Ritvan Chasan

Quadripolar Left Ventricular Lead in a Patient with CRT-D Does Not Overcome Phrenic Nerve Stimulation

Effective cardiac resynchronization therapy (CRT) requires an accurate atrio-biventricular pacing system. The innovative Quartet lead is a quadripolar, over-the-wire left ventricular lead with four electrodes and has recently been designed to provide more options and greater control in pacing vector selection. A lead with multiple pacing electrodes is a potential alternative to physical adjustment of the lead and may help to overcome high thresholds and phrenic nerve stimulation (PNS).

Diagnostic value of dynamic contrast-enhanced magnetic resonance imaging in the evaluation of the biliary obstruction.

Purpose. In this study, our purpose was to investigate the diagnostic efficacy of the dynamic contrast-enhanced magnetic resonance imaging (MRI) method in the patients with bile duct obstruction. Materials and Methods. 108 consecutive patients (53 men, 55 women, mean age; 55.77 ± 14.62, range 18–86 years) were included in this study. All the patients underwent conventional upper abdomen MRI using intravenous contrast material (Gd-DTPA) and MRCP in 1.5 Tesla MRI scanner. MRCP images were evaluated together with the T1 and T2w images, and both biliary ducts and surrounding tissues were examined for possible pathologies that may cause obstruction. Results. MRI/MRCP findings compared with final diagnoses, MRI/MRCP in the demonstration of bile duct obstruction sensitivity 96%, the specificity 100%, and accuracy 96.3%, in the detection of presence and level of obstruction, the sensitivity 96.7%, specificity 100%, and accuracy 97.2%, in the diagnosis of choledocholithiasis, the sensitivity 82.3%, specificity 96%, and accuracy 91.7%, and in the determination of the character of the stenosis, sensitivity 95.6%, specificity 91.3%, and accuracy 94.5% were found. Conclusion. The combination of dynamic contrast-enhanced MRI and MRCP techniques in patients with suspected biliary obstruction gives the detailed information about the presence of obstruction, location, and causes and is a highly specific and sensitive method.

Applicability of a Novel Formula (Bogossian formula ) for Evaluation of the QT-Interval in Heart Failure and Left Bundle Branch Block Due to Right Ventricular Pacing: QT-INTERVAL IN PATIENTS WITH BUNDLE BRANCH BLOCK AND HEART FAILURE

The presence of left bundle branch block (LBBB) due to right ventricular pacing represents a particular challenge in properly measuring the QTc interval. In 2014, a new formula for the evaluation of QT interval in patients with LBBB was reported.

Safety of the Wearable Cardioverter Defibrillator (WCD) in Patients with Implanted Pacemakers: WCD PACEMAKER INTERACTIONS

The wearable cardioverter defibrillator (WCD) is an important approach for better risk stratification, applied to patients considered to be at high risk of sudden arrhythmic death. Patients with implanted pacemakers may also become candidates for use of the WCD. However, there is a potential risk that pacemaker signals may mislead the WCD detection algorithm and cause inappropriate WCD shock delivery. The aim of the study was to test the impact of different types of pacing, various right ventricular (RV) lead positions, and pacing modes for potential misleading of the WCD detection algorithm.

Baroreceptor stimulation in a patient with preexisting subcutaneous implantable cardioverter defibrillator: WEIPERT et al.

Many patients with severe heart failure (HF) have an indication for baroreflex activation therapy (BAT) and an implantable cardioverter‐defibrillator (ICD). Concerns about device‐device interactions were addressed in a study with small sample size that concluded combined BAT and ICD therapy is safe. There are no published data, however, concerning device‐device interactions between BAT and a subcutaneous ICD (S‐ICD). Since BAT frequently interferes with surface electrocardiogram recordings, there are doubts about compatibility of BAT and S‐ICD devices.

Effects of parathyroid hormone-related peptide on the large conductance calcium-activated potassium channel and calcium homeostasis in vascular smooth muscle cells.

Abstract Aim: To demonstrate the impact of the parathyroid hormone–related peptide (PTHrP) on the large conductance calcium–activated potassium (BKCa) channels in vascular smooth muscle cells (VSMC) and hyperpolarization of the cell membrane and its dependence on calcium. Materials and Methods: VSMC were isolated from rat aorta and further subcultured. Four experiments were conducted in calcium–release measurements and each of them consisted of a control group, PTHrP, chemical substance, and PTHrP + chemical substance. Chemical substances used were: iberiotoxin, xestospongin C, xestospongin D, and thapsigargin, respectively. Fura–2 imaging was used to determine changes in calcium release of VSMC. In membrane–potential experiments, groups were designed similarly to the Fura–2 imaging experiments: iberiotoxin, BAPTA, and xestospongin D were added, in respective order. Changes in the membrane potential were examined using the fluorescence dye (DiBAC). Results: Given in a dose between 0.01 and 1.0 μmol/L, PTHrP caused a concentration–dependent decrease in fluorescence intensity, with a maximum effect at 0.5 μmol/L. The decrease, therefore, demonstrated a PTHrP–induced hyperpolarization of the VSMC. The effect was blocked by use of iberiotoxin (100 nmol/L), a highly selective inhibitor of BKCa. Furthermore, when the calcium chelator BAPTA (10 μmol/L) was added, there was a significant reduction in PTHrP–induced hyperpolarization. Use of PTHrP (0.5 μmol/L) also decreased the fluorescence intensity of the indicator for intracellular calcium, Fura–2AM (a membrane–permeable derivative of Fura 2). This effect was re–blocked by use of iberiotoxin. Xestospongin C (3 μmol/L) and xestospongin D (6 μmol/L), both inhibitors of the inositol 1,4,5 trisphosphate–triggered calcium release, inhibited the effects of PTHrP. Additionally, thapsigargin (1 μmol/L), a sarcoplasmic/endoplasmic reticulum Ca2+–ATPase inhibitor, inhibited the effect of PTHrP. Conclusion: The results of our study show that PTHrP induces hyperpolarization and activates BKCa in VSMC. The activation of BKCa channels is calcium dependent; activation is linked to the inositol 1,4,5 trisphosphate–triggered calcium release and is also dependent on the endo/sarcoplasmic reticulum calcium pump.

RF ablation of WPW syndrome using Ensite Array balloon mapping and Hansen-Sensei robotic Cool-path catheter

Wolff-Parkinson-White syndromes (WPW) are examples of preexcitation that affects approximately 0.15-0.2% of the general population (2). Of these individuals, 60-70% has no other heart disease, men are affected more often and typically, those affected are young, or healthy individuals. Death from WPW is secondary to the associated arrhythmias or mistreatment of them. RF ablation remains the first line therapy in symptomatic WPW patients. A 22-year-old woman with known preexcitation, WPW was diagnosed at age of 11, had developed 4 episodes of sustained symptomatic palpitations with a pulse up to 190 beats/min., in the past 4 weeks. WPW had been diagnosed in grandfather and aunt. An echocardiography performed in the patient did not demonstrate any abnormalities. The patient’s WPW has been asymptomatic until 4 weeks prior to presentation. Due to the clinical manifestations, an electrophysiological study (EPS) was performed aiming to map and ablate the accessory pathway (3). Catheters were placed to right atrium, ventricle and coronary sinus (CS). During the programmed atrial stimulation, an antegrade transmitting right sided posterior septal pathway was found. Following multiple radiofrequency (RF) ablations, the pre-excitation signal was remained. The EPS was ended, in order to plan a new RF-ablation with the Ensite Array (SJM, St. Paul, MN, USA) (EA) balloon mapping (3). EA provides a virtual activation of intracardiac transmission on a beatto -beat basis (3). At the second EPS, a catheter was placed in the CS, a non-contactmapping EA balloon at the right atrium and the ablation catheter by means also superior and inferior vena cava, and right atrium is mapped. The EA balloon mapped capture beat documented an accessory pathway at the right side of the posterior septum (3). A CS imaging was also performed in order to assess an aneurysm, with a negative result. RF-ablation was performed using remote navigation system, coolpath radiofrequency (Hansen-Sensei, Mountain View, CA, USA) (RNS) (4). The RNS improves the catheter stability and increase procedural success and the safety by avoiding serious complications (4). Focal RF-ablation of the accessory path through RNS was performed, with a total time of 606sec and 8983Ws energy. The ablation of the pathway was successful. In this manner, although the high cost, we have decided to use both EA and RNS considering the young age, and the cardiac anatomy of the patient. In some cases, even though in WPW ablations, the EA and/or RNS usage could be considered in order to increase the success rate and minimize the potential complications of an ablation.

Tilt testing and what you should know about it - Experience with 835 consecutive patients with syncope of unknown origin

BACKGROUND Numerous tilt testing protocols with and without a preceding passive phase or the administration of nitrates have already been investigated. However, a truely standardized method for the investigation does not yet exist. METHODS AND RESULTS A total of 835 consecutive patients who underwent tilt testing between January 2005 and March 2015 were included in this study. Results of a passive tilt test (PTT), a nitrate-stimulated tilt test (NSTT) with a preceding passive phase of 20 min, or an early nitrate-stimulated tilt test (ENSTT) without a preceding passive phase were compared and analyzed retrospectively in 735 patients. In addition, a further 100 consecutive patients were prospectively randomized 1:1 to compare NSTT and ENSTT. In the retrospective analysis, 38% of the patients in the ENSTT group had a positive test response compared with 45% in the NSTT group and only 27% in the PTT group (p = 0.0002). In the prospective study, 34% of the patients had a positive test response in the ENSTT group compared with 42% in the NSTT group (p = 0.537). The mean duration to a positive test response was significantly shorter in the ENSTT group (retrospective and prospective p < 0.001). The nitrate-stimulated groups did not differ significantly with respect to the hemodynamic characteristics of a positive test response (retrospective: p = 0.773; prospective: p = 0.086). CONCLUSION Due to the rate of positive test response being comparable to other protocols and its significantly shorter test duration, nitrate-stimulated tilt testing without a preceding passive tilt test may be favored for use in a busy clinical practice.

First-in-Man Coronary Sinus Lead Stabilization Using a Bioresorbable Vascular Scaffold System

Cardiac resynchronization therapy has become an integral part of treatment in patients presenting with reduced ventricular function (left ventricular ejection fraction <35%), clinically symptomatic dyspnea (New York Heart Association II–IV), and complete left bundle branch block. Currently, the standard approach of left ventricular lead placement is transvenously via the coronary sinus (CS). Although a wide range of CS leads, sheaths, and subselectors are available, peri- or postinterventional lead dislodgement is still a cause for placement failure. Interventional stabilization by metallic stents of the CS lead has been described, but there are concerns on mid- and long-term effects because of possible mechanical irritation. Here we describe the first case in which a bioresorbable vascular scaffold was used to stabilize a CS lead in a lateral side branch against the vessel wall. A 74-year-old man with dilated cardiomyopathy, New York Heart Association Class III, had an implantable cardioverter defibrillator placed in 2008 for primary prophylaxis of sudden cardiac death. In January 2015, …

The Impact of Statins on FGF–2—Stimulated Human Umbilical Vein Endothelial Cells

Abstract Aim: To determine the effects of different types of statins on proliferative and migrative behaviors of basic fibroblastic growth factor (FGF)–2–stimulated endothelial cells. Materials and Methods: Human umbilical vein endothelial cells (HUVECs) were isolated and cultured. Groups were arranged in order to observe the impact of each individual substance alone, or under stimulation with statin on FGF–2–stimulated endothelial cells. Endothelial cells were stimulated with human growth factor (HGF), statins, methyl–β–cyclodextrin (β–MCD), and either farnesyl pyrophosphate (FPP) ammonium salt, or geranylgeranyl–pyrophosphate (GGPP), respectively. Cell proliferation analyses were performed 48 hours after stimulation and gaps between migration borders were used in migration analyses. Results: The statins showed significant antiproliferative and anti–migrative effects and inhibited the proliferative behavior of FGF–2. However, endothelial cell proliferation and migration were significantly increased after mevalonate co–incubation. Experiments with β–MCD indicated that the destruction of lipid rafts had a negative impact on the action of FGF–2. Stimulation of statin–incubated cells with FPP had no additional effect on proliferation or migration. Notably, although FGF–2 exerted a pro–migrative effect, the effect was not shown in the FPP + FGF–2 group. The anti–migrative actions of statins along with disruption of membrane integrity were reversed by the addition of GGPP. Conclusion: The angiogenic effect of FGF–2 is suppressed through inhibition of the intracellular cholesterol biosynthesis via statins. Inhibitory effects of statins on FGF–2—stimulated HUVECs were observed to result from both the inhibition of isoprenylation and the destruction of lipid rafts on the cell membrane.