Journal of Innovations in Cardiac Rhythm Management最新文献

Bundle branch re-entrant (BBR) tachycardia is an uncommon form of ventricular tachycardia (VT). This arrhythmia typically occurs in patients with a structural heart disease, especially dilated cardiomyopathy, and significant conduction system impairment, although affected patients with a structurally normal heart or normal conduction system have been reported. The QRS morphology during tachycardia can vary; it typically has a left bundle branch block (LBBB) morphology in which the antegrade conduction is over the right bundle and the retrograde limb is over the left bundle. The reverse of this circuit results in a right bundle branch block (RBBB) QRS morphology. A re-entrant circuit also can utilize interfascicular conduction, such as antegrade conduction over the left anterior fascicle and retrograde conduction up the left posterior fascicle or vice versa. Although there are reports of BBR tachycardia and interfascicular VT occurring in the same patient, to our knowledge, there are no prior reports of BBR tachycardia that has both LBBB and RBBB morphologies in the same patient. This case illustrated a BBR tachycardia with both left bundle and right bundle branch morphologies occurring in a patient with a non-dilated left ventricle.

Digoxin, a cardiac glycoside and sodium-potassium adenosine triphosphatase inhibitor, has a narrow therapeutic index and is primarily prescribed for conditions such as systolic heart failure and atrial fibrillation. This narrow window increases the risk of toxicity, especially among susceptible populations. Although digoxin use has declined in recent decades and cases of toxicity have become less frequent, clinicians must remain vigilant, particularly with geriatric patients, who are more susceptible due to polypharmacy and reduced renal function. Here, we present a case of a 77-year-old woman with dementia who exhibited elevated digoxin levels and was successfully treated with digoxin immune Fab. While the use of immune Fab in chronic toxicity cases remains uncertain, our retrospective review of similar cases, managed both with and without immune Fab, provides insights into its role and limitations. We further underscore the importance of regular digoxin monitoring rather than checking the levels only during toxic episodes, as consistent monitoring can prevent fatal cases and reduce overall mortality.

Left bundle branch area pacing (LBBAP) is a type of conduction system pacing wherein the left bundle branch and/or the left side of the interventricular septum are stimulated with a permanent pacing lead to maintain physiological electrical activation of the left ventricle. As understanding grows regarding trifascicular activation in the left ventricle and left septal fascicular block (LSFB), there is an indication that new electrocardiographic alterations may emerge, particularly in instances of arterial occlusions. Here, we present a case study delineating LSFB subsequent to LBBAP.

Diagnosing paroxysmal cardiac arrhythmias early poses a challenge, yet it holds paramount significance. Certain patients hold strong beliefs regarding the moon's impact on cardiac arrhythmias. This study aims to examine the potential correlation. In our emergency room, each patient presentation is assigned an "admission diagnosis." An analysis was conducted on admission diagnoses from 2012-2020 (before the coronavirus disease 2019 pandemic). The frequency of rhythmological diagnoses was investigated, both collectively and separately, as well as categorized by the underlying pathomechanism, in relation to the lunar phase and the moon's proximity to the Earth at the time of admission. Moreover, the impacts of sex, age, and weight were evaluated. A total of 58,230 patient presentations were recorded, with 16.9% coded with rhythmological diagnoses. No significant differences were found in the distribution of cardiac arrhythmias concerning lunar phases or the moon-Earth distance. Sex, age, and weight did not influence this distribution, except in a small group of underweight patients (<55 kg), where a statistically significant difference was observed with greater moon distance. To verify this result, we investigated all existing Holter records of underweight patients presenting to the emergency room between 2017 and 2020. In 195 24-h Holter recordings, a uniform burden of supraventricular extrasystoles and atrial fibrillation/flutter irrespective of the moon's distance from the Earth was observed. Contrary to patients' beliefs, the moon does not seem to affect the presentations with rhythmological complaints and diagnoses in our single-center analysis, irrespective of age, sex, or the arrhythmia type. The moon cannot aid in diagnosing paroxysmal arrhythmias.

We present a case report of a patient undergoing implantation of a cardiac contractility modulation (CCM) device. The Optimizer^® Smart Implantable Pulse Generator (Impulse Dynamics, Orangeburg, NY, USA) provides electrical energy to the right ventricular septum to modulate cardiac contractility and improve cardiac function in heart failure patients. The non-excitatory electrical signals are delivered by transvenous leads during the refractory period. Anesthetic administration during implantation can affect appropriate lead positioning. Propofol at high doses can attenuate diaphragmatic contraction and discomfort from inappropriate lead positioning, resulting in diaphragm stimulation. Therefore, local or conscious sedation is preferred during CCM device implantation. In patients undergoing procedures with this CCM device in situ, the Optimizer^® activity causes upward deflections of the RS segment on the electrocardiogram. Also, strong electromagnetic fields can disrupt device function. This case report reviews the novel CCM device and its major anesthetic considerations.

This case report presents a 71-year-old man undergoing repeat ablation for atypical atrial flutter after prior pulmonary vein isolation and subsequent re-ablation involving an anterior mitral line and a posterior box. High-density mapping revealed reconnection at the left superior pulmonary vein, which was successfully re-isolated. Although bidirectional block of the anterior mitral line was confirmed via local activation time (LAT) mapping during differential pacing, burst stimulation induced atrial flutter. Further LAT mapping during flutter identified very slow conduction through a gap in the anterior mitral line. Ablation at this site restored sinus rhythm, and the arrhythmia was no longer inducible. This case highlights that bidirectional block confirmation alone may not suffice to detect gaps with slow conduction. It underscores the necessity of arrhythmia induction and mapping to reliably identify and address such gaps.

Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment by modulating immune responses, leading to enhanced anti-tumor activity. ICIs, including agents targeting cytotoxic T-lymphocyte antigen 4, programmed cell death 1, and programmed cell death ligand, are now widely used in various malignancies, either as monotherapy or in combination with chemotherapy, radiotherapy, or targeted therapies. However, ICIs are associated with immune-related adverse events, affecting multiple organ systems, with myocarditis emerging as a rare but potentially fatal complication. We present a 67-year-old man with a history of prostate and renal cell carcinoma treated with pembrolizumab and lenvatinib, who developed myocarditis secondary to ICI therapy. The patient initially presented with generalized fatigue and bradycardia, later progressing to more severe symptoms, including sinus bradycardia and elevated troponin levels. An electrocardiogram revealed a sinus rhythm with first-degree atrioventricular block, non-specific intraventricular conduction delay, and elevated high-sensitivity troponin levels progressively increasing to 50,000 pg/mL. A comprehensive diagnostic workup ruled out ischemic causes, leading to the diagnosis of ICI-induced myocarditis. The patient was treated with high-dose corticosteroids, intravenous immunoglobulin, and temporary pacemaker insertion, resulting in clinical improvement. This case highlights the need for vigilance and prompt intervention in patients receiving ICI therapy, as early recognition and treatment of myocarditis are crucial to optimizing patient outcomes in this high-risk population.

Inappropriate sinus tachycardia (IST) is a type of cardiovascular autonomic dysfunction (CVAD) that mainly affects young women and has a prevalence of 1%-2%. IST is characterized by a sinus heart rate of >100 bpm at rest with a mean 24-h heart rate of >90 bpm associated with distressing symptoms such as palpitations, dizziness, and syncope. Here, we discuss a case of a 30-year-old woman who presented with complaints of tachycardia and associated symptoms, including dizziness, diaphoresis, and sudden loss of consciousness. The 24-h Holter monitoring was consistent with the diagnosis of IST. The patient had minimal improvement on β-blocker therapy. Due to persistent symptoms consistent with IST, she was started on non-invasive vagal nerve stimulation (n-VNS) therapy. Following 2 months of n-VNS applied twice daily over the carotid artery, the patient noted near-complete relief of her tachycardia and other debilitating symptoms. While n-VNS has recently been reported as a possible treatment for postural orthostatic tachycardia syndrome, another type of CVAD, to the best of our knowledge, this is the first report of low-level n-VNS as a treatment for IST. Our case study highlights the need for further clinical studies on the benefits of n-VNS in treating IST.