BackgroundHis bundle pacing is a new method for delivering cardiac resynchronization therapy (CRT).ObjectivesThe authors performed a head-to-head, high-precision, acute crossover comparison between His bundle pacing and conventional biventricular CRT, measuring effects on ventricular activation and acute hemodynamic function.MethodsPatients with heart failure and left bundle branch block referred for conventional biventricular CRT were recruited. Using noninvasive epicardial electrocardiographic imaging, the authors identified patients in whom His bundle pacing shortened left ventricular activation time. In these patients, the authors compared the hemodynamic effects of His bundle pacing against biventricular pacing using a high-multiple repeated alternation protocol to minimize the effect of noise, as well as comparing effects on ventricular activation.ResultsIn 18 of 23 patients, left ventricular activation time was significantly shortened by His bundle pacing. Seventeen patients had a complete electromechanical dataset. In them, His bundle pacing was more effective at delivering ventricular resynchronization than biventricular pacing: greater reduction in QRS duration (−18.6 ms; 95% confidence interval [CI]: −31.6 to −5.7 ms; p = 0.007), left ventricular activation time (−26 ms; 95% CI: −41 to −21 ms; p = 0.002), and left ventricular dyssynchrony index (−11.2 ms; 95% CI: −16.8 to −5.6 ms; p < 0.001). His bundle pacing also produced a greater acute hemodynamic response (4.6 mm Hg; 95% CI: 0.2 to 9.1 mm Hg; p = 0.04). The incremental activation time reduction with His bundle pacing over biventricular pacing correlated with the incremental hemodynamic improvement with His bundle pacing over biventricular pacing (R = 0.70; p = 0.04).ConclusionsHis resynchronization delivers better ventricular resynchronization, and greater improvement in hemodynamic parameters, than biventricular pacing.

Objective: Hepatic steatosis may occur in association with insulin resistance and obesity, two features commonly seen in Cushing's syndrome (CS). The aim of this report is to assess the prevalence of hepatic steatosis in patients with active CS using computed tomography (CT) and to identify any associations between hepatic steatosis, endocrine and biochemical variables and body fat distribution. Patients and measurements: We identified 50 patients with active CS in whom appropriate CT was available to allow measurement of liver and spleen attenuation. In 26 patients, abdominal fat measurements were also available. Serum markers of CS and liver function tests were recorded. Results: Ten of 50 patients had a liver-to-spleen CT attenuation ratio (L/S) of less than 1, indicating hepatic steatosis. There was a significant negative correlation between both liver attenuation and L/S ratio with total abdominal fat area, visceral fat area, the percentage of visceral fat and the visceral to subcutaneous fat ratio; the strongest negative correlation was found between visceral fat area and L/S ratio (r ¼ 2 0.638, P , 0.001, n ¼ 26). L/S ratio positively correlated with alkaline phosphatase levels (r ¼ þ0.423, P ¼ 0.044, n ¼ 23) but with no other serum marker of CS activity or liver enzyme. Conclusions: We have demonstrated hepatic steatosis on CT in 20% of patients with active CS. The presence of hepatic steatosis was significantly correlated with total abdominal fat area and visceral fat area.

Objective: Our aims were to describe the abdominal fat distribution in male patients with Cushing's syndrome (CS) on computerised tomography (CT), to compare our findings with non-cushingoid patients, to validate previous reports of increased visceral fat in female patients with CS and to identify any correlations between fat distribution and biochemical findings. Design: Retrospective and observational. Patients: Appropriate CT scans were identified in 31 patients (seven male) with active CS. Measurements: Total, visceral and subcutaneous fat areas were obtained. The percentage of visceral fat and the visceral to subcutaneous fat ratio (V:S ratio) were calculated. Biochemical data were recorded. Control data of fat distribution were obtained from the literature. Results: There was a significant increase in the V:S ratio in male patients with CS when compared with non-cushingoid controls (1.175^0.59 vs 0.77^0.39, 95% confidence interval (CI) 0.0817 -0.728). There was a significant increase in the V:S ratio in female patients with CS (0.845^0.53 vs 0.38^0.19, 95% CI 0.269 -0.661). There was no difference in the V:S ratio between male and female patients with CS (1.175^0.59 vs 0.845^0.53, 95% CI 20.144 -0.804). No significant correlations between fat distribution and glucose levels, circulating cortisol, ACTH or lipids were found. Conclusions: Our data demonstrate an increase in visceral fat distribution in both male and female patients with CS, with the abolition of the normal male to female difference in visceral fat. Increased visceral fat may increase the risk of the metabolic syndrome in this group of patients.

BackgroundLocalizing the origin of outflow tract ventricular tachycardias (OTVT) is hindered by lack of accuracy of electrocardiographic (ECG) algorithms and infrequent spontaneous premature ventricular complexes (PVCs) during electrophysiological studies.ObjectivesTo prospectively assess the performance of noninvasive electrocardiographic mapping (ECM) in the pre-/periprocedural localization of OTVT origin to guide ablation and to compare the accuracy of ECM with that of published ECG algorithms.MethodsPatients with symptomatic OTVT/PVCs undergoing clinically indicated ablation were recruited. The OTVT/PVC origin was mapped preprocedurally by using ECM, and 3 published ECG algorithms were applied to the 12-lead ECG by 3 blinded electrophysiologists. Ablation was guided by using ECM. The OTVT/PVC origin was defined as the site where ablation caused arrhythmia suppression. Acute success was defined as abolition of ectopy after ablation. Medium-term success was defined as the abolition of symptoms and reduction of PVC to less than 1000 per day documented on Holter monitoring within 6 months.ResultsIn 24 patients (mean age 50 ± 18 years) recruited ECM successfully identified OTVT/PVC origin in 23/24 (96%) (right ventricular outflow tract, 18; left ventricular outflow tract, 6), sublocalizing correctly in 100% of this cohort. Acute ablation success was achieved in 100% of the cases with medium-term success in 22 of 24 patients. PVC burden reduced from 21,837 ± 23,241 to 1143 ± 4039 (P < .0001). ECG algorithms identified the correct chamber of origin in 50%–88% of the patients and sublocalized within the right ventricular outflow tract (septum vs free-wall) in 37%–58%.ConclusionsECM can accurately identify OTVT/PVC origin in the left and the right ventricle pre- and periprocedurally to guide catheter ablation with an accuracy superior to that of published ECG algorithms.