Pharmacokinetic Disposition of Amiodarone When Given with an Intralipid Rescue Strategy

While the antiarrhythmic drug amiodarone is commonly used in clinical practice, it has a narrow therapeutic index that can lead to acute overdose. One proposed method to deal with this toxicity is lipid emulsion therapy, which may potentially quench the free amiodarone in blood and prevent its further distribution to target organs and tissues. In this study, we utilize an established swine model to examine the effects of Intralipid™ (IL) administration for acute amiodarone toxicity. A total of 14 pigs received an overdose of intravenous amiodarone. After twenty minutes, half of the pigs (n = 7) received IL while the control group (n = 7) received normal saline. Serum concentrations of amiodarone were then analyzed using a validated high-performance liquid chromatography (HPLC) method. Noncompartmental pharmacokinetic analyses were performed on the observed concentrations. There were no statistical differences in the area under the concentration time curve (6 h) or clearance, but there was a difference in the half-life between the two groups (3.12 vs. 0.85 h, p = 0.01). The administration of IL did not statistically change the overall exposure of amiodarone in the blood in the first 6 h; however, trends toward prolonged blood retention in the IL group were seen.

Supraventricular Tachycardia in Pregnancy

The commonest arrhythmia in women of reproductive age, is paroxysmal supraventricular tachycardia (SVT). We present a rare case of SVT who presented for the first time during pregnancy, who failed to respond to Electrical cardioversion(ECV), but reverted back to sinus rhythm by secondline pharmacotherapy. PROCEDURE: A 22 year old primigravidapresented at 37weeks in labour with complaints of breathlessness and severe palpitations when she was diagnosed to have supraventricular tachycardia(SVT) on ECG and was referred to a tertiary care centre for further management.Pharmacological cardioversion was attempted with intravenous diltiazem, but in vain. Decision was taken for electrical cardioversion with synchronized DC shocks of 50 joules and 100 joules successively, but was not successful too. As a last resort, bolus of intravenous Amiodarone 150 mg was given over 10 minutes followed by infusion at the rate of 24 mg per hour(2ml/hr), which finally brought down the heart rate to 98bpm. In view of non-reassuring fetal heart rate observed on CTG, patient was taken up for an emergency caesarean section under epidural anaesthesia with grave risk consent and shifted to ICCU post-operatively. RESULT: Patient delivered a male baby of birth weight 2.35kg. Patient tolerated the surgery well and did not experience any episodes of PSVT throughout the intra-operative period. Postoperatively patient was managed in consultation with cardiologist. Amiodarone infusion was continued for 24 hours at 24mg/ hour. Post-operative period was uneventful, patient was started on oral anti arrhythmic medications and discharged on the same. CONCLUSION : Accurate diagnosis, regular follow up and multidisciplinary approach during acute episode and during delivery can prevent life threatening risks that might be posed to the mother and fetus in a case of PSVT. Treatment options include nonpharmacological therapy, followed by adenosine and other drugs if required, and lastly electrical cardioversion

Infective endocarditis of an aortic bioprosthesis causing life-threatening incessant junctional tachycardia: a case report

Background Infective endocarditis with paravalvular abscess can be complicated by atrioventricular block (AVB), but junctional ectopic tachycardia (JET) has as yet never been described. Case summary A 68-year-old male recently admitted with Staphylococcal aureus endocarditis of his aortic valve bioprosthesis, presented with a regular tachycardia at 240 b.p.m. with a pre-existent right bundle branch block pattern. Haemodynamic collapse necessitated electrical cardioversion, following which high-grade AVB was observed. Multiple recurrences of the same tachycardia required repeated electrical cardioversions and emergent electrophysiological study, which indicated JET. The tachycardia was unresponsive to overdrive pacing, adenosine and intravenous amiodarone, and external cardioversions. Radiofrequency catheter ablation of the atrioventricular node was performed emergently with interruption of the tachycardia. A temporary external pacemaker was implanted via a jugular route. The tachycardia recurred after 48 h at a slower rate, and the patient underwent redo ablation. Transoesophageal echocardiography revealed a pseudoaneurysm of the right sinus of Valsalva probably corresponding to an evacuated abscess. A permanent pacemaker was implanted after active infection had been ruled out. At 3 months of follow-up, the patient had complete AVB, without arrhythmia recurrence. Discussion This is the first case report of JET complicating a paravalvular abscess of the aortic valve with concomitant AVB. Junctional ectopic tachycardia is very rare arrhythmia which is usually seen in children as a congenital arrhythmia or following surgical correction of paediatric heart disease. The differential diagnosis is discussed in detail in the article.