Table 1.

HLM classification

Heart (H)	Lungs (L)	Other organs (M)
H1: Diastolic dysfunction and/or presence of structural cardiac damage a in absence of LV systolic dysfunction (LVEF ≥ 50%)	L0: Absence of any lung involvement	M0: Absence of malfunction of other organs b
H2: LV systolic (LVEF < 50%) or diastolic dysfunction with structural damage without LV dilation	L1: Haemodynamic lung involvement, assessed by CXR, and/or sPAP ≥ 35 mmHg at rest, assessed by TTE, with absence of clinical signs of lung congestion	M1: Presence of single systemic organ damage (except heart and lungs)
H3: LV dilation, structural cardiac damage with systolic (LVEF < 50%) or diastolic dysfunction, or right ventricular systolic dysfunction (TAPSE < 17 mm)	L2: Clinical signs and symptoms for lung congestion assessed by physical examination (crepitation, raised jugular venous pressure, orthopnoea, dyspnoea, and necessity of supplemental oxygen) and increase of left ventricular filling pressure, assessed by echocardiographic evaluation and, if feasible, by right heart catheterization	M2: Presence of double systemic organ damage (except heart and lungs)
H4: Biventricular systolic dysfunction (LVEF < 50% and TAPSE < 17 mm)	L3: ‘Cardiac lung’ defined by arterialization of pulmonary vasculature, with post‐capillary hypertension (type II) and necessity of supplemental oxygen at discharge, despite use of congestion‐relief therapy and absence of congestion	M3: Presence of ≥3 systemic organ damage (except heart and lungs)

CXR, chest X‐rays; HLM, heart, lungs, and systemic multiorgan involvement; LV, left ventricular; LVEF, left ventricular ejection fraction; sPAP, systolic pulmonary arterial pressure; TAPSE, tricuspid annular plane systolic excursion; TTE, transthoracic echocardiography.

Definition of the stages for each parameter included in the HLM classification for heart failure.

^a Structural damage is defined by at least one among abnormal wall motion, left ventricular hypertrophy, and moderate to severe left‐sided valvular disease.

^b Malfunction of other organs are estimated glomerular filtration rate < 60 mL/min for kidney dysfunction; at least one among aspartate aminotransferase/alanine aminotransferase/total bilirubin/gamma‐glutamyl transferase/alkaline phosphatase elevated at least two times more than normal, for liver dysfunction; haemoglobin of <13 g/dL for men and <12 g/dL for women, for anaemia; transferrin saturation < 20% with serum ferritin between 100 and 299 ng/mL or serum ferritin < 100 ng/mL alone, for iron deficiency; more than 5% oedema‐free body weight loss during the previous year or less, for HF‐related cachexia; and the Beck Depression Inventory and Cardiac Depression Scale have been used to assess HF‐related depression and anxiety disorders and computed tomography/magnetic resonance imaging to exclude ischaemic or haemorrhagic stroke, for central nervous system involvement.