Mexiletine: Antiarrhythmic mechanisms, emerging clinical applications and mortality.

Mexiletine, a class Ib antiarrhythmic drug, exhibits its major antiarrhythmic effect via inhibition of the fast and late Na+ currents in myocardial tissues that are dependent on the opening of Na+ channels for their excitation. Through a comprehensive examination of mexiletine's therapeutic benefits and potential risks, we aim to provide valuable insights that reinforce its role as a vital therapeutic option for patients with ventricular arrhythmias, long QT syndrome, and other heart rhythm disorders. This review will highlight the current understandings of the antiarrhythmic effects and rationales for recent off-label use and address the mortality and proarrhythmic effects of mexiletine utilizing published basic and clinical studies over the past five decades.

Marked QTc Reduction Immediately Following Direct Current Cardioversion of Atrial Fibrillation: Clinical Implications and Mechanisms.

BACKGROUND: The QTc in sinus rhythm (SR) following direct current cardioversion (DCCV) of atrial fibrillation (AF) is commonly used as a baseline QTc for patients who require initiation of antiarrhythmic drugs for rhythm control. Inaccurate baseline QTc may cause drug-induced torsades de pointes. OBJECTIVES: This study sought to assess time-dependent QTc changes following DCCV. METHODS: We prospectively assessed QTc changes with Bazett's QTc and Fridericia's QTc formulas in 65 patients following conversion of AF to SR. Among these 65 patients, 48 underwent DCCV and 17 spontaneously converted to SR. RESULTS: There was a large and statistically significant decrease in QTc in SR immediately following DCCV in 40 patients, which occurred with an abrupt reduction in heart rate postcardioversion. This finding excluded 8 patients with ventricular-paced QRS. The mean decrease from QTc in AF was 70.7 ± 37.2 milliseconds in the QTc interval for heart rate using Bazett's formula and 33.8 ± 17.9 milliseconds in the QTc interval for heart rate using Fridericia's formula at 1-minute post-DCCV. In 17 patients with spontaneous conversion from AF to SR, the QTc reduction was comparable to those in patients with DCCV. The QTc increased with time and reached a steady state at 5 minutes following conversion. Initiation of Class III drugs based on the "shortened" baseline QTc following DCCV was associated with drug-induced torsades de pointes. CONCLUSIONS: In patients with AF following conversion, regardless spontaneous or DCCV, the QTc shortened significantly with decreases in heart rate, likely via the mechanism of time-dependent rate adaption of ventricular repolarization. A steady-state QTc at 5-minutes following DCCV should be used as real baseline for guidance of pharmacotherapy in patients with AF.

One Beat Is All It Takes-Wide Complex Tachycardia in a Middle-aged Man.

A man in his mid-50s with a medical history of nonspecific T-wave abnormalities on electrocardiogram reported new-onset chest discomfort, diaphoresis, and shortness of breath that woke him from sleep. Emergency medical services found him to be in a wide complex tachycardia. What would you do next?

Pragmatic assessment of resident performed cardiac point of care ultrasound using a validated scoring metric.

Background: Cardiac point of care ultrasound (POCUS) is increasingly utilized by trainees across various specialties and can rapidly assess the cardiac status of unstable patients. However, the quality of trainee performed cardiac examinations has been reported only in controlled studies. In this study we aimed to assess the quality of all cardiac POCUS performed by internal medicine trainees at a major academic medical center over a three-year period. Methods: 256 studies were included and were graded by experts blinded to postgraduate year (PGY) using a previously validated scoring metric. Results: We found significant improvement in overall quality of resident performed cardiac POCUS from PGY 1 to 3 (10.8, 10.2, 13.2, p = 0.012). Assessment of left ventricular function was possible in 82% of studies and increased from PGY 1 to PGY 3 (77%, 76%, 88%, p = 0.025). Similar trends were seen in the assessment of the pericardial space (67%, 71%, 84%, p = 0.012). Images sufficient for right ventricular and volume status assessment were less commonly found (65%, 60%, 75% and 60%, 49%, 57%, respectively). Conclusions: This study provides a real world experience of the level of diagnostic accuracy that can be expected from IM trainees with minimal hands-on supervision.

A Conservative Approach to a Large Mycotic Pulmonary Pseudoaneurysm.

Pulmonary mycotic pseudoaneurysm is a rare complication of bacteremia with high associated mortality. We present a case of a large proximal pulmonary artery pseudoaneurysm as a result of methicillin-sensitive Staphylococcus aureus bacteremia, originating from a tunneled dialysis catheter infection. This case was ultimately managed conservatively with surveillance imaging and a prolonged intravenous antibiotic course, rather than with surgical or interventional management. To our knowledge, this is the first reported case of a mycotic pulmonary pseudoaneurysm due to septic embolization of an infected superior vena cava thrombus.

Diagnosis and treatment of effusive-constrictive pericarditis: a case report.

BACKGROUND: Effusive-constrictive pericarditis (ECP) is a rare syndrome involving pericardial effusion and concomitant constrictive pericarditis. The hallmark is a persistently elevated right atrial pressure of >10 mmHg or reduction of less than 50% from baseline despite pericardiocentesis. Aetiologies include radiation, infection, malignancy, and autoimmune disease. CASE SUMMARY: A 71-year-old man with a history of atrial fibrillation, obesity, hypertension, obstructive sleep apnoea, managed with continuous positive airway pressure presented with acute pericarditis complicated by pericardial effusion leading to cardiac tamponade. He was diagnosed with ECP after pericardiocentesis and was managed surgically with a pericardial window. DISCUSSION: Early detected cases of ECP can be managed by medical therapy. Therapeutic interventions include pericardiocentesis, balloon pericardiostomy, and pericardiectomy. This report describes a case of new-onset congestive heart failure secondary to ECP.

Coexisting Coronary and Carotid Artery Disease - Which Technique and in Which Order? Case Report and Review of Literature.

Coexisting carotid artery stenosis and coronary artery disease is common and there is currently no consensus in treatment guidelines on the timing, sequence and methods of revascularization. We report a case of a patient with symptomatic triple vessel coronary artery disease as well as asymptomatic severe right internal carotid artery stenosis. Our patient underwent myocardial revascularization first, because she presented with unstable angina and was asymptomatic neurologically. This article summarizes current literature about the approach to carotid and coronary artery revascularization and addresses the decision-making process regarding the timing and sequence of revascularization.

A Rare Case of ARDS Caused by Bupropion Inhalation and Treated with Noninvasive Ventilation.

Acute respiratory distress syndrome, characterized by the Berlin criteria, is associated with a high mortality rate. Its treatment includes addressing the underlying etiology, general supportive measures, and achievement of effective oxygenation. New key data indicates that in a subset of patients, noninvasive ventilation techniques can be a therapeutic and equivalent alternative to traditional invasive ventilation. We present a rare case of ARDS triggered by nasal bupropion inhalation and effectively treated with noninvasive positive pressure ventilation resulting in complete resolution.

Apixaban as a Rare Cause of Leukocytoclastic Vasculitis.

Apixaban is a rare cause of leukocytoclastic vasculitis (LCV). To our knowledge, there is only one other reported case due to apixaban in the literature. We present a case of apixaban-induced leukocytoclastic vasculitis in a 95-year-old male. He had been started on apixaban 12 days prior to presentation and developed worsening palpable purpura of his lower extremities. Possible etiologies of this new rash were excluded, with biopsy showing extensive purpura with superficial perivascular neutrophilic infiltrate and leukocytoclasis. Apixaban was discontinued, and the patient was started on a slow prednisone taper with subsequent resolution of his rash.

TAVR: A Review of Current Practices and Considerations in Low-Risk Patients.

Transcatheter aortic valve replacement (TAVR) is an established treatment for severe, symptomatic, aortic stenosis (AS) in patients of all risk categories and now comprises 12.5% of all aortic valve replacements. TAVR is a less invasive alternative to traditional surgical aortic valve replacement (SAVR), with equivalent or superior outcomes. The use of TAVR has increased rapidly. The success and increase in use of TAVR are a result of advances in technology, greater operator experience, and improved outcomes. Indications have recently expanded to include patients considered to be at low risk for SAVR. While TAVR outcomes have improved, remaining challenges include the management of coexistent coronary artery disease, prevention of periprocedural stroke, and issue of durability. These issues are even more relevant for low-risk, younger patients.