The problem of synthesizing the standard 12-lead electrocardiogram (ECG) from the signals recorded using three special ECG leads is studied in detail. The implementation of that concept into the design of a new mobile ECG transtelephonic system is presented. The system has two separate units: a stationary diagnostic-calibration center and a mobile ECG device with integrated electrodes. The patient records by himself three special leads with the mobile ECG recorder and sends data via cellular phone to the personal computer in the diagnostic center where standard 12-lead ECG is numerically reconstructed on the base of the patient transformation matrix previously calculated into the calibration process. The experimental study shows high accuracy of the reconstructed ECG.

Introduction Chronic right ventricular pacing can deteriorate cardiac function. Consequently, pacemaker system upgrades are more frequently indicated. These interventions can be hindered by venous thrombosis. In literature, it is rarely described that this problem is resolved by implanting a new lead for left ventricle (LV) stimulation on the opposite side of the previously implanted pacemaker and then subcutaneously transferring it to the old pocket. Case outline A 75-year-old male patient was hospitalized due to a planned pacemaker upgrade in December 2015. A dual-chamber pacemaker had been implanted due to sinus node dysfunction in 2011. During the previous 18 months he had been complaining about symptoms of heart failure. An upgrade to the cardiac resynchronization therapy (CRT) with a new CRT-P device was indicated due to the LV dilatation with the ejection fraction decrease, clinical deterioration, and the presence of high percentage of ventricular pacing. In October 2015, the mentioned intervention was unsuccessful due to total left subclavian vein thrombosis on the side of the previously implanted pacemaker. Anticoagulation therapy was ordinated and the reevaluation was postponed. During this hospitalization, venography confirmed total left subclavian vein thrombosis despite the anticoagulation therapy. It was decided to implant a new LV lead on the right side and then subcutaneously shift it by pre-sternal tunneling to the previous left prepectoral pocket. The intervention was uneventful. The first controls have shown stable pacemaker parameters. Conclusion This case report confirms that contralateral lead placement and subcutaneous pre-sternal tunnelling of the lead is feasible and safe in patients with an implanted pacemaker, an indication for system upgrade and ipsilateral vein obstruction.

Introduction/Objective Pneumothorax is one of the most common complications of cardiac rhythm management (CRM) devices implantation. We aimed to assess the incidence of pneumothorax after implantation of these devices and to determine risk factors for this complication. Methods A retrospective, observational study included patients in whom CRM devices were implanted, pacing system was upgraded, or lead revision was performed during 2012 at the Pacemaker Center, Clinical Center of Serbia. We determined the connection between different variables, including sex, age, type of implanted device, prior history of chronic obstructive pulmonary disease, operator experience, venous access, the use of intravenous contrast during procedure, and the development of pneumothorax as the procedure-related complication, using multiple logistic regression. Results A total of 999 patients were included in this study. The patients' mean age was 68.1 ± 9.2 years; 665 (66.6%) patients were male. The incidence of pneumothorax was 1.8% and an invasive treatment of this complication was required in 13 (72.2%) patients. Pneumothorax was more frequent in women (B = -2.136, p = 0.015), in patients with age > 75 years (B = 4.315, p = 0.001), venous access with subclavian vein puncture (B = 2.672, p = 0.045), and use of intravenous contrast during procedure (B = 3.155, p = 0.007). Conclusion Pneumothorax is a relatively rare complication of CRM device implantation, and for reducing its incidence, cephalic vein cut-down should be preferred to subclavian or axillary vein puncture as venous access, axillary vein puncture should not be avoided when cephalic vein cannot be found or used, and in the case of difficult vein puncture, contrast venography should be done immediately, before risky punctures.

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Application of cardiac electrostimulation in strictly defined indications has been on the increase over the last few decades. Frequent use of this therapy as well as the fact that it is applied predominantly in patients in the seventh decade of life, implies possible signifficant comorbidities and need for various diagnostic and surgical procedures. These are the reasons we decided to point out certain specific features in approaching this patient group in preparation and implementation of these procedures. Preoperative approach starts with usual patient history, with additional information on the type of pacemaker, last pacemaker check and electrocardiogram. This general approach is not substantialy different for pacemaker or ICD patients. What is specific is the possible interferrence caused by devices used in diagnostic or therapeutic procedures (diathermy, lithotripsy). Complications that may arise are usually related to the underlying disease rather than the pacemaker malfunction, but still, careful approach and pacemaker check are warranted, especially in the group marked as "pacemaker dependent". Adequate preoperative assessment, only slightly different from the usual, represents a sufficient guarantee for safe procedures diagnostic, therapeutic or surgical.