RECOMMENDATION
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This Canadian Cardiovascular Society position statement is focused on the acute and long-term management of sustained ventricular tachycardia (VT) and ventricular fibrillation (VF) in patients with structural heart disease (SHD), defined by the presence of abnormal myocardium and scar. SHD includes conditions such as myocardial infarction (MI), dilated cardiomyopathies, hypertrophic cardiomyopathy, infiltrative cardiomyopathies (eg, sarcoidosis), and arrhythmogenic right ventricular
This position statement was written by a multidisciplinary panel of experts who care for patients with VT/VF (see Supplemental Table S1). The recommendations were developed using the Grading of Recommendations, Assessment, Development, and Evaluation standards with strength of recommendations classified as “strong” or “conditional.” The recommendations are presented, along with their background and rationale.
Sustained VT is defined as an episode of VT lasting > 30 seconds or requiring intervention before 30 seconds.5 Hemodynamically stable VT is defined as VT without signs or symptoms of organ hypoperfusion. Electrical storm (also known as VT/VF storm) is defined as the occurrence of 3 or more distinct episodes of VT/VF within 24 hours. Monomorphic VT has similar QRS complexes on the electrocardiogram (ECG), whereas polymorphic VT has changing beat-to-beat morphology. Torsade de pointes is
Ventricular arrhythmias can cause sudden cardiac death (SCD) or arrest, most frequently in those with previous MI.6 The past decade saw a decreasing incidence of post-MI VT/VF causing SCD, yet no change in the incidence of SCD in patients without ischemic heart disease.7 The development of VT/VF in patients with SHD is associated with a higher risk of future episodes of VT/VF, of electrical storm, and of death.8
Patients who present with VT/VF often have a preexisting diagnosis of SHD. However, VT/VF might be the initial indication of the presence of SHD for some patients. The initial evaluation must rapidly assess the need for acute intervention and identify potential etiologies or precipitating factors. When the patient is stabilized, the evaluation should include a complete history and examination, comprehensive laboratory testing, and assessment of cardiac function (Fig. 1). WeRECOMMENDATION
Although appropriate ICD shocks are often acutely life-saving, they are associated with a subsequent increased mortality risk, even compared with VT/VF terminated with ATP therapy. Furthermore, ICD shocks can result in significant psychosocial morbidity (see section 11. Psychosocial Care of Patients With VT/VF). Treating VT/VF should aim to reduce VT/VF burden and ICD shocks. Optimization of ICD programming (see section 9. ICD Programming in Patients With Sustained VT/VF in the Setting of SHD)
AADs (with the exception of β-blockers) are not known to improve survival in patients with SHD38,39 and cannot replace ICD therapy, which has consistently resulted in survival benefit compared with AAD therapy for VT/VF. Nevertheless, in patients who are not candidates for ICD implantation, amiodarone might be useful for treatment of VT/VF.40
Catheter ablation is effective for patients with monomorphic VT and SHD. Procedural success is generally highest for patients with hemodynamically tolerated monomorphic VT and those with higher left ventricular ejection fraction,31,46 although substrate ablation techniques have improved ablation effectiveness in patients with worse ventricular systolic function.47,48 There is a wide spectrum of SHD that leads to scar-related VT. Distribution, location, and heterogeneity of the underlying scar
The goals of ICD programming are to ensure appropriate therapy for VT/VF, to minimize inappropriate shocks, to minimize symptoms from VT/VF, and to prevent mortality (Table 2). Secondary goals include avoidance of arrhythmia induction and of nonessential therapies.64,65 ICD shocks are associated with increased mortality, hospitalization, and health care costs compared with ATP therapy alone.64,66
In patients with VT/VF, prolonged detection times reduce inappropriate therapy and nonessential
Initial suppressive therapies for VT/VF in patients with SHD are sotalol, amiodarone, or catheter ablation. After failure of one of these therapies, a trial of an alternate first-line therapy should be undertaken. Amiodarone and catheter ablation have similar efficacy after failure of sotalol treatment.34 A significant proportion of patients will have recurrent VT/VF despite first-line therapy, and alternate strategies must be considered.
Studies of the roles of psychosocial factors in the genesis and management of VT/VF are appearing with increasing frequency. Individuals experiencing VT/VF might be susceptible to poor mental health and reduced quality of life as they manage the symptoms of the VT/VF and those of its treatment.
Implantable defibrillators have dramatically modified the prognosis and the management of ventricular arrhythmias in the presence of SHD. Further study is needed to minimize sudden death risk in the population, to understand when and which arrhythmia-suppressive therapy is best, and to understand the short-and long-term clinical outcomes of available therapies, as well as their effects on mortality, cost-effectiveness, and quality of life.
This position statement was funded by the Canadian Cardiovascular Society.
Please see Supplemental Table S1 for a complete list of disclosures.
The authors thank Brittany Forrest from the Canadian Cardiovascular Society for her tireless efforts.
Members of the Secondary Panel who contributed to this work are: Eugene Crystal, MD (Schulich Heart Centre, Sunnybrook Health Sciences); Paul Dorian, MD (St Michael’s Hospital, University of Toronto); Jaqueline Joza, MD (Division of Cardiology, McGill University Health Centre, Montreal Quebec); Vikas P. Kuriachan, MD (Libin Cardiovascular Institute of Alberta, University of Calgary); Peter
The disclosure information of the authors and reviewers is available from the CCS on their guidelines library at www.ccs.ca.
This statement was developed following a thorough consideration of medical literature and the best available evidence and clinical experience. It represents the consensus of a Canadian panel comprised of multidisciplinary experts on this topic with a mandate to formulate disease-specific recommendations. These recommendations are aimed to provide a reasonable and practical approach to care for specialists and allied health professionals obliged with the duty of bestowing optimal care to patients and families, and can be subject to change as scientific knowledge and technology advance and as practice patterns evolve. The statement is not intended to be a substitute for physicians using their individual judgement in managing clinical care in consultation with the patient, with appropriate regard to all the individual circumstances of the patient, diagnostic and treatment options available and available resources. Adherence to these recommendations will not necessarily produce successful outcomes in every case.