LUX-Dx TRENDS Evaluates Diagnostics Sensors in Heart Failure Patients Receiving Boston Scientific's Investigational ICM System.

The primary objective of this study is to collect sensor data from insertable cardiac monitor systems.

Key Inclusion Criteria: * Patient is currently in NYHA Class II or III. * For patients with LVEF \>40% measured on most recent available echocardiography within the previous 12 months: * ONE (1) of the following echocardiography findings: LA width (diameter) \>3.8 cm, LA length \>5.0 cm, LA area \>20 cm2, LA volume \>55 ml, LA volume index \>29 ml/m2, LVH defined by septal thickness or posterior wall thickness of \>1.1 cm AND * ONE (1) of the following: Elevated BNP/NT-proBNP as defined by: BNP \>100 pg/ml or NT-proBNP \>300 pg/ml within the previous 90 days for patients not in atrial fibrillation or BNP \>300 pg/ml or NT-proBNP \>900 pg/ml for patients in atrial fibrillation at the time of screening for eligibility OR Documented heart failure hospitalization or unscheduled heart failure IV therapy in the previous 12 months * For patients with LVEF \150 pg/ml or NT-proBNP \>600 pg/ml within the previous 90 days for patients not in atrial fibrillation or BNP \>450 pg/ml or NT-proBNP \>1800 pg/ml for patients in atrial fibrillation at the time of screening for eligibility OR Documented heart failure hospitalization or unscheduled heart failure IV therapy in the previous 12 months * Patient is willing to be monitored in LATITUDE Clarity and use the ICM patient mobile app. * Patient is of legal age to give informed consent and is willing to participate in the trial. Key Exclusion Criteria: * Patient is currently implanted with any other active electronic medical device. * Patient has undergone a heart transplant. * Patient is currently enrolled in another investigational study (excluding registries) without prior written approval from Boston Scientific. * Patient is known to be pregnant at the time of enrollment or plans to become pregnant during study participation. * Patient is diagnosed with amyloidosis or hypertrophic cardiomyopathy.