Application of the Bogossian formula for evaluation of the QT interval in pacemaker patients with stimulated left bundle branch block.

BACKGROUND: The presence of left bundle branch block (LBBB) represents a particular challenge in properly measuring the QT interval. Here we demonstrate the applicability of the "Bogossian formula" in pacemaker patients with LBBB due to apical or nonapical right ventricular (RV) pacing and preserved left ventricular function. METHODS: A total of 163 patients with a cardiac one- or two-chamber pacemaker were included in this prospective, multicentre observational study. Twelve-lead ECG recordings were obtained during both intrinsic rhythm and RV pacing with induced LBBB. The QT interval measured during LBBB was corrected using the Bogossian formula to obtain the "modified QT" (QTm). The QTmc interval was calculated with the Bazett formula, and this was compared with the QTc interval during intrinsic rhythm. RESULTS: Eighty-three patients (78 ± 9 years; male n = 83) with apical and eighty patients (71 ± 13 years; male n = 80) with non-apical RV pacing were included in this study. In the apical group the QTmc was determined to be 444 ± 39 ms in paced rhythm and the QTc interval 413 ± 36 ms in intrinsic rhythm. In the non-apical group these values were 430 ± 34 ms in paced and 416 ± 32 ms in intrinsic rhythm. CONCLUSION: The Bogossian formula is a reliable tool for QTc interval evaluation in pacemaker patients with LBBB due to apical or non-apical RV pacing. However, an overestimation of 30 ms should be included in the calculation.

Ventricular tachycardias in patients with pulmonary hypertension: an underestimated prevalence? A prospective clinical study.

BACKGROUND: Sudden cardiac death (SCD) accounts for approximately 30 % in patients with pulmonary arterial hypertension (PAH). The exact circumference for SCD in this patient population is still unclear. Malignant cardiac arrhythmias are reported to be rarely present. There are no systematic data concerning long-term electrocardiographic (ECG) recording in patients with PAH. OBJECTIVES: We sought to investigate the rate of potentially relevant arrhythmias in patients with pulmonary hypertension (PH). METHODS: Consecutive patients without diagnosis of known cardiac arrhythmias followed in our outpatient clinic for PH were enrolled in the study. All patients underwent a 72-h Holter ECG. Clinical data, 6-min walk distance, laboratory values, and echocardiography were collected/performed. RESULTS: Ninety-two consecutive patients (New York Heart Association class (NYHA) III/IV: 65.2 %/5.4 %, PH Group 1: 35.9 %, Group 3: 10.9 %, Group 4: 28.3 %, Group 5: 2.2 %) were investigated. Relevant arrhythmias were newly detected in 17 patients: non-sustained ventricular tachycardia (n = 12), intermittent second-degree heart block (n = 1), intermittent third-degree heart block (n= 3), and atrial flutter (n = 1). Echocardiographic systolic pulmonary pressure and diameter of the right heart were elevated in patients with relevant arrhythmias. Right heart catheterization revealed higher pulmonary vascular resistance (672 vs. 542 dyn · s · cm(-5), p = 0.247) and lower cardiac index (2.46 vs. 2.82 l/min/m(2), p = 0.184). CONCLUSIONS: Ventricular tachycardias occur more often in PH patients than previously reported. However, the prognostic relevance of non-sustained ventricular tachycardias in this cohort remains unclear. As a large number of PH patients die from SCD, closer monitoring, e.g., using implantable event recorders, might be useful to identify patients at high risk.

Primary hepatic aspergillosis following induction chemotherapy for acute leukemia.

Invasive aspergillosis (IA) contributes significantly to the burden of infectious complications in heavily immunosuppressed patients with acute leukemia. The infection is typically acquired via inhalation into the respiratory tract, and the lungs are most commonly involved. However, disseminated disease may occur and reports of isolated extrapulmonary infection suggest the gastrointestinal tract is likely an additional portal of entry for this organism. We describe a case of primary hepatic aspergillosis in a patient with acute myelogenous leukemia. The patient did not respond to medical therapy with antifungals and ultimately required surgical exploration and drainage. IA should be considered in an immunosuppressed patient with hepatic abscesses and may require a combined surgical and medical approach to therapy.

Effects of caffeic acid phenethyl ester (CAPE) on membrane potential and intracellular calcium in human endothelial cells.

UNLABELLED: BACKGROUNG AND OBJECTIVES: Caffeic acid phenethyl ester (CAPE) is an active component of the resin propolis obtained from beehives. Propolis has a long history of medicinal use and a number of studies have already reported on some of its pharmaceutical properties. This study aimed to explore the effects of CAPE on the cytosolic Ca2+ concentration, cell proliferation, membrane potential and NO levels in human endothelial cells. MATERIALS AND METHODS: Isolated human umbilical vein endothelial cells (HUVEC) were incubated with CAPE (1-100 µM) at 37°C for 48 hours. Cell proliferation was estimated by counting cell numbers with use of a Neubauer chamber. The effect of CAPE (1-100 µM) on the membrane potential was measured with the fluorescence dye DIBAC4(3) whereas its effect on the cytosolic Ca2+ concentration was measured by use of the fluorescence probe Fluo-3 AM (Invitrogen, Leiden, Netherlands). NO production was assayed using the flourophore DAF~AM (Invitrogen, Leiden, Netherlands). Changes in fluorescence intensity was determined with the GENios plate reader (Genios, Tecan, Austria). RESULTS: A dose-dependent hyperpolarization of the endothelial cell membrane was observed with CAPE stimulation. The initial increase in the intracellular Ca2+ concentration showed a subsequent decrease over time. CAPE stimulation also resulted in an increase in NO production; however, at higher doses a decrease in NO levels was observed. HUVEC proliferation was inhibited by CAPE. CONCLUSIONS: Here we report on the effect of CAPE stimulation on the cytosolic Ca2+ concentration, cell proliferation, membrane potential and NO production in HUVEC in a dose-dependent manner. These findings provide important insights into some potential key roles that both calcium and the membrane potential play in the CAPE activation of endothelial cells in a concentration-dependent manner.

Activation of the easter zymogen is regulated by five other genes to define dorsal-ventral polarity in the Drosophila embryo.

The product of the Drosophila easter gene, a member of the trypsin family of serine proteases, must be more active ventrally than dorsally to promote normal embryonic polarity. The majority of the easter protein in the embryo is present in the unprocessed zymogen form and appears to be evenly distributed in the extracellular space, indicating that the asymmetric activity of wild-type easter must arise post-translationally. A dominant mutant form of easter that does not require cleavage of the zymogen for activity (ea delta N) is active both dorsally and ventrally. The ea delta N mutant bypasses the requirement for five other maternal effect genes, indicating that these five genes exert their effects on dorsal-ventral patterning solely by controlling the activation of the easter zymogen. We propose that dorsal-ventral asymmetry is initiated by a ventrally-localized molecule in the vitelline membrane that nucleates an easter zymogen activation complex, leading to the production of ventrally active easter enzyme.