Remote-control Interrogation, Testing, and Reprogramming of Cardiac Implantable Electronic Devices with Telehealth Protocol for the Management of Patients at Home: The DOMUM REMOTUS Study.

Remote control (RC) of cardiac implantable electronic devices (CIEDs) has been tested as safe and effective in the magnetic resonance imaging space. We sought to evaluate RC applications of patients at home. RC of cardiac devices in patients' homes is feasible, safe, and effective, with consistent patient satisfaction. Patients with CIEDs using the CareLink™ network (Medtronic, Minneapolis, MN, USA) participated in a pair of home RC sessions. A technician visited the patient's house and set up a telehealth tablet and a programmer, which included inputting a session key enabling programmer access via a third-party host. The investigator video-conferenced with the patient and remotely controlled the programmer for device testing and data assessment, using a cellular hotspot for Internet connection. Reprogramming was performed as necessary. In all cases, an RC session legend was programmed in the device information field as a control. The patients then completed an experience questionnaire. One hundred fifty patients (99 pacemakers and 51 implantable cardioverter-defibrillators) completed 2 RC sessions, for 300 RC sessions in total. There were no complications or communication interruptions once the system communication proved stable after the first minute. In 26 sessions, initial communication was interrupted upon device interrogation, requiring communication to be re-established (which sometimes necessitated switching to an alternative carrier). Clinically driven parameter reprogramming was performed in 58 RC sessions (39%). Programming of notations concerning RC sessions was performed in all 300 sessions. The average duration of the RC sessions was 11 min. Patients' satisfaction scored 4.5 out of 5 points. In conclusion, RC management of cardiac devices at patients' homes is safe, effective, convenient, and associated with high patient satisfaction. This technology may prove very useful in a changing health care delivery system, especially amid the coronavirus disease 2019 pandemic.

Preliminary results from the LUX-Dx insertable cardiac monitor remote programming and performance (LUX-Dx PERFORM) study.

Despite the wide adoption of insertable cardiac monitors (ICMs), high false-positive rates, suboptimal signal quality, limited ability to detect atrial flutter, and lack of remote programming remain challenging. The LUX-Dx PERFORM study was designed to evaluate novel technologies engineered to address these issues. Here, we present preliminary results from the trial focusing on the safety of ICM insertion, remote monitoring rates, and the feasibility of remote programming. LUX-Dx PERFORM is a multicenter, prospective, single-arm, post-market, observational study with planned enrollment of up to 827 patients from 35 sites in North America. A preliminary cohort consisting of the first 369 patients who were enrolled between March and October 2021 was selected for analysis. Three hundred sixty-three (363) patients had ICM insertions across inpatient and outpatient settings. The mean time followed was 103.4 ± 61.8 days per patient. The total infection rate was 0.8% (3/363). Interim results show high levels of remote monitoring with a median 94% of days with data transmission (interquartile range: 82-99). Thirteen (13) in-clinic and 24 remote programming sessions were reported in 34 subjects. Reprogramming examples are presented to highlight signal quality, the ability to detect atrial flutter, and the positive impact of remote programming on patient management. Interim results from LUX-Dx PERFORM study demonstrate the safety of insertion, high data transmission rates, the ability to detect atrial flutter, and the feasibility of remote programming to optimize arrhythmia detection and improve clinical workflow. Future results from LUX-Dx PERFORM will further characterize improvements in signal quality and arrhythmia detection.

Incidental Cardiac Computed Tomography Findings in Patients Undergoing Atrial Fibrillation Catheter Ablation.

BACKGROUND: Catheter ablation (CA) is an effective technique for the management of atrial fibrillation (AF). Cardiac computed tomography (CCT) is a non-invasive imaging modality that is used as a crucial part of planning before CA procedures which can detect other incidental findings and require further diagnostic investigations. OBJECTIVES: We sought to assess the prevalence and distribution of incidental CCT findings in patients with AF undergoing CA. METHODS: Retrospective analysis over a three-year period (2013-2016) of 218 patients undergoing CCT prior to AF CA. CCT findings were analyzed and incident clinically important findings were reported. RESULTS: Over the three-year period, 218 patients had undergone CCT. Of these, 28.8% showed clinically significant incidental findings in the chest and upper abdomen. Incidental findings included coronary artery disease (CAD), incomplete cor triatriatum, pericardial effusion, pleural effusion, pulmonary nodules, pulmonary infiltrates, pulmonary mass, thoracic aortic aneurysm, mediastinal nodes, abdominal mass, and liver nodules. CONCLUSIONS: CCT is a cornerstone investigation prior to AF CA and can show multiple incidental findings, thus potentially functioning as a screening method for the detection of other significant conditions. There is still a debate whether further workup is needed or not as most findings will eventually be benign and further investigations could mean financial burden and clinical risks to the patients. Further larger prospective studies are needed with long-term follow-up to determine whether incidental findings on CCT have an impact on the long-term outcomes of patients.

Treatment of Cryptogenic Stroke Patients with Atrial Fibrillation Detected by Insertable Cardiac Monitors Reduces Recurrent Stroke Risk to Background Levels.

Atrial fibrillation (AF) is a known risk factor of ischemic stroke with a reported fivefold increase in incidence. However, it is not well established whether treatment with oral anticoagulation (OAC) in cryptogenic stroke patients with AF, detected by insertable cardiac monitors (ICMs), reduces the risk of recurrent stroke. We aimed to compare recurrent stroke rates between cryptogenic stroke patients who have AF detected by ICMs and thus started on OAC treatment and those without detected AF. We performed a combined retrospective and prospective analysis of consecutive patients who received an ICM indicated for cryptogenic stroke and were followed up with between July 2015 and November 2019. Patients with a prior documented history of AF were excluded. All patients were required to have a home remote monitoring system. We calculated the rates of AF detection and OAC initiation, then compared recurrent annualized stroke rates (ASRs) between patients with and without AF detected. A total of 298 patients with ICMs were included in the study [mean ± standard deviation age: 77 ± 11.7 years; female/male: 147/151; virtual CHA2DS2-VASc score: 4.96 ± 1.28 points]. AF was discovered in 91 patients (~30%) over a mean 19.3 months follow-up. Of those, 65 (71.4%) were started on OAC, 12 (13.2%) were already on OAC, and 10 (11%) remained non-anticoagulated. In four (4.4%) patients, OAC was started after recurrent stroke when AF was diagnosed. A total of 24 of 298 patients developed recurrent strokes (ASR: 5.0%). Among the 24 patients with recurrent strokes, four had new AF and were on OAC (ASR: 3.23%), six had new AF and were not anticoagulated (ASR: 26.62%), and 14 had no AF detected and no OAC (ASR: 4.20%). Our study found new AF detected by ICMs in almost one-third (30%) of cryptogenic stroke patients (consistent with previous studies), and the majority of them (89%) received OACs. There was no significant difference in the recurrent stroke rate among patients without AF detected and those with AF detected and on OAC. Rigorous arrhythmia monitoring using ICMs can increase new AF detection rates in cryptogenic stroke patients, thereby allowing early initiation of OACs, ultimately reducing the risk of recurrent stroke to background levels.

A rare case of Brugada syndrome induced by hyperglycemia.

Brugada syndrome is a rare genetic disorder of the cardiac sodium channels associated with an increased risk of sudden cardiac death. It is characterized by an electrocardiogram (EKG) showing a right bundle branch block with an elevation in the ST segment. This condition is associated with mutations in several pathologic genes including the most notable mutation in the SCN5A gene, which encodes for a voltage-gated cardiac sodium channel. The Brugada pattern on EKG can be spontaneous but can also be induced by a variety of etiologies including fever, electrolyte abnormalities, increased vagal tone and drugs such as sodium channel blockers, calcium channel blockers, tricyclic antidepressants and alcohol. One uncommon cause of Brugada syndrome is hyperglycemia. Of particular importance in diabetic patients, hyperglycemia can induce chronic cardiovascular complications as well as acute cardiac events via the induction of the Brugada pattern on EKG. We present a case of a 21-year-old non-insulin compliant diabetic man presenting to the Emergency Department with diabetic ketoacidosis (DKA) who exhibits the Brugada pattern EKG prior to developing ventricular tachycardia followed by cardiac arrest. The patient's condition was induced by prolonged hyperglycemia in the setting of DKA with relatively mild electrolyte and pH abnormalities. Herein, this case is presented to highlight the Brugada pattern leading to cardiac arrest as a potential consequence of hyperglycemia and inform physicians on its incidence.

Impact of Remote Monitoring on Hospitalizations for Heart Failure: A Five-year Single-center Experience.

The impact of a provider-driven assessment and treatment algorithm based on remote OptiVol (Medtronic, Minneapolis, MN, USA) fluid index levels on hospitalizations for congestive heart failure (CHF) remains unknown. We implemented a physician-guided screening and educational strategy for elevated OptiVol fluid index levels measured on remote implantable cardioverter-defibrillator (ICD) monitoring and assessed clinical outcomes over a five-year period. Patients with CHF and a left ventricular ejection fraction (LVEF) of 40% or less with a previously implanted ICD underwent monthly remote monitoring from January 2015 to November 2019. An OptiVol fluid index of 60 Ω-days or more triggered a protocol-based CHF screening and therapy adjustment according to clinical presentation. Among 279 patients included in the study, 228 (81%) were male and 205 (73%) had ischemic cardiomyopathy. The average LVEF was 29% (± 7.3%). A total of 6,616 monthly transmissions were reviewed over five years; of those, 575 (8.7%) were associated with elevated OptiVol fluid index levels in 178 (64%) patients, and clinical follow-up data were available in 459 of 575 (80%) cases. Following abnormal OptiVol fluid levels on remote monitoring, CHF hospitalization occurred in 10 of 459 (2.2%) patient cases. In conclusion, monthly remote monitoring of OptiVol fluid index levels with a health care provider-guided CHF screening and an educational approach to abnormal OptiVol fluid index levels were associated with a low CHF hospitalization rate. This compared favorably to prior similar studies, and randomized controlled prospective studies evaluating similar algorithms are warranted.

Remote Control of Cardiac Implantable Electronic Devices: Exploring the New Frontier-First Clinical Application of Real-time Remote-control Management of Cardiac Devices Before and After Magnetic Resonance Imaging.

The purpose of the present study was to evaluate the performance of remote-control (RC) management of cardiac implantable electronic devices (CIEDs) in clinical practice using a new service model in patients undergoing magnetic resonance imaging (MRI) scans. The number of CIEDs is constantly growing, alongside the demands for prompt checks. Although remote CIED interrogation exists, ultimately, real-time remote management is the goal. In this study, patients with MRI-conditional devices suitable for RC interaction who required an MRI were enrolled. An onsite technician began the RC session by contacting the remote operator, applying the programmer wand, and keying in an access code. The device was remotely checked via encrypted Wi-Fi by an electrophysiologist using a laptop. An MRI-safe mode was programmed per a preestablished proprietary algorithm. Following the scan, patient devices were remotely reinterrogated and reprogrammed to baseline, with adjustments made as clinically necessary. Patients subsequently were asked to complete a survey. Ultimately, a total of 100 RC CIED reprogrammings were performed in 50 MRI sessions, prescan and postscan. The average RC time interaction was four minutes prescan and three minutes postscan, respectively. No complications occurred. Five patients had more than one MRI in this study and 15 patients had had previous MRIs. In eight patients, baseline settings were reprogrammed. Most patients (82%) were very satisfied, preferring device specialist remote management. Only 14 (32%) patients used home remote monitoring. In conclusion, RC management of CIEDs in the MRI setting is feasible, safe, and clinically relevant. Use of the MRI mode determination algorithm was safe, consistent, and efficient. Expanding RC in CIED management for service anytime, anywhere is the next challenge.

The Axillary Fossa: An Uncovered Hidden Site as a New Alternative for Cardiac Pacemaker and Defibrillator Implantation.

Inadequate thickness of subcutaneous tissue, pectoralis muscle wasting, and/or a lack of availability of subpectoral space can become significant issues in patients with or requiring cardiovascular implantable electronic devices (CIEDs). This is particularly concerning but not exclusive in the elderly population, who may experience discomfort and hypersensitivity of the site as well as the potential for erosion and an increased risk of infection. Thus, the use of an alternative location, the axillary fossa, offers several advantages that make it a suitable option. Specifically, it usually has a preserved fat pad (even in thin patients); is unperturbed by arm movement; is not directly exposed to contact; is easily accessed with no significant compromise of neurovascular structures; and is near the conventional subclavicular sites, with enough lead length to reach in case of the need for generator replacement. Here, we present a series of five patients, including details of their anatomy and the implant techniques used. Two underwent device replacements, with one of them presenting with significant ongoing site discomfort and the other with extreme tissue thinning, respectively. Two patients with no significant fat layer or pectoral muscle wasting had new pacemakers implanted. Lastly, a biventricular implantable cardioverter-defibrillator generator was reimplanted in a younger patient who had issues with protrusion and discomfort in the setting of thin subcutaneous tissue and the subpectoral space being occupied by a large breast implant. In conclusion, the use of the axillary fossa as a new alternative CIED implantation site, using the proposed implant technique, appears feasible and safe and demonstrated excellent results related to patient comfort and adequate device cover in five cases.

Resetting criteria during ventricular overdrive pacing successfully differentiate orthodromic reentrant tachycardia from atrioventricular nodal reentrant tachycardia despite interobserver disagreement concerning QRS fusion.

BACKGROUND: The beginning of ventricular overdrive pacing (VOP) during supraventricular tachycardia (SVT) accurately distinguishes orthodromic reentrant tachycardia (ORT) from atrioventricular nodal reentrant tachycardia (AVNRT) even when pacing terminates tachycardia. Tachycardia resetting most often occurs during this transition zone (TZ) of QRS fusion in ORT and after this TZ in AVNRT. The end of the TZ is marked by the first beat with a stable QRS morphology but is a subjective assessment. Disagreement concerning this beat may change tachycardia diagnosis. OBJECTIVE: The purpose of this study was to assess interobserver agreement for identifying the TZ and whether disagreement affected diagnosis. METHODS: Seventy-nine consecutive patients with inducible ORT and AVNRT were included. Resetting of tachycardia was evaluated by (1) atrial timing perturbation and (2) fixed stimulation-atrial activation timing (SA). Two blinded observers identified the end of the TZ and used the two resetting criteria to establish a diagnosis. Diagnostic results were compared with standard criteria for SVT diagnosis. The diagnosis was considered correct if both electrophysiologists' TZ assessment resulted in a correct diagnosis. RESULTS: Agreement on the TZ occurred in 80% (148/186) of VOP trains. In ORT patients, tachycardia resetting occurred during the TZ and correctly diagnosed ORT based on atrial timing perturbation and fixed SA in 91% and 98% of VOP trains, respectively. In AVNRT patients, tachycardia resetting occurred after the TZ and correctly diagnosed AVNRT based on atrial timing perturbation and fixed SA in 93% and 94% of VOP trains, respectively. CONCLUSION: Resetting criteria used during the VOP TZ accurately differentiate between ORT and AVNRT despite interobserver disagreement concerning identification of the TZ.

Substrate characterization and catheter ablation for monomorphic ventricular tachycardia in patients with apical hypertrophic cardiomyopathy.

UNLABELLED: VT Ablation in Apical Hypertrophic Cardiomyopathy. INTRODUCTION: Monomorphic ventricular tachycardia (VT) is uncommon in apical hypertrophic cardiomyopathy (HCM). The purpose of this study was to define the substrate and role of catheter ablation for VT in apical HCM. METHODS: Four patients with apical HCM and frequent, drug refractory VT (mean age of 46 ± 10 years, left ventricular [LV] ejection fraction; 54 ± 14%) underwent catheter ablation with the use of electroanatomic mapping. Endocardial mapping was performed in 4 patients and 3 patients underwent epicardial mapping. RESULTS: In 3 patients, VT was related to areas of scar in the apical LV where maximal apical wall thickness ranged from 14.5 to 17.8 mm, and 2 patients had apical aneurysms. Endocardial and epicardial substrate mapping revealed low voltage (<1.5 mV) scar in both endocardial and epicardial LV in 2 and only in the epicardium in 1 patient. Inducible VT was abolished with a combination of endocardial and epicardial ablation in 2 patients, but was ineffective in the third patient who had intramural reentry that required transcoronary ethanol ablation of an obtuse marginal vessel for abolition. The fourth patient had focal nonsustained repetitive VT from right ventricular outflow tract (RVOT), consistent with idiopathic RVOT-VT, that was successfully ablated. During follow-ups of 3-9 months, all patients remained free from VT. CONCLUSION: Monomorphic VT in apical HCM can be due to endocardial, epicardial or intramural reentry in areas of apical scar. Epicardial ablation or transcoronary alcohol ablation is required in some cases.

The origin of epicardial ventricular tachycardia revealed by entrainment from a permanent epicardial left ventricular pacing lead.

Entrainment From Left Ventricular Pacing Lead. Recognizing ventricular tachycardias (VTs) that require epicardial ablation is desirable, but challenging when prior surgery prevents percutaneous epicardial mapping. This patient had cardiomyopathy, prior cardiac surgery, and VT that failed endocardial ablation. Observing that the Bi-V implantable cardioverter defibrillator (ICD), left ventricular (LV) lead was epicardial to the area of infarct scar, it was used to pace during VT. Entrainment with concealed fusion with long stimulus to QRS interval, consistent with an epicardial VT circuit, was observed. Surgical cryoablation targeting the area around the LV lead eliminated VT. Thus pacing maneuvers from permanent epicardial leads can occasionally help identify an epicardial VT origin.

Ventricular arrhythmias in patients treated with methadone for opioid dependence.

PURPOSE: Over the last decade, there has been a significant rise in reported cases of methadone induced QT prolongation (QTP) and Torsades de Pointes (TdP) in patients treated for opioid dependence. Optimal management of these patients is challenging. METHODS: We report a case series of 12 consecutive patients admitted to our institution with methadone-induced QTP and ventricular arrhythmias. RESULTS: All patients survived the presenting arrhythmia. Successful transition to buprenorphine was accomplished in three patients. QT interval normalized and none of these patients had recurrent arrhythmias. Methadone dose was reduced in five patients with improvement of QT interval and resolution of arrhythmia. Four patients, including two with ICDs, refused or did not tolerate a reduction in their methadone dose. CONCLUSION: Ventricular arrhythmias in patients on methadone are an uncommon but important problem. Buprenorphine, a partial micro-opiate-receptor agonist and a kappa-opiate-receptor antagonist does not cause QTP or TdP. Buprenorphine is a useful and effective alternative to methadone in a select group of patients, including those with documented ventricular arrhythmias on methadone. Pacemakers or defibrillators should be reserved for patients who have failed buprenorphine or a reduced methadone dose.

Atrial rate and rhythm abnormalities in a patient with hyperkalemia.

A 67 year old man presented with a serum potassium of 7.7 mEq/L and slow atrial flutter with variable A-V block and peaked T waves. Initial treatment for hyperkalemia was followed by an increase in the atrial flutter rate to 300 beats per minute. After hemodialysis the rhythm converted to sinus.

The role of heart-type fatty acid-binding protein in the diagnosis of acute coronary syndrome.

BACKGROUND: Heart-type fatty acid-binding protein (H-FABP) is a membrane-bound protein that facilitates transport of fatty acids from the blood into the heart. It is currently being used outside the United States for the early diagnosis of myocardial infarction (MI). However, previous studies have shown inconsistent correlation of H-FABP with standard cardiac biomarkers. METHODS: Fifty patients admitted with ST segment elevation MI (n=25), non-ST segment elevation MI (n=15) or unstable angina (n=10) were evaluated. The CardioDetect med cardiac infarction test (rennesens GmbH, Germany) was used to measure both qualitative and quantitative H-FABP. RESULTS: Of the 40 patients with acute MI, the initial troponin assay was positive in 35 patients (88%), the qualitative H-FABP assay was positive in 23 patients (58%) and the quantitative H-FABP assay was positive in 15 patients (38%) (P=0.001). No patient with MI had a positive H-FABP assay with a negative initial troponin assay. CONCLUSION: In the present study, the results of both the qualitative and quantitative H-FABP assays neither appeared earlier nor provided increased sensitivity compared with troponin in diagnosing acute MI. Accordingly, the use of H-FABP as a diagnostic tool for MI is limited.

Successful transition to buprenorphine in a patient with methadone-induced torsades de pointes.

A 56-year-old-man presented with syncope and torsades de pointes secondary to methadone-induced QT prolongation. After transition from methadone to buprenorphine, a partial mu-opiate-receptor agonist and a kappa-opiate-receptor antagonist, the QT normalized and ventricular arrhythmias resolved. Buprenorphine should be used for opiate dependence and chronic pain in patients with methadone-induced QT prolongation and as first line therapy in patients with risk factors for torsades de pointes.

Non-ischemic cardiomyopathy patients derive superior mortality benefit from cardiac resynchronization therapy.

BACKGROUND: Cardiac Resynchronization Therapy (CRT) is indicated for the treatment of advanced heart failure with severe systolic dysfunction and intraventricular conduction delay. Patient selection for this technology is vital, though it remains unclear which patients benefit most from CRT. We tested the hypothesis that patients with non-ischemic cardiomyopathy have a superior mortality benefit from CRT than ischemic cardiomyopathy patients. METHODS: We evaluated 95 CRT patients to determine which factors predict mortality. RESULTS: Patients with non-ischemic cardiomyopathy had a significantly better prognosis than patients with ischemic cardiomyopathy. CONCLUSION: Larger prospective studies can substantiate this finding and better delineate which patients benefit most from CRT.

Wide QRS tachycardia: what is the rhythm?

We report a case of an elderly man who presented to the emergency room complaining of palpitations. Electrocardiogram revealed wide QRS tachycardia with a narrow beat within the tachycardia. Most commonly, a narrow complex beat during a wide complex tachycardia suggests a capture or fusion beat in the setting of ventricular tachycardia. However, there are situations where supraventricular tachycardia can also manifest this way. In our patient a pacemaker interrogation clarified the diagnosis.

Lack of correlation between coronary artery calcium and myocardial perfusion imaging.

BACKGROUND: Coronary artery calcium (CAC) provides evidence of coronary atherosclerosis and has significant prognostic power. Although prior studies have documented a relationship between CAC and hemodynamically significant coronary artery stenosis, the results have not been conclusive. METHODS AND RESULTS: We evaluated 126 consecutive patients who underwent electron beam computed tomography CAC scoring by use of the Agatston method and stress myocardial perfusion imaging (MPI) within 3 months of each other. The analysis revealed no correlation between absolute CAC score and age- and gender-adjusted CAC scores with MPI. Overall, 18% of patients had abnormal MPI results irrespective of their CAC. CONCLUSION: CAC scoring and stress MPI should be thus considered complementary approaches rather than exclusionary in the evaluation of the patient at risk for coronary artery disease.