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AIMS: Malfunctions of cardiac implantable electronical devices (CIED) have been described after high-energy radiation therapy even in the absence of direct exposure to ionizing radiation, due to diffusion of neutrons (n) causing soft errors in inner circuits. The purpose of the study was to analyse the effect of scattered radiation on different types and models of CIED and the possible sources of malfunctions. METHODS AND RESULTS: Fifty-nine explanted CIED were placed on an anthropomorphous phantom of tissue-equivalent material, and a high-energy photon (15 MV) radiotherapy course (total dose = 70 Gy) for prostate treatment was performed. All devices were interrogated before and after radiation. Radiation dose, the electromagnetic field, and neutron fluence at the CIED site were measured. Thirty-four pacemakers (PM) and 25 implantable cardioverter-defibrillators (ICD) were analysed. No malfunctions were detected before radiation. After radiation a software malfunction was evident in 13 (52%) ICD and 6 (18%) PM; no significant electromagnetic field or photon radiations were detected in the thoracic region. Neutron capture was demonstrated by the presence of the (198)Au((197)Au + n) or (192)Ir((191)Ir + n) isotope activation; it was significantly greater in ICD than in PM and non-significantly greater in damaged devices. A greater effect in St Jude PM (2/2 damaged), Boston (9/11), and St Jude ICD (3/6) and in older ICD models was observed; the year of production was not relevant in PM. CONCLUSION: High-energy radiation can cause different malfunctions on CIED, particularly ICD, even without direct exposure to ionizing radiation due to scattered radiation of neutrons produced by the linear accelerator.
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Desfibriladores Implantables , Marcapaso Artificial , Radioterapia/efectos adversos , Análisis de Falla de Equipo , Humanos , Ensayo de Materiales , Neutrones , Diseño de Prótesis , Falla de Prótesis , Dosificación Radioterapéutica , Dispersión de Radiación , Diseño de SoftwareRESUMEN
BACKGROUND: Patients with nonischemic dilated cardiomyopathy (DCM), severe left ventricular (LV) dysfunction, and complete left bundle branch block benefit from cardiac resynchronization therapy (CRT). However, a large heterogeneity of response to CRT is described. Several predictors of response to CRT have been identified, but the role of the underlying genetic background is still poorly explored. OBJECTIVES: In the present study, the authors sought to define differences in LV remodeling and outcome prediction after CRT when stratifying patients according to the presence or absence of DCM-causing genetic background. METHODS: From our center, 74 patients with DCM subjected to CRT and available genetic testing were retrospectively enrolled. Carriers of causative monogenic variants in validated DCM-causing genes, and/or with documented family history of DCM, were classified as affected by genetically determined disease (GEN+DCM) (n = 25). Alternatively, by idiopathic dilated cardiomyopathy (idDCM) (n = 49). The primary outcome was long-term LV remodeling and prevalence of super response to CRT (evaluated at 24-48 months after CRT); the secondary outcome was heart failure-related death/heart transplant/LV assist device. RESULTS: GEN+DCM and idDCM patients were homogeneous at baseline with the exception of QRS duration, longer in idDCM. The median follow-up was 55 months. Long-term LV reverse remodeling and the prevalence of super response were significantly higher in the idDCM group (27% in idDCM vs 5% in GEN+DCM; P = 0.025). The heart failure-related death/heart transplant/LV assist device outcome occurred more frequently in patients with GEN+DCM (53% vs 24% in idDCM; P = 0.028). CONCLUSIONS: Genotyping contributes to the risk stratification of patients with DCM undergoing CRT implantation in terms of LV remodeling and outcomes.
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Terapia de Resincronización Cardíaca , Cardiomiopatía Dilatada , Remodelación Ventricular , Humanos , Femenino , Masculino , Cardiomiopatía Dilatada/genética , Cardiomiopatía Dilatada/terapia , Cardiomiopatía Dilatada/fisiopatología , Persona de Mediana Edad , Estudios Retrospectivos , Remodelación Ventricular/genética , Remodelación Ventricular/fisiología , Anciano , Resultado del Tratamiento , Insuficiencia Cardíaca/genética , Insuficiencia Cardíaca/terapia , Insuficiencia Cardíaca/fisiopatología , Adulto , Disfunción Ventricular Izquierda/genética , Disfunción Ventricular Izquierda/fisiopatología , Disfunción Ventricular Izquierda/terapia , Bloqueo de Rama/genética , Bloqueo de Rama/terapia , Bloqueo de Rama/fisiopatologíaAsunto(s)
Mutación con Ganancia de Función/genética , Canales Regulados por Nucleótidos Cíclicos Activados por Hiperpolarización/genética , Proteínas Musculares/genética , Canales de Potasio/genética , Taquicardia Sinusal/genética , AMP Cíclico/fisiología , Femenino , Células HEK293 , Humanos , Canales Regulados por Nucleótidos Cíclicos Activados por Hiperpolarización/química , Canales Regulados por Nucleótidos Cíclicos Activados por Hiperpolarización/fisiología , Masculino , Proteínas Mutantes/metabolismo , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/fisiología , Linaje , Recurrencia , Síncope/genéticaRESUMEN
AIMS: In Italy, 12-month survival in the general population between 90 and 94 years old is 26%. In very old patients, the benefit of pacemaker implantation in terms of quality and duration of life is unclear. The aim of our study was to analyse clinical characteristics, outcome and factors associated with survival in patients at least 90 years old at the time of the first pacemaker implant. METHODS: Clinical parameters, device characteristics, survival and predictors of outcome in patients at least 90 years old treated with a pacemaker in our centre in 2019-2020 were evaluated. RESULTS: Among the 554 patients undergoing pacemaker implantation in our centre during the study interval, 69 (12%) were at least 90 years old; a complete/advanced atrioventricular block was present in 65%. A cardiological comorbidity (excluding atrial fibrillation) was present in 22 patients (32%). Oncological, pulmonary and neurological comorbidities were present in 12 (17%), 19 (28%) and 32 (46%), respectively. Renal impairment was present in 25 patients (36%). After pacemaker implantation, a pneumothorax developed in two patients and lead dislodgment in one. During follow-up (median 17 months, interquartile range: 13-24), 32 patients died (46%), with a 12-month mortality probability of 24.6%. At multivariate analysis, the presence of oncological (hazard ratio (HR) 5.31; Pâ<â0.001) and neurological (HR 6.44; Pâ<â0.001) comorbidities was associated with mortality. Truncating the outcome at 6 months, renal impairment (HR 8.01; Pâ=â0.003), anticoagulant therapy (HR 8.14; Pâ=â0.003), oncological comorbidities (HR 14.1; Pâ<â0.001) and left ventricular function (5% increase of left ventricular ejection fraction: HR 0.66; Pâ<â0.001) were significantly associated with outcome. CONCLUSION: At our centre, patients at least 90 years old underwent pacemaker implantation mainly for advanced atrioventricular block. One-year survival was excellent, even better than expected in the general population.
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Fibrilación Atrial , Bloqueo Atrioventricular , Cardiología , Marcapaso Artificial , Humanos , Anciano de 80 o más Años , Bloqueo Atrioventricular/terapia , Italia/epidemiología , Marcapaso Artificial/efectos adversosRESUMEN
BACKGROUND: Multicenter ventricular tachycardia (VT) ablation studies have shown poorer outcomes compared with single-center experiences. This difference could be related to heterogeneous mapping and ablation strategies. OBJECTIVES: This study evaluated a homogenous simplified catheter ablation strategy for different substrates and compared the results with those of a single referral center. METHODS: This was a multicenter prospective VT ablation registry of patients with the following 4 causes of VT: previous myocardial infarction; previous myocarditis; arrhythmogenic right ventricular dysplasia; or idiopathic dilated cardiomyopathy. The procedural protocol included precise mapping and ablation steps with the combined endpoint of late potential (LP) abolition and noninducibility of VT. The long-term primary efficacy endpoint was freedom from VT. RESULTS: A total of 309 patients were enrolled. LPs were present in 70% of patients and were abolished in 83%. At the end of the procedure 74% of LPs were noninducible. The primary combined endpoint of LP abolition and noninducibility was achieved in 64% of patients with LPs at baseline. Freedom from VT at 12 months was observed in 67% of patients. In the overall study group, VT inducibility was the only predictor of freedom from VT (P = 0.013). In patients with LPs, the VT recurrence rate was lower both for patients with complete LP abolition (P = 0.040) and for patients meeting the composite endpoint (P = 0.035). CONCLUSIONS: A standardized VT mapping and ablation technique reproduced the procedural outcomes of a single referral center in a multicenter prospective study. LP abolition and noninducibility were effective in reducing VT recurrences in patients with 4 causes of cardiomyopathy. (Ventricular Tachycardia Ablation Registry; NCT03649022).
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Ablación por Catéter , Taquicardia Ventricular , Humanos , Estudios Prospectivos , Resultado del Tratamiento , Taquicardia Ventricular/epidemiología , Taquicardia Ventricular/cirugía , Taquicardia Ventricular/etiología , Lipopolisacáridos , Ablación por Catéter/efectos adversos , Ablación por Catéter/métodos , Sistema de RegistrosRESUMEN
A 64-year-old man underwent catheter ablation (CA) of atrial fibrillation with intracardiac echocardiography (ICE) assistance. As the probe was advanced toward the right atrium, sudden abdominal pain was felt by the patient with hypotension and tachycardia requiring fluids and vasopressors for hemodynamic stabilization. The inferior vena cava (IVC) was injured by the passing probe and open repair was then performed. To our knowledge, this is the first reported case of symptomatic IVC laceration by the probe used for ICE during CA.
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AIM: During radiotherapy, in patients with implantable cardioverter-defibrillators (ICDs) malfunctions are considered more likely if doses more than 2âGy reach the ICD site; however, most malfunctions occur with high-energy (>10âMV) radiations, and the risk is less defined using 6-MV linear accelerators. The purpose of the study is to experimentally evaluate the occurrence of malfunctions in ICDs radiated with a 6-MV linear accelerator at increasing photon doses. METHODS: Thirty-two ICDs from all manufacturers (31 explanted and one demo) were evaluated; all devices with a sufficient battery charge underwent multiple radiations with a 6-MV photon beam reaching a cumulative dose at ICD site of 0.5, 1, 2, 3, 5 and 10âGy and interrogated after every session. All antitachycardia therapies were left enabled; two ICDs were connected to a rhythm simulator (one simulating a complete atrioventricular block without ventricular activity) and visually monitored by external ECG and the ICD programmer during radiation. RESULTS: Thirteen ICDs were excluded before radiation because of battery depletion; after radiation up to the cumulative dose at the cardiac implantable electronic device site of 10âGy, in the remaining 19 devices, programmation and battery charge remained unchanged and no switch to safety mode was observed; oversensing, pacing inhibition or inappropriate antitachycardia therapy were neither recorded nor visually observed during radiation. CONCLUSION: With a low-energy accelerator, neither malfunctions nor electromagnetic interferences were detected radiating the ICDs at doses usually reaching the ICD pocket during radiotherapy sessions. In this context, magnet application to avoid oversensing and inappropriate therapy seems, therefore, useless.
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Desfibriladores Implantables , Análisis de Falla de Equipo , Radioterapia , Falla de Equipo , Humanos , Dosificación Radioterapéutica , RiesgoRESUMEN
BACKGROUND: Together with the afferent branches of the autonomic nervous system, the sinoatrial node (SAN) forms a functional unit whose function is to fire rhythmic action potentials at a rate optimal for coping with the metabolic needs of the body. Dysfunctional behavior of this complex unit may thus result in SAN rhythm disorders. Among these disorders, there is the inappropriate sinus tachycardia (IST) which occurs when an unjustified fast SAN rate is present. METHODS: We here present a critical review of the role of pacemaker f/HCN channels in cardiac rhythm generation and modulation and their involvement in IST. RESULTS: Recent evidence demonstrates that a familial form of IST is associated with a gain-of-function mutation in the HCN4 pacemaker channel (R524Q) which confers an increased sensitivity to the second messenger cAMP, a key mediator in sympathetic modulation. CONCLUSIONS: This finding is consistent with the general view that hypersympathetic tone is one of the causes of IST and introduces the novel concept of defective funny channel-dependent tachyarrhythmias.
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Potenciales de Acción , Relojes Biológicos , Frecuencia Cardíaca , Canales Regulados por Nucleótidos Cíclicos Activados por Hiperpolarización/metabolismo , Nodo Sinoatrial/fisiopatología , Taquicardia Sinusal/fisiopatología , Animales , AMP Cíclico/metabolismo , Humanos , Activación del Canal Iónico , Modelos CardiovascularesRESUMEN
OBJECTIVES: The purpose of this study was to investigate the role of ivabradine in the treatment of symptomatic inappropriate sinus tachycardia using a double-blind, placebo-controlled, crossover design. BACKGROUND: Due to its I(f) blocking properties, ivabradine can selectively attenuate the high discharge rate from sinus node cells, causing inappropriate sinus tachycardia. METHODS: Twenty-one patients were randomized to receive placebo (n=10) or ivabradine 5 mg twice daily (n=11) for 6 weeks. After a washout period, patients crossed over for an additional 6 weeks. Each patient underwent symptom evaluation and heart rate assessment at the start and finish of each phase. RESULTS: After taking ivabradine, patients reported elimination of >70% of symptoms (relative risk: 0.25; 95% CI: 0.18 to 0.34; p<0.001), with 47% of them experiencing complete elimination. These effects were associated with a significant reduction of heart rate at rest (from 88±11 beats/min to 76±11 beats/min, p=0.011), on standing (from 108±12 beats/min to 92±11 beats/min, p<0.0001), during 24 h (from 88±5 beats/min to 77±9 beats/min, p=0.001), and during effort (from 176±17 beats/min to 158±16 beats/min, p=0.001). Ivabradine administration was also associated with a significant increase in exercise performance. No cardiovascular side effects were observed in any patients while taking ivabradine. CONCLUSIONS: In this cohort, ivabradine significantly improved symptoms associated with inappropriate sinus tachycardia and completely eliminated them in approximately half of the patients. These findings suggest that ivabradine may be an important agent for improving symptoms in patients with inappropriate sinus tachycardia.
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Benzazepinas/administración & dosificación , Electrocardiografía/efectos de los fármacos , Frecuencia Cardíaca/efectos de los fármacos , Nodo Sinoatrial/fisiopatología , Taquicardia Sinusal/tratamiento farmacológico , Administración Oral , Adulto , Estudios Cruzados , Canales Catiónicos Regulados por Nucleótidos Cíclicos , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Esquema de Medicación , Femenino , Estudios de Seguimiento , Humanos , Ivabradina , Masculino , Estudios Prospectivos , Nodo Sinoatrial/efectos de los fármacos , Taquicardia Sinusal/fisiopatología , Resultado del TratamientoRESUMEN
BACKGROUND: QRS-ST changes in the inferior and lateral ECG leads are frequently observed in athletes. Recent studies have suggested a potential arrhythmogenic significance of these findings in the general population. The aim of our study was to investigate whether QRS-ST changes are markers of cardiac arrest (CA) of unexplained cause or sudden death in athletes. METHODS AND RESULTS: In 21 athletes (mean age, 27 years; 5 women) with cardiac arrest or sudden death, the ECG recorded before or immediately after the clinical event was compared with the ECG of 365 healthy athletes eligible for competitive sport activity. We measured the height of the J wave and ST elevation and searched for the presence of QRS slurring in the terminal portion of QRS. QRS slurring in any lead was present in 28.6% of cases and in 7.6% of control athletes (P=0.006). A J wave and/or QRS slurring without ST elevation in the inferior (II, III, and aVF) and lateral leads (V(4) to V(6)) were more frequently recorded in cases than in control athletes (28.6% versus 7.9%, P=0.007). Among those with cardiac arrest, arrhythmia recurrences did not differ between the subgroups with and without J wave or QRS slurring during a median 36-month follow-up of sport discontinuation. CONCLUSIONS: J wave and/or QRS slurring was found more frequently among athletes with cardiac arrest/sudden death than in control athletes. Nevertheless, the presence of this ECG pattern appears not to confer a higher risk for recurrent malignant ventricular arrhythmias.
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Arritmias Cardíacas/complicaciones , Atletas , Muerte Súbita Cardíaca/etiología , Paro Cardíaco/etiología , Sistema de Conducción Cardíaco/fisiopatología , Esfuerzo Físico , Potenciales de Acción , Adolescente , Adulto , Arritmias Cardíacas/diagnóstico , Arritmias Cardíacas/fisiopatología , Estudios de Casos y Controles , Distribución de Chi-Cuadrado , Electrocardiografía , Femenino , Paro Cardíaco/fisiopatología , Humanos , Italia , Masculino , Oportunidad Relativa , Puntaje de Propensión , Recurrencia , Medición de Riesgo , Factores de Riesgo , Factores de Tiempo , Adulto JovenAsunto(s)
Arteria Braquial/fisiología , Carbolinas/uso terapéutico , Disfunción Eréctil/tratamiento farmacológico , Disfunción Eréctil/fisiopatología , Inhibidores de Fosfodiesterasa 5/uso terapéutico , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Flujo Sanguíneo Regional , TadalafiloRESUMEN
Endothelial dysfunction and underperfusion of exercising muscle contribute to exercise intolerance, hyperventilation, and breathlessness in atrial fibrillation (AF). Cardioversion (CV) improves endothelial function and exercise performance. We examined whether CV is equally beneficial in diabetes and hypertension, diseases that cause endothelial dysfunction and are often associated with AF. Cardiopulmonary exercise and pulmonary and endothelial (brachial artery flow-mediated dilation) function were tested before and after CV in patients with AF alone (n = 18, group 1) or AF with hypertension (n = 19, group 2) or diabetes (n = 19, group 3). Compared with group 1, peak exercise workload, O2 consumption (Vo2), O2 pulse, aerobic efficiency (Delta Vo2/Delta WR), and ratio of brachial diameter changes to flow changes (Delta D/Delta F) were reduced in group 2 and, to a greater extent, in group 3; exercise ventilation efficiency (Ve/Vco2 slope) and dead space-to-tidal volume ratio (Vd/Vt) were similar among groups. CV had less effect on peak workload (+7% vs. +18%), peak Vo2 (+12% vs. +17%), O2 pulse (+33% vs. +50%), Delta Vo2/Delta WR (+7% vs. +12%), Ve/Vco2 slope (-6% vs. -12%), Delta D/Delta F (+7% vs. +10%), and breathlessness (Borg scale) in group 2 than in group 1 and was ineffective in group 3. The antioxidant vitamin C, tested in eight additional patients in each cohort, improved flow-mediated dilation in groups 1 and 2 before, but not after, CV and was ineffective in group 3, suggesting that the oxidative injury is least in lone AF, greater in hypertension with AF, and greater still in diabetes with AF. Comorbidities that impair endothelial activity worsen endothelial dysfunction and exercise intolerance in AF. The advantages of CV appear to be inversely related to the extent of the underlying oxidative injury.