Improved Rate Responsive Algorithm in QT Driven Pacemakers—Evaluation of Initial Response to Exercise

The QT pacemaker is a rate modulated pacemaker that uses the evoked QT interval as an indicator to determine its optimal pacing rate. Despite the generally favorable clinical results with this form of pacing, some flaws in the system have been reported, such as the frequently observed rather slow initial response of the pacing rate to physical exercise, and the phenomenon of oscillation of the heart rate. These problems can be attributed to the rate adaptive algorithm used in the current QT pacemaker. Recently, in a reexamination of the relationship between evoked QT interval and pacing rate, a curvilinear relationship between these parameters has been demonstrated. As a result, a new algorithm has been developed for the next generation of the QT pacemaker. Before this new algorithm was implemented in new implantable devices, it was evaluated in a multicenter clinical investigation, with emphasis on the initial response of the pacing rate to exercise. This study was carried out by means of special software in the programmer of the QT pacemaker. By employing real-time bidirectional telemetry, it was possible to submit the study population, consisting of 37 patients with implanted QT pacemakers of the current generation, to identical exercise tests. Comparing these exercise tests, it appears that a considerable gain in speed of response to exercise can be achieved by using the same sensor with a faster reacting, nonlinear rate adaptive algorithm.     

Direct Stenting Versus Pre‐Dilation in ST‐Elevation Myocardial Infarction: A Systematic Review and Meta‐Analysis

Objectives

This study aimed at comparing direct stenting (DS) versus stenting with pre‐dilation (SP) in patients with ST‐elevation myocardial infarction (STEMI), using a systematic review and meta‐analysis of published evidence.

Background

There is conflicting evidence whether stenting strategy impacts clinical outcomes in patients with STEMI.

Methods

We searched EMBASE, MEDLINE, and CENTRAL, from inception to December 2014. The primary endpoint was mortality. Secondary endpoints included major adverse cardiac events (MACEs), ST‐segment resolution, and angiographic outcomes.

Results

A total of 9,331 patients enrolled in 12 studies (3 randomized controlled trials, RCTs; 9 non‐randomized studies, NRSs) were included. DS was associated with lower mortality (OR 0.55; 95%CI: 0.33–0.94; P = 0.03) in NRSs, and overall (OR 0.56; 95%CI: 0.37–0.86; P = 0.008). Mortality was non‐significantly reduced in RCTs (OR 0.56; 95%CI: 0.26–1.23; P = 0.15). DS was also associated with lower MACE rate (OR 0.71; 95%CI 0.60–0.84; P < 0.0001) in NRSs, but not in RCTs (OR 0.99; 95%CI: 0.61–1.60; P = 0.96). ST‐segment resolution, no reflow, final thrombolysis in myocardial infarction (TIMI) flow and final TIMI myocardial perfusion or blush grade were significantly better with DS in NRSs, and non‐significantly better in RCTs.

Conclusions

The available evidence suggests that DS in STEMI might be associated with better clinical and procedural outcomes, as compared with SP. However, the fact that RCTs account for the minority of available data and that most of the available studies poorly reflect current clinical practice, as well as the existence of publication bias, preclude drawing definitive conclusions.

     

Acquired auditory agnosia in childhood and normal sleep electroencephalography subsequently diagnosed as Landau–Kleffner syndrome: a report of three cases

Aim We report three cases of Landau–Kleffner syndrome (LKS) in children (two females, one male) in whom diagnosis was delayed because the sleep electroencephalography (EEG) was initially normal. Method Case histories including EEG, positron emission tomography findings, and long‐term outcome were reviewed. Results Auditory agnosia occurred between the age of 2 years and 3 years 6 months, after a period of normal language development. Initial awake and sleep EEG, recorded weeks to months after the onset of language regression, during a nap period in two cases and during a full night of sleep in the third case, was normal. Repeat EEG between 2 months and 2 years later showed epileptiform discharges during wakefulness and strongly activated by sleep, with a pattern of continuous spike‐waves during slow‐wave sleep in two patients. Patients were diagnosed with LKS and treated with various antiepileptic regimens, including corticosteroids. One patient in whom EEG became normal on hydrocortisone is making significant recovery. The other two patients did not exhibit a sustained response to treatment and remained severely impaired. Interpretation Sleep EEG may be normal in the early phase of acquired auditory agnosia. EEG should be repeated frequently in individuals in whom a firm clinical diagnosis is made to facilitate early treatment.     

Fuchs Syndrome Associated with Mycoplasma pneumoniae (Stevens–Johnson Syndrome without Skin Lesions)

Abstract: Stevens–Johnson syndrome is a severe mucocutaneous disease following drugs or infections. We present a 7‐year‐old boy with mucous membrane lesions (stomatitis, conjunctivitis, and urethritis) but without skin lesions. The diagnosis of acute Mycoplasma pneumoniae infection strongly suggests a concomitant Fuchs syndrome.     

Lead Extraction Via the Femoral Artery of a Left Ventricular Pacing Lead Inserted in the Subclavian Artery

We describe the extraction of a pacing lead via the femoral artery 5 months after it was inadvertently introduced through the right subclavian artery and positioned in the left ventricle. The lead was dislocated from the myocardium by traction from the subpectoral area and subsequently removed with a retriever inserted through the femoral artery in order to minimize the risk of cerebral embolization and bleeding at the entry site. Bleeding was controlled at the subclavian artery entry site by temporary inflation of a balloon catheter inserted through the brachial artery, and at the insertion site of the retriever in the femoral artery with a closure device. (PACE 2003; 26[Pt. I]:1544–1547)     

Multisite Pacing as a Supplemental Treatment of Congestive Heart Failure: Preliminary Results of the Medtronic Inc. InSync Study

This report describes the initial results of the "InSync" study, a European and Canadian multicenter trial that examines the safety and efficacy of a multisite pacemaker (Medtronic InSync) and of left ventricular pacing leads (Medtronic 2187 and 2188) implanted via a cardiac vein as a supplemental treatment of refractory congestive heart failure. Over a 10-month period, the system was implanted successfully in 68 of the 81 (84%) patients who had been enrolled in the study. The 68 patients were, on average, 66 ± 10 years old, had a mean left ventricular ejection fraction (LVEF) = 21 %± 9%, and 63% were in NYHA functional Class III and 37% were in Class IV. No system implant related complication occurred. During follow-up, 7 of 10 patients who exited the study had died, 4 suddenly. There was a clinical benefit among surviving patients, which was corroborated by a significant improvement in NYHA functional class and in the Minnesota Living with Heart Failure Quality of Life Questionnaire Score (MLS) and by a longer distance covered during a 6-minute walk test. This clinical improvement was associated with a significant narrowing of the paced QRS complex during biventricular pacing, a significant decrease in the interventricular mechanical delay, and a trend towards an increase in the duration of ventricular filling. These encouraging preliminary results confirm the feasibility and reliability of this new multisite pacing system in the management of dilated cardiomyopathy and support the continuation of further evaluations of this complementary treatment of refractory congestive heart failure.     

Symptomatic Pericardial Disease Associated with Patch Electrodes of the Automatic Implantable Cardioverter Defibrillator: An Underestimated Complication?

Constrictive pericarditis can be associated with ICD patch electrodes. During a mean follow-up of 24 months, in a population of 35 patients who received ICDs with a patch electrodes configuration, we identified three patients with clinical and hemodynamic signs compatible with this event. Patient 1, a 35-year-old male, underwent implantation of an ICD because of a primary electrical disease complicated by cardiac arrest. Fourteen months later he complained ofexertional dyspnea without any signs of heart failure. Right heart catheter- ization showed high filling pressures and diastolic dip and plateau in pressure curves. Thoracotomy and pericardia! exploration were performed. Three months after removal of the patches and insertion of an endocardial lead system, the patient had normal respiration. Patients 2 and 3, who suffered from coronary heart disease without heart failure, exhibited a hemodynamic profile suggestive of constrictive pericarditis: in one patient, 10 months after ICD implantation, associated with right heart failure; and in the other, 18 months after ICD implantation with left heart failure. Patch electrodes were removed in these two patients and replaced by endocardial lead electrodes with subsequent clinical improvement. It is concluded that constrictive pericarditis related to epicardial patch is not an uncommon occurrence during ICD therapy and should be considered in patients who show clinical signs of cardiac decompensation.     

Evidence for a particular binding capacity of rat peritoneal macrophages to rat glomerular mesangial cells in vitro

The adhesion of normal rat peritoneal macrophages to normal rat glomerular epithelial or mesangial cells has been studied in vitro after a 60 min incubation at 37 degree C. After washing, the cell preparations were examined by phase contrast or scanning electron microscopy. Quantitative studies were also performed using macrophages labelled with 99mTc tin colloids. Peritoneal macrophages predominantly adhered to the cultured mesangial cells. The percent-age of labelled macrophages adhering to these cells was about 10 times higher than that of labelled macrophages adhering to the cultured epithelial cells. This percentage increased proportionally to the number of labelled macrophages added, and was strongly reduced by the prior incubation of macrophagic cells with aggregated IgG, with anti-fibronectin IgG, or with F(ab')2 fragments of anti-fibronectin IgG. Furthermore, the macrophage-mesangial cell interaction was significantly reduced by the prior incubation of mesangial cells with anti-fibronectin IgG or with F(ab')2 fragments of anti-fibronectin IgG. The data demonstrate that normal rat peritoneal macrophages preferentially adhere in vitro to normal rat glomerular mesangial cells, and that this binding may be modulated, at least, by: (a) the Fc receptor binding activity of macrophages; (b) the fibronectin molecules available at the surface of macrophages and of mesangial cells.     

Incessant Atrio‐Ventricular Node Reentrant Tachycardia Induced by Unapparent Dual Atrio‐Ventricular Node Conduction

We present the case of a patient with incessant slow‐fast atrio‐ventricular (AV) node reentrant tachycardia induced by dual AV node conduction with aborted conduction to the ventricles. The unapparent conduction over the slow pathway was suspected here because of spontaneous nodal echoes without QRS complexes occurring during sinus rhythm, manifested as isolated premature atrial beats and which repetitively induced the tachycardia.