Ventricular arrhythmias occur commonly in clinical practice, and range from benign asymptomatic premature ventricular contractions (PVCs) to sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) resulting in sudden cardiac death (SCD). The presence of structural heart disease plays a major role in risk stratification; however, it is important to recognize potentially lethal arrhythmias can occur in structurally normal-appearing hearts. Management depends on the associated symptoms, underlying pathologic substrate, hemodynamic consequences, and associated long-term prognosis. Given the complexity of these arrhythmias, initial management, risk stratification, and treatment of ventricular arrhythmias pose a significant challenge to clinicians.
This chapter provides an overview of the clinical presentation, natural history, diagnosis, and therapeutic options for the ventricular arrhythmias encountered in clinical practice. Given the differences in management, this chapter has been divided into two major sections: ventricular arrhythmias in patients with structurally normal and abnormal hearts.
This chapter incorporates the recommendations from the most recent professional society guidelines, including the American College of Cardiology (ACC)/American Heart Association (AHA)/Heart Rhythm Society (HRS) 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities,1 the 2012 ACC/AHA/HRS Focused Update Incorporated Into the ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities,2 the HRS/ACC/AHA Expert Consensus Statement on the Use of Implantable Cardioverter-Defibrillator Therapy in Patients Who Are Not Included or Not Well Represented in Clinical Trials3, the 2013 HRS/European Heart Rhythm Association (EHRA)/Asia-Pacific Heart Rhythm Association (APHRS) Expert Consensus Statement on the diagnosis and Management of Patients with Primary Inherited Arrhythmia Syndromes,4 the 2009 EHRA/HRS Consensus on Catheter Ablation of Ventricular Arrhythmias,5 the 2014 EHRA/HRS/APHRS Expert Consensus on Ventricular Arrhythmias,6 and the 2015 European Society of Cardiology (ESC) Guidelines for the Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death.7 As with all guidelines, these documents provide specific categories of recommendation, according to the level of evidence available.
VENTRICULAR TACHYCARDIA DEFINITIONS
Sustained VT: Duration of VT is > 30 seconds or < 30 seconds associated with hemodynamic collapse.
Nonsustained VT: Duration > 3 beats and < 30 seconds, not associated with hemodynamic collapse.
Repetitive Monomorphic VT: Episodes of nonsustained VT that continuously repeat.
VT Storm: More than three separate episode of VT in 24 hours requiring intervention to terminate.
Monomorphic VT: All beats have same QRS morphology (some variation may be seen at initiation).
Polymorphic VT: Continuously changing morphology of the VT is seen from beat to beat.
Pleomorphic VT: More than one distinct morphology during the same episode of VT.
VENTRICULAR TACHYARRHYTHMIAS IN THE SETTING OF A STRUCTURALLY NORMAL HEART
Premature Ventricular Contractions/Nonsustained Ventricular Tachycardia in the Absence of Organic Heart Disease
PVCs/nonsustained ventricular tachycardia (NSVT) are commonly seen in clinical practice in patients with structurally normal hearts. The significance of PVCs/NSVT depends on the frequency, the presence and severity of structural heart disease, and ...