Malfunction of cardiac devices after radiotherapy without direct exposure to ionizing radiation: mechanisms and experimental data.

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.

Genetic Risk of Arrhythmic Phenotypes in Patients With Dilated Cardiomyopathy.

BACKGROUND: Genotype-phenotype correlations in dilated cardiomyopathy (DCM) and, in particular, the effects of gene variants on clinical outcomes remain poorly understood. OBJECTIVES: The purpose of this study was to investigate the prognostic role of genetic variant carrier status in a large cohort of DCM patients. METHODS: A total of 487 DCM patients were analyzed by next-generation sequencing and categorized the disease genes into functional gene groups. The following composite outcome measures were assessed: 1) all-cause mortality; 2) heart failure-related death, heart transplantation, or destination left ventricular assist device implantation (DHF/HTx/VAD); and 3) sudden cardiac death/sustained ventricular tachycardia/ventricular fibrillation (SCD/VT/VF). RESULTS: A total of 183 pathogenic/likely pathogenic variants were found in 178 patients (37%): 54 (11%) Titin; 19 (4%) Lamin A/C (LMNA); 24 (5%) structural cytoskeleton-Z disk genes; 16 (3.5%) desmosomal genes; 46 (9.5%) sarcomeric genes; 8 (1.6%) ion channel genes; and 11 (2.5%) other genes. All-cause mortality was no different between variant carriers and noncarriers (p = 0.99). A trend toward worse SCD/VT/VF (p = 0.062) and DHF/HTx/VAD (p = 0.061) was found in carriers. Carriers of desmosomal and LMNA variants experienced the highest rate of SCD/VT/VF, which was independent of the left ventricular ejection fraction. CONCLUSIONS: Desmosomal and LMNA gene variants identify the subset of DCM patients who are at greatest risk for SCD and life-threatening ventricular arrhythmias, regardless of the left ventricular ejection fraction.

Radiotherapy and risk of implantable cardioverter-defibrillator malfunctions: experimental data from direct exposure at increasing doses.

AIM: During radiotherapy, in patients with implantable cardioverter-defibrillators (ICDs) malfunctions are considered more likely if doses more than 2 Gy reach the ICD site; however, most malfunctions occur with high-energy (>10 MV) 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 10 Gy 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 10 Gy, 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.

[Make a point on left ventricular noncompaction]. / Facciamo il punto: miocardio non compatto.

Hypertrabeculation is a feature of the left ventricle that, by itself, does not coincide with left ventricular non compaction (LVNC), which represents a specific cardiomyopathy. Nowadays, in the absence of gold standard diagnostic criteria, the clinician must integrate imaging aspects together with medical history. The family inheritance for LVNC, presence of neuromuscular disorders, symptoms or signs of heart failure, thromboembolic events, unexplained syncope, pathological findings at rest ECG, Holter ECG, stress test, systolic/diastolic dysfunction at rest echocardiogram, late gadolinium enhancement at cardiac magnetic resonance, and identification of specific mutations are all considered features useful for the diagnosis. Many aspects are not fully understood: multicenter studies, registers and observational studies are needed for a better comprehension of the pathology, adequate risk stratification and targeted follow-up.

Usefulness of Addition of Magnetic Resonance Imaging to Echocardiographic Imaging to Predict Left Ventricular Reverse Remodeling in Patients With Nonischemic Cardiomyopathy.

Defining short-term prognosis in nonischemic cardiomyopathy (NICM) is challenging in clinical practice. Although left ventricular reverse remodeling (LVRR) is a key prognostic marker in NICM there are few parameters able to predict it. We investigated whether a complete structural and functional cardiac magnetic resonance imaging (cMRI) evaluation was incremental to the classic clinical-echocardiographic approach in predicting LVRR in a large cohort of NICM patients receiving evidence-based treatment. Patients with a recent diagnosis of NICM (<3 months) who underwent complete clinical, echocardiographic and cMRI assessment were consecutively enrolled from 2008 to 2016. LVRR was defined as an increase in ≥10 points or normalization of left ventricular ejection fraction, associated with a ≥10% reduction or normalization of left ventricular end-diastolic diameter at midterm (median time 20 months) echocardiographic follow-up. Among 80 NICM patients included in the study, LVRR was observed in 43 (54%). At multivariate analysis, the clinical-echocardiographic evaluation failed to identify independent predictors of LVRR. However, absence of late gadolinium enhancement (odds ratio [OR] 9.07; confidence interval [CI] 2.7 to 13.1; p value 0.0003), left ventricular mass (OR 1.018; CI 1.001 to 1.036; p value 0.045) and peak circumferential strain (OR 1.213; CI 1.011 to 1.470; p value 0.049) assessed by cMRI were independently associated with LVRR. A model for LVRR prediction based on cMRI and clinical-echocardiographic parameters performed significantly better than the clinical-echocardiographic model alone (area under curve 0.84 vs 0.72; p value 0.023). In conclusion, an integrated imaging approach with the addition of a structural and functional cMRI study to the standard-of-care evaluation improves the prediction of LVRR in a large cohort of patients with recently diagnosed NICM receiving evidence-based treatment.

Predicting device failure after percutaneous repair of functional mitral regurgitation in advanced heart failure: Implications for patient selection.

BACKGROUND: Patients with heart failure (HF) and severe symptomatic functional mitral regurgitation (FMR) may benefit from MitraClip implantation. With increasing numbers of patients being treated the success of procedure becomes a key issue. We sought to investigate the pre-procedural predictors of device failure in patients with advanced HF treated with MitraClip. METHODS: From April 2012 to November 2016, 76 patients with poor functional class (NYHA class III-IV) and severe left ventricular (LV) remodeling underwent MitraClip implantation at University Hospitals of Trieste and Bologna (Italy). Device failure was assessed according to MVARC criteria. Patients were subsequently followed to additionally assess the patient success after 12months. RESULTS: Mean age was 67±12years, the mean Log-EuroSCORE was 23.4±16.5%, and the mean LV end-diastolic volume index and ejection fraction (EF) were 112±33ml/m2 and 30.6±8.9%, respectively. At short-term evaluation, device failure was observed in 22 (29%) patients. Univariate predictors of device failure were LVEF, LV and left atrial volumes and anteroposterior mitral annulus diameter. Annulus dimension (OR 1.153, 95% CI 1.002-1.327, p=0.043) and LV end-diastolic volume (OR 1.024, 95% CI 1.000-1.049, p=0.049) were the only variables independently associated with the risk of device failure at the multivariate model. CONCLUSIONS: Pre-procedural anteroposterior mitral annulus diameter accurately predicted the risk of device failure after MitraClip in the setting of advanced HF. Its assessment might aid the selection of the best candidates to percutaneous correction of FMR.

[Work-up and management of constrictive pericarditis: a critical review]. / Inquadramento e gestione della pericardite costrittiva: revisione critica.

Constrictive pericarditis is a rare pericardial disorder that causes an impairment of cardiac filling and frequently heart failure. The clinical presentation is non-specific and the differential diagnosis includes myocardial diseases, particularly restrictive cardiomyopathy. Echocardiography has a central role in the initial diagnosis. Some peculiar signs, such as abnormal inspiratory shift of the interventricular septum, increased respiratory variations of transmitral, transtricuspid and hepatic vein flow velocities and the normality of early diastolic relaxation velocity (e') at tissue Doppler, increase the likelihood of the disease. These signs are an expression of increased ventricular interdependence and dissociation between intrathoracic and intracardiac pressures typical of pericardial constriction. For further diagnosis, computed tomography and magnetic resonance are used to identify the presence of pericardial thickening. Invasive cardiac catheterization is indicated in dubious cases and in the assessment of the severity of hemodynamic abnormalities, especially in cases with surgical indication. Pericardiectomy is indicated in symptomatic patients meeting the diagnostic criteria of constrictive pericarditis and is able to improve the prognosis.

A Review of the Giant Protein Titin in Clinical Molecular Diagnostics of Cardiomyopathies.

Titin (TTN) is known as the largest sarcomeric protein that resides within the heart muscle. Due to alternative splicing of TTN, the heart expresses two major isoforms (N2B and N2BA) that incorporate four distinct regions termed the Z-line, I-band, A-band, and M-line. Next-generation sequencing allows a large number of genes to be sequenced simultaneously and provides the opportunity to easily analyze giant genes such as TTN. Mutations in the TTN gene can cause cardiomyopathies, in particular dilated cardiomyopathy (DCM). DCM is the most common form of cardiomyopathy, and it is characterized by systolic dysfunction and dilation of the left ventricle. TTN truncating variants have been described as the most common cause of DCM, while the real impact of TTN missense variants in the pathogenesis of DCM is still unclear. In a recent population screening study, rare missense variants potentially pathogenic based on bioinformatic filtering represented only 12.6% of the several hundred rare TTN missense variants found, suggesting that missense variants are very common in TTN and are frequently benign. The aim of this review is to understand the clinical role of TTN mutations in DCM and in other cardiomyopathies. Whereas TTN truncations are common in DCM, there is evidence that TTN truncations are rare in the hypertrophic cardiomyopathy (HCM) phenotype. Furthermore, TTN mutations can also cause arrhythmogenic right ventricular cardiomyopathy (ARVC) with distinct clinical features and outcomes. Finally, the identification of a rare TTN missense variant cosegregating with the restrictive cardiomyopathy (RCM) phenotype suggests that TTN is a novel disease-causing gene in this disease. Clinical diagnostic testing is currently able to analyze over 100 cardiomyopathy genes, including TTN; however, the size and presence of extensive genetic variation in TTN presents clinical challenges in determining significant disease-causing mutations. This review discusses the current knowledge of TTN genetic variations in cardiomyopathies and the impact of the diagnosis of TTN pathogenic mutations in the clinical setting.

Relationship between C3 levels and common carotid intima-media thickness in overweight and obese patients.

OBJECTIVE: The study aim was to compare C3 levels with the common carotid artery intima-media thickness (CCAIMT) in subjects of both genders, with a wide range of BMI, independently of age, gender, and abdominal obesity. METHOD: 140 euthyroid, mainly overweight/obese subjects (age 18-30 years) were examined. BMI, waist circumference, blood pressure, fasting insulin, glucose, lipids, C3 and C-reactive protein serum concentrations, and insulin resistance degree (estimated by homeostasis model assessment for insulin resistance (HOMAIR)) were measured. RESULTS: CCA-IMT was positively (p < 0.001) correlated with BMI, waist circumference, systolic and diastolic blood pressures, HOMAIR, and insulin, CRP, and C3 serum levels. The multiple linear regression analysis showed that only male gender and waist circumference maintained an independent relation with the CCA-IMT. CONCLUSION: This study suggests that central fat accumulation and male gender independently increase the thickness of the arterial wall, whereas inflammation and inflammatory markers do not have an independent effect on this parameter.