Jinu John

Current Oral Antiplatelets: Focus Update on Prasugrel

Platelet activation and aggregation plays an integral role in the pathogenesis of acute coronary syndrome (ACS). The mainstay of ACS treatment revolves around platelet inhibition. It is known that greater platelet inhibition results in better ischemic outcomes; hence, focus in drug development has been to create more potent inhibitors of platelet aggregation. Prasugrel, a potent, third-generation thienopyridine, was approved by the US Food and Drug Administration in July 2009 for its use in ACS and percutaneous coronary intervention. The addition of prasugrel to aspirin for dual antiplatelet therapy has been shown to reduce the ischemic outcomes compared with clopidogrel and aspirin in combination. However, being a more potent antiplatelet agent, prasugrel increases the risk of bleeding, especially in those patients who are at a higher risk of bleeding complications. Elderly patients ≥75 years, patients who weigh ≥60 kg, and patients with a history of stroke or transient ischemic attack are at a higher risk of bleeding complications when prasugrel is used in combination with aspirin. Newer antiplatelets currently are being clinically evaluated to assess their efficacy in reducing ischemic events without increasing the bleeding risk.

Torsade de Pointes due to Methadone Use in a Patient with HIV and Hepatitis C Coinfection

We present a case of Torsade de Pointes secondary to multiple factors including patient susceptibility and iatrogenic influences. Contributing causes are presented, and the approach to treatment is discussed.

Medication-induced Takotsubo Cardiomyopathy presenting with cardiogenic shock—utility of extracorporeal membrane oxygenation (ECMO): case report and review of the literature

Takotsubo cardiomyopathy (TTC) is a transient condition that affects the myocardium and is seen mostly in post-menopausal women secondary to an emotional or physical stressor; however, certain drugs have been described as cause of this syndrome. We report the case of a young female with medication--induced TTC, who presented with cardiogenic shock as initial manifestation, treated successfully with extracorporeal membrane oxygenation (ECMO). To our knowledge, this is the first case in the literature describing the use of ECMO in cardiogenic shock due to medication-induced TTC.

Change in P wave morphology after convergent atrial fibrillation ablation.

Convergent atrial fibrillation ablation involves extensive epicardial as well as endocardial ablation of the left atrium. We examined whether it changes the morphology of the surface P wave. We reviewed electrocardiograms of 29 patients who underwent convergent ablation for atrial fibrillation. In leads V1, II and III, we measured P wave duration, area and amplitude before ablation, and at 1, 3 and 6 months from ablation. After ablation, there were no significant changes in P wave amplitude, area, or duration in leads II and III. There was a significant reduction in the area of the terminal negative deflection of the P wave in V1 from 0.38 mm2 to 0.13 mm2 (p = 0.03). There is also an acute increase in the amplitude and duration of the positive component of the P wave in V1 followed by a reduction in both by 6 months. Before ablation, 62.5% of the patients had biphasic P waves in V1. In 6 months, only 39.2% of them had biphasic P waves. Hybrid ablation causes a reduction of the terminal negative deflection of the P wave in V1 as well as temporal changes in the duration and amplitude of the positive component of the P wave in V1. This likely reflects the reduced electrical contribution of the posterior left atrium after ablation as well as anatomical and autonomic remodeling. Recognition of this altered sinus P wave morphology is useful in the diagnosis of atrial arrhythmias in this patient population.

Novel Oral Anticoagulants in Atrial Fibrillation: Update on Apixaban.

Almost 800,000 new or recurrent strokes occur every year. Atrial fibrillation, the most common cardiac arrhythmia, is a major risk factor for stroke, accounting for 15-20% of ischemic strokes. Apixaban is a direct inhibitor of Factor Xa that was approved in December 2012 by the US Food and Drug Administration (FDA) for the prevention of stroke in patients with non-valvular atrial fibrillation. It is part of a family of novel oral anticoagulants (NOACs) which has advantage over warfarin of less dosing variability, rapid onset of action and no INR monitoring required. Apixaban showed superiority to warfarin in both primary efficacy and primary safety outcomes by simultaneously showing both significantly lower rates of strokes and systemic embolism and a reduced risk of major clinical bleeding in clinical trials. Warfarin remains the anticoagulant of choice for patients with prosthetic heart valves and significant mitral stenosis. There are currently no head-to-head studies that directly compare the different NOACs with one another, but it is expected that there will be more trials in the future that will explore this comparison. Dabigatran is the only NOAC with an FDA approved reversal agent. However, a reversal agent for apixaban is being developed and was successful in recent clinical trials. This review summarizes the clinical trial data on apixaban for atrial fibrillation, compares apixaban to other NOACs and discusses apixaban use in clinical practice.

Refractory atrioventricular nodal re-entrant tachycardia: A rare manifestation of acute massive pulmonary embolism

With a wide array of manifestations ranging from mild dyspnea to fatal cardiogenic shock, acute pulmonary embolism (PE) remains an enigmatic clinical entity. Vivid electrocardiography (ECG) patterns portrayed in different clinical instances of acute PE have always remained an interesting, yet debatable subject since the classic S1Q3T3 pattern on ECG secondary to PE was first described in 1935. Atrial fibrillation, atrial flutter and atrial tachycardia are commonly described supraventricular tachycardias in association with PE; however, there is scant description of PE in the literature presenting as atrioventricular nodal re-entrant tachycardia (AVNRT). The present report describes the clinical course of an elderly woman presenting with refractory typical AVNRT who was subsequently found to have bilateral multilobar acute PE. To the authors’ knowledge, the present report is the first to describe a case involving acute PE presenting as hemodynamically unstable AVNRT requiring cardioversion.

Addison's disease masking a potentially life-threatening condition

Addisons disease (AD) is a metabolic disorder that affects the metabolism of potassium. The hyperkalemia that results from this condition can be reflected in the electrocardiogram, which could confound the diagnosis of other cardiac conditions. Such a challenging situation was encountered when a 73-year-old male with history of AD presented to the emergency department with chest pain.