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Unipolar Leads (unipolar + lead)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Transient Exit Block of a DDD Pacemaker with Unipolar Leads in Subcutaneous Emphysema Following Pneumothorax

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 5 2001
CHRÍSTOPHE MELZER
MELZER, C., et al.: Transient Exit Block of a DDD Pacemaker with Unipolar Leads in Subcutaneous Emphysema Following Pneumothorax. This case report describes a transient pacemaker exit block due to subcutaneous emphysema following pneumothorax. Pneumothorax after pacemaker implantation is rare, but development of subcutaneous emphysema under such circumstances is even more uncommon. Exit block develops only with the use of unipolar leads; with implantation of bipolar leads, this complication cannot occur. [source]

Cardiac Pacing: Memories of a Bygone Era

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 9 2008
HARRY G. MOND M.D.
The first cardiac pacemaker implants occurred in the late 1950s and involved insertion of epicardial or epimyocardial leads and abdominal pulse generators. By the mid 1960s, cardiologists were making attempts to insert transvenous leads into the right ventricle. These early unipolar leads had large, polished, high polarization electrodes, no fixation device, and no lumen in which to place a stylet for lead positioning. The lead implantation procedures were usually long and the irradiation to both patient and operator excessive. Pulse generators were powered by zinc-mercury cells, which were large, unreliable, and prone to sudden output failure. Postoperative complications such as lead dislodgement, exit block, and premature power source failure were very common with most patients requiring further surgery within a year. Little has been written of this period and in particular the experiences of the operators, such that today's pacemaker implanters have virtually no knowledge of this bygone era. This historical report by four Australian cardiologists details the operative procedures and follow-up management of those original pacemaker recipients. [source]

Transient Exit Block of a DDD Pacemaker with Unipolar Leads in Subcutaneous Emphysema Following Pneumothorax

Value of leads V4R and CM5 in the detection of coronary artery disease during exercise electrocardiographic test

CLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 4 2010
Merja Puurtinen
Summary The usefulness of the right precordial unipolar leads and the value of the bipolar lead CM5 in the detection of coronary artery disease (CAD) with exercise electrocardiographic (ECG) test are not well documented. The objective of this study was to evaluate the diagnostic performance of leads V4R and CM5. The study population comprised 579 patients referred for a bicycle exercise ECG test in the Finnish Cardiovascular Study. Patients were divided into three groups: angiographically proven CAD (CAD, n = 255), no CAD by angiography (NoCAD, n = 126), and low likelihood of CAD (LLC, n = 198). The maximum ST-segment depression at peak exercise was used as a parameter, and the diagnostic accuracy of different leads was assessed by receiver operating characteristic (ROC) analysis. Sensitivity and specificity values at a cut-off criterion of ,0·10 mV ST-segment, 1-mm ST depression, were determined. According to the results, incorporating lead V4R with the standard leads decreased the ROC area from 0·71 to 0·69 (comparison CAD versus LLC) and from 0·55 to 0·53 (comparison CAD versus NoCAD) and had no effect on sensitivity or specificity. Adding lead CM5 to the standard leads did not affect the ROC area but increased the sensitivity and decreased the specificity. In conclusion, the use of right precordial lead V4R along with the standard 12-lead system does not improve the performance of the exercise ECG in diagnosing CAD. Adding lead CM5 to the standard leads increases the sensitivity but does not change the overall diagnostic performance. [source]