Amiodarone: a candidate for the title ‘riskiest drug’
Hugh Mcgavock in Pitfalls in Prescribing and How to Avoid Them, 2017
Amiodarone is a remarkably useful drug for treating cardiac arrhythmias. Its indications include atrial fibrillation and flutter, paroxysmal ventricular tachycardia, nodal and ventricular tachycardia, ventricular fibrillation and tachyarrhythmia. It is part of the management of many patients, greatly improving their quality of life and life expectancy. This is because amiodarone presents the prescriber with two complex problems: an unenviable list of adverse drug reactions (ADRs) due to amiodarone itself an extensive and complex set of interactions with many other commonly used drugs – adverse drug interactions (ADIs). Most family doctors know some of amiodarone’s ADRs (e.g. phototoxicity and thyroid problems). Fewer prescribers are aware of all of them, and consequently the risks to the patient of lasting harm, with loss of quality of life and irreversible morbidity, are great. Because of the possibility of phototoxic reactions, patients should be advised to shield the skin from light during treatment and for several months after discontinuing amiodarone.
The acutely collapsed patient
Andrew Stewart in Pocket On Call, 2015
Patients with a transient loss of consciousness may have suffered an episode of syncope. Vasovagal syncope is the ‘simple’ faint and represents a complex autonomic reflex. Patients experience a varied prodrome with features such as feeling hot and dizzy with wobbly legs. Patients make a rapid recovery following loss of consciousness. Other potential causes for transient loss of consciousness include concussion and short runs of significant cardiac dysrhythmias for example ventricular tachycardia. Following an acute intra-cranial event, various cardiovascular side effects may occur, many of which can result in low blood pressure. When clinicians refer to an acutely ‘collapsed’ patient, they are usually describing a patient who has suddenly lost consciousness, often in a dramatic fashion, either by falling to the floor or by collapsing backwards in bed. The altered consciousness level may be transient or sustained. This, therefore, provides a rare example whereby the patient’s low level of consciousness may not be completely attributed to the co-existing hypotension.
Investigations
Gregory YH Lip in Atrial Fibrillation in Practice, 2020
Thyroid function tests should be measured in all patients with atrial fibrillation (AF) even if there are no symptoms suggestive of thyrotoxicosis, as subclinical thyroid disease is often present in the elderly and AF may be its first presentation. Rapid AF with a rapid ventricular response may be mistaken for other supraventricular arrhythmias or if a bundle branch block is present, ventricular tachycardia. Subtle variations in the relative risk interval are the important clues. Most cardiologists would request a transthoracic echocardiogram for the initial evaluation of most patients with AF. Although transthoracic echocardiography is adequate for assessing chamber size, detection of atrial thrombi or the assessment of left atrial appendage anatomy and/or function requires transoesophageal echocardiography, especially if a prosthetic mitral valve is present or in cases where transthoracic imaging is inadequate.
Clinical and genetic investigation of catecholaminergic polymorphic ventricular tachycardia in a consanguineous Tunisian family
Published in Acta Cardiologica, 2020
Sonia Nouira, Sonia Chabrak, Houyem Ouragini
Background: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare disease presenting with syncopal events and sudden cardiac death at a young age in the absence of structural heart disease. Two major genes have been shown to be responsible for CPVT: RYR2 and CASQ2 genes involved in calcium homeostasis. Methods: We report here clinical and molecular investigation of a consanguineous Tunisian family including three affected members. Involvement of RYR2 and CASQ2 genes was investigated. Results: Mutation screening for RYR2 gene showed that no mutation were detected in the coding sequence. A novel variation c.572C/T was identified in CASQ2 gene leading to a p.Pro191Leu. Conclusion: To our knowledge, this is the first clinical and genetic investigation of CPVT in North Africa.
New strategies for ventricular tachycardia and ventricular fibrillation ablation
Published in Expert Review of Cardiovascular Therapy, 2015
Darren A Hooks, Benjamin Berte, Seigo Yamashita, Saagar Mahida, Jean-Marc Sellal, Nora Aljefairi, Antonio Frontera, Nicolas Derval, Arnaud Denis, Mélèze Hocini, Michel Haïssaguerre, Pierre Jaïs, Frederic Sacher
Patients with ventricular tachycardia (VT) and ventricular fibrillation (VF) and no reversible cause are difficult to treat. While implantable defibrillators prolong survival, many patients remain symptomatic due to device shocks and syncope. To address this, there have been recent advances in the catheter ablation of VT and VF. For example, non-invasive imaging has improved arrhythmia substrate characterisation, 3D catheter navigation tools have facilitated mapping of arrhythmia and substrate and ablation catheters have advanced in their ability to deliver effective lesions. However, the long-term success rates of ablation for VT and VF remain modest, with nearly half of treated patients developing recurrence within 2–3 years, and this drives the ongoing innovation in the field. This review focuses on the challenges particular to ablation of life-threatening ventricular arrhythmia, and the strategies that have been recently developed to improve procedural efficacy. Patient sub-groups that illustrate the use of new strategies are described.
Catecholaminergic Polymorphic Ventricular Tachycardia: An Unusual Case of Fright-Induced Prehospital Cardiac Arrest in a Healthy 6-Year-Old Child
Published in Prehospital Emergency Care, 2020
Michael Wilson, Steven Schwartz, P. Richard Verbeek
Catecholaminergic Polymorphic Ventricular Tachycardia is a rare but often lethal genetic disorder that affects approximately 1 in 10,000 people. It often first manifests as stress or exercise-related syncope or sudden unexplained cardiac death, primarily in the pediatric and young adult population. We present a case of a 6-year-old male who had a sudden unexplained prehospital cardiac arrest after being scared by a domestic animal and who presented in ventricular fibrillation. The patient was subsequently defibrillated with a return of spontaneous circulation. During the course of care, medications with beta-1 and -2 agonist properties were administered, followed by multiple further episodes of polymorphic ventricular tachycardia (PVT)/ventricular fibrillation (VF). Once these medications were discontinued and beta blockers were administered, the patient had no further episodes of PVT/VF and was subsequently discharged from hospital 7 days later, completely neurologically intact. This case suggests the need for caution when considering administering beta agonists in a pediatric cardiac arrest patient with no known history of heart disease who presents in VF or PVT after an incident of extreme stress or strenuous physical activity.