The purpose of this study is to determine, among a large cohort of 300 consecutive patients with hypertrophic cardiomyopathy, if extended ambulatory monitoring using the iRhythm Technologies, Inc. Zio XT device results in identifying a greater burden of nonsustained ventricular tachyarrhythmia (nsVT) compared to current ACCF/AHA guideline recommended 48-hour monitoring.

Optimal duration to monitor patients for identifying nsVT remains unclear. The investigators aim to determine the prevalence and burden of nsVT with longer term monitoring with the iRhythm Zio XT device over a 2-week period vs. 48 hours; and whether, this greater burden of nsVT compared to conventional shorter monitoring potentially identifies a subset of HCM patients who may be at higher risk of sudden cardiac death.

Inclusion Criteria:

• Subject must be 18 to 65 years of age at time of informed consent and must not be a member of a vulnerable population.
• Subject has been diagnosed with hypertrophic cardiomyopathy, as defined by a maximal LV wall thickness of ≥15 mm anywhere in LV wall, in absence of another cause that could be responsible for the LV hypertrophy.
• Subject eligible to receive the Zio XT device per the current approved indications for use.

Exclusion Criteria:

• Subject with pacemaker
• Known skin allergies or reaction to adhesives
• The investigator deems a condition that could limit a subject's ability or unwillingness to participate in the study, comply with study required monitoring and/or follow-up visits.

Patients from the hypertrophic cardiomyopathy population will be recruited.