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Background: Effects of direct radiation on implantable cardiac devices have been well studied. However, the effects of scatter radiation are not as clear. Recommendations on management of patients with implantable cardiac devices undergoing radiotherapy are based on limited studies mostly involving pacemakers. We sought to elucidate the effects of scatter radiation on implantable cardioverter-defibrillators (ICDs) and cardiac resynchronization therapy (CRT)-ICDs. Methods: We exposed 12 ICDs and eight CRT-ICDs to 400 cGy of scatter radiation from a 6-MV photon beam. Devices were programmed with nominal parameters and interrogated prior to radiation, after each fraction, upon completion of the radiation course and again 1 week later. A retrospective review of patients undergoing radiotherapy at the Mayo Clinic–Rochester between 2002 and 2007 in whom the device was outside the radiation field was also performed. There were 13 patients with devices undergoing radiotherapy during this time period, 12 of whom were interrogated prior to and after radiation. Results: Interrogation reports were reviewed for device reset or parameter changes. There was no evidence of reset or malfunction during or after radiation. Also, no episodes of device reset, inappropriate sensing or therapy, or changes in programmed parameters were found in our review of patients undergoing radiotherapy. Conclusions: Device reset or malfunction associated with scatter radiation likely represents an unpredictable, rare occurrence. While we see no clear contraindication to radiotherapy in patients with ICDs or CRT-ICDs, precautions should be taken to avoid direct radiation exposure and to closely evaluate patient outcomes before and after the radiation course.

Obstructive sleep apnea (OSA) is highly prevalent in the United States, with an estimated 1 in 4 Americans at risk for OSA. In recent years, there has been a large body of work assessing the role of OSA as an independent risk factor for hypertension. Certain patient characteristics, such as age and the type of elevated blood pressure, may confer increased likelihood that the hypertension is secondary to underlying sleep apnea. Furthermore, early diagnosis and treatment of OSA may be beneficial in the management of hypertensive patients, particularly in those with poorly controlled hypertension. The focus of this brief review is on recent developments in the characteristics and treatment of sleep apnea-associated hypertension. Because of space limitations, only limited references are provided. The seventh report of the Joint National Committee identified OSA as an important identifiable cause of hypertension. As many as half of all patients with sleep apnea may have underlying hypertension, and many patients with hypertension, particularly resistant hypertension, may have OSA. In fact, there seems to be an interaction between OSA severity and resistance to antihypertensive medications.1 Elevated nocturnal blood pressure and reduced blood pressure “dipping” during sleep also suggest a higher likelihood of underlying sleep apnea, even in normotensive patients. Whether hypertension contributes to OSA remains unknown. OSA patients may not always exhibit elevated systolic pressures but may have a high prevalence of isolated diastolic hypertension.2–4 One study suggested that there was a significant association between the incidence of combined systolic and diastolic hypertension and the presence of sleep apnea in younger patients (

Despite wide use of dedicated bipolar sensing electrodes in implantable cardioverter-defibrillator (ICD) systems, oversensing occasionally occurs, leading to unwarranted shocks or antitachycardia pacing. This case report highlights an individual with hypertrophic cardiomyopathy (HCM) who experienced inappropriate shocks from oversensing of repolarization electrograms (T-waves). During the implantation procedure, no excessive T-wave amplitudes were detected during sinus rhythm, ventricular pacing, or induced ventricular fibrillation. T-wave oversensing leading to shocks only developed after maturation of the lead-tissue interface. An adequate safety margin for discrimination between ventricular electrograms and T-waves could not be assured. Thus, insertion of a new dedicated pacing-sensing electrode was required. The degree to which intracardiac repolarization signals may be heightened in patients with HCM has not been investigated systematically. However, a relative decrease in the ventricular electrogram amplitude without a concomitant decline of the intracardiac T-wave amplitude appears to have led to the problem in this patient. Special caution in technique and device selection with a particular emphasis on T-wave sensing may be prudent when ICDs are implanted in individuals with HCM. Additional programmable variables may also be beneficial in such cases.

Agenesis of the dorsal pancreas is very rare and may be associated with other congenital disease states. It has a rare association with polysplenia/heterotaxy syndrome. Most commonly, these states occur due to errors in development of the asymmetric organs and may be associated with benign to severe congenital cardiac malformations.We report a case of a 25-year-old male with known coarctation of the aorta who was otherwise asymptomatic. Following a routine cardiac examination, he was incidentally discovered to have an absent body and tail of the pancreas on imaging. Further testing demonstrated findings consistent with a diagnosis of polysplenia/heterotaxy syndrome with agenesis of the dorsal pancreas.In patients with congenital heart disease, there is increased likelihood for the presence of other congenital malformations. In particular, polysplenia/heterotaxy syndrome, while very rare, has been shown to be associated with cardiac abnormalities. The importance in diagnosis lies in the potential clinical consequences of polysplenia/heterotaxy syndrome and agenesis of the dorsal pancreas, including late-onset diabetes mellitus, pancreatitis, and intestinal volvulus.

Modern methods of cardiovascular monitoring encompass a vast array of sensing, transmitting, and processing technologies that have variable utility depending on the physiologic parameter and disease process being evaluated. As the population continues to age and technology improves—both by miniaturization of existing hardware and by improvement in the ability to collect, process, and transmit real-time information for a variety of physiologic variables—the options to treat patients in the ambulatory setting will continue to evolve. The cardiac electrophysiologist will often be responsible for the choice of monitoring technology, the implantation or implementation of it, and the interpretation of the resultant data. Furthermore, with improved availability of these technologies, both physicians and patients will continue to encounter an increasing ability and desire to treat or monitor patients at home, which will require a thorough understanding of current options and their corresponding indications and limitations. Thus, a thorough understanding of remote monitoring technologies and the data underlying their use is critical to the modern electrophysiologist. In this issue of Cardiac Electrophysiology Clinics, we focus on remote monitoring, including the history underlying its development, the current state of the technology, and potential future routes of development and study. Also found in this issue are current data on the utility of existing remote monitoring technologies in disease processes ranging from atrial fibrillation to stroke. Also presented are state-of-the-art, not yet clinically available technologies to widen the scope of the reader on what the future of these technologies may hold. Thus, through this edition of the Cardiac Electrophysiology Clinics, the reader may expect to attain a comprehensive outlook on the current state of remote monitoring and physiologic sensing technologies along with perspectives on how they

background: Atrial fibrillation (AF) is heterogeneous in its epidemiology, pathophysiology, and treatment options based on individual patient characteristics. Ageing is well recognized as an independent risk factor for AF. We hypothesized that fundamental differences may exist between young and older individuals with AF. The aim of our study was to investigate contemporary data in hospitalization rates, comorbidities, length of stay (LOS) and mortality in AF in young vs. older individuals.

A patient with multiple vessel disease presented with symptoms of significant bilateral upper extremity pain and weakness that was more significant on the right side. On carotid duplex scanning, brachiocephalic artery occlusion with retrograde flow was noted through the right common carotid and right vertebral arteries at rest. Furthermore, 50% to 90% occlusion of the left internal carotid was noted. Filling of the right subclavian artery was noted to be through the right vertebral and right common carotid arteries. Unlike isolated subclavian steal syndrome, brachiocephalic artery occlusion induces significant hemodynamic alterations in extracranial arterial flow, which normally produces no symptoms at rest, but may produce symptoms with exercise. The occurrence of subclavian steal phenomenon in the presence of brachiocephalic occlusion is extremely rare. The present case is the first to report a patient presenting with bilateral upper extremity rest pain in the presence of brachiocephalic artery occlusive disease.

(2004). THE EFFECT OF WEATHER AND AIR POLLUTION ON EMS CALLS FOR BREATHING-RELATED COMPLAINTS IN AN URBAN CITY. Prehospital Emergency Care: Vol. 8, No. 1, pp. 107-107.

Cardiac ablation is an established treatment modality for the management of patients with cardiac arrhythmias. Current approaches to cardiac ablation employ thermal based energy to achieve lesions (damage) within the heart. There are many shortcomings and limitations of thermal based approaches. Electroporation (DC energy) is a non-thermal alternative approach to ablation that has shown significant promise in animal studies. Areas covered: An extensive review of the literature on the application of electroporation for ablation (both cardiac and collateral cardiac tissue) was undertaken. This review explores irreversible electroporation as a cardiac ablation modality. Specifically, it focuses and explains the biophysics of electroporation, the limitations of current thermal based approaches and examines the current data published on electroporation cardiac ablation. Expert commentary: Electroporation is a fast-growing novel ablation modality that has many advantages over current thermal based approaches. Current research in animal models shows its can be safely and efficaciously applied to the heart. Although further research is required, electroporation represents an appealing option for the ablation cardiac arrhythmias.

Sinus node dysfunction requiring pacemaker implantation is commonly associated with atrial fibrillation (AF) but may not be clinically apparent until restoration of sinus rhythm with ablation or cardioversion. We sought to determine frequency, time course and predictors for pacemaker implantation