The Wearable Cardioverter-Defibrillator

The wearable cardioverter-defibrillator (WCD) is a rechargeable external device that can be worn under the clothing all day long and protects the wearer from potentially life-threatening ventricular tachyarrhythmias. When a dangerous arrhythmia is detected, the WCD can deliver high-energy shocks. The WCD has been shown to be effective in accurately detecting and appropriately treating ventricular tachycardia (VT) and ventricular fibrillation (VF). It is intended for temporary use as a bridge to an implantable cardioverter-defibrillator (ICD), heart transplantation, or left ventricular assist device; patients with heart failure with reduced ejection fraction may benefit from the WCD while their condition improves. It can be used temporarily after explant of an ICD until reimplantation is deemed possible. In select patients with myocardial infarction, a WCD may be useful during the immediate period after infarction. It is indicated for use when a permanently implanted ICD must be explanted because of infection; the patient can use the WCD until the infection resolves, and a new ICD can be implanted. The role of the WCD is emerging as an important therapeutic option to protect patients at elevated risk of sudden cardiac death (SCD)

The Subcutaneous Implantable Cardioverter-Defibrillator

The subcutaneous ICD (S-ICD) represents an important advancement in defibrillation therapy that obviates the need for a transvenous lead, the most frequent complication with transvenous devices. The S-ICD has been shown similarly safe and effective as transvenous ICD therapy, but the two devices are not interchangeable. The S-ICD is only suitable for patients who do not require bradycardia or antitachycardia pacing functionality. In patients with underlying diseases associated with polymorphic ventricular tachycardia and a long life expectancy, an S-ICD may be the preferred choice. Moreover, it is advantageous in the situation of increased risk of endocarditis, i.e., previous device system infection and immunosuppression, including hemodialysis. In patients with abnormal vascular access and/or right-sided heart structural abnormalities, it may be the only option. The S-ICD is bulkier, the battery longevity is shorter, and the device cost is higher, even though remote follow-up is possible. A two- or three-incision implant procedure has been described with a lateral placement of the device and a single subcutaneous lead. The rate of inappropriate therapy for both S-ICD and transvenous systems is similar, but S-ICD inappropriate shocks are more frequently attributable to oversensing, which can often be resolved with sensing adjustments

Gabapentinoid use disorder. Update for clinicians

Gabapentinoids (gabapentin and pregabalin) are versatile drugs, indicated mainly for epilepsy and neuropathic pain, and have long been viewed as agents with little potential for abuse. Burgeoning prescribing patterns and studies indicate that these drugs are increasingly being abused, particularly by polydrug abusers who also abuse opioids. Gabapentinoid abuse is found in less 2% of the general population but may be as high as 15% to 22% among opioid abusers. Other risk factors for gabapentinoid abuse are less clear-cut but include mental health disorders. Gabapentinoids are relatively easy for drug abusers to obtain and many clinicians are not fully aware of their abuse potential. It is thought that gabapentinoids may offer psychoactive effects or enhance the effects of other drugs of abuse. Those who discontinue gabapentinoids abruptly may suffer withdrawal symptoms, but gabapentinoid overdose fatality is rare. Since gabapentinoids are often prescribed off-label to treat psychiatric disorders, these drugs may be dispensed to a particularly vulnerable population. Clinicians must be aware of the potential for Gabapentinoid Use Disorder: Update for Clinicians

Sudden Cardiac Death in Hereditary Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) is characterized by the phenotype of a dilated left ventricle with systolic dysfunction. It is classified as hereditary when it is deemed of genetic origin; more than 50 genes are reported to be related to the condition. Symptoms include, among others, dyspnea, fatigue, arrhythmias, and syncope. Unfortunately, sudden cardiac death may be the first manifestation of the disease. Risk stratification regarding sudden death in hereditary DCM as well as preventive management poses a challenge due to the heterogeneity of the disease. The purpose of this chapter is to present the epidemiology, risk stratification, and preventive strategies of sudden cardiac death in hereditary DCM

Leadless Pacemakers

Leadless or transcatheter pacemakers have recently been introduced to market with important benefits and some limitations. Implanted entirely within the right ventricle, these devices eliminate the need for transvenous pacing leads and pacemaker pockets and thus reduce the risk of infections and lead-related problems. Currently, they offer only VVI/R pacing and they cannot provide atrial sensing, antitachycardia pacing, or AV synchrony. They offer a number of features (such as rate response) and electrogram storage, albeit more limited than in a transvenous system. Real-world clinical data are needed to better comment on projected battery life, which manufacturers suggest will be at least equivalent to transvenous devices. Extracting an implanted leadless pacemaker remains a challenge, although proprietary snare and removal systems are available. However, a leadless pacemaker at end of service may be programmed to OOO and left in place; a revised device may be implanted adjacent. These innovative new devices may have important uses in special populations. Initial data on implant success and adverse events are favorable. Currently, there are two leadless pacemakers available: the Micra™ device by Medtronic and the Nanostim™ device by Abbott (formerly St. Jude Medical)

Postoperative Pain Control Following Cardiac Implantable Electronic Device Implantation

Postoperative pain following cardiac implantable electronic device (CIED) surgery may not always be adequately treated. The postoperative pain trajectory occurs over several days following the procedure with tenderness and limited arm range of motion lasting for weeks after surgery. Pain control typically commences in the perioperative period while the patient is in the hospital and may continue after discharge; outpatients may be given a prescription and advice for their analgesic regimen. It is not unusual for CIED patients to be discharged a few hours after implantation. While opioids are known as an effective analgesic to manage acute postoperative pain, growing scrutiny on opioid use as well as their side effects and potential risks have limited their use. Opioids may be considered for appropriate patients for a short course of treatment of acute postoperative pain, but other analgesics may likewise be considered

Atrial Fibrillation and the Role of Thumb ECGs

Atrial fibrillation (AF) may be underdiagnosed, and there is much that remains unknown about this prevalent and potentially life-threatening arrhythmia. AF epidemiology has been thwarted in part by the fact that about a third of patients with AF have no symptoms, those with symptoms may experience them intermittently or have vague symptoms, and it can be challenging to capture an episode on a 12-lead ECG, which is required for diagnosis. There are many significant knowledge gaps in our understanding of AF etiology and progression. A new user-friendly device that allows for frequent self-monitoring of the heart rhythm has been introduced. With the thumb ECG, patients can record a tracing multiple times a day. A smartphone app will soon allow them to interact with their healthcare providers about these ECG recordings. An ECG parser will allow for an algorithm-directed, rapid, automatic interpretation of these recordings with high specificity and sensitivity. This may help researchers learn more about the so-called silent AF, AF progression (and possible remission), and risk factors for AF. This technology holds great promise for patient care as well as for research into AF

Anticoagulation in Atrial Fibrillation Patients

Atrial fibrillation (AF) is the most common arrhythmia and may cause thromboembolic events, typically stroke. Advances in pharmacological approaches to anticoagulation and groundbreaking large randomized controlled trials of non-vitamin K antagonist oral anticoagulants (NOACs) have changed the paradigm of anticoagulation therapy. Furthermore, observational studies support the efficacy and safety of NOAC. Few studies address the differences among NOACs, but prescriptions should be based on a thorough understanding of their pharmacological differences, including interactions, side effects, reversibility, and practical approach. In a subset of patients with AF, warfarin may still be the preferable option. Consequently, an individualized approach to oral anticoagulation is crucial

A closer look at opioid-induced adrenal insufficiency. A narrative review

Among several opioid-associated endocrinopathies, opioid-associated adrenal insufficiency (OIAI) is both common and not well understood by most clinicians, particularly those outside of endocrine specialization. OIAI is secondary to long-term opioid use and differs from primary adrenal insufficiency. Beyond chronic opioid use, risk factors for OIAI are not well known. OIAI can be diagnosed by a variety of tests, such as the morning cortisol test, but cutoff values are not well established and it is estimated that only about 10% of patients with OIAI will ever be properly diagnosed. This may be dangerous, as OIAI can lead to a potentially life-threatening adrenal crisis. OIAI can be treated and for patients who must continue opioid therapy, it can be clinically managed. OIAI resolves with opioid cessation. Better guidance for diagnosis and treatment is urgently needed, particularly in light of the fact that 5% of the United States population has a prescription for chronic opioid therapy