Sections View Full Chapter Figures Tables Videos Full Chapter Figures Tables Videos Supplementary Content ++ KEY FEATURES ++ ESSENTIALS OF DIAGNOSIS ++ Rapid ventricular tachycardia (VT), usually with left bundle branch block morphology Generally occurs with advanced nonischemic dilated cardiomyopathy HV interval during the tachycardia is usually the same as in sinus rhythm ++ GENERAL CONSIDERATIONS ++ The impulse reenters within the bundle branch conduction system Right bundle antegrade in 90% and left bundle retrograde conduction Left bundle antegrade in 10% and right bundle retrograde conduction Intraventricular conduction system disease is common This type of VT is also occasionally seen in valvular cardiomyopathy Delay within the conduction system is critical for reentry to sustain this arrhythmia ++ CLINICAL PRESENTATION ++ SYMPTOMS AND SIGNS ++ Syncope Cardiac arrest ++ PHYSICAL EXAM FINDINGS ++ Features of cardiomyopathy During tachycardia, patients typically experience hypotension and tissue hypoperfusion S3 may be present secondary to cardiomyopathy ++ DIFFERENTIAL DIAGNOSIS ++ Intramyocardial reentrant VT Supraventricular tachycardia with aberrancy Mahaim tachycardia ++ DIAGNOSTIC EVALUATION ++ LABORATORY TESTS ++ Basic metabolic panel Thyroid-stimulating hormone Serum magnesium level ++ ELECTROCARDIOGRAPHY ++ ECG during tachycardia typically shows left bundle branch block morphology tachycardia ECG in sinus rhythm usually shows intraventricular conduction delay ++ IMAGING STUDIES ++ Echocardiography to evaluate left ventricular function and valvular abnormalities ++ DIAGNOSTIC PROCEDURES ++ Invasive electrophysiologic study to establish mechanism of arrhythmia and determine feasibility of ablation ++ TREATMENT ++ CARDIOLOGY REFERRAL ++ All patients with suspected bundle branch reentry VT should be referred to a cardiac electrophysiologist ++ HOSPITALIZATION CRITERIA ++ All patients with this condition require hospitalization for management ++ MEDICATIONS ++ No effective medication therapy exists ++ THERAPEUTIC PROCEDURES ++ Invasive electrophysiologic study followed by ablation of the right bundle branch ++ SURGERY ++ Implantable cardioverter-defibrillator (ICD) is recommended concurrent with ablation because of the risk of sudden death associated with poor left ventricular function ++ MONITORING ++ Ablation is curative Patients with an ICD require follow-up of the device every 3 months ++ DIET AND ACTIVITY ++ Once treated, no special restrictions required other than for the underlying heart disease ++ ONGOING MANAGEMENT ++ HOSPITAL DISCHARGE CRITERIA ++ Twenty-four hours after successful ablation ++ FOLLOW-UP ++ Follow-up for cardiomyopathy and ICD ++ COMPLICATIONS ++ Once treated, no complications occur Patients remain at risk for sudden cardiac death secondary to the substrate of cardiomyopathy ++ PROGNOSIS ++ Once the condition ... GET ACCESS TO THIS RESOURCE Sign In Username Error: Please enter User Name Password Error: Please enter Password Forgot Username? Forgot Password? Sign in via OpenAthens Sign in via Shibboleth Get Free Access Through Your Institution Contact your institution's library to ask if they subscribe to McGraw-Hill Medical Products. What is MyAccess? Create a FREE MyAccess profile to: Use this site remotely Bookmark your favorite content Track your self-assessment progress and more! GET ACCESS TO THIS RESOURCE Subscription Options Pay Per View Timed Access to all of AccessCardiology 24 Hour $34.95 (USD) Buy Now 48 Hour $54.95 (USD) Buy Now Best Value AccessCardiology Full Site: One-Year Individual Subscription $595 USD Buy Now View All Subscription Options