Antidysrhythmic Drugs in Pediatrics
Sam Kacew in Drug Toxicity and Metabolism in Pediatrics, 1990
Flecainide was the first of the Class 1C drugs to be approved in the U.S. for treatment of life-threatening ventricular dysrhythmias. In greater than 85% of patients given flecainide, over 80% of premature ventricular contractions has been suppressed.176,177 In this regard, flecainide is significantly more effective in suppression of PVCs than quinidine (80 vs. 57%) and disopyramide (92 vs. 39%). 177,178 When assessed by programmed electrical stimulation (PES) in patients with more severe ventricular ectopy and/or decreased left ventricular function, flecainide was found to be efficacious in 12 to 65% of patients.176,179,180 This wide range may reflect different patient populations assessed and different drug dosages employed. Flecainide has also been used for conversion of acute SVT to sinus rhythm and in children for the treatment of SVTs (especially junctional) refractory to conventional drugs.181,183 It is a potent antiarrhythmic agent, but has numerous cardiovascular effects.
Ofloxacin
M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson in Kucers’ The Use of Antibiotics, 2017
Ofloxacin has potential interactions with several antiarrhythmic agents in addition to procainamide. Cardiac QT prolongation has been described as a class effect of fluoroquinolones, although there are differences between agents, with sparfloxacin and grepafloxacin appearing to have the greatest potential for this adverse event (Adamantidis et al., 1998; Ball, 2000; Milberg et al., 2007). Ofloxacin is composed of an R-isomer and an S-isomer, the latter of which is marketed as levofloxacin (see Chapter 104, Levofloxacin). There were 11 cases of torsades de pointes and one case of polymorphic ventricular tachycardia in three million spontaneous reports of adverse events to the FDA in patients taking levofloxacin, although many patients had concurrent medical conditions or were taking other drugs with cardiac effects (Ball et al., 1999; Samaha 1999; Kahn, 2000; see Chapter 104, Levofloxacin). The risk is most marked in patients taking type IA antiarrhythmic agents such as quinidine and procainamide and type III antiarrhythmic agents such as amiodarone or sotalol (Iannini, 2001; AHFS, 2015). Given these reports, care should be exercised in concurrently prescribing ofloxacin with these antiarrhythmic agents.
Management of Atrial Fibrillation in Patients with Heart Failure
Andreas P. Kalogeropoulos, Hal A. Skopicki, Javed Butler in Heart Failure, 2023
Pharmacological therapy of AF aims at rate and/or rhythm control, with the goal of hemodynamic and clinical improvement. Rate control is particularly important in cases of fast ventricular response. Adequate ventricular rate control increases diastolic LV filling and reduces risk of further deterioration due to arrhythmia-induced cardiomyopathy. However, the latter risk is not completely abolished, as the irregularity of the underlying rhythm may still have a significant impact on LV function. On the other hand, effective long-term rhythm control is not feasible in most cases. Pharmacologic therapies, such as antiarrhythmic drugs, have limited efficacy in the maintenance of sinus rhythm in HF. Moreover, the safety profile and the side effects of antiarrhythmic agents, especially in frail HF patients who have several comorbidities, limit their widespread use. Apart from ion channel blocking drugs, agents with favorable hemodynamic, antifibrotic, or other pleiotropic effects may have a role in a rhythm control strategy. Optimal medical therapy of HF per se may be quite effective in reducing AF burden, especially agents that inhibit the renin-angiotensin-aldosterone system, which have been shown to reduce the incidence of AF in HFrEF when administered in optimal doses,74 although no such benefit was shown in HFpEF patients.74 Furthermore, aldosterone receptor antagonists may be effective in AF prevention, especially in the HFrEF setting.75
Current pharmacotherapeutic strategies for cardiac arrhythmias in heart failure
Published in Expert Opinion on Pharmacotherapy, 2020
Ashish Correa, Yogita Rochlani, Wilbert S. Aronow
Cardiac arrhythmias are frequently seen in patients with HF. These rhythm disturbances can be related to the underlying pathology that causes the HF (such as atrial myopathy, ischemic cardiomyopathy, and scar related arrhythmia). Conversely, the arrhythmia itself can precipitate HF, such as with tachycardia-mediated cardiomyopathy. Regardless of the etiology, arrhythmias often lead to worsening of HF and are the leading cause of death in this patient population. It is important to treat these arrhythmias to control symptoms, slow disease progression and prevent sudden death. Management depends on the type of arrhythmia (atrial or ventricular), the stage of HF and other comorbidities. Antiarrhythmic agents are often used along with device therapy and catheter ablation. However, antiarrhythmic agents come with their own problems, such as proarrhythmic and negative inotropic effects. The knowledge of cardiac arrhythmias seen in HF patients and their evidence-based pharmacologic management strategies are important for physicians caring for these patients.
The potassium channel blocker, dalfampridine diminishes ouabain-induced arrhythmia in isolated rat atria
Published in Archives of Physiology and Biochemistry, 2019
Nahid Ghebleh Zadeh, Gholamhassan Vaezi, Azam Bakhtiarian, Zahra Mousavi, Abdolhossein Shiravi, Vahid Nikoui
Potassium (K+) channels are the main type of ion channel and are distributed in all living organisms (Littleton and Ganetzky 2000). These channels make potassium-selective pores that located inside cell membranes. Moreover, these channels are localized on various cell types and regulate numerous cellular functions (Schmitt et al. 2014). These channels also control the repolarization of atrial action potentials (Schmitt et al. 2014). It is well-known that prolongation of cardiac action potential and effective refractory period prevents cardiac arrhythmias, particularly in short action potential conditions. Recent investigations are focused on discovering the antiarrhythmic agents the prolong action potentials without proarrhythmic adverse effects. As well as sodium channel blockers, potassium channel blockers also exert antiarrhythmic properties (Gerlach 2003). Based on Vaughan-Williams classification scheme, potassium channel blockers are class III antiarrhythmic agents. These agents block the potassium channels, which mediate phase 3 of repolarization. Consequently, blockade of these channels delays repolarization, which prolongs both action potential duration and effective refractory period (Singh and Ahmed 1994, Dorian 2000).
The challenges of an aging tetralogy of Fallot population
Published in Expert Review of Cardiovascular Therapy, 2021
Jennifer P. Woo, Doff B. McElhinney, George K. Lui
While pharmacotherapy can be useful for controlling or limiting the impact of arrhythmias, there are often adverse side effects and limited effectiveness associated with antiarrhythmic agents. Electrophysiologic issues continue to pose substantial challenges in the context of an aging TOF population: prediction tools for SCD are poor and the risk-benefit calculations for ICD therapy can be difficult, given the relatively high incidence of side effects. While cryoablation during surgical PVR in conjunction with antiarrhythmic drug therapy appears promising in decreasing burden of ventricular tachycardia, especially in patients with limited antiarrhythmic options and refractory ventricular tachycardia, this will be a less attractive option with the trend toward transcatheter PVR.
Related Knowledge Centers
- Atrial Fibrillation
- Beta Blocker
- Calcium Channel
- Potassium
- Sodium
- Supraventricular Tachycardia
- Tachycardia
- Sympathetic Nervous System
- Ventricular Tachycardia
- Medication