Failing with Cyanosis-Heart Failure in End-Stage Unrepaired or Partially Palliated Congenital Heart Disease.

Heart failure in cyanotic congenital heart disease (CHD) is diagnosed clinically rather than relying solely on ventricular function assessments. Patients with cyanosis often present with clinical features indicative of heart failure. Although myocardial injury and dysfunction likely contribute to cyanotic CHD, the primary concern is the reduced delivery of oxygen to tissues. Symptoms such as fatigue, lassitude, dyspnea, headaches, myalgias, and a cold sensation underscore inadequate tissue oxygen delivery, forming the basis for defining heart failure in cyanotic CHD. Thus, it is pertinent to delve into the components of oxygen delivery in this context.