Distinct spectral dynamics of implanted cardiac defibrillator signals in spontaneous termination of polymorphic ventricular tachycardia and fibrillation in patients with electrical and structural diseases.

AIMS: To determine the spectral dynamics of early spontaneous polymorphic ventricular tachycardia and ventricular fibrillation (PVT/VF) in humans. METHODS AND RESULTS: Fifty-eight self-terminated and 173 shock-terminated episodes of spontaneously initiated PVT/VF recorded by Medtronic implanted cardiac defibrillators (ICDs) in 87 patients with various cardiac pathologies were analyzed by short fast Fourier transform of shifting segments to determine the dynamics of dominant frequency (DF) and regularity index (RI). The progression in the intensity of DF and RI accumulations further quantified the time course of spectral characteristics of the episodes. Episodes of self-terminated PVT/VF lasted 8.6 s [95% confidence interval (CI): 8.1-9.1] and shock-terminated lasted 13.9 s (13.6-14.3) (P < 0.001). Recordings from patients with primarily electrical pathologies displayed higher DF and RI values than those from patients with primarily structural pathologies (P < 0.05) independently of ventricular function or antiarrhythmic drug therapy. Regardless of the underlying pathology, the average DF and RI intensities were lower in self-terminated than shock-terminated episodes [DF: 3.67 (4.04-4.58) vs. 4.32 (3.46-3.93) Hz, P < 0.001; RI: 0.53 (0.48-0.56) vs. 0.63 (0.60-0.65), P < 0.001]. In a multivariate analysis controlled by the type of pathology and clinical variables, regularity remained an independent predictor of self-termination [hazard ratio: 0.954 (0.928-0.980)]. Receiver operating characteristic (ROC) curve analysis of DF and RI intensities demonstrated increased predictability for self-termination in time with 95% CI above the 0.5 cut-off limit at about t = 8.6 s and t = 6.95 s, respectively. CONCLUSION: Consistent with the notion that fast organized sources maintain PVT/VF in humans, reduction of frequency and regularity correlates with early self-termination. Our findings might help generate ICD methods aiming to reduce inappropriate shock deliveries.

Safety, long-term outcomes and predictors of recurrence after first-line combined endoepicardial ventricular tachycardia substrate ablation in arrhythmogenic cardiomyopathy. Impact of arrhythmic substrate distribution pattern. A prospective multicentre study.

BACKGROUND: First-line endoepicardial ventricular tachycardia (VT) ablation has been proposed for patients with arrhythmogenic cardiomyopathy (AC). This study reports procedural safety, outcomes, and predictors of recurrence. METHODS AND RESULTS: Forty-one consecutive patients [12 with left ventricle (LV) involvement, 7 left-dominant] underwent first-line endoepicardial VT substrate ablation. Standard bipolar and unipolar thresholds were used to define low-voltage areas (LVA). Arrhythmogenic substrate area (ASA) was defined as the area containing electrograms with delayed components. Implantable cardioverter defibrillator interrogations were evaluated for VT recurrence. Epicardial LVA was larger in all cases (102.5 ± 78.6 vs. 19.3 ± 24.4 cm2; P< 0.001). Consistent with an epicardium-to-endocardium arrhythmogenic substrate progression pattern, epicardial ASA (epi-ASA) was negatively correlated with bipolar endocardial LVA (r = -0.368; P= 0.035) and with endocardial bipolar/unipolar-LVA (Bi/Uni-LVA) ratio (r= -0.38; P= 0.037). A Bi/Uni-LVA ratio >0.23 predicted an epi-ASA ≤10 cm2 (100% sensitivity, 84% specificity). Patients showing an epi-ASA < 10 cm2 required less epicardial (8.4 ± 5.8 vs. 25.3 ± 16; P= 0.045) and more endocardial (16.5 ± 8.6 vs. 7.5 ± 8.2; P= 0.047) radiofrequency applications. One patient with epi-ASA < 10 cm2 died of cardiac tamponade after epicardial puncture. Acute success (no VT inducibility after procedure) was achieved in 36 patients (90%). After 32.2 ± 21.8 months, 11 (26.8%) patients had VT recurrences. Left-dominant AC was associated with an increased risk of recurrence (HR = 3.41 [1.1-11.2], P= 0.044; log-rank P= 0.021). CONCLUSION: First-line endoepicardial VT substrate ablation achieves good long-term results in AC. Left-dominant AC is associated with an increased risk of recurrence. The Bi/Uni-LVA ratio identifies patients with limited epicardial arrhythmogenic substrate in whom the indication of epicardial approach should be more cautiously assessed.

Catheter ablation vs. antiarrhythmic drug treatment of persistent atrial fibrillation: a multicentre, randomized, controlled trial (SARA study).

BACKGROUND: Catheter ablation (CA) is a highly effective therapy for the treatment of paroxysmal atrial fibrillation (AF) when compared with antiarrhythmic drug therapy (ADT). No randomized studies have compared the two strategies in persistent AF. The present randomized trial aimed to compare the effectiveness of CA vs. ADT in treating persistent AF. METHODS AND RESULTS: Patients with persistent AF were randomly assigned to CA or ADT (excluding patients with long-standing persistent AF). Primary endpoint at 12-month follow-up was defined as any episode of AF or atrial flutter lasting >24 h that occurred after a 3-month blanking period. Secondary endpoints were any atrial tachyarrhythmia lasting >30 s, hospitalization, and electrical cardioversion. In total, 146 patients were included (aged 55 ± 9 years, 77% male). The ADT group received class Ic (43.8%) or class III drugs (56.3%). In an intention-to-treat analysis, 69 of 98 patients (70.4%) in the CA group and 21 of 48 patients (43.7%) in the ADT group were free of the primary endpoint (P = 0.002), implying an absolute risk difference of 26.6% (95% CI 10.0-43.3) in favour of CA. The proportion of patients free of any recurrence (>30 s) was higher in the CA group than in the ADT group (60.2 vs. 29.2%; P < 0.001) and cardioversion was less frequent (34.7 vs. 50%, respectively; P = 0.018). CONCLUSION: Catheter ablation is superior to medical therapy for the maintenance of sinus rhythm in patients with persistent AF at 12-month follow-up. CLINICAL TRIAL REGISTRATION INFORMATION: NCT00863213 (http://clinicaltrials.gov/ct2/show/NCT00863213).

[Myocardial disease mortality in children and young adults. A population-based observational study]. / Mortalidad por enfermedades del miocardio en niños y jóvenes. Estudio observacional de base poblacional.

INTRODUCTION AND OBJECTIVES: Few studies have investigated death due to myocardial disease in children and young adults. The aim of this study was to analyze the epidemiological, clinical, and pathologic characteristics of death in these cases. PATIENTS AND METHOD: Population-based observational study of all deaths in individuals aged 1-35 years in the Spanish province of Biscay over a period of 12 years. RESULTS: Forty deaths from myocardial disease occurred in 29 males and 11 females (mean age 25.3 years): 30 sudden and 10 non-sudden deaths. The mortality rate was 0.64 per 100,000 persons-year. The relative risk of sudden death was significantly greater than that of non-sudden death, particularly in adolescents and young males. The cause of death was myocarditis in 12 cases (83.3% sudden death), dilated cardiomyopathy in 10 (80% non-sudden death), arrhythmogenic cardiomyopathy in seven, hypertrophic cardiomyopathy in six, and idiopathic concentric left ventricular hypertrophy in five (100% sudden death). Myocardial disease was diagnosed before sudden death in only three cases. Ten subjects had symptoms and electrocardiogram abnormalities but their cardiomyopathy had not been diagnosed. Six individuals had a comorbid condition (morbid obesity in four), six had prodromal symptoms, and 11 had arrhythmic triggering factors (sporting activity in seven). Ventricular fibrillation was frequently observed during cardiopulmonary resuscitation. CONCLUSIONS: Mortality due to myocardial disease in children and young adults is uncommon. Most deaths are sudden. However, some may be preventable. Preventative measures should be aimed at sudden death in adolescents and young males. There was a noticeable association between arrhythmogenic cardiomyopathy and sporting activity.

Papel de las sustancias tóxicas en la muerte súbita cardiaca / The role of toxic substances in sudden cardiac death

El consumo de sustancias tóxicas constituye un factor de riesgo significativo para la muerte súbita cardiaca. Los tóxicos con mayor relevancia son las drogas ilegales (especialmente la cocaína), el alcohol y el tabaco, y en menor medida, las sustancias dopantes. Diversos medicamentos también incrementan el riesgo de muerte súbita cardiaca. En el presente artículo se hace una revisión sobre el mecanismo de acción y la patología inducida por estos tóxicos; se ofrece información epidemiológica, se destaca la trascendencia de una investigación forense protocolizada y se discuten las implicaciones de la patología forense en la prevención. La posibilidad de consumo de drogas de abuso debería ser tenida en cuenta en toda muerte súbita cardiaca de un adolescente, joven o adulto de edad mediana, principalmente en varones. En deportistas sería conveniente descartar el uso de sustancias dopantes; y en pacientes que toman psicofármacos valorar su influencia en el fallecimiento, aún con niveles terapéuticos (AU)

The use of toxic substances is a main risk factor for sudden cardiac death. The most relevant toxic substances are the illegal drugs (especially cocaine), ethanol, tobacco, and doping substances. Additionally, several therapeutic drugs are able to increase the risk for sudden cardiac death. The aim of the present paper is to review the mechanism of action and the main pathological problems induced by toxic substances. Moreover, we provide epidemiological information, underlie the importance of a standardised forensic investigation, and discuss the role of forensic pathology in the prevention of this phenomenon. The possibility of consumption of any drug of abuse should be considered in any case of sudden cardiac death in adolescents, young, or middle-age patients, especially in men. In athletes the use of doping substances should be ruled-out. In patients under psychopharmacological treatment, the putative influence of these drugs should be borne in mind (AU)

Ablación con radiofrecuencia de una taquicardia de aurícula izquierda en un niño de 3 meses sin foramen oval permeable / Radiofrequency ablation of left atrial tachycardia in a three-month-old infant without patent foramen ovale

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Mortalidad por enfermedades del miocardio en niños y jóvenes. Estudio observacional de base poblacional / Myocardial disease mortality in children and young adults. A population-based observational study

Introducción y objetivos. Hay pocos estudios sobre la mortalidad por enfermedades del miocardio en niños y jóvenes. El objetivo de este estudio es analizar sus características epidemiológicas y clinicopatológicas. Pacientes y método. Estudio observacional sobre la población general de todas las muertes en personas de 1-35 años de edad en Bizkaia durante 12 años. Resultados. Hubo 40 fallecimientos por enfermedades del miocardio: 30 muertes súbitas y 10 no súbitas; 29 varones y 11 mujeres (edad media, 25,3 años). La tasa de mortalidad fue de 0,64/100.000 habitantes/año. El riesgo relativo de muerte súbita fue significativamente más alto que el de muerte no súbita, en particular entre adolescentes y varones jóvenes. Las causas de muerte fueron: miocarditis en 12 casos (el 83,3% por muerte súbita), miocardiopatía dilatada en 10 (el 80% por muerte no súbita), miocardiopatía arritmogénica en 7, miocardiopatía hipertrófica en 6 e hipertrofia ventricular izquierda concéntrica idiopática en 5 (el 100% por muerte súbita). Sólo en 3 casos de muerte súbita la enfermedad se diagnosticó en vida. Diez sujetos presentaron en vida síntomas o anomalías electrocardiográficas, pero sin diagnóstico de la enfermedad. Se detectaron condiciones comórbidas en 6 casos (obesidad mórbida en 4), síntomas prodrómicos en 6 y factores desencadenantes de la arritmia letal en 11 (deporte en 7). Durante la reanimación cardiopulmonar se observó con frecuencia fibrilación ventricular. Conclusiones. La mortalidad por enfermedades del miocardio en niños y jóvenes es infrecuente y la mayoría son muertes súbitas. Algunos casos podrían ser potencialmente previsibles. Los principales esfuerzos de prevención deberían orientarse al grupo de varones adolescentes y jóvenes Es destacable la relación entre miocardiopatía arritmogénica y deporte

Introduction and objectives. Few studies have investigated death due to myocardial disease in children and young adults. The aim of this study was to analyze the epidemiological, clinical, and pathologic characteristics of death in these cases. Patients and method. Population-based observational study of all deaths in individuals aged 1-35 years in the Spanish province of Biscay over a period of 12 years. Results. Forty deaths from myocardial disease occurred in 29 males and 11 females (mean age 25.3 years): 30 sudden and 10 non-sudden deaths. The mortality rate was 0.64 per 100,000 persons-year. The relative risk of sudden death was significantly greater than that of non-sudden death, particularly in adolescents and young males. The cause of death was myocarditis in 12 cases (83.3% sudden death), dilated cardiomyopathy in 10 (80% non-sudden death), arrhythmogenic cardiomyopathy in seven, hypertrophic cardiomyopathy in six, and idiopathic concentric left ventricular hypertrophy in five (100% sudden death). Myocardial disease was diagnosed before sudden death in only three cases. Ten subjects had symptoms and electrocardiogram abnormalities but their cardiomyopathy had not been diagnosed. Six individuals had a comorbid condition (morbid obesity in four), six had prodromal symptoms, and 11 had arrhythmic triggering factors (sporting activity in seven). Ventricular fibrillation was frequently observed during cardiopulmonary resuscitation. Conclusions. Mortality due to myocardial disease in children and young adults is uncommon. Most deaths are sudden. However, some may be preventable. Preventative measures should be aimed at sudden death in adolescents and young males. There was a noticeable association between arrhythmogenic cardiomyopathy and sporting activity