High-output cardiac failure

High output cardiac failure refers to a state of cardiac failure that is associated with a higher than normal cardiac output which is still not sufficient for body tissue demands.

Clinical presentation

Patients can present with a number of symptoms of varying degrees which include tachycardia, elevated pulse pressure, hyperkinetic precordium, and jugular venous distension.

Pathology

There are three major mechanisms of high output heart failure:

There are several conditions that can predispose to this situation:

• arteriovenous malformations
  • large single arteriovenous malformation capable of shunting
  • hereditary hemorrhagic telangiectasia
  • vein of Galen malformation
  • angio-osteo-hypertrophic syndromes
    • Klippel-Trénaunay-Weber syndrome
    • F. P. Weber syndrome
• arteriovenous shunting without a distinct malformation
  • Paget disease of bone
  • fibrous dysplasia
  • multiple myeloma
  • hepatopulmonary syndrome
• other conditions that can lead to high output states
  • sepsis
  • hypercapnia
  • hyperthyroidism
  • chronic anemia
  • beriberi
  • morbid obesity

The most common etiology in the United States is morbid obesity, which decreases systemic vascular resistance through several distinct mechanisms;

• adipokine mediated shunting of flow through their local vascular beds
• exuberant elaboration of capillary beds within the adipose tissue by similar mediators
• displacement of the cardiac axis by the mass effect of adipose tissue, which may decrease the efficiency of cardiac work
• subsequent activation of renin-angiotensin-aldosterone system due to decreased perfusion of the kidneys
  • salt and water retention increases plasma volume and cardiac work

Radiographic features

Echocardiography

The hemodynamic milieu of the heart failure syndrome is present, despite a normal to hyperdynamic ejection fraction, with elevated left sided filling pressures (E/e' > 15), right sided pressure overload (measured right ventricular systolic pressure (RVSP) >42 mmHg) and cardiac indices typically above 3.5 liters per minute per square kilogram. Other common features include increased left ventricular end diastolic diameters, with subnormal end systolic diameters. An elevated heart rate is also commonly present.

The single finding with the best ROC curve is the right ventricular systolic pressure; as measured by Doppler, a right ventricular systolic pressure >42 mmHg has demonstrated a 92% sensitivity and 100% specificity (in a study group with abnormally elevated cardiac indices) .