the supine position. Orthopnea has a reported sensitivity
of 22% to 50% and a specificity of 74% to 77% for
heart failure.12,13 Patients with heart failure require increased
numbers of pillows to sleep at night in order to
avoid symptoms of orthopnea. The number of pillows
required can be used to gauge the severity of heart failure.
PND refers to attacks of shortness of breath that
occur at night and may awaken the patient from sleeping.
The sensitivity and specificity of PND for heart
failure range from 39% to 41% and from 80% to 84%,
respectively