Wireless Smartphone ECG Enables Large-Scale Screening in Diverse Populations.

BACKGROUND: The ubiquitous presence of internet-connected phones and tablets presents a new opportunity for cost-effective and efficient electrocardiogram (ECG) screening and on-demand diagnosis. Wireless, single-lead real-time ECG monitoring supported by iOS and android devices can be obtained quickly and on-demand. ECGs can be immediately downloaded and reviewed using any internet browser. OBJECTIVE: We compared the standard 12-lead ECG to the smartphone ECG in healthy young adults, elite athletes, and cardiology clinic patients. Accuracy for determining baseline ECG intervals and rate and rhythm was assessed. METHODS: In 381 participants, 30-second lead I ECG waveforms were obtained using an iPhone case or iPad. Standard 12-lead ECGs were acquired immediately after the smartphone tracing was obtained. De-identified ECGs were interpreted by automated algorithms and adjudicated by two board-certified electrophysiologists. RESULTS: Both smartphone and standard ECGs detected atrial rate and rhythm, AV block, and QRS delay with equal accuracy. Sensitivities ranged from 72% (QRS delay) to 94% (atrial fibrillation). Specificities were all above 94% for both modalities. CONCLUSION: Smartphone ECG accurately detects baseline intervals, atrial rate, and rhythm and enables screening in diverse populations. Efficient ECG analysis using automated discrimination and an enhanced smartphone application with notification capabilities are features that can be easily incorporated into the acquisition process.

Cardiac resynchronization therapy: double cannulation approach to coronary venous lead placement via a prominent thebesian valve.

We report identification of a prominent Thebesian valve by cardiovascular computed tomography (CT) angiography impeding cannulation of the coronary sinus, with subsequent successful coronary venous lead placement with cannulation of the coronary sinus ostium via a transvenous femoral vein approach and subsequent cannulation of the ostium with the coronary venous lead with a left subclavian approach. A 57-year-old man with nonischemic dilated cardiomyopathy, New York Heart Association Class III heart failure, left bundle branch block, and an ejection fraction of 15%, underwent an attempted cardiac resynchronization therapy implantable cardiac defibrillator (ICD). As the coronary sinus ostium could not be cannulated, a dual chamber ICD was placed. The patient subsequently underwent cardiovascular CT angiography, which identified a prominent Thebesian valve at the coronary sinus ostium as the anatomic obstacle to cannulation. Reattempted transvenous cardiac resynchronization therapy was accomplished successfully with a double cannulation approach: cannulation of the coronary sinus ostium with a catheter via a transvenous femoral vein approach and subsequent cannulation with the coronary venous lead via a left subclavian approach. When a prominent Thebesian valve is identified as an obstacle to transvenous left ventricular lead placement, cannulation of the coronary sinus by an alternate venous approach may allow for a coronary venous route rather than necessitate an epicardial approach.

Identifying, characterizing, and classifying congenital anomalies of the coronary arteries.

The clinical manifestations of coronary artery anomalies vary in severity, with some anomalies causing severe symptoms and cardiovascular sequelae and others being benign. Cardiovascular computed tomography (CT) has emerged as the standard of reference for identification and characterization of coronary artery anomalies. Therefore, it is important for the reader of cardiovascular CT images to be thoroughly familiar with the spectrum of coronary artery anomalies. Hemodynamically significant anomalies include atresia, origin from the pulmonary artery, interarterial course, and congenital fistula. Non-hemodynamically significant anomalies include duplication; high origin; a prepulmonic, transseptal, or retroaortic course; shepherd's crook right coronary artery; and systemic termination. In general, coronary arteries with an interarterial course are associated with an increased risk of sudden cardiac death. Coronary artery anomalies that result in shunting, including congenital fistula and origin from the pulmonary artery, are also commonly symptomatic and may cause steal of blood from the myocardium. Radiologists should be familiar with each specific variant and its specific constellation of potential implications.

Magnetic resonance imaging in patients with cardiac pacemakers: era of "MR Conditional" designs.

Advances in cardiac device technology have led to the first generation of magnetic resonance imaging (MRI) conditional devices, providing more diagnostic imaging options for patients with these devices, but also new controversies. Prior studies of pacemakers in patients undergoing MRI procedures have provided groundwork for design improvements. Factors related to magnetic field interactions and transfer of electromagnetic energy led to specific design changes. Ferromagnetic content was minimized. Reed switches were modified. Leads were redesigned to reduce induced currents/heating. Circuitry filters and shielding were implemented to impede or limit the transfer of certain unwanted electromagnetic effects. Prospective multicenter clinical trials to assess the safety and efficacy of the first generation of MR conditional cardiac pacemakers demonstrated no significant alterations in pacing parameters compared to controls. There were no reported complications through the one month visit including no arrhythmias, electrical reset, inhibition of generator output, or adverse sensations. The safe implementation of these new technologies requires an understanding of the well-defined patient and MR system conditions. Although scanning a patient with an MR conditional device following the strictly defined patient and MR system conditions appears straightforward, issues related to patients with pre-existing devices remain complex. Until MR conditional devices are the routine platform for all of these devices, there will still be challenging decisions regarding imaging patients with pre-existing devices where MRI is required to diagnose and manage a potentially life threatening or serious scenario. A range of other devices including ICDs, biventricular devices, and implantable physiologic monitors as well as guidance of medical procedures using MRI technology will require further biomedical device design changes and testing. The development and implementation of cardiac MR conditional devices will continue to require the expertise and collaboration of multiple disciplines and will need to prove safety, effectiveness, and cost effectiveness in patient care.

"MR-conditional" pacemakers: the radiologist's role in multidisciplinary management.

OBJECTIVE: The recent approval of an "MR-conditional" pacemaker system by the U.S. Food and Drug Administration allows patients with that pacemaker system to undergo MRI examinations within specific conditions. These examinations must be attended by radiology health care professionals with training for the use of the pacemaker system. CONCLUSION: Radiologists should be knowledgeable of the specific limitations with regard to patient isocenter and coil positioning within the required 1.5-T MR system and the importance that the pacer be programmed before and after scanning.

Impact of relaxation training on patient-perceived measures of anxiety, pain, and outcomes after interventional electrophysiology procedures.

BACKGROUND: Electrophysiology procedures vary in invasiveness, duration, and anesthesia utilized. While complications are low and efficacy high, cases are elective and patient experiences related to anxiety, pain, and perceived outcomes are not well studied. We sought to determine if a 30-minute audio compact disc (CD) that teaches relaxation techniques and wellness perception prior to an elective procedure impacts validated measures of anxiety, pain, and procedural outcomes. METHODS: Sixty-one patients were randomly assigned to a control group (CG) (N(CG) = 31) or interventional group (IG) (N(IG) = 30). Both groups answered a baseline Hospital Anxiety and Depression Scale (HADS-A) survey consisting only of anxiety assessment questions. The IG listened to the CD the night prior to their procedure. Heart rate and blood pressure were monitored on admission and prior to the procedure. Postprocedure, both groups completed two HADS-A surveys as well as two Patient Experience Surveys (PES). There was no statistical difference in the demographics and the rate of procedural complications between the groups. The statistical significance of our data was determined using a Student's t-test and χ(2) test. RESULTS: At baseline, both groups had equal amounts of anxiety prior to their procedures (P = 0.2). The patients in the IG had lower systolic blood pressures during admission and prior the administration of analgesics in comparison to the CG. Postprocedure, results from administering the HADS-A demonstrated that the IG had 33% lower anxiety (P = 0.02) than CG patients. CONCLUSION: The implementation of basic relaxation teaching techniques prior to planned electrophysiology procedures lowers systolic blood pressure and postprocedural anxiety.

Coronary Artery Aneurysm in Kawasaki Disease: Coronary CT Angiography through the Lens of Pathophysiology and Differential Diagnosis.

Kawasaki disease (KD) is an inflammatory autoimmune vasculitis affecting the coronary arteries of very young patients, which can result in coronary artery aneurysms (CAAs) with lifelong manifestations. Accurate identification and assessment of CAAs in the acute phase and sequentially during the chronic phase of KD is fundamental to the treatment plan for these patients. The differential diagnosis of CAA includes atherosclerosis, other vasculitic processes, connective tissue disorders, fistulas, mycotic aneurysms, and procedural sequelae. Understanding of the initial pathophysiology and evolutionary arterial changes is important to interpretation of imaging findings. There are multiple applicable imaging modalities, each with its own strengths, limitations, and role at various stages of the disease process. Coronary CT angiography is useful for evaluation of CAAs as it provides assessment of the entire coronary tree, CAA size, structure, wall, and lumen characteristics and visualization of other cardiothoracic vasculature. Knowledge of the natural history of KD, the spectrum of other conditions that can cause CAA, and the strengths and limitations of cardiovascular imaging are all important factors in imaging decisions and interpretation. Keywords: Pediatrics, Coronary Arteries, Angiography, Cardiac © RSNA, 2021.

Prospective randomized trial of venous cardiac computed tomographic angiography for facilitation of cardiac resynchronization therapy.

BACKGROUND: Cardiovascular computed tomographic angiography (CTA) can visualize the coronary veins. We sought to assess the ability of CTA to facilitate resynchronization therapy (CRT) procedures using a prospective randomized single-center pilot study. METHODS: Patients underwent CTA for characterization of cardiomyopathy prior to biventricular implantable cardiac-defibrillator implant. Randomization was performed with operator review of the CTA for coronary venous anatomy prior to CRT in one-half of the cases. Invasive coronary venous angiograms were used in all procedures. Analysis included procedure times and utilization of contrast, fluoroscopy, and guide catheters. RESULTS: Characteristics of the 26 patients enrolled were mean age 55 ± 11 years, male 76.9%, ischemic etiology 35%, ejection fraction 25 ± 3%, class III congestive heart failure 100%, and QRS duration 179 ± 29 ms. Of patients enrolled, 22 had both CTA and procedure initiation. Three patients (two with CTA review and one without CTA review) had aborted procedures due to hemodynamic issues. Analysis of the 22 patients (nine with preprocedure CTA review and 13 without CTA review) demonstrated that preprocedure review of CTA coronary venous anatomy led to significantly decreased procedure times and utilization of contrast, fluoroscopy, and guide catheters. CONCLUSIONS: Preprocedure review of CTA coronary venous anatomy may lead to decreased procedural times and utilization of contrast, fluoroscopy, and guide catheters. These preliminary results will need to be evaluated in larger heart failure populations undergoing CRT.

Cardiovascular Computed Tomographic Angiography as a Virtual Patient Avatar for Individualized Surgical Planning of Complex Anomalous Coronary Artery Anatomy.

Cardiovascular computed tomographic angiography (CCTA) 3-D thoracic reconstruction can serve as a "virtual patient avatar" providing surgical views for approach to complex anomalous coronary artery anatomy. Images demonstrated a single coronary artery ostium arising from the right aortic sinus with trifurcation into a prepulmonic left anterior descending coronary artery (LAD), an interarterial circumflex with a subsequent intraseptal course, and normal course of the right coronary artery. Virtual 3-D CCTA reconstructions were important to planning an incisional plane for surgical correction.

Virtual medicine: Utilization of the advanced cardiac imaging patient avatar for procedural planning and facilitation.

Advances in imaging technology have led to a paradigm shift from planning of cardiovascular procedures and surgeries requiring the actual patient in a "brick and mortar" hospital to utilization of the digitalized patient in the virtual hospital. Cardiovascular computed tomographic angiography (CCTA) and cardiovascular magnetic resonance (CMR) digitalized 3-D patient representation of individual patient anatomy and physiology serves as an avatar allowing for virtual delineation of the most optimal approaches to cardiovascular procedures and surgeries prior to actual hospitalization. Pre-hospitalization reconstruction and analysis of anatomy and pathophysiology previously only accessible during the actual procedure could potentially limit the intrinsic risks related to time in the operating room, cardiac procedural laboratory and overall hospital environment. Although applications are specific to areas of cardiovascular specialty focus, there are unifying themes related to the utilization of technologies. The virtual patient avatar computer can also be used for procedural planning, computational modeling of anatomy, simulation of predicted therapeutic result, printing of 3-D models, and augmentation of real time procedural performance. Examples of the above techniques are at various stages of development for application to the spectrum of cardiovascular disease processes, including percutaneous, surgical and hybrid minimally invasive interventions. A multidisciplinary approach within medicine and engineering is necessary for creation of robust algorithms for maximal utilization of the virtual patient avatar in the digital medical center. Utilization of the virtual advanced cardiac imaging patient avatar will play an important role in the virtual health care system. Although there has been a rapid proliferation of early data, advanced imaging applications require further assessment and validation of accuracy, reproducibility, standardization, safety, efficacy, quality, cost effectiveness, and overall value to medical care.

Taser-induced rapid ventricular myocardial capture demonstrated by pacemaker intracardiac electrograms.

INTRODUCTION: A Taser weapon is designed to incapacitate violent individuals by causing temporary neuromuscular paralysis due to current application. We report the first case of a Taser application in a person with a dual-chamber pacemaker demonstrating evidence of Taser-induced myocardial capture. METHODS AND RESULTS: Device interrogation was performed in a 53-year-old man with a dual-chamber pacemaker who had received a Taser shot consisting of two barbs delivered simultaneously. Assessment of pacemaker function after Taser application demonstrated normal sensing, pacing thresholds, and lead impedances. Stored event data revealed two high ventricular rate episodes corresponding to the exact time of the Taser application. CONCLUSIONS: This report describes the first human case of ventricular myocardial capture at a rapid rate resulting from a Taser application. This raises the issue as to whether conducted energy devices can cause primary myocardial capture or capture only in association with cardiac devices providing a preferential pathway of conduction to the myocardium.

Multiphase contrast medium injection for optimization of computed tomographic coronary angiography.

RATIONALE AND OBJECTIVES: Electron beam angiography is a minimally invasive imaging technique. Adequate vascular opacification throughout the study remains a critical issue for image quality. We hypothesized that vascular image opacification and uniformity of vascular enhancement between slices can be improved using multiphase contrast medium injection protocols. MATERIALS AND METHODS: We enrolled 244 consecutive patients who were randomized to three different injection protocols: single-phase contrast medium injection (Group 1), dual-phase contrast medium injection with each phase at a different injection rate (Group 2), and a three-phase injection with two phases of contrast medium injection followed by a saline injection phase (Group 3). Parameters measured were aortic opacification based on Hounsfield units and uniformity of aortic enhancement at predetermined slices (locations from top [level 1] to base [level 60]). RESULTS: In Group 1, contrast opacification differed across seven predetermined locations (scan levels: 1st versus 60th, P < .05), demonstrating significant nonuniformity. In Group 2, there was more uniform vascular enhancement, with no significant differences between the first 50 slices (P > .05). In Group 3, there was greater uniformity of vascular enhancement and higher mean Hounsfield units value across all 60 images, from the aortic root to the base of the heart (P < .05). CONCLUSIONS: The three-phase injection protocol improved vascular opacification at the base of the heart, as well as uniformity of arterial enhancement throughout the study.

Digital monitoring and care: Virtual medicine.

Remote digital health monitoring technologies can be synergistically organized to create a virtual medical system providing more continuous care centered on the patient rather than the bricks and mortar medical complex. Utilization of the digitalized patient health monitoring can facilitate diagnosis, treatment plans, physician-patient interaction, and accelerate the progress of medical research, education, and training. The field of cardiac electrophysiology has been an early adopter of this shift in care and serves as a paradigm applicable to all areas of medicine. The overall impact of this remote virtual care model on the quality of medical care and patient experience requires greater study, as well as vigilance as to the differences between technology and care in order to preserve the intangible and immeasurable factors that bring humanity to the art and science of medicine.

Coronary venous imaging with electron beam computed tomographic angiography: three-dimensional mapping and relationship with coronary arteries.

BACKGROUND: The coronary venous system can provide vascular access for diagnostic and therapeutic procedures. Visualization of the coronary veins and their relationship to other cardiac structures may play an important role in facilitating these procedures. We sought to assess the ability of electron beam computed tomographic angiography (EBCTA) to characterize 3-dimensional (3-D) coronary venous anatomy. METHODS: Two hundred thirty-one consecutive EBCTA coronary studies were analyzed. The coronary venous system was mapped and analyzed using 2- and 3-D images with definition of diameter and angulations of branch vessels and distance from CS os. RESULTS: The coronary sinus (CS), great cardiac, middle cardiac, left ventricular (LV) anterior interventricular, LV marginal, LV posterior, left atrial, and right atrial veins were visualized in 100%, 100%, 100%, 100%, 78%, 81%, 6%, and 8% of the studies, respectively, with definition of diameter and angulations of branch vessels and distance from CS os. There was a significant linear correlation between CS diameter and right atrial end systolic volume (R = 0.244, n = 81, P < .05). No significant correlation existed between CS os diameter and other cardiac size or function parameters. The 3-D spatial arrangements between the coronary veins and the coronary arteries in relation to the epicardium were able to be defined, on the basis of the vessel closer to the epicardium in overlapping segments. CONCLUSIONS: EBCTA can provide 3-D visualization of most components of the coronary venous system and definition of the spatial relationships with coronary arteries. EBCTA may potentially serve as a useful noninvasive tool for coronary venous imaging for procedures involving coronary veins, such as resynchronization therapy.

Comparison of coronary artery calcium screening image quality between C-150 and e-Speed electron beam scanners.

RATIONALE AND OBJECTIVE: The newest generation of electron beam tomographic scanner (e-Speed) has increased spatial and temporal resolution compared with the C-150 XP scanner. The aim of this study was to evaluate coronary artery calcium screening image quality between the e-Speed and C-150 scanners (GE Imatron, San Francisco, CA). MATERIALS AND METHODS: Studies from 41 patients (14 women and 27 men) who underwent serial coronary artery calcium screening with the C-150 (first study) and the e-Speed (second study) were analyzed. Individual computed tomography (CT) slices were assessed for coronary artery motion artifacts, and CT Hounsfield units (HU) and noise values (CT HU standard deviation) at 16 discrete cardiac sites were measured and averaged. RESULTS: With the e-Speed scanner, there were significant decreases in right coronary artery motion artifacts compared with the C-150 scanner (0.3% versus 1.8%, P < .001) as well as decreased noise values (24.3 versus 32.0 HU, P < .001). CONCLUSION: Image quality is significantly improved with use of the e-Speed scanner, due to its improved temporal and spatial resolution, compared with the C-150 scanner.

Computed tomographic cardiovascular imaging.

The chapter presents the Cardiac CT for the assessment of cardiovascular pathology with an emphasis on the detection of coronary atherosclerosis. Cardiac CT is a robust technology for the non-invasive assessment for a spectrum of cardiovascular disease processes. This imaging modality can provide assessment of atherosclerotic plaque burden and coronary artery disease risk through coronary calcium scoring. Advances in spatial and temporal resolution, electrocardiographic triggering methodology, and image reconstruction software have helped in the evaluation of coronary artery anatomy and vessel patency, providing the ability to noninvasively diagnose or rule out significant epicardial coronary artery disease. This technique also allows the 3-Dimensional simultaneous imaging of additional cardiac structures including coronary veins, pulmonary veins, atria, ventricles, aorta and thoracic arterial and venous structures, with definition of their spatial relationships for the comprehensive assessment of a variety of cardiovascular disease processes.

Electrocardiographic patch devices and contemporary wireless cardiac monitoring.

Cardiac electrophysiologic derangements often coexist with disorders of the circulatory system. Capturing and diagnosing arrhythmias and conduction system disease may lead to a change in diagnosis, clinical management and patient outcomes. Standard 12-lead electrocardiogram (ECG), Holter monitors and event recorders have served as useful diagnostic tools over the last few decades. However, their shortcomings are only recently being addressed by emerging technologies. With advances in device miniaturization and wireless technologies, and changing consumer expectations, wearable "on-body" ECG patch devices have evolved to meet contemporary needs. These devices are unobtrusive and easy to use, leading to increased device wear time and diagnostic yield. While becoming the standard for detecting arrhythmias and conduction system disorders in the outpatient setting where continuous ECG monitoring in the short to medium term (days to weeks) is indicated, these cardiac devices and related digital mobile health technologies are reshaping the clinician-patient interface with important implications for future healthcare delivery.

Methodology for improved detection of coronary stenoses with computed tomographic angiography.

BACKGROUND: Noninvasive angiography is a promising technique for visualization of the coronary lumen; however, current methodologies lead to limited accuracy. We assessed the accuracy of electron beam computed tomographic angiography (EBA) for detection of coronary stenoses, using improved triggering techniques and thinner slice collimation. METHODS: Eighty-six patients with suspected coronary disease were studied with EBA and conventional invasive coronary angiography. Electrocardiographic triggering was performed at a fixed time in end systole to reduce cardiac motion. Thin (1.5 mm) slices were obtained with 1.5 mm table incrementation. In axial (2-dimensional) EBA images and 3-dimensional reconstructions, all coronary arteries and side branches with a diameter of >or=1.5 mm were assessed for the presence of stenoses with >50% diameter reduction. Both EBA and invasive angiographic images were assessed in a blinded manner. RESULTS: In comparison to invasive coronary angiography, EBA correctly classified 49 of 53 patients (92%) as having at least 1 coronary stenosis. Overall, 103 stenoses with >50% diameter reduction were present, and 93 of these lesions were correctly detected by EBA (sensitivity 90%, specificity 93%, positive predictive value 84%, and negative predictive value 96%). Only 5% of vessels could not be assessed, predominantly due to significant calcification. CONCLUSIONS: Thinner slice collimation and end-systolic electrocardiographic triggering improves accuracy and assessment of coronary EBA for the detection of obstructive coronary artery disease, making this study clinically useful in the evaluation of obstructive coronary artery disease.