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Journal: Pacing and clinical electrophysiology : PACE


Cardioversion remains an important therapy in the management of atrial fibrillation. Here, we report a case where direct current cardioversion resulted in a sudden dramatic change of heart rate that was associated with multiple ventricular fibrillation arrests in a manner akin to that previously observed post-atrioventricular node ablation. (PACE 2012;35:e361-e364).

Concepts: Scientific method, Cardiology, Heart, Atrial fibrillation, Direct current, Amiodarone, Defibrillation, DC offset


BACKGROUND: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and it is associated with an increased stroke risk, due mainly to cardiac embolism from the left atrial appendage (LAA). Percutaneous LAA closure is a method to reduce stroke risk in AF without using anticoagulant agents. In this study we report data from an Italian experience with the LAA occluder Amplatzer Cardiac Plug (ACP) device (Aga Medical Corporation, Plymouth, MN, USA). METHODS: The study was designed to evaluate the safety of LAA closure using ACP and the efficacy of the procedure in preventing strokes during a 1-year follow-up. Patients with permanent or paroxysmal AF, high stroke risk, and contraindication to warfarin therapy were selected for the procedure. RESULTS: The LAA closure was attempted in 37 patients and succeeded in 34 cases (91.9%). Four patients experienced serious complications (one cardiac tamponade requiring pericardiocentesis, two device embolizations, one low-rate response AF requiring artificial pacing). During a 1-year follow-up, ischemic stroke occurred in one of 34 patients, resulting in a stroke rate of 2.94%; thus there was a stroke rate reduction of 50.2% and 26.5% compared to the expected stroke rate, according to CHADS(2) and CHA(2) DS(2) VASc score. None of the patients who received ACP experienced major bleeding during the follow-up. CONCLUSION: LAA closure using ACP is a relatively feasible procedure which can be performed by highly experienced operators to reduce stroke rate in patients with AF, high stroke risk, and contraindication to oral anticoagulants.

Concepts: Heart, Stroke, Atrial fibrillation, Pulmonary embolism, Cardiac arrest, Warfarin, Anticoagulant, Left atrial appendage


Background:  Whether the functional status of the heart can influence the coronary venous system itself has not yet been examined. In order to answer this question, we used multislice computed tomography (CT) imaging. Purpose:  To answer the question of whether the heart failure (HF) is associated with significant anatomical changes in the coronary venous system? Methods:  In 136 (aged 56.6±11.5) patients, a 64-slice CT was performed. Patients were divided into three groups according their ejection fraction. In each case, nine 3D volume rendering reconstructions, using a 2-mm layer with electrocardiographic-gating, were created at 0% to 90% R-R intervals (step 10%). The visualization of coronary veins (CVs) was graded independently by two experts trained in multislice computed tomography on a 0-5 point scale (0-not visible/lack of vein; 5-smoothly bordered vascular structure). Results:  The average number of visible CVs per case was 3.44 in the HF group and 2.72 in patients with a normal ejection fraction (P = 0.0246). The statistical correlation between a reduction in ejection fraction and the increase in the number of veins was found (r =-0.2446, P < 0.05). For two of seven common variants of the coronary venous system at least two target veins (posterolateral and lateral) for cardiac resynchronization were presented. Conclusions:  The statistically higher number of veins in patients with heart failure may suggest an association between a failing heart and cardiac venous retention. (PACE 2012;35:1472-1479).

Concepts: Heart, Artery, Vein


Catheter cryoablation of supraventricular tachycardias involving the perinodal regions is considered to be a safer alternative compared to radiofrequency ablation. Limited information is available for efficacy, midterm outcomes, and complications regarding the ablation of parahissian accessory pathways (APs) in pediatric patients.

Concepts: Medical terms, Physician, Supraventricular tachycardia, Radiofrequency ablation


BACKGROUND: Stability of threshold currents during long-term use of phrenic nerve stimulation has been questioned. METHODS AND RESULTS: Between January 5, 1988, and March 5, 2008, 49 patients with functional C2-tetraplegia received an Atrostim PNS (Atrotech Ltd., Tampere, Finland) as treatment of their respiratory insufficiency; a follow-up of 35 of such patients was carried out exclusively in our institution for 6.3 (4.44) 0.04-15.75 years (mean [standard deviation (SD)] range). The device employed four-pole sequential nerve stimulation, which provided four threshold currents subsequently evaluated for each phrenic nerve. Stimulation data were prospectively recorded. The differences between threshold currents recorded 1 year after implantation and the last recorded values were 0.33-0.43 (0.44-0.63) 0-2.9 mA. After having excluded the data of eight patients with values >1 mA (= mean + SD), we registered the differences for the remaining patients of 0.15-0.24 (0.14-0.24) 0-0.95 mA, which is just twice the adjustment accuracy of the device. Out of the eight problem cases one had, and two were suspected to have, surgical trauma; all three nerves recovered. In two cases the values steadily increasing over years might have been caused by unspecific foreign body reaction. Two cases with values >1mA for different durations at different electrodes might be caused by biofilm, and one patient displaying steadily increasing values lived, unwilling to live, only 2 years after the implantation. CONCLUSION: Thus, there was no permanent nerve injury and in 77% of the presented cases threshold currents remained stable.

Concepts: Action potential, Mean, Thoracic diaphragm, Standard deviation, Nerve, Phrenic nerve, Nerves of the head and neck, Kehr's sign


Pacemaker generators are routinely implanted in the anterior chest. However, where to place the generator may need to be considered from the mental, functional, and cosmetic standpoints.

Concepts: Electricity, Alternating current, Axillary vein, Alternator


New evidence suggests that the CHA2 DS2 VASc score may be reliable tool to predict the risk of thromboembolic events in patients without documented atrial fibrillation (AF).

Concepts: Heart, Atrial fibrillation, SCORE Association


We present a case of Twiddler syndrome in a patient with a subcutaneous implantable cardioverter-defibrillator (S-ICD). The patient presented herself to outpatient clinic with pain in the left chest. Chest x-ray confirmed Twiddler syndrome and ICD read out revealed lead failure resulting in absent heart rhythm sensing in one vector. The lead and pulse generator were extracted and a new S-ICD system was re-implanted sub muscular underneath the Serratus Anterior muscle to prevent reoccurrence. Lead investigation revealed an insulation defect caused by excessive mechanical stress. This article is protected by copyright. All rights reserved.

Concepts: Heart, Implantable cardioverter-defibrillator, All rights reserved, Copyright, Serratus anterior muscle, Wearable cardioverter defibrillator


Removal of an entire cardiovascular implantable electronic device (CIED) is associated with morbidity and mortality. We sought to establish a risk classification scheme according to the outcomes of transvenous lead removal in a single center, with the goal of using that scheme to guide electrophysiology lab vs. operating room extraction.

Concepts: Mortality rate, According to Jim, Electronics, Electronic engineering, Electronic design automation


Prophylactic implantable cardioverter-defibrillator (ICD) therapy prevents sudden cardiac death (SCD) among young adults with cardiogenetic conditions, but might reduce quality of life (QoL) due to potential device complications, ongoing medical appointments and lifestyle restrictions. We investigated QoL in the first year after ICD implantation for the primary prevention of SCD and compared QoL scores with population norms.

Concepts: Biology