Local dose rate effects in implantable cardioverter-defibrillators with flattening filter free and flattened photon radiation.

PURPOSE: In the beam penumbra of stereotactic body radiotherapy volumes, dose rate effects in implantable cardioverter-defibrillators (ICDs) may be the predominant cause for failures in the absence of neutron-generating photon energies. We investigate such dose rate effects in ICDs and provide evidence for safe use of lung tumor stereotactic radioablation with flattening filter free (FFF) and flattened 6 Megavolt (MV) beams in ICD-bearing patients. METHODS: Sixty-two ICDs were subjected to scatter radiation in 1.0, 2.5, and 7.0 cm distance to 100 Gy within a 5â€¯× 5 cm2 radiation field. Radiation was applied with 6 MV FFF beams (constant dose rate of 1400 cGy/min) and flattened (FLAT) 6 MV beams (430 cGy/min). Local dose rates (LDR) at the position of all ICDs were measured. All ICDs were monitored continuously. RESULTS: With 6 MV FFF beams, ICD errors occurred at distances of 1.0 cm (LDR 46.8 cGy/min; maximum ICD dose 3.4 Gy) and 2.5 cm (LDR 15.6 cGy/min; 1.1 Gy). With 6 MV FLAT beams, ICD errors occurred only at 1 cm distance (LDR 16.8 cGy/min; 3.9 Gy). No errors occurred at an LDR below 7 cGy/min, translating to a safe distance of 2.5 cm (1.5 Gy) in flattened and 7 cm (0.4 Gy) in 6 MV FFF beams. CONCLUSION: A LDR in ICDs larger than 7 cGy/min may cause ICD malfunction. At identical LDR, differences between 6 MV FFF and 6 MV FLAT beams do not yield different rates of malfunction. The dominant reason for ICD failures could be the LDR and not the total dose to the ICD. For most stereotactic treatments, it is recommended to generate a planning risk volume around the ICD in which LDR larger than 7 cGy/min are avoided.

Interdisciplinary Clinical Target Volume Generation for Cardiac Radioablation: Multicenter Benchmarking for the RAdiosurgery for VENtricular TAchycardia (RAVENTA) Trial.

PURPOSE: Cardiac radioablation is a novel treatment option for therapy-refractory ventricular tachycardia (VT) ineligible for catheter ablation. Three-dimensional clinical target volume (CTV) definition is a key step, and this complex interdisciplinary procedure includes VT-substrate identification based on electroanatomical mapping (EAM) and its transfer to the planning computed tomography (PCT). Benchmarking of this process is necessary for multicenter clinical studies such as the RAVENTA trial. METHODS AND MATERIALS: For benchmarking of the RAVENTA trial, patient data (epicrisis, electrocardiogram, high-resolution EAM, contrast-enhanced cardiac computed tomography, PCT) of 3 cases were sent to 5 university centers for independent CTV generation, subsequent structure analysis, and consensus finding. VT substrates were first defined on multiple EAM screenshots/videos and manually transferred to the PCT. The generated structure characteristics were then independently analyzed (volume, localization, surface distance and conformity). After subsequent discussion, consensus structures were defined. RESULTS: VT substrate on the EAM showed visible variability in extent and localization for cases 1 and 2 and only minor variability for case 3. CTVs ranged from 6.7 to 22.9 cm3, 5.9 to 79.9 cm3, and 9.4 to 34.3 cm3; surface area varied from 1087 to 3285 mm2, 1077 to 9500 mm2, and 1620 to 4179 mm2, with a Hausdorff-distance of 15.7 to 39.5 mm, 23.1 to 43.5 mm, and 15.9 to 43.9 mm for cases 1 to 3, respectively. The absolute 3-dimensional center-of-mass difference was 5.8 to 28.0 mm, 8.4 to 26 mm, and 3.8 to 35.1 mm for cases 1 to 3, respectively. The entire process resulted in CTV structures with a conformity index of 0.2 to 0.83, 0.02 to 0.85, and 0.02 to 0.88 (ideal 1) with the consensus CTV as reference. CONCLUSIONS: Multicenter efficacy endpoint assessment of cardiac radioablation for therapy-refractory VT requires consistent CTV transfer methods from the EAM to the PCT. VT substrate definition and CTVs were comparable with current clinical practice. Remarkable differences regarding the degree of agreement of the CTV definition on the EAM and the PCT were noted, indicating a loss of agreement during the transfer process between EAM and PCT. Cardiac radioablation should be performed under well-defined protocols and in clinical trials with benchmarking and consensus forming.

Effectivity and applicability of the German DEGRO/DGK-guideline for radiotherapy in CIED-bearing patients.

BACKGROUND AND PURPOSE: No evidence has been presented until now whether recommendations given in recently issued guidelines concerning CIED-bearing patients significantly decrease RT-related complications. MATERIALS AND METHODS: 160 RT-cases were prospectively treated with 3D-CRT, IMRT, SBRT using exclusively 6 MV photons (n = 146) and electrons (n = 14) according to the 2015 issued German DEGRO/DGK-guideline for CIED-bearing patients and compared to 40 RT-cases (3D-CRT, 10-23 MV photons (n = 39) and electrons (n = 1)) of CIED-bearing patients which were treated in concordance to the 1994 issued AAPM-guideline. RESULTS: With AAPM-recommendations, complications occurred in 7/39 (17.95%) photon-RT cases, one patient experienced inadequate defibrillation therapy. For all patients treated with photon energies between 6 and 23 MV, a relative risk for CIED failure if treated with > 6 MV was calculated to be 9.03 (95% CI 5.24-15.55). After implementation of the DEGRO/DGK guideline, no complications were noted in 147 cases treated with photons, even though CIED-doses were as high as 5.37 Gy. In 13 cases treated with electrons, one PM lost patient-related data in a patient receiving antiproliferative RT to mammary glands. CONCLUSIONS: Implementation of the German DEGRO/DGK-guideline effectively prevented radiation-associated CIED failures in patients treated with photons. Limitation of photon energy to 6 MV, suspension of defibrillation therapy in ICDs, surveillance of patients according to risk stratification and avoidance of direct irradiation of CIEDs should become standard of care.

Interaction between CIEDs and modern radiotherapy techniques: Flattening filter free-VMAT, dose-rate effects, scatter radiation, and neutron-generating energies.

BACKGROUND AND PURPOSE: Providing evidence for radiotherapy (RT)-induced effects on cardiac implantable electric devices (CIEDs) with focus on flattening filter free-volumetric modulated arc therapy (FFF-VMAT) at 6 and 10 MV as well as 3D-conformal radiotherapy (3D-CRT) at 18 MV. MATERIALS AND METHODS: 68 CIEDs (64 implantable cardioverter-defibrillators (ICDs) and 4 cardiac pacemakers (PMs)) were located on the left chest position on a slab phantom and irradiated under telemetrical surveillance either directly, or distant to 3D-CRT or FFF-VMAT, dose-rate 2500 cGy/min, and target dose of 150 Gy. Devices were placed within, close by (2.5 cm and 5 cm), and distant (35 cm) to the radiation field. Scatter radiation (SR) and photon neutrons (PN) were recorded. CIEDs were investigated in following groups: 1a) 18 MV 3D-CRT - 4 ICDs/4 PMs out of radiation field, 1b) 18 MV open field - 4 ICDs/4 PMs within radiation field, 2) 6 MV FFF-VMAT, 15 ICDs in 35 cm distance to VMAT, 3) 10 MV-FFF VMAT, 15 ICDs in 35 cm distance to VMAT, 4) 6 MV FFF-VMAT, 15 ICDs in 2.5 cm distance to VMAT, 5) 10 MV FFF-VMAT, 15 ICDs in 2.5 cm distance to VMAT. RESULTS: No incidents occurred at 6 MV FFF. 10 MV FFF-VMAT and 18 MV 3D-CRT resulted in data loss, reset, and erroneous sensing with inhibition of pacing (leading to inadequate defibrillation) in 8/34 ICDs and 2/4 PMs which were not located within radiation. Direct radiation triggered instantaneous defibrillation in 3/4 ICDs. CONCLUSIONS: 6 MV FFF-VMAT is safe even at high dose-rates of 2500 cGy/min, regardless whether CIEDs are located close (2.5 cm) or distant (35 cm) to the radiation beam. CIEDs should never be placed within radiation and energy should always be limited to 6 MV. At 6 MV, VMAT at high dose-rates can be used to treat tumors, which are located close to CIEDs.

Cardioprotective Effects of Dronedarone Mediated by the Influence on the Expression of Urokinase-Type Plasminogen Activator Receptor.

PURPOSE: Dronedarone is a multichannel-blocking antiarrhythmic drug for the treatment of atrial fibrillation. Observational data hypothesized a cardioprotective effect. In an in vitro endothelial cell-platelet model, we evaluated the molecular atheroprotective effects of dronedarone. METHODS: Following a 24-h incubation of human umbilical vein endothelial cells (HUVECs) with dronedarone (concentration 50, 100, and 150 ng/mL), they were then stimulated for 1 h with lipopolysaccharide (LPS) and were subsequently incubated in direct contact with thrombin-activated platelets. After incubation, the expression of CD40L and CD62P on platelets, and the expression of ICAM-1, VCAM-1, urokinase-type plasminogen activator receptor (uPAR), and membrane type 1 matrix metalloproteinase (MT1-MMP) on endothelial cells were measured by flow cytometry. RESULTS: Preincubation with 150 ng/mL of dronedarone reduced the expression of uPAR on endothelial cells after proinflammatory stimulation with LPS and also by direct endothelial contact with activated platelets (p = 0.0038). In contrast, the expression of CD40L and CD62P on platelets after proinflammatory stimulation with thrombin was significantly increased through direct preincubation with 50/100/150 ng/mL of dronedarone. However, dronedarone had no effects on the expression of MT1-MMP and ICAM-1 in HUVECs. CONCLUSION: In this in vitro analysis, dronedarone directly increased platelet activation but showed significant direct effects on endothelial cells and indirect effects on platelets on selected markers of atherosclerosis.

Therapy optimization in patients with heart failure: the role of the wearable cardioverter-defibrillator in a real-world setting.

BACKGROUND: The wearable cardioverter-defibrillator (WCD) has emerged as a valuable tool to temporarily protect patients at risk for sudden cardiac death (SCD). The aim of this study was to determine the value of the WCD for therapy optimization of heart failure patients. METHODS: One hundred five consecutive patients that received WCD between 4/2012 and 9/2016 were included in the study. All patients were followed for clinical outcome and echocardiographic parameters during WCD therapy and had continued follow-up after WCD therapy, irrespective of subsequent implantable cardioverter-defibrillator (ICD) implantation. RESULTS: The most common indication for WCD were newly diagnosed ischemic (ICM) or non-ischemic cardiomyopathy (NICM) with left ventricular ejection fraction (LVEF) ≤35%. Mean WCD wear time was 68.8 ± 50.4 days with a mean daily use of 21.5 ± 3.5 h. Five patients (4.8%) received a total of five appropriate WCD shocks. During WCD wear, patients with ICM and NICM showed significant improvement in LVEF, reducing the proportion of patients with a need for primary preventive ICD implantation to 54.8% (ICM) and 48.8% (NICM). An ICD was finally implanted in 51.4% of the study patients (24 trans-venous ICDs, 30 subcutaneous ICDs). After discontinuation of WCD therapy, all patients were followed for a mean of 18.6 ± 12.3 months. 5.6% of patients with implanted ICDs received appropriate therapies. No patient with subcutaneous ICD needed change to a trans-venous device. None of the patients without an implanted ICD suffered from ventricular tachyarrhythmias and no patient died suddenly. In patients with NICM a significant LVEF improvement was observed during long-term follow-up (from 34.8 ± 11.1% to 41.0 ± 10.2%). CONCLUSIONS: WCD therapy successfully bridged all patients to either LVEF recovery or ICD implantation. Following WCD, ICD implantation could be avoided in almost half of the patients. In selected patients, prolongation of WCD therapy beyond 3 months might further prevent unnecessary ICD implantation. The WCD as an external monitoring system contributed important information to optimize device selection in patients that needed ICD implantation.

Prevalence of malignant arrhythmia and sudden cardiac death in takotsubo syndrome and its management.

Aims: Recent studies have highlighted that takotsubo syndrome (TTS) is associated with a poor clinical outcome. Our study was conducted to determine the short- and long-term prevalence, recurrence rate and impact of life-threatening arrhythmias (LTA) on the clinical outcome of TTS. Methods and results: Our institutional database constituted a collective of 114 patients diagnosed with TTS between 2003 and 2015. The patient groups, divided according to the presence (n = 13, 11.4%) or absence (n = 101, 88.6%) of LTAs, were followed-up over a period of 3 years so as to determine the clinical outcome. Our analyses suggest that patients comprising the LTA group suffered significantly more often from an acute cardiovascular event including cases of a newly diagnosed atrial fibrillation (38.4% vs. 2.9%), cardiogenic shock with use of inotropic agents (53.8% vs. 14.8%) and cardiopulmonary resuscitation (61.5% vs. 1%). The short-term recurrence rate of a LTA episode was 15.3%, while the long-term recurrence rate of any LTA was around 5%. Whereas, in-hospital mortality was significantly higher in TTS associated with LTAs, the overall survival rate over 3 years was similar. A multivariate Cox regression analysis suggested atrial fibrillation, EF ≤ 35%, cardiogenic shock, and glomerular filtration rate <60 mL/min. as independent predictors of adverse outcome. Conclusion: The short- as well as the long-term prevalence and recurrence of LTAs in TTS patients is high. The long-term mortality rates were similar to the TTS patients presenting without any LTAs. LTAs in TTS could be triggered by a concomitant atrial fibrillation.

Early repolarization pattern: a marker of increased risk in patients with catecholaminergic polymorphic ventricular tachycardia.

AIMS: The early repolarization pattern (ERP) has been shown to be associated with arrhythmias in patients with short QT syndrome, Brugada syndrome, and ischaemic heart disease. Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmia syndrome and related to malignant ventricular tachyarrhythmias in a structurally normal heart. The aim of this study was to evaluate the prevalence of ERP and clinical events in patients with CPVT. METHODS AND RESULTS: Digitalized resting 12-lead ECGs of patients were analysed for ERP and for repolarization markers (QT and Tpeak-Tend interval). The ERP was diagnosed as 'notching' or 'slurring' at the terminal portion of QRS with ≥0.1 mV elevation in at least two consecutive inferior (II, III, aVF) and/or lateral leads (V4-V6, I, aVL). Among 51 CPVT patients (mean age 36 ± 15 years, 11 males), the ERP was present in 23 (45%): strictly in the inferior leads in 9 (18%) patients, in the lateral leads in 9 (18%) patients, and in infero-lateral leads in 5 (10%) patients. All patients with ERP were symptomatic at presentation (23 of 23 patients with ERP vs. 19 of 28 patients without ERP, P = 0.003). Syncope was also more frequent in patients with ERP (18 of 23 patients with ERP vs. 11 of 28 patients without ERP, P = 0.005). CONCLUSION: A pathologic ERP is present in an unexpected large proportion (45%) of patients and is associated with an increased frequency of syncope. In patients with unexplained syncope and ERP at baseline, exercise testing should be performed to detect CPVT.

The relationship between changes in functional cardiac parameters following anthracycline therapy and carbonyl reductase 3 and glutathione S transferase Pi polymorphisms.

The aim of this prospective clinical study is to evaluate the relationship between changes in functional cardiac parameters following anthracycline therapy and carbonyl reductase 3 (CBR3p.V244M) and glutathione S transferase Pi (GSTP1p.I105V) polymorphisms. Seventy patients with normal cardiac function and no history of cardiac disease scheduled to undergo anthracycline chemotherapy were included in the study. The patients' cardiac function was evaluated by gated blood pool scintigraphy and echocardiography before and after chemotherapy, as well as 1 year following therapy. Gene polymorphisms were genotyped in 70 patients using TaqMan probes, validated by DNA sequencing. A deteriorating trend was observed in both systolic and diastolic parameters from GG to AA in CBR3p.V244M polymorphism. Patients with G-allele carriers of GSTP1p.I105V polymorphism were common (60%), with significantly decreased PFR compared to patiens with AA genotype. Variants of CBR3 and GSTP1 enzymes may be associated with changes in short-term functional cardiac parameters.

Long term clinical outcomes of brachytherapy, bare-metal stenting, and drug-eluting stenting for de novo and in-stent restenosis lesions: five year follow-up.

BACKGROUND: We aimed to investigate the effects of brachytherapy, drug-eluting stent (DES) and bare metal stent (BMS) applications in the treatment of coronary artery disease, on five-year clinical outcomes and mortality. METHODS: Two hundred and seventeen patients who were treated in our clinics between January 2000 and December 2003 with brachytherapy, DES, or BMS for both de novo and in-stent restenosis lesions were included in this cohort study. Of these 217 patients, 69 received brachytherapy, 80 were given BMS and 68 were given DES. The clinical outcomes of the patients during hospitalization and over a long-term follow-up were evaluated. Cardiovascular events, revascularizations and mortality rates were compared among the three groups over a five-year follow-up. RESULTS: The mean age was 60.1 ± 9.5 years in the brachytherapy group, 55.7 ± 9.2 years in the BMS group, and 58.9 ± 9.8 years in the DES group (p = 0.44). All-cause mortality rates were 20 (29%) brachytherapy patients, 22 (27.5%) BMS patients, and four (5.9%) DES patients (p = 0.01). Cardiovascular event was the cause of death for 14 (20.3%) brachytherapy patients, 16 (20%) BMS patients and four (5.9%) DES patients (p = 0.001). All-cause mortality rates were 20 (29%) brachytherapy patients, 22 (27.5%) BMS patients and four (5.9%) DES patients. All-cause and cardiovascular mortality rates were significantly lower in the DES group compared to both the BMS and the brachytherapy groups (p = 0.01 and p = 0.001, respectively). CONCLUSIONS: DES application for in-stent restenosis and de novo lesions was superior to brachytherapy and BMS application with respect to all-cause and cardiovascular mortalities.

The association between circulating endothelial progenitor cells and coronary collateral formation.

AIM: We investigated the relationship between coronary collateral formation and circulating endothelial progenitor cells (EPC) in patients undergoing coronary angiography. METHODS AND RESULTS: Circulating CD133(+)/34(+) and CD34(+)/KDR(+) EPCs were determined in 68 patients (normal coronary vessels in 24 patients and coronary artery disease (CAD) in 44 patients) (age: 58.7 ± 10.1, 64.7% male). Circulating EPCs were higher among patients with normal coronary vessels compared to patients with CAD for CD133(+)/34(+) (p < 0.05) and CD34(+)/KDR(+) cells (p < 0.05). The number of EPCs were significantly greater in patients with good coronary collateral formation (p < 0.05). EPC count was independent predictor for coronary collateral formation after adjustment for other cardiovascular risk factors and extent of CAD (p = 0.037). CONCLUSION: In patients with severe coronary stenosis, those with increased circulating EPCs had better collateral formation compared to those with lower EPC counts. Our findings implicate that in addition to presence of critical stenosis, intact response of bone marrow is necessary for collateral formation in CAD.

A novel method for the diagnosis of neurocardiogenic syncope: heart rate recovery index.

OBJECTIVES: Neurocardiogenic syncope is a common and challenging problem in clinical practice. Heart rate recovery after the first minute of exercise is mainly controlled by the parasympathetic nervous system. The aim of the present study was to evaluate heart rate recovery as an index of parasympathetic tonus for the diagnosis of neurocardiogenic syncope. METHODS AND RESULTS: Ninety five patients (mean age 36.5 +/- 11.8 years), who had vasovagal syncope episodes documented by tilt table testing and 70 healthy subjects (mean age 32.9 +/- 9.1 years) were included in this study. Maximal exercise stress testing was performed in both groups and heart rate recovery values were calculated. Heart rate recovery was calculated by subtracting recovery heart rate in the first minute after exercise from peak heart rate. Heart rate recovery was significantly higher in the vasovagal syncope group than the control group during the first minute (42.1 vs. 30.9, p < 0.001). When the cutoff point for heart rate recovery was taken as 35, the sensitivity for the diagnosis of vasovagal syncope was 81% and the specificity was 78%. CONCLUSION: Results of our study show that heart rate recovery is greater in the first minute after exercise in vasovagal syncope patients and that it has a supportive role in the diagnosis of neurocardiogenic syncope.

[The early predictors of ventricular remodeling after myocardial infarction: the role of tumor necrosis factor-alpha]. / Akut miyokard infarktüsü sonrasi ventriküler yeniden biçimlenme erken belirleyicileri: Tümör nekrozis faktör-alfa'nin rolü.

OBJECTIVE: Ventricular remodeling (VR) is a pathologic process characterized by progressive ventricular dilatation occurring after acute myocardial infarction (MI) leading to left ventricular systolic dysfunction. The purpose of the study was to evaluate the efficacy of plasma tumor necrosis factor alpha (TNF-alpha) levels to predict the left VR. METHODS: This prospective observational cohort study included 72 consecutive patients with newly diagnosed MI with age ranging between 38-87 years (mean 59 +/- 12 years). Control group was consisted of 30 patients with no additional systemic disease and normal coronary arteriograms. Transthoracic echocardiography was performed to all patients and controls both in the beginning of the study and in the 6th follow-up. A coronary arteriography was also performed to all patients. Patients with an increment in the diastolic volume index more than 20% in the follow-up compared with basal values included in the VR subgroup. The patient subgroup with VR consisted of 19 patients. Statistical analyses were performed using ANOVA and Kruskal Wallis tests for comparison of variables between groups. Logistic regression and ROC analyses were used for evaluation of accuracy of TNF-alpha in prediction of VR. RESULTS: There were no significant differences between groups according to demographic characters. The basal plasma levels of TNF-alpha were higher in the patient subgroup with VR as compared with patients without VR and controls (14.59 +/- 4.28 pg/ml vs 7.30 +/- 4.48 pg/ml, and 1.64 +/- 1.49 pg/ml, p< 0.001). In logistic regression analysis only TNF-alpha predicted the VR (OR-1.356, 95% CI 1.117-1.647). Plasma TNF-alpha levels with a cut-off > or = 10.33 pg/ml were found to have 89.5% sensitivity and 79.3% specificity to predict the development of VR. CONCLUSION: These results demonstrate the increment of plasma TNF-alpha levels in the acute phase of MI and the close relationship between the TNF-alpha levels and VR in the patients with first MI.