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Implantable cardioverter defibrillator (ICD) lead insulation failure and conductor externalization have been increasingly reported. The 7.8F silicon-insulated Linox SD and Linox S ICD leads (Biotronik, Berlin, Germany) were released in 2006 and 2007, respectively, with an estimated 85,000 implantations worldwide. A 39-year-old female suffered an out-of-hospital ventricular fibrillation (VF) arrest with successful resuscitation. An ICD was implanted utilizing a single coil active fixation Linox(Smart) S lead (Biotronik, Berlin, Germany). A device-triggered alert approximately 3 years after implantation confirmed nonphysiological high rate sensing leading to VF detection. A chest X-ray showed an abnormality of the ICD lead and fluoroscopic screening confirmed conductor externalization proximal to the defibrillator coil. In view of the combined electrical and fluoroscopic abnormalities, urgent lead extraction and replacement were performed. A review of Linox (Biotronik) and Vigila (Sorin Group, Milan, Italy) lead implantations within our center (n = 98) identified 3 additional patients presenting with premature lead failure, 2 associated with nonphysiological sensed events and one associated with a significant decrease in lead impedance. All leads were subsequently removed and replaced. This case provides a striking example of insulation failure affecting the Linox ICD lead and, we believe, is the first to demonstrate conductor externalization manifesting both electrical and fluoroscopic abnormalities.

Introduction : Insulation defects with externalized conductors have been reported in the St. Jude Riata® family of defibrillation leads (St. Jude Medical, Sylmar, CA, USA). The objective of the Northern Ireland Riata® lead screening program was to identify insulation defects and externalized conductors by systematic fluoroscopic and electrical assessment in a prospectively defined cohort of patients. We sought to estimate the prevalence, identify risk factors, and determine the natural history of this abnormality. Methods : All patients with a Riata® lead under follow-up at the Royal Victoria Hospital were invited for fluoroscopic imaging and implantable cardioverter-defibrillator lead parameter checks. Fluoroscopic images were read independently by two cardiologists and the presence of externalized conductors was classified as positive, negative, or borderline. Results: One hundred and sixty-five of 212 patients with a Riata lead were evaluated by fluoroscopy and lead parameter measurements. The mean duration after implantation was 3.98+/−1.43 years. After screening 25 (15%) patients were classified as positive, 137 (83%) negative, and three (1.8%) borderline. Time since implantation (P = 0.001), presence of a single coil lead (P = 0.042), and patient age (P = 0.034) were significantly associated with externalized conductors. The observed rate of externalized conductors was 26.9% for 8-French and 4.7% for 7-French leads. No leads that were identified prospectively with externalized conductors had electrical abnormalities. Seven of 25 (28%) patients had a defective lead extracted by the end of this screening period. Conclusion: A significant proportion (15%) of patients with a Riata lead had an insulation breach 4 years after implantation. High-resolution fluoroscopic imaging in at least two orthogonal views is required to identify this abnormality. (PACE 2012;35:1498–1504)

Background:The optimal waveform tilt for defibrillation is not known. Most modern defibrillators used for the cardioversion of atrial fibrillation (AF) employ high-tilt, capacitor-based biphasic waveforms. Methods:We have developed a low-tilt biphasic waveform for defibrillation. This low-tilt waveform was compared with a conventional waveform of equivalent duration and voltage in patients with AF. Patients with persistent AF or AF induced during a routine electrophysiology study (EPS) were randomized to receive either the low-tilt waveform or a conventional waveform. Defibrillation electrodes were positioned in the right atrial appendage and distal coronary sinus. Phase 1 peak voltage was increased in a stepwise progression from 50 V to 300V. Shock success was defined as return of sinus rhythm for ≥30 seconds. Results:The low-tilt waveform produced successful termination of persistent AF at a mean voltage of 223 V (8.2 J) versus 270 V (6.7 J) with the conventional waveform (P = 0.002 for voltage, P = ns for energy). In patients with induced AF the mean voltage for the low-tilt waveform was 91V (1.6 J) and for the conventional waveform was 158 V (2.0 J) (P = 0.005 for voltage, P = ns for energy). The waveform was much more successful at very low voltages (less than or equal to 100 V) compared with the conventional waveform (Novel: 82% vs Conventional 22%, P = 0.008). Conclusion:The low-tilt biphasic waveform was more successful for the internal cardioversion of both persistent and induced AF in patients (in terms of leading edge voltage).

As nonpharmacologic therapies for atrial fibrillation expand, the complexity of the anatomical and electrical substrates of atrial fibrillation requires integration of multiple imaging modalities for successful treatment. Combining chamber-specific imaging and electrophysiologic data points during ablation therapy has improved pulmonary vein isolation accuracy while diminishing risk. Merging 3-dimensional computed tomography left atrial renditions, intracardiac echocardiography, and electroanatomical mapping during pulmonary vein isolation is a reality that relates the complex anatomy of the left atrium to its often variable electrical targets. Direct visualization of radiofrequency lesion formation as well as electrode-tissue contact during current delivery has been accomplished in animal models using ultrasound and infrared imaging tools. The combination of these early integrative stepping stones may lead to imaging with real-time feedback relating tissue desiccation to electrical effect and lesion transmurality. Atrial fibrillation ablation outcome will improve as the electrophysiology laboratory continues to integrate real-time 3-dimensional cardiac chamber and tissue images before, during, and after radiofrequency or cryoablation of specific electrophysiologic targets.

Epicardial electrical events were reconstructed using an inverse model for left ventricular (LV) pacing and during ventricular tachycardia (VT) induced during implantation of a biventricular pacemaker and/or internal defibrillator. The electrocardiographic position of the pacing lead, determined from the region of most negative potential 30 ms after the pacing spike, was compared with the radiographic position. Activation characterized by isochronal maps was correlated with the echocardiographic/myocardial scintigraphic data. Reconstructed epicardial isopotential/isochronal maps during VT were used to determine the presence of reentry. In 7 patients during LV pacing, epicardial isopotential maps located the maximum negative potentials anterolaterally (n = 3), posterolaterally (n = 2), and posteriorly (n = 2). Isochronal maps demonstrated activation patterns including regions of delayed activation that, in 5 patients, correlated with areas of akinesia/hypokinesia or fixed defects on echocardiography/myocardial scintigraphy. The mean difference between the radiographically measured right ventricular to LV pacing lead distance and calculated electrocardiographic right ventricular to LV pacing site distance was 1.7 cm. During VT, induced in 5 patients, single-loop reentry was observed in 3 and figure-of-8 reentry in 2. Exit site and regions of fast/slow conduction and conduction block that correlated with anatomic areas of infarction defined by echocardiography/myocardial scintigraphy were demonstrated. In conclusion, epicardial maps reconstructed from the body surface map can identify LV pacing sites and demonstrate reentry during VT. The body surface map could thus identify optimal pacing sites for LV pacing and targets for VT ablation.

An 87-year-old man presented at the hospital with shortness of breath and syncope. His medical history included ischemic heart disease, emphysema, and hypertension. An electrocardiogram showed complete heart block and nonsustained polymorphic ventricular tachycardia. A temporary ventricular pacing wire was inserted. In the coronary care unit, the patient was treated for a community-acquired chest infection. A dual-chamber permanent pacemaker (PPM) was inserted by means of left cephalic vein cutdown. Active-fixation leads were used. After implantation, a device check, lead check, and chest radiograph revealed nothing abnormal. Eight days later, the patient had dyspnea and hemoptysis. A chest radiograph showed patchy consolidation in the lower zone of both lung fields, the right atrial pacing lead's tip situated outside the cardiac silhouette, and evidence of pneumopericardium (Fig. 1). At the regional cardiology center, the right atrial pacing lead was uneventfully removed and replaced with a passive-fixation lead. The patient was discharged from the center 3 days later. Fig. 1 Chest radiograph shows an extracardiac location of the right atrial pacing lead tip (arrow) and pneumopericardium. The arrowhead indicates the pericardial outline.

Fifty-nine consecutive patients presenting within 6 hours of the onset of symptoms of an acute myocardial infarction were treated with 150 mg of soluble aspirin orally, and either 70 or 100 mg of alteplase divided into 2 intravenous bolus injections separated by 30 minutes. Dosage regimens were either 20 followed by 50 mg (group A), 50 followed by 20 mg (group B), or 50 followed by 50 mg (group C). Coronary angiography 60 minutes after the first bolus showed infarct-related coronary artery patency (Thrombolysis in Myocardial Infarction score 2 or 3) in 13 of 16 (81%) patients in group A, 12 of 17 (71%) in group B, and 10 of 11 (91%) in group C (overall patency rate at 60 minutes: 35 of 44 [80%] patients; 95% confidence interval 68 to 91%). At 90 minutes, patency rates were 15 of 20 (75%) patients in both groups A and B, and 18 of 19 (95%) in group C (overall patency rate 48 of 59 [81%] patients; 95% confidence interval 72 to 91%). Residual thrombus was identified with the 90-minute angiogram in 7 patients in group A, 5 in group B, and 3 in group C. Although there was no statistically significant difference in patency between the 3 dosage regimens at either 60 or 90 minutes there was a trend toward increased patency and more complete thrombolysis at 90 minutes in group C. No episodes of bradyarrhythmia, hypotension or cerebrovascular bleeding were observed after double bolus therapy. There were 7 episodes (12%) of reocclusion, and 3 deaths (5%) within 1-month follow-up. Double bolus alteplase therapy is a convenient and highly effective method of promoting early coronary artery patency.

A cellular transtelephonic defibrillator facilitates early defibrillation in remote areas and involves electrocardiographic diagnosis and defibrillation control by a physician remote from but in voice contact with the patient-unit operator. The patient unit contains a microprocessor, microphone, defibrillator, electrocardiogram/defibrillator electrode pads and cellular telephone. Activation of the patient-unit initiates automatic dialing and contact with the remotely sited base station within 35 to 50 seconds. The physician at the base station identifies the rhythm and controls defibrillator charging and discharge. The minimal interaction required between the system and the local operator makes it suitable for use by minimally trained first responders. The cellular transtelephonic defibrillator has been tested in 211 calls responded to by a physician-manned mobile coronary care unit over distances up to 15 miles in an urban area. Satisfactory electrocardiographic transmission and voice communication were established in 172 of 211 calls (81.5%). In 39 (18.5%), connection with the base station either could not be established or maintained mainly because of geographic location or battery failure. One hundred direct current shocks of 50 to 360 J were effectively administered to 22 patients with 48 episodes of ventricular fibrillation or ventricular tachycardia with successful correction of 46 of 48 episodes using 1 to 4 shocks per episode. Widespread distribution of such devices could improve survival in patients with cardiac arrest outside the hospital.

Background Noncontact endocardial mapping allows accurate beat-to-beat reconstruction of the reentrant pathway of ventricular tachycardia and improves outcomes after ablation. Several studies support electrocardiographic imaging (ECGI) as a means of noninvasively outlining epicardial activation despite constraints of internal geometry. However, few have explored its clinical application. This study aims to evaluate ECGI during selective left ventricular (LV) pacing, relative to an invasive approach. Methods Multisite pacing was performed within the left ventricles of 3 patients undergoing invasive procedures. Simultaneous recording of endocardial potentials using a noncontact multielectrode array and body surface potentials (BSP) using an 80-electrode torso vest was performed. A total of 16 recordings were made. The inverse solution was applied to BSP to reconstruct epicardial activation. Single-paced beats from real and virtual electrograms were used to construct 3-dimensional isochronal and isopotential maps. Endocardial and epicardial data were then superimposed onto a single geometry to allow quantitative comparison of activation foci. Results Good correlation was observed between endocardial activation patterns and those reconstructed from BSP using ECGI. This was repeatedly demonstrated in all LV regions except for the septum (3 recordings). Epicardial isochronal maps were able to locate early and late activation to mean distances of 13.8 ± 4.7 and 12.5 ± 3.7 mm from endocardial data. Isopotential maps localized pacing sites with comparable accuracy (14 ± 5.3 mm). Conclusions Body surface potentials and reconstructed epicardial activation patterns during LV pacing correlate well with endocardial data acquired invasively. The exception was during pacing of the septum. Although early results are encouraging, further quantitative data are required to fully validate and apply this noninvasive tool in the clinical arena.

A 45-year-old woman with a 5-year history of treated essential hypertension presented with a 2-month history of exertional dyspnea and a 2-week history of intermittent palpitations. Two weeks earlier, she presented to the emergency department of another hospital with palpitations, but these had terminated on arrival. She was told her ECG displayed “low voltages.” During the next 2 weeks, she became increasingly dyspneic, feeling short of breath most …

The Riata series of leads (St Jude Medical) are defibrillator leads with silicone as the insulation material. In December 2010, Riata & Riata ST leads were no longer marketed. The manufacturer-quoted lead failure rate at this time was 0.47p over 9 years2. However we observed a 15p

Of consecutive patients seen with first myocardial infarction (88 of whom were treated out-of-hospital by mobile coronary care staff), 139 received 30 units of intravenous anistreplase at a mean of 101 minutes (range 35-180) from onset of symptoms. Thrombolysis in myocardial infarction patency grade 2 or 3 was found in 76/91 (83.5%) patients. At 3-4 months after hospital discharge, the mean global left ventricular ejection fraction and mean infarct-related regional third ejection fraction declined with increasing delay to anistreplase. For the first, second and third hour administrations, global ejection fraction was 54%, 50% and 45% (P = 0.002) and for regional third ejection fractions 49%, 43% and 41% (P = 0.02) respectively. Of the patients, 130 were reviewed at approximately 1 year: reinfarction had occurred in 9, 6 had undergone coronary angioplasty and 1 had coronary arterial bypass grafting performed since discharge. Mean global left ventricular ejection fraction was 52% and mean infarct-related regional third ejection fraction was 51%. Thus, intravenous anistreplase induces high rates of arterial patency. Global and regional third ejection fractions decline with increasing delay in the time of administration of anistreplase. Mortality and morbidity is low in the first year.

of 195 (PEM, standard) ECG pairs; and (b) 24 ambulatory cardiac patients recorded during their routine visit at the cardiology hospital of Lyon. Both the standard and the derived 12-lead ECGs have been reprocessed by the Lyon Program. A quantitative comparison of the computerized global and lead-by-lead measurements was performed on data set a (Table 1), and a qualitative comparison was made on data set b (Table 2) by a cardiologist who blindly analyzed, in measurements and interpretation, the 2 derived ECGs with reference to the standard 12-lead ECG. In conclusion, the patient-specific transform provides better results, similar to the Mason-Likar lead system.

On the morning of 19 August 1772 Gustavus III seized supreme power in Sweden, overthrew the authority of the Estates, and amid the applause of almost all Swedes outside the circle of professional politicians brought the Age of Liberty to an end. On the morrow of the revolution he explicitly abjured sovereignty for himself; he promised his.subjects the constitution of Gustav Adolf; and he did in fact confer on them a liberal and tempered despotism, which may be described as being by Mercier de la Rivière out of The Patriot King. It was a revolution bloodless, popular, and uniquely clement; but it was profoundly disturbing to international relations. Twice in the next nine months it produced crises from which, for a moment, there seemed no issue save a general European war involving all the great powers. It might have been supposed, indeed, that England could stand aside from such a struggle: the countrymen of Wilkes and Junius cared little for Swedish liberty, and had but a dim and confused notion of a parliamentary system in some respects more advanced than their own. But by an odd combination of circumstances, the Constitution of 1720—which Gustavus had overthrown on 19 August—had for some years acquired the status of a major British interest; its maintenance had become one of the linch pins of British foreign policy; and its overthrow was a challenge to a whole system of ideas which had prevailed and grown stronger in the years since the Peace of Paris.

Objectives . The purpose of this study was to assess the efficacy of 150 mg of aspirin plus 100 mg of alteplase, administered as two intravenous bolus injections of 50 mg each given 30 min apart, and followed by intravenous heparin, on infarct-related coronary artery patency (Thrombolysis in Myocardial Infarction [TIMI] flow grade 3). Background . previous workers have shown in animals that reducing the duration of an infusion of recombinant tissue-type plasminogen activator increases the initial rate of thrombolysis, resulting in high early infarct-related coronary artery patenecy rates. The logical progression of this idea is bolus administration. Methods , Consecutive patients presenting up to 6 h from the onset of symptoms were recruited for the study. Angiography was performed at 60 and 90 min after the first bolus and between 19 to 48 h after study entry. Patients were followed up for 1 month. Results . At 60 min, angiography revealed infarct-related coronary artery patency of TIMI flow grade 3 in 55 (86%) of 64 patients (95% confidence interval [CI] 75% to 93%) and TIMI flow grade 2 or 3 in 58 (91%) of 64 patients (95% CI 81% to 97%). At 90 min, infarct-related artery patency of TIMI flow grade 3 was achieved in 74 (88%) of 84 patients (95% CI 79% to 94%) and TIMI flow grade 2 or 3 in 78 (93%) of 84 patients (95% CI 85% to 97%). Two patients (2.4%) had early angiographic reocclusion whereas 10 (11.9%) had late reinfarction. Bleeding episodes were mostly minor, and there was no cerebrovascular bleeding. Five patients (6.0%) died within 1 month of the acute myocardial infarction. Conclusions . In 84 patients with acute myocardial infarction, administration of 100 mg of double-bolus (2 × 50 mg) alteplase, aspirin and heparin is associated with remarkably high early infarct-related coronary artery patency rates (TIMI flow grade 3) of 86% and 88%, respectively, at 60 and 90 min.