Therapeutic implications of implantable device-based monitoring of patients with heart failure

Abstract

Heart failure is one of the most common medical problems faced by patients and clinicians. It has the potential for high morbidity and mortality, and its overall financial cost to society is enormous. Management of heart failure is often difficult and time consuming, and is sometimes frustrating. The usual signs and symptoms of heart failure may not be obvious early in an exacerbation, which has prompted the development of other methods to identify early and subtle clinical changes to initiate early intervention. Current implantable devices, such as defibrillators and pacemakers, can monitor changes in heart rate and heart rate variability, patient activity, arrhythmia frequency, and thoracic impedance, all of which may be markers of clinical decline. Newer implantable devices can also measure right ventricular pressures, oxygen saturation, and pulmonary artery pressures. Many of these technologies have been shown to be feasible and potentially helpful, but outcomes data showing reductions in morbidity and mortality are currently limited. Importantly, none of these newer technologies should be used in isolation; all must be used in combination with clinical findings to provide effective disease management.

PRecision Event Monitoring for PatienTs with Heart Failure using HeartLogic (PREEMPT‐HF) study design and enrolment

“…It is well known that arrhythmias are more common as HF progresses. Acute HF exacerbations are presumed to trigger arrhythmias through multiple mechanisms, including increased cardiac filling pressures and neurohormonal activation 23–26 . Current patient risk assessment for malignant arrhythmias is subjective, and device sensor‐based algorithms for risk stratification using traditional sensors have had only modest accuracy 27–30 .…”

“…Acute HF exacerbations are presumed to trigger arrhythmias through multiple mechanisms, including increased cardiac filling pressures and neurohormonal activation. 23 , 24 , 25 , 26 Current patient risk assessment for malignant arrhythmias is subjective, and device sensor‐based algorithms for risk stratification using traditional sensors have had only modest accuracy. 27 , 28 , 29 , 30 The management of ventricular arrhythmias is largely reactive, with further evaluation and treatment occurring after the arrhythmia is detected and often following ICD therapy.…”

Assessment of Intrathoracic Impedance Algorithm in the Pediatric and Adult Congenital Population

“…The algorithm is based on the decrease in impedance across the chest due to improved conductivity of electricity with an acute increase in intrathoracic fluid (e.g., from pulmonary edema). Acute decreases in thoracic impedance, as measured by an implanted device, have been shown in adult studies to be a sensitive marker of worsening HF …”