and a positive predictive value (PPV) of 94.1% to predict the correction of the LBBB (area under the curve [AUC] = .70). In patients with rS pattern, a ratio between the descending and the ascending S wave component duration ≥0.64 was a very good predictor of the correction of the LBBB (AUC = .968); with a value ≥0.64, the sensitivity, specificity, and PPV was 92%, 100%, and 100%, respectively. CONCLUSIONS: In patients with LBBB and CRT indication, the QS pattern in lead V1 predicts the correction of the QRS with HBP. In the case of rS pattern in lead V1, the ratio descending/ascending S wave component duration has a strong correlation with the LBBB correction.

Early improvement of left ventricular ejection fraction by cardiac resynchronization through His bundle pacing in patients with heart failure.

AIMS: Permanent His bundle pacing (p-HBP) can correct intraventricular conduction disorders and could be an alternative to traditional cardiac resynchronization therapy (CRT) via the coronary sinus. We describe the short-term impact of HBP on left ventricular ejection fraction (LVEF) and improvement of left intraventricular synchrony. METHODS AND RESULTS: This prospective descriptive study, performed from January 2018 to February 2019, included patients with left bundle branch block (LBBB) and an CRT indication who were resynchronized by p-HBP. We used the Medtronic C315 His catheter or a combination of the CPS-Direct-Universal introducer, CPS-AIM™-Universal subselector (Abbot), and SelectSecure™ MRI-SureScan™ 3830 lead. Correction of the LBBB by HBP had been previously checked. At 1 month of follow-up, we analysed the quantification of LVEF and measurement of the delay of the septal wall with the posterior wall as a parameter of intraventricular synchrony. We included 48 patients with LBBB and an indication for CRT. With HBP, we corrected the LBBB in 81% of patients (n = 39), and we achieved cardiac resynchronization through permanent HBP in 92% of these patients (n = 36). Left ventricular ejection fraction and intraventricular mechanical resynchronization improved in all patients, which was demonstrated by echocardiography through the improvement of the delay of the septal wall with the posterior wall from 138 ms (range 131-151) to 41 ms (19-63). CONCLUSION: There is early improvement after p-HBP in LVEF and left ventricular electromechanical synchronization in patients with LBBB, heart failure, and an indication for CRT.

Repeated procedures at the generator pocket are a determinant of implantable cardioverter-defibrillator infection.

BACKGROUND: Rates of cardiac-device infections have increased in recent years, but the current incidence and risk factors for infection in patients with implantable cardioverter-defibrillators (ICDs) are not well known. HYPOTHESIS: The increasing number of ICD infections is related to accumulated pocket manipulations over time. METHODS: This single-center, prospective study included patients that underwent ICD implantation from 2008 to 2015. The endpoint was time to infection. Multivariate analysis was performed to identify independent risk factors related to infection. RESULTS: The study included a total of 570 patients, of whom 419 (73.5%) underwent a first implantation. Mean age was 59 ± 14 years, and 80% were male. During a median follow-up of 36 months (interquartile range, 18-61 months; 1887 patient-years), infection was identified in 26 patients (4.56%), an incidence of 14.9 × 1000 patient-years. Median time to infection was 9.7 months (interquartile range, 1.35-23.4 months), and 38.5% were late infections (beyond 12 months of follow-up). In patients with replacement implants, the incidence was 3-fold higher than in first implantations (27.7 vs 9.1 × 1000 patient-years; P = 0.002). Cox regression identified 2 independent predictors of ICD infection: cumulative number of interventions at the generator pocket (hazard ratio: 1.92, 95% confidence interval: 1.42-2.6, P < 0.001) and pocket hematoma (hazard ratio: 7.0, 95% confidence interval: 2.7-17.9, P < 0.0001). CONCLUSIONS: The incidence of infection in ICD patients is greater than previously reported, largely due to late infections. Each new cumulative intervention at the same generator pocket nearly doubles the risk of infection.

Prognosis of patients with syncope seen in the emergency room department: an evaluation of four different risk scores recommended by the European Society of Cardiology guidelines.

AIM: To apply, analyze, and evaluate the four syncope risk scores recommended by the 2009 European guidelines and the different parameters that they use to predict death, syncope recurrence, and hospital readmission in the population seen in the emergency room department (ERD) for syncope. METHODS AND RESULTS: A total of 323 patients aged older than 14 years [mean age 59 (32-75) years] and seen in ERD for syncope over a 2-month period were included in the study; 50.7% were women. Patients were evaluated using the four risk scores and were followed up for at least 2 years. In all, 275 patients (85.2%) were discharged directly from ERD after evaluation. During 28±5 months of follow-up, 8% died, 18.3% presented a further syncopal episode, and 18.6% were readmitted to hospital. Only two of the four risk scores were useful in risk discrimination, but no statistically significant differences were detected between predicted risk and observed risk. Multivariate analysis indicated relationships between age and death, a history of cardiovascular disease and syncope recurrence, and between presyncopal palpitations and hospital readmission. CONCLUSION: Although a large number of events occur after syncope, the risk scores recommended by guidelines overestimate risk, but there were no statistically significant differences between observed and predicted risk.

Comparative Evaluation of Four Risk Scores for Predicting Mortality in Patients With Implantable Cardioverter-defibrillator for Primary Prevention.

INTRODUCTION AND OBJECTIVES: Several clinical risk scores have been developed to identify patients at high risk of all-cause mortality despite implantation of an implantable cardioverter-defibrillator. We aimed to examine and compare the predictive capacity of 4 simple scoring systems (MADIT-II, FADES, PACE and SHOCKED) for predicting mortality after defibrillator implantation for primary prevention of sudden cardiac death in a Mediterranean country. METHODS: A multicenter retrospective study was performed in 15 Spanish hospitals. Consecutive patients referred for defibrillator implantation between January 2010 and December 2011 were included. RESULTS: A total of 916 patients with ischemic and nonischemic heart disease were included (mean age, 62 ± 11 years, 81.4% male). Over 33.4 ± 12.9 months, 113 (12.3%) patients died (cardiovascular origin in 86 [9.4%] patients). At 12, 24, 36, and 48 months, mortality rates were 4.5%, 7.6%, 10.8%, and 12.3% respectively. All the risk scores showed a stepwise increase in the risk of death throughout the scoring system of each of the scores and all 4 scores identified patients at greater risk of mortality. The scores were significantly associated with all-cause mortality throughout the follow-up period. PACE displayed the lowest c-index value regardless of whether the population had heart disease of ischemic (c-statistic = 0.61) or nonischemic origin (c-statistic = 0.61), whereas MADIT-II (c-statistic = 0.67 and 0.65 in ischemic and nonischemic cardiomyopathy, respectively), SHOCKED (c-statistic = 0.68 and 0.66, respectively), and FADES (c-statistic = 0.66 and 0.60) provided similar c-statistic values (P ≥ .09). CONCLUSIONS: In this nontrial-based cohort of Mediterranean patients, the 4 evaluated risk scores showed a significant stepwise increase in the risk of death. Among the currently available risk scores, MADIT-II, FADES, and SHOCKED provide slightly better performance than PACE.

Prevención primaria con cardiodesfibrilador implantable y terapia de resincronización cardíaca en pacientes ancianos: resultados de un estudio multicéntrico español

Propósito: a la fecha sigue sin haber pruebas en cuanto a los resultados del uso de dispositivos para arritmias ventriculares en pacientes añosos, y menos aun para indicaciones de prevención primaria. La finalidad del estudio fue describir la evolución en términos de la eficacia y seguridad de la terapia con cardiodesfibriladores implantables (CDI) en una gran cohorte de pacientes añosos. Métodos y resultados: estudio multicéntrico retrospectivo realizado en 15 hospitales españoles. Se incluyeron pacientes consecutivos referidos para implante de CDI antes de 2011. Se consideró que 162 de los 1.174 pacientes (13,8%) con 75 años o más eran “añosos”. Comparado con aquellos pacientes <75 años, este subgrupo presentaba más comorbilidades como hipertensión, enfermedad pulmonar obstructiva crónica y falla renal, y más internaciones previas debido a insuficiencia cardíaca (IC). A lo largo de una media de seguimiento de 104,4 ± 3,3 meses, fallecieron 162 pacientes (14%), 120 de los más jóvenes (12,4%) y 42 (24,4%) de los añosos. El análisis de Kaplan-Meier mostró un aumento de la probabilidad de morir con el aumento de la edad (17, 24, 28, y 69% a los 12, 24, 48, y 60 meses de seguimiento en el grupo de pacientes añosos). No hubo diferencias entre la tasa de intervenciones con CDI apropiadas o inapropiadas. Conclusión: en el mundo real, los pacientes añosos constituyen ~15% de los implantes de CDI para prevención primaria de la muerte súbita cardíaca (MSC). Si bien la tasa de terapias apropiadas es similar en los diferentes grupos, el beneficio de CDI se ve atenuado por un mayor aumento del riesgo de mortalidad entre los pacientes que son mayores de 75 años al momento del implante.

Impact of Contact Force Monitoring in Acute Pulmonary Vein Isolation Using an Anatomic Approach. A Randomized Study.

BACKGROUND: The impact of contact force (CF) monitoring in pulmonary vein (PV) isolation after a circumferential anatomic ablation (CAA) is unknown. We analyze the usefulness of CF monitoring in acute PV isolation and procedure parameters using a CAA. METHODS: Fifty patients with paroxysmal atrial fibrillation were randomized into CF-on (CF >10 grams; n = 25) or CF-off (CF blinded; n = 25) groups. We performed a first round of CAA with a ThermoCool(®) SmartTouch(®) catheter blinded to the LASSO(®) catheter (Biosense Webster, Diamond Bar, CA, USA), with radiofrequency (RF) lesions tagged with the VisiTag(™) Module. After the CAA, each PV was reviewed with the LASSO(®) catheter recording the segments with gaps. RESULTS: All the PVs were isolated with a CAA in 20 patients of the CF-on versus eight of the CF-off (P = 0.001). Of the 45 segments with gaps in the left PVs, 38 were from the CF-off (P = 0.0001). Of the eight segments with gaps in the right PVs, seven were from the CF-off (P = 0.06). The CF in the left PVs was higher in the CF-on (16.3 ± 3.2 grams vs 10.5 ± 4.3 grams; P = 0.0001) and similar in the right PVs (17.6 ± 3.6 grams vs 15.2 ± 5.3 grams; P = 0.08). All of the gaps were closed with additional RF LASSO(®) -guided touch-up. Procedure and fluoroscopy times were shorter in the CF-on (139 ± 24 minutes vs 157 ± 32 minutes and 20 ± 6 minutes vs 24 ± 7 minutes; both P = 0.039). At 12 months the patients free of AF recurrence was 84% CF-on versus 75% CF-off (log-rank P = 0.4) [corrected]. CONCLUSIONS: In paroxysmal atrial fibrillation, a CAA guided by CF reduces PV gaps and shortens the procedure parameters at the expense of the left PVs.

Primary prevention implantable cardioverter-defibrillator and cardiac resynchronization therapy-defibrillator in elderly patients: results of a Spanish multicentre study.

AIMS: Currently, there continues to be a lack of evidence regarding outcomes associated with device-based therapy for ventricular arrhythmias in elderly patients, even more in primary-prevention indications. We aimed to describe the follow-up in terms of efficacy and safety of implantable cardioverter-defibrillator (ICD) therapy in a large cohort of elderly patients. METHODS AND RESULTS: Retrospective multicentre study performed in 15 Spanish hospitals. Consecutive patients referred for ICD implantation before 2011 were included. One hundred and sixty-two of 1174 patients (13.8%) ≥75 years were considered as 'elderly'. When compared with those patients <75, this subgroup presented more co-morbid conditions, including hypertension, chronic obstructive pulmonary disease , and renal failure, and more previous hospitalizations due to heart failure (HF). During a mean follow-up of 104.4 ± 3.3 months, 162 patients (14%) died, 120 in the younger age (12.4%), and 42 (24.4%) in the elderly. Kaplan-Meier analysis showed an increased probability of death with increasing age (17, 24, 28, and 69% at 12, 24, 48, and 60 months of follow-up in the elderly group). There was neither difference regarding the rate of appropriate nor inappropriate ICD intervention. CONCLUSION: In a real-world scenario, elderly patients comprise ∼15% of ICD implantations for primary prevention of sudden cardiac death (SCD). Although the rate of appropriate therapy is similar between groups, the benefit of ICD is attenuated for a major increase in mortality risk among those patients ≥75 years at the moment of device implantation.

A simple surgical technique to prevent atrial reentrant tachycardia in surgery for congenital heart disease†.

OBJECTIVES: To present and test a simple surgical technique that may prevent atrial reentrant tachycardia following surgery for congenital heart disease. This arrhythmia is one of the commonest long-term complications of such a surgery. It may occur many years (even decades) after the operation. It is usually explained as a late consequence of right atriotomy, which is an inherent component of many operations for congenital heart disease. Right atriotomy results in a long scar on the right atrial myocardium. This scar, as any scar, is a barrier to electrical conduction, and macro-reentrant circuits may form around it, causing reentrant tachycardia. However, this mechanism may be counterchecked and neutralized by our proposed method, which prevents reentrant circuits around right atriotomy scars. METHODS: The proposed method is implemented after termination of cardiopulmonary bypass and tying the venous purse-strings. It consists of constructing a full-thickness suture line on the intact right atrial wall from the inferior vena cava (IVC) (a natural conduction barrier) to the atriotomy incision. This suture line is made to cross the venous cannulation sites if these are on the atrial myocardium (rather than being directly on the venae cavae). Thus, the IVC, atriotomy and cannulation sites are connected to each other in series by a full-thickness suture line on the atrial wall. If this suture line becomes a conduction barrier, it would prevent reentrant circuits around right atrial scars. This was tested in 13 adults by electroanatomical mapping. All 13 patients had previously undergone right atriotomy for atrial septal defect closure: 8 of them with the addition of the proposed preventive suture line (treatment group) and 5 without (control group). RESULTS: In all 13 cases, the atriotomy scar was identified as a barrier to electrical conduction with electrophysiological evidence of fibrosis (scarring). In the 8 patients with the proposed suture line, this had also become a scar and a complete conduction barrier. In the 5 patients without this suture line, there was free electrical conduction between the IVC and atriotomy scar. CONCLUSIONS: The proposed suture line becomes a scar and conduction barrier. Therefore, it would prevent reentrant circuits around atrial scars and their consequent arrhythmias.

Primary Prevention of Sudden Death in Patients With Valvular Cardiomyopathy.

INTRODUCTION AND OBJECTIVES: Few data exist on the outcomes of valvular cardiomyopathy patients referred for defibrillator implantation for primary prevention. The aim of the present study was to describe the outcomes of this cardiomyopathy subgroup. METHODS: This multicenter retrospective study included consecutive patients referred for defibrillator implantation to 15 Spanish centers in 2010 and 2011, and to 3 centers after 1 January 2008. RESULTS: Of 1174 patients, 73 (6.2%) had valvular cardiomyopathy. These patients had worse functional class, wider QRS, and a history of atrial fibrillation vs patients with ischemic (n=659; 56.1%) or dilated (n=442; 37.6%) cardiomyopathy. During a follow-up of 38.1 ± 21.3 months, 197 patients (16.7%) died, without significant differences among the groups (19.2% in the valvular cardiomyopathy group, 15.8% in the ischemic cardiomyopathy group, and 17.9% in the dilated cardiomyopathy group; P=.2); 136 died of cardiovascular causes (11.6%), without significant differences among the groups (12.3%, 10.5%, and 13.1%, respectively; P=.1). Although there were no differences in the proportion of appropriate defibrillator interventions (13.7%, 17.9%, and 18.8%; P=.4), there was a difference in inappropriate interventions (8.2%, 7.1%, and 12.0%, respectively; P=.03). CONCLUSIONS: All-cause and cardiovascular mortality in patients with valvular cardiomyopathy were similar to those in other patients referred for defibrillator implantation. They also had similar rates of appropriate interventions. These data suggest that defibrillator implantation in this patient group confers a similar benefit to that obtained by patients with ischemic or dilated cardiomyopathy.

[Electrical storm in patients with prophylactic defibrillator implantation]. / Evolución de los pacientes portadores de desfibrilador como prevención primaria tras un episodio de tormenta arrítmica.

INTRODUCTION: Little is known about the prevalence of electrical storm, baseline characteristics and mortality implications of patients with implantable cardioverter defibrillator in primary prevention versus those patients without electrical storm. We sought to assess the prevalence, baseline risk profile and survival significance of electrical storm in patients with implantable defibrillator for primary prevention. METHODS: Retrospective multicenter study performed in 15 Spanish hospitals. Consecutives patients referred for desfibrillator implantation, with or without left ventricular lead (at least those performed in 2010 and 2011), were included. RESULTS: Over all 1,174 patients, 34 (2,9%) presented an electrical storm, mainly due to ventricular tachycardia (82.4%). There were no significant baseline differences between groups, with similar punctuation in the mortality risk scores (SHOCKED, MADIT and FADES). A clear trigger was identified in 47% of the events. During the study period (38±21 months), long-term total mortality (58.8% versus 14.4%, p<0.001) and cardiac mortality (52.9% versus 8.6%, p<0.001) were both increased among electrical storm patients. Rate of inappropriate desfibrillator intervention was also higher (14.7 versus 8.6%, p<0.001). CONCLUSIONS: In the present study of patients with desfibrillator implantation for primary prevention, prevalence of electrical storm was 2.9%. There were no baseline differences in the cardiovascular risk profile versus those without electrical storm. However, all cause mortality and cardiovascular mortality was increased in these patients versus control desfibrillator patients without electrical storm, as was the rate of inappropriate desfibrillator intervention.

Analyses of inappropriate shocks in a Spanish ICD primary prevention population: Predictors and prognoses.

BACKGROUND: ICDs have been demonstrated to be highly effective in the primary prevention of sudden death, but inappropriate shocks (IS) occur frequently and represent one of the most important adverse effects of ICDs. The aim of this study was to analyze IS and identify the clinical predictors and prognostic implications of ISs in a real-world primary prevention ICD population. METHODS: This multicenter retrospective study was performed in 13 centers with experience in the field of ICD implantation (at least 30 per year) and ICD follow-up in Spain. All consecutive patients who underwent ICD implantation for primary prevention between January 2008 and May 2014 were included. RESULTS: One-thousand-sixteen patients were included, and 4 (0.39%) were lost to follow-up. Two-hundred-seventeen (21.4%) patients suffered from shock; 69 (6.8%) of these patients experienced IS, and 154 (15.4%) experienced appropriate shocks (AS). Age (<65 years, hazard ratio (HR) 2.588 [95% CI 1.282-5.225]; p=0.008), history of atrial fibrillation (HR 2.252 [95% CI 1.230-4.115]; p=0.009), non-ischemic myocardiopathy (HR 2.258 [95% CI 1.090-4.479]; p=0.028), and cardiac resynchronization therapy (HR 0.385 [95% CI 0.200-0.740]; p=0.004) were identified as IS predictors in a multivariate analysis. IS was not associated with rehospitalization due to heart failure, myocardial infarction, cardiovascular mortality or all-cause mortality. CONCLUSIONS: This analysis of our national registry identified the independent IS predictors of age, atrial fibrillation history and cardiac resynchronization therapy and suggests that ISs are not linked to poorer clinical endpoints.