Propensity-score matched comparison of renal and neurohormonal effects of catheter ablation for frequent premature ventricular contractions in patients with and without systolic dysfunction.

Background: Catheter ablation (CA) for premature ventricular contractions (PVCs) restores cardiac and renal functions in patients with reduced left ventricular ejection fraction (LVEF); however, its effects on preserved EF remain unelucidated. Methods: The study cohort comprised 246 patients with a PVC burden of >10% on Holter electrocardiography. Using propensity matching, we compared the changes in B-type natriuretic peptide (BNP) levels and estimated glomerular filtration rate (eGFR) in patients who underwent CA or did not. Results: Postoperative BNP levels were decreased significantly in the CA group, regardless of the degree of LVEF, whereas there was no change in those of the non-CA group. Among patients who underwent CA, BNP levels decreased from 44.1 to 33.0 pg/mL in those with LVEF ≥50% (p = .002) and from 141.0 to 87.9 pg/mL in those with LVEF <50% (p < .001). Regarding eGFR, postoperative eGFR was significantly improved in the CA group of patients with LVEF ≥50% (from 71.4 to 74.7 mL/min/1.73 m2, p = .006), whereas it decreased in the non-CA group. A similar trend was observed in the group with a reduced LVEF. Adjusted for propensity score matching, there was a significant decrease in the BNP level and recovery of eGFR after CA in patients with LVEF >50%. Conclusions: This study showed that CA for frequent PVCs decreases BNP levels and increases eGFR even in patients with preserved LVEF.

A novel coronary angiographic index for predicting correlation between fractional flow reserve and resting full-cycle ratio.

OBJECTIVES: The discordant results between fractional flow reserve (FFR) and resting full-cycle ratio (RFR) and the influence of angiographic characteristics on their correlation have not been sufficiently investigated. We aimed to identify angiographic characteristics that can predict FFR and RFR correlations using a novel angiographic scoring system. METHODS: This retrospective analysis included 220 patients with 252 intermediate coronary lesions assessed using FFR and RFR. Each branch distal to the target lesion was scored based on the vessel diameter (0 points: < 1.5 mm, 1 point: 1.5-2.0 mm, and 2 points: > 2.0 mm) measured using quantitative coronary angiography. The angiographic score was calculated by adding these scores. RESULTS: In a propensity score-matched cohort including 84 lesions (42 lesions in each low-and high-angiographic score group), the correlation between FFR and RFR in the high-angiographic score group (>4) was weaker than that in the low-score group (≤4) (Spearman's correlation: r = 0.44 vs. r = 0.80, P  < 0.01). Considering a threshold of functional myocardial ischemia as FFR ≤ 0.80 and RFR ≤ 0.89, the low-angiographic score group showed a significantly lower discordance rate of abnormal FFR/normal RFR than the high-angiographic score group (7.1% vs. 23.8%, P  = 0.03), whereas the discordance rates of normal FFR/abnormal RFR were similar in both groups (7.1% vs. 9.5%, P  = 0.69). CONCLUSION: This retrospective analysis highlights the influence of angiographic characteristics on the correlation between FFR and RFR. Our simple angiographic assessment method may be useful for interpreting physiological evaluations in daily clinical practice.

Higher power achieves greater local impedance drop, shorter ablation time, and more transmural lesion formation in comparison to lower power in local impedance guided radiofrequency ablation of atrial fibrillation.

BACKGROUND: Since the local impedance (LI) of the ablation catheter reflects tissue characteristics, the efficacy of higher power (HP) compared to lower power (LP) in LI-guided ablation may differ from other index-guided ablations. OBJECTIVE: This study aimed to assess the efficacy of HP ablation in LI-guided ablation of atrial fibrillation (AF). METHODS: A prospective observational study was conducted, enrolling patients undergoing de novo ablation for AF. Pulmonary vein isolation was performed using point-by-point ablation with a RHYTHMIA HDxTM Mapping System and an open-irrigated ablation catheter with mini-electrodes (IntellaNav MIFI OI). Ablation was stopped when the LI drop reached 30 ohms, three seconds after the LI plateaued, or when ablation time reached 30 s. To balance the baseline differences, a unique method was used in which the power was changed between HP (45 W to anterior wall/40 W to posterior wall) and LP (35 W/30 W) alternately for each adjacent point. RESULTS: A total of 551 ablations in 10 patients were analyzed (HP, n = 276; LP, n = 275). The maximum LI drop was significantly larger (HP: 28.3 ± 5.4 vs. LP: 24.8 ± 6.3 ohm), and the time to minimum LI was significantly shorter (HP: 15.0 ± 6.3 vs. LP: 19.3 ± 6.6 s) in the HP setting. The unipolar electrogram analysis of three patients revealed that the electrogram indicating transmural lesion formation was observed more frequently in the HP setting. CONCLUSION: In LI-guided ablation, the HP could achieve a larger LI drop and shorter time to minimum LI, which may result in more transmural lesion formation compared to a LP setting.

Improved Algorithm for Estimation of Linear Energy Transfer in Carbon Ion Radiotherapy Plans.

BACKGROUND/AIM: This study aimed to develop an improved algorithm for linear energy transfer (LET) estimation in carbon ion radiotherapy (CIRT) using relative biological effectiveness (RBE) and to establish a clinical pipeline for LET assessment. MATERIALS AND METHODS: New approximation functions for LET versus RBE were developed for the overkill region. LET estimation performance was examined at two facilities (A and B) using archival- and Monte Carlo simulation-derived LET data, respectively, as a reference. A clinical pipeline for LET assessment was developed using Python and treatment planning systems (TPS). RESULTS: In dataset A, LET estimation accuracy in the overkill region was improved by 80.0%. In dataset B, estimation accuracy was 2.3%±0.67% across 5 data points examined. LET distribution and LET-volume histograms were visualized for multiple CIRT plans. CONCLUSION: The new algorithm showed a greater LET estimation performance at multiple facilities using the same TPS. A clinical pipeline for LET assessment was established.

The angle of the tines before the pull and hold test predicts engagement of the tines in Micra leadless pacemaker implantation.

Background: Micra leadless pacemaker is secured to the myocardium by engagement of at least 2/4 tines confirmed with pull and hold test. However, the pull and hold test is sometimes difficult to assess. This study was performed to evaluate whether the angle of the tines before the pull and hold test predicts engagement of the tines in Micra leadless pacemaker implantation. Methods: We retrospectively enrolled 93 consecutive patients (52.7% male, age 82.4 ± 9.4 years), who received Micra implantation from September 2017 to June 2020 at our institution. After deployment and before the pull and hold test, the angle of the visible tines to the body of the pacemaker was measured using the RAO view of the fluoroscopy image. The engagement of the tines was then confirmed with the pull and hold test. Results: A total of 326 tines were analyzed. The angle of the engaged tines was significantly lower than the non-engaged tines (9.2 degrees [4.0-14.0] vs. 16.6 degrees [14.2-18.8], p < .0001). All tines with angles <10 degrees were engaged. In higher angles, engagement could not be predicted. Conclusion: A low angle of the tines before the pull and hold test can predict engagement of the tines in Micra leadless pacemaker implantation. The tines which are already open after deployment may be presumed that they are engaged.

Analysis of the relationship between LET, γH2AX foci volume and cell killing effect of carbon ions using high-resolution imaging technology.

The strong cell killing effect of high linear energy transfer (LET) carbon ions is dependent on lethal DNA damage. Our recent studies suggest that induction of clusters of double-strand breaks (DSBs) in close proximity is one of the potential mechanisms. However, the relationship between LET, the degree of DSB clustering and the cell killing effect of carbon ions remains unclear. Here, we used high-resolution imaging technology to analyze the volume of γH2AX foci induced by monoenergetic carbon ions with a clinically-relevant range of LET (13-100 keV/µm). We obtained data from 3317 γH2AX foci and used a gaussian function to approximate the probability (p) that 1 Gy-carbon ions induce γH2AX foci of a given volume (vth) or greater per nucleus. Cell killing effects were assessed in clonogenic assays. The cell killing effect showed high concordance with p at vth = 0.7 µm3 across various LET values; the difference between the two was 4.7% ± 2.2%. This relationship was also true for clinical carbon ion beams harboring a mixed LET profile throughout a spread-out Bragg peak width (30-120 mm), with the difference at vth = 0.7 µm3 being 1.6% ± 1.2% when a Monte Carlo simulation-derived dose-averaged LET was used to calculate p. These data indicate that the cell killing effect of carbon ions is predictable by the ability of carbon ions to induce γH2AX foci containing clustered DSBs, which is linked to LET, providing the biological basis for LET modulation in the planning of carbon ion radiotherapy.

The Prognostic Value of B-Type Natriuretic Peptide in Patients With Cardiac Sarcoidosis Without Heart Failure: Insights From ILLUMINATE-CS.

Background The prognostic role of BNP (B-type natriuretic peptide) in patients with cardiac sarcoidosis without evident heart failure is unknown. Methods and Results This is a post hoc analysis of ILLUMINATE-CS (Illustration of the Management and Prognosis of Japanese Patients With Cardiac Sarcoidosis), a multicenter, retrospective, and observational study that evaluated the clinical characteristics and prognosis of cardiac sarcoidosis. We analyzed patients with cardiac sarcoidosis without evident heart failure at the time of diagnosis. The association between baseline BNP levels and prognosis was investigated. The primary end point was the combined end point of all-cause death, heart failure hospitalization, and fatal ventricular arrhythmia. In total, 238 patients (61.0±11.1 years, 37% men) were analyzed, and 61 primary end points were observed during a median follow-up period of 3.0 (interquartile range, 1.7-5.8) years. Patients with high BNP (BNP above the median value of BNP) were older and had a lower renal function and left ventricular ejection fraction than those with low BNP values. Kaplan-Meier curve analysis indicated that high BNP levels were significantly associated with a high incidence of primary end points (log-rank P=0.004), and this association was retained even in multivariable Cox regression (hazard ratio, 2.06 [95% CI, 1.19-3.55]; P=0.010). Log-transformed BNP as a continuous variable was associated with the primary end point (hazard ratio, 2.12 [95% CI, 1.31-3.43]; P=0.002). Conclusions High baseline BNP level was an independent predictor of future adverse events in patients with cardiac sarcoidosis without heart failure at the time of diagnosis. Registration URL: https://www.umin.ac.jp/english/; Unique Identifier: UMIN-CTR: UMIN000034974.

Clinical dose assessment for scanned carbon-ion radiotherapy using linear energy transfer measurements and Monte Carlo simulations.

Objective. Dosimetric commissioning of treatment planning systems (TPS) focuses on validating the agreement of the physical dose with experimental data. For carbon-ion radiotherapy, the commissioning of the relative biological effectiveness (RBE) is necessary to predict the clinical outcome based on the radiation quality of the mixed radiation field. In this study, we proposed a approach for RBE commissioning using Monte Carlo (MC) simulations, which was further strengthen by RBE validation based on linear energy transfer (LET) measurements.Approach. First, we tuned the MC simulation based on the results of dosimetric experiments including the beam ranges, beam sizes, and MU calibrations. Furthermore, we compared simulated results to measured depth- and radial-LET distributions of the 430 MeV u-1carbon-ion spot beam with a 1.5 mm2, 36µm thick silicon detector. The measured dose-averaged LET (LETd) and RBE were compared with the simulated results. The RBE was calculated based on the mixed beam model with linear-quadratic parameters depending on the LET. Finally, TPS-calculated clinical dose profiles were validated through the tuned MC-based calculations.Main results. A 10 keVµm-1and 0.15 agreement for LETdand RBE, respectively, were found between simulation and measurement results obtained for a 2σlateral size of 430 MeV u-1carbon-ion spot beam in water. These results suggested that the tuned MC simulation can be used with acceptable precision for the RBE and LET calculations of carbon-ion spot beam within the clinical energy range. For physical and clinical doses, the TPS- and MC-based calculations showed good agreements within 1.0% at the centre of the spread-out Bragg peaks.Significance. The tuned MC simulation can accurately reproduce the actual carbon-ion beams, and it can be used to validate the physical and clinical dose distributions calculated by TPS. Moreover, the MC simulation can be used for dosimetric commissioning, including clinical doses, without LET measurements.

Normal Tissue Complication Probability Model for Acute Radiation Dermatitis in Patients With Head and Neck Cancer Treated With Carbon Ion Radiation Therapy.

PURPOSE: This study aimed to explore the prognostic factors associated with acute radiation dermatitis (ARD). A normal tissue complication probability (NTCP) model for ARD in patients with head and neck cancer treated with carbon ion radiation therapy was developed. MATERIALS AND METHODS: A total of 187 patients were included in the analysis, and the endpoint was ≥grade 2 ARD. The biological and physical dose-surface parameters associated with ARD were used in the logistic regression model. The mean areas under the receiver operating characteristic curve in the internal cross-validation and Akaike's corrected Information Criterion were examined for model evaluation and selection. The multivariate logistic regression NTCP models were established based on factors with weak correlation. RESULTS: Tumor volume, planning target volume to the skin, radiation technique and all dose-surface parameters were significantly associated with ARD (P < .05). Models with high performance for grade 2 to 3 ARD were constructed. The most significant prognostic predictors were S40Gy(relative biological effectiveness,RBE) and S20Gy (absolute surface area receiving RBE-weighted dose of 40 Gy (RBE) or physical dose of 20 Gy). The internal cross-validation-based areas under the receiver operating characteristic curve for models with S40Gy(RBE) and S20Gy were 0.78 and 0.77, respectively. The biological and physical dose-surface parameters had similar performance at various dose levels. However, the performance of the multivariate NTCP models based on 2 factors was not better than that of the univariate models. CONCLUSIONS: NTCP models for ARD may provide a basis for the development of individualized treatment strategies and reduce the incidence of severe ARD in patients with head and neck cancer receiving carbon ion radiation therapy. Furthermore, biological and physical dose-surface parameter-based models are comparable. However, further validation with more evaluation parameters is warranted.

Clinical implication of initial intravenous diuretic dose for acute decompensated heart failure.

Although intravenous diuretics is a cornerstone of acute heart failure treatment (AHF), its optimal initial dose is unclear. This is a post-hoc analysis of the REALITY-AHF, a prospective multicentre observational registry of AHF. The initial intravenous diuretic dose used in each patient was categorised into below, standard, or above the recommended dose groups according to guideline-recommended initial intravenous diuretic dose. The recommended dose was individualised based on the oral diuretic dose taken at admission. We compared the study endpoints, including 60-day mortality, diuretics response within six hours, and length of hospital stay (HS). Of 1093 patients, 429, 558, and 106 were assigned to the Below, Standard, and Above groups, respectively. The diuretics response and HS were significantly greater in the Below group than in the Standard group after adjusting for covariates. Kaplan-Meier analysis indicated a significantly higher incidence of 60-day mortality in the Above group than the Standard group. This difference was retained after adjusting for other prognostic factors. Treatment with a lower than guideline-recommended intravenous diuretic dose was associated with longer HS, whereas above the guideline-recommended dose was associated with a higher 60-day mortality rate. Our results reconfirm that the guideline-recommended initial intravenous diuretic dose is feasible for AHF.

Leadless pacemaker implantation sites confirmed by computed tomography and their parameters and complication rates.

BACKGROUND: Implantations of leadless pacemakers in the septum lower the risk of cardiac perforation. However, the relationship between the implantation site and the success rate, complication rate, and pacemaker parameters are not well-investigated. METHODS: Patients who underwent leadless pacemaker implantation with postprocedural computed tomography (CT) between September 2017 and November 2020 were analyzed. Septum was targeted with fluoroscopic guidance with contrast injection. We divided patients into two groups based on the implantation site confirmed by CT: septal and non-septal, which included the anterior/posterior edge of the septum and free wall. We compared the complication rates and pacemaker parameters between the two groups. RESULTS: A total of 67 patients underwent CT after the procedure; among them, 28 were included in the septal group and 39 were included in the non-septal group. The non-septal group had significantly higher R wave amplitudes (6.5 ± 3.3 vs. 9.7 ± 3.9 mV, p = .001), lower pacing threshold (1.0 ± 0.94 vs. 0.63 ± 0.45 V/0.24 ms, p = .02), and higher pacing impedance (615 ± 114.1 vs. 712.8 ± 181.3 ohms, p = .014) after the procedure compared to the septal group. Cardiac injuries were observed in four patients (one cardiac tamponade, one possible apical hematoma, two asymptomatic pericardial effusion), which were only observed in the non-septal group. CONCLUSIONS: Leadless pacemaker implantation may be technically challenging with substantial number of patients with non-septal implantation when assessed by CT. Septal implantation may have a lower risk of cardiac injury but may lead to inferior pacemaker parameters than non-septal implantation.

Three-dimensional dose-distribution measurement of therapeutic carbon-ion beams using a ZnS scintillator sheet.

The accurate measurement of the 3D dose distribution of carbon-ion beams is essential for safe carbon-ion therapy. Although ionization chambers scanned in a water tank or air are conventionally used for this purpose, these measurement methods are time-consuming. We thus developed a rapid 3D dose-measurement tool that employs a silver-activated zinc sulfide (ZnS) scintillator with lower linear energy transfer (LET) dependence than gadolinium-based (Gd) scintillators; this tool enables the measurement of carbon-ion beams with small corrections. A ZnS scintillator sheet was placed vertical to the beam axis and installed in a shaded box. Scintillation images produced by incident carbon-ions were reflected with a mirror and captured with a charge-coupled device (CCD) camera. A 290 MeV/nucleon mono-energetic beam and spread-out Bragg peak (SOBP) carbon-ion passive beams were delivered at the Gunma University Heavy Ion Medical Center. A water tank was installed above the scintillator with the water level remotely adjusted to the measurement depth. Images were recorded at various water depths and stacked in the depth direction to create 3D scintillation images. Depth and lateral profiles were analyzed from the images. The ZnS-scintillator-measured depth profile agreed with the depth dose measured using an ionization chamber, outperforming the conventional Gd-based scintillator. Measurements were realized with smaller corrections for a carbon-ion beam with a higher LET than a proton. Lateral profiles at the entrance and the Bragg peak depths could be measured with this tool. The proposed method would make it possible to rapidly perform 3D dose-distribution measurements of carbon-ion beams with smaller quenching corrections.

Outcomes of deep sedation for catheter ablation of paroxysmal supraventricular tachycardia, with adaptive servo ventilation.

BACKGROUND: Catheter ablation for paroxysmal supraventricular tachycardia (PSVT) is an established treatment, but the effect of deep sedation on PSVT inducibility remains unclear. AIM: We sought to examine PSVT inducibility and outcomes of catheter ablation under deep sedation using adaptive servo ventilation (ASV). METHODS: We retrospectively evaluated consecutive patients who underwent catheter ablation for PSVT under deep sedation (Propofol + Dexmedetomidine) with use of ASV. Anesthetic depth was controlled with BIS™ monitoring, and phenylephrine was administered to prevent anesthesia-induced hypotension. PSVT induction was attempted in all patients using extrastimuli at baseline, and after isoproterenol (ISP) infusion when necessary. RESULTS: PSVT was successfully induced in 145 of 147 patients, although ISP infusion was required in the majority (89%). The PSVT was atrioventricular nodal reentrant tachycardia (AVNRT) in 77 (53%), atrioventricular reciprocating tachycardia (AVRT) in 51 (35%), and atrial tachycardia (AT) in 17 (12%). A higher ISP dose was required for AT compared to other PSVT (AVNRT: 0.06 (IQR 0.03-0.06) vs AVRT: 0.03 (0.02-0.06) vs AT: 0.06 (0.03-0.12) mg/h, P = .013). More than half (51%) of the patients developed hypotension requiring phenylephrine; these patients were older. Acute success was obtained in 99% (patients with AVNRT had endpoints with single echo on ISP in 46%). Long-term success rate was 136 of 144 (94%) (AVNRT 96%, AVRT 92%, and AT 93%). There were no complications related to deep sedation. CONCLUSIONS: Deep sedation with use of ASV is a feasible anesthesia strategy for catheter ablation of PSVT with good long-term outcome. PSVT remains inducible if ISP is used.

Clinical impact of serial change in brain natriuretic peptide before and after catheter ablation in patients with atrial fibrillation and heart failure.

BACKGROUND: Brain natriuretic peptide (BNP) predicts the prognosis in patients with atrial fibrillation (AF) and heart failure (HF); however, the level of BNP can change immediately after restoration of sinus rhythm. We aimed to investigate the clinical impact of serial change in BNP level before and after catheter ablation for AF, on the prognosis. METHODS: In this retrospective single center study, 162 consecutive patients (67±9 years, 66.7% male) with AF and concomitant HF who underwent catheter ablation were examined. We analyzed the cardiac rhythm and % change in BNP pre- and post-ablation. RESULTS: BNP increased by 32.7% (-4.5% to 51.3%) in patients with sinus rhythm at baseline (sinus rhythm group: N=50) and decreased by 47.6% (20.9 to 61.6%) in patients with AF rhythm at baseline. Patients with AF rhythm at baseline were categorized into two groups according to the median value of reduction in % BNP; patients with good % BNP reduction (good BNP-R group; N=56), and with poor % BNP reduction (poor BNP-R group; N=56). Although the rate of recurrence of AF after ablation was comparable between the good and poor BNP-R groups, poor BNP-R was an independent predictor of subsequent composite events including HF hospitalization, ischemic stroke, and all cause of death after ablation, even after adjusting for other confounders (hazard ratio: 6.85, 95% confidence interval: 2.16 to 21.7, p-value=0.001). In the longitudinal analysis of echocardiographic parameters, shortening of the left ventricular end-diastolic diameter with preserved ejection fraction was evident except in the poor BNP-R group. CONCLUSION: In patients with AF and HF, poor % BNP reduction was an independent predictor of adverse outcome, although the rate of recurrence of AF was comparable. Serial BNP measurement might help in better identification of high-risk patients in whom sinus rhythm is restored with catheter ablation.

Risk factors for venous bleeding complication at the femoral puncture site after catheter ablation of atrial fibrillation.

BACKGROUND: Venous bleeding complication is often observed after catheter ablation of atrial fibrillation (AF), but the risk factors remain unclear. METHODS: We retrospectively evaluated 570 consecutive patients who underwent catheter ablation of AF from April 2012 to March 2017. After the procedure, the sheaths were removed, and hemostasis was obtained by manual compression followed by application of rolled gauze with elastic bandage and continuous pressure to the puncture site. We evaluated the risk factors for venous bleeding complications defined as hemorrhage from the puncture site that needed recompression after removal of the elastic bandage and rolled gauze. RESULTS: After excluding 11 patients because of missing data, 559 patients (395 [70.7%] men, mean age: 65.6 ± 8.7 years) were included for analysis. Venous bleeding complication was observed in 213 patients (38.1%). In the multivariate logistic regression analysis, low body mass index (BMI; odds ratio [OR] 0.95, 95% CI 0.90-1.00, P = .04), short compression time (OR 0.77, 95% CI 0.68-0.88, P < .001), and antiplatelet therapy (OR 1.86, 95% CI 1.09-3.16, P = .02) were independent risk factors for venous bleeding complication. CONCLUSIONS: Low BMI, short compression time, and antiplatelet therapy were independent risk factors for venous bleeding complication after catheter ablation of AF. Longer compression time may be needed for patients with low BMI and/or those receiving antiplatelet therapy.

Predictive value of noninducibility after catheter ablation for paroxysmal and persistent atrial fibrillation.

BACKGROUND: It is unclear whether pacing maneuver at the end of catheter ablation for atrial fibrillation (AF) predicts recurrence of atrial tachyarrhythmia postintervention. OBJECTIVE: To investigate whether the predictive value of incremental pacing maneuver after catheter ablation for AF depends on the pacing cycle length and type of AF. METHODS: This study included 298 consecutive patients who underwent initial catheter ablation for nonvalvular AF (61% paroxysmal AF [PAF], 39% persistent AF [PeAF]). Rapid atrial pacing was performed at the end of the procedure. We analyzed minimum coupling interval (CI) of pacing, arrhythmia-inducibility, and atrial tachyarrhythmia recurrence in patients with PAF and PeAF. RESULTS: Patients were divided into the following three groups according to their response to pacing maneuver: AF-inducible (inducible group; n = 86), noninducible at CI ≥200 ms (non-CI ≥200 group; n = 100), and noninducible at CI <200 ms (non-CI <200 group; n = 112). Kaplan-Meier analysis showed that response to pacing maneuver was significantly associated with recurrence of atrial tachyarrhythmias (P = .028). Cox-regression analysis showed that non-CI <200 was an independent predictor when the inducible group was used as a reference (hazard ratio 0.60, 95% confidence interval 0.40-0.96, P = .031). However, when PAF and PeAF were analyzed separately, non-CI <200 was an independent predictor only in PeAF. CONCLUSION: Noninducibility with shorter CI predicted atrial tachyarrhythmia recurrence only for PeAF. Pacing CI and type of AF could influence the predictive value of atrial tachyarrhythmia recurrence.

Impact of brain natriuretic peptide reduction on the worsening renal function in patients with acute heart failure.

AIMS: The prognostic impact of worsening renal function (WRF) in patients with acute heart failure (AHF) remains under debate. Successful decongestion might offset the negative impact of WRF, but little is known about indicators of successful decongestion in the very acute phase of AHF. We hypothesized that decongestion as evaluated by the percent reduction in brain natriuretic peptide (BNP) could identify relevant prognostic implications of WRF in the very acute phase of AHF. METHODS AND RESULTS: Data on 907 consecutive hospitalized patients with AHF in the REALITY-AHF study (age: 78±12 years; 55.1% male) were analyzed. Creatinine and BNP were measured at baseline and 48 hours from admission. WRF was defined as an increase in creatinine >0.3 mg at 48 hours from admission. The primary endpoint was 1-year all-cause mortality. Patients were divided into four groups according to the presence/absence of WRF and a BNP reduction higher/lower than the median: no-WRF/higher-BNP-reduction (n = 390), no-WRF/lower-BNP-reduction (n = 397), WRF/higher-BNP-reduction (n = 63), and WRF/lower-BNP-reduction groups (n = 57). Kaplan-Meier curve analysis showed that the WRF/lower-BNP-reduction group had a worse prognosis than the other groups. In a Cox regression analysis, only the WRF/lower-BNP-reduction group had higher mortality compared to the no-WRF/higher-BNP-reduction group (hazard ratio: 3.34, p<0.001). CONCLUSION: In the very acute phase of AHF, BNP reduction may aid in identifying relevant prognostic significance of WRF.

Simultaneous determination of the dose and linear energy transfer (LET) of carbon-ion beams using radiochromic films.

Radiochromic films are useful as dosimeters in high-precision radiotherapy owing to their high spatial resolution. However, when a particle beam is measured using a radiochromic film, the dose cannot be estimated accurately because the film darkness varies with variations in linear energy transfer (LET). This paper proposes a novel method for estimating the LET and the dose based on the film darkness. In this method, after a high-LET particle beam, such as a carbon-ion beam, was incident on the film, the film was digitized and its net optical density was determined. Further, the non-linearity of the film response curve between the dose and the darkness, depending on LET, was used. Then, calibration curves were created using 290 MeV u-1 mono energetic carbon-ion beams. We used LETs of 20, 50, 100, and 150 keV µm-1 and a physical dose of 2-14 Gy. The calibration curves were approximated for each LET using a quadratic function. The correlations between the coefficients of the quadratic function and the LET were also obtained. To verify the proposed method, the films were irradiated under 12 different conditions corresponding to various depths and doses. Four depths of -2, -5, -10, and -20 mm with respect to the Bragg peak, and three different preset values were used for the film measurements. The films were analyzed in four groups, where each group comprised films irradiated at the same depth. The LETs obtained from the film analysis, ordered from the upstream of the beam, were 20, 41, 56, and 97 keV µm-1, and the doses for the lowest preset value were 3.95, 4.07, 4.03, and 3.99 Gy for the four groups. The LETs obtained from the film analysis increased toward the Bragg peak, and the doses measured in the ionization chamber were almost equal to 4 Gy.