Whenever possible, we reference data from the acute clinical care environment; however, in some cases, the reference studies from the invasive electrophysiology labo- ratory inform our understanding of arrhythmia diagnosis and management. Although this document is aimed at the adult population ( 18 years of age) and offers no specific recom- mendations for pediatric patients, as per the reference list, we examined literature that included pediatric patients. In some cases, the data from noninfant pediatric patients helped inform this guideline. In the current healthcare environment, cost consider- ation cannot be isolated from shared decision making and patient-centered care. The AHA and ACC have acknowl- edged the importance of value in health care, calling for eventual development of a Level of Value for practice rec- ommendations in the 2014 ACC/AHA Statement on Cost/ Value Methodology in Clinical Practice Guidelines and Although quality-of-life and cost- effectiveness data were not sufficient to allow for devel- opment of specific recommendations, the GWC agreed the data warranted brief discussion (Sections 10 and 11). Throughout this document, and associated with all rec- ommendations and algorithms, the importance of shared decision making should be acknowledged. Each approach, ranging from observation to drug treatment to ablation, must be considered in the setting of a clear discussion with the patient regarding risk, benefit and personal preference. See Section 12 for additional information. In developing this guideline, the GWC reviewed prior pub- lished guidelines and related statements. Table 2 contains a list of guidelines and statements deemed pertinent to this writing effort and is intended for use as a resource, thus obviating the need to repeat existing guideline recommendations. 2. General Principles 2.1. Mechanisms and Definitions For the purposes of this guideline, SVT is defined as per Table 3, which provides definitions and the mechanism(s) of each type of SVT. 