1,329 calculators and references across 60 specialties, with formula confidence shown up front.
Amyloidosis Cardiac Stage (Mayo 2012): Explanation and Clinical Context The Mayo 2012 staging system is designed for patients with systemic light-chain (AL) amyloidosis and provides prognostic information based on cardiac involvement. It uses three biomarkers: NT-proBNP (>1800 pg/mL), Troponin T (>0.025 ng/mL), and difference in free light chains (dFLC >180 mg/L). Each abnormal biomarker counts as one risk factor. St
Apical HCM Index: Explanation and Clinical Context The Apical HCM Index is a simple echocardiographic metric calculated as the ratio of maximal apical wall thickness to the left ventricular end-diastolic diameter (LVEDD). It was first described by Kobayashi et al. to identify patients with apical hypertrophic cardiomyopathy (HCM), particularly in populations where this variant is more prevalent, such as in Japan. An
Arrhythmogenic Left Ventricular Cardiomyopathy (ALVC) Score: Explanation and Clinical Context ALVC Score is a validated risk prediction tool for patients with arrhythmogenic left ventricular cardiomyopathy, aimed at estimating the risk of arrhythmic events over a 5-year period. It incorporates key clinical and imaging parameters, including age, sex, presence of non-sustained ventricular tachycardia (NSVT), left ventr
Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) Risk Calculator (ESC 2022): Explanation and Clinical Context This tool estimates the 5-year risk of ventricular arrhythmias in patients diagnosed with ARVC based on the ESC 2022 risk model (Cadrin-Tourigny J, et al., Eur Heart J. 2022;43:1664–1678). The model incorporates age, sex, right ventricular dysfunction, history of non-sustained ventricular tachycardia, n
CS-CHD Score: Explanation and Clinical Context The CS-CHD Score is a prognostic model developed to estimate the risk of adverse cardiovascular events in patients with cardiac sarcoidosis. It incorporates clinical parameters such as left ventricular ejection fraction (LVEF), B-type natriuretic peptide (BNP) levels, history of ventricular arrhythmias, and need for ablation therapy. Higher scores indicate increased risk
DCM Mortality Score: Explanation and Clinical Context The DCM Mortality Score is a clinical risk prediction tool developed for patients with dilated cardiomyopathy (DCM) to estimate 1-year mortality risk. It integrates age, NYHA functional class, left ventricular ejection fraction (LVEF), and history of ventricular arrhythmia. Higher scores correspond to worse prognosis. This tool helps clinicians stratify patients f
ECV% Threshold Index (Amyloid Detection): Explanation and Clinical Context Extracellular Volume (ECV) quantification by cardiac MRI provides a non-invasive measure of myocardial amyloid infiltration. Elevated ECV% indicates expansion of the extracellular matrix, commonly due to amyloid fibril deposition. ECV > 40% is strongly suggestive of cardiac amyloidosis, while values between 30–39% indicate intermediate probabi
Familial Dilated Cardiomyopathy (DCM): Explanation and Clinical Context Familial DCM is a hereditary form of dilated cardiomyopathy characterized by left ventricular dilation and systolic dysfunction. It is typically inherited in an autosomal dominant pattern, with variable expressivity and incomplete penetrance. The condition can lead to heart failure, arrhythmias, and sudden cardiac death. Early identification and
Gillmore Staging (ATTR Amyloidosis): Explanation and Clinical Context Gillmore staging is a validated system to stratify prognosis in patients with transthyretin (ATTR) cardiac amyloidosis, using serum NT-proBNP and renal function (eGFR) as key predictors. Stage 1 corresponds to NT-proBNP < 3000 ng/L and eGFR > 45 mL/min/1.73m², indicating the lowest risk group. Stage 2 includes patients who meet only one of the abov
HCM Risk-SCD (ESC 2014): Explanation and Clinical Context The HCM Risk-SCD score is a validated tool developed by the European Society of Cardiology in 2014 to estimate the 5-year risk of sudden cardiac death in patients with hypertrophic cardiomyopathy (HCM). It incorporates clinical variables including age, maximal left ventricular wall thickness, left atrial diameter, maximal LV outflow tract gradient, family hist
HCM Risk-SCD 2.0 (ESC 2023 Update): Explanation and Clinical Context The HCM Risk-SCD 2.0 score is a validated tool to estimate the 5-year risk of sudden cardiac death (SCD) in patients with hypertrophic cardiomyopathy (HCM). It integrates clinical, echocardiographic, and family history parameters, including age, maximal left ventricular wall thickness, left atrial diameter, maximal LV outflow tract gradient, family
InterTAK Diagnostic Score: Explanation and Clinical Context The InterTAK Diagnostic Score is a validated clinical tool designed to estimate the likelihood of Takotsubo syndrome (TTS) in patients presenting with acute chest pain and suspected acute coronary syndrome. The score incorporates clinical variables readily available at presentation, including female sex, emotional or physical triggers, ST-segment depression
Left Atrial (LA) Volume Severity Index in Hypertrophic Cardiomyopathy (HCM): Explanation and Clinical Context The Left Atrial Volume Index (LAVI) is calculated as the left atrial volume (LAV) divided by the body surface area (BSA), providing a body size–adjusted measure of LA enlargement. LA enlargement in HCM reflects chronic diastolic dysfunction, elevated left ventricular filling pressures, and contributes to risk
LGE % Fibrosis Index (CMR): Explanation and Clinical Context The Late Gadolinium Enhancement (LGE) % Fibrosis Index is a quantitative measure of myocardial fibrosis obtained from cardiac magnetic resonance (CMR) imaging. It is calculated as the ratio of LGE mass to total left ventricular (LV) mass multiplied by 100, expressed as a percentage. Normal myocardium typically has minimal or no LGE; a value >5% suggests sig
LMNA Mutation Risk Score: Explanation and Clinical Context The LMNA mutation risk score is a clinical tool developed to predict the 5-year risk of life-threatening ventricular tachyarrhythmias (VTA) in patients with LMNA gene mutations. This score incorporates factors such as sex, presence of non-missense mutations, degree of atrioventricular block, occurrence of non-sustained ventricular tachycardia (NSVT), and left
LV Global Strain Abnormality Index (HCM/DCM): Explanation and Clinical Context The LV Global Strain Abnormality Index quantifies the extent of segmental myocardial dysfunction in patients with hypertrophic cardiomyopathy (HCM) or dilated cardiomyopathy (DCM). It combines global longitudinal strain (GLS) assessment and segmental strain abnormalities to provide a percentage score reflecting myocardial involvement. GLS
Left Ventricular (LV) Scar Burden: Explanation and Clinical Context LV Scar Burden (%) represents the proportion of left ventricular myocardial mass affected by fibrosis or infarction, typically quantified using Late Gadolinium Enhancement (LGE) on cardiac MRI. This parameter is clinically significant as higher LV scar burden is associated with an increased risk of ventricular arrhythmias, sudden cardiac death, and a
LV Wall Thickness Z-score: Explanation and Clinical Context The LV Wall Thickness Z-score is a standardized metric to assess left ventricular hypertrophy (LVH) relative to body size in children and adolescents. It compares the measured interventricular septal (IVS) and posterior wall thickness (LVPW) to age- and body size–specific normative data, providing a Z-score that indicates how many standard deviations the mea
LVOT Gradient Severity Index: Explanation and Clinical Context The LVOT Gradient Severity Index is a composite tool used to assess the severity of left ventricular outflow tract (LVOT) obstruction in patients, especially those with hypertrophic cardiomyopathy. It incorporates peak LVOT gradient, NYHA functional class, and presence of syncope to stratify patients into mild, moderate, or severe obstruction risk. This i
Maron Model (HCM SCD Prediction): Explanation and Clinical Context The Maron Model is a validated risk prediction tool for estimating the 5-year risk of sudden cardiac death (SCD) in patients with hypertrophic cardiomyopathy (HCM). It incorporates easily obtainable clinical and echocardiographic variables, including maximal left ventricular wall thickness, left atrial diameter, left ventricular outflow tract gradient
Myocardial Conduction Abnormality Score (MCAS): Explanation and Clinical Context The Myocardial Conduction Abnormality Score (MCAS) is a clinical tool developed to estimate the risk of conduction disturbances in patients with underlying cardiac disease, particularly those with prior myocardial infarction or age-related conduction changes. The score combines key variables including age, QRS duration, PR interval, pres
Myocardial Edema Ratio (MER): Explanation and Clinical Context The Myocardial Edema Ratio (MER) is a quantitative index derived from T2-weighted cardiac MRI images, calculated as the ratio of myocardial signal intensity (SI) to skeletal muscle SI. It is used to identify myocardial edema, commonly observed in acute myocardial injury such as myocarditis, acute myocardial infarction, or inflammatory cardiomyopathies. A
Myocarditis Severity Index (MRI-based): Explanation and Clinical Context The Myocarditis Severity Index (MSI) is a composite score derived from key cardiac MRI parameters, including Left Ventricular Ejection Fraction (LVEF), T2 Mapping, and Late Gadolinium Enhancement (LGE). This index aids in assessing the severity of myocarditis and predicting clinical outcomes. A higher MSI indicates greater myocardial inflammatio
National Amyloidosis Centre (NAC) Risk Score: Explanation and Clinical Context The NAC staging system stratifies patients with transthyretin cardiac amyloidosis (ATTR-CA) into prognostic categories based on NT-proBNP and eGFR levels. Stage 1 indicates a lower risk of mortality, while Stage 3 denotes a higher risk. This system aids clinicians in assessing disease severity and guiding treatment decisions.
PYP Quantitative Uptake Index (QUI): Explanation and Clinical Context The PYP Quantitative Uptake Index (QUI) is a ratio of the radiotracer counts measured in the myocardial region of interest (ROI) to the contralateral chest ROI during 99mTc-Pyrophosphate (PYP) scintigraphy. It is used to quantify myocardial uptake and improve the diagnostic accuracy for transthyretin cardiac amyloidosis (ATTR-CA). A higher QUI valu
PYP Scintigraphy Visual Score: Explanation and Clinical Context PYP (99mTechnetium-Pyrophosphate) scintigraphy is a non-invasive imaging technique used to detect cardiac amyloidosis, particularly transthyretin amyloidosis (ATTR-CM). The visual score ranges from 0 to 3 based on myocardial radiotracer uptake relative to bone: - Grade 0: No cardiac uptake; ATTR-CM is very unlikely. - Grade 1: Mild uptake, less than bone
About This Calculator Relative Wall Thickness (RWT) is a geometric index used in echocardiography to assess the pattern of left ventricular remodeling. It is calculated as: RWT = (2 × PWd) / LVEDD Interpretation commonly used in clinical practice: - RWT ≤ 0.42 → Normal geometry or eccentric hypertrophy - RWT > 0.42 → Concentric remodeling or concentric hypertrophy References 1. Lang RM et al. Recommendations for Card
Right Ventricular (RV) Involvement Index: Explanation and Clinical Context The RV Involvement Index is a composite echocardiographic score designed to quantify right ventricular dysfunction by integrating three key parameters: RV fractional area change (FAC), tricuspid annular plane systolic excursion (TAPSE), and the right ventricular myocardial performance index (RV MPI). This index provides a continuous measure of
Sarcoidosis Cardiac Involvement Score (SCIS): Explanation and Clinical Context The SCIS is a scoring system designed to assess the likelihood of cardiac involvement in patients with sarcoidosis. It incorporates clinical and imaging parameters to stratify risk and guide management decisions. A higher score indicates a greater likelihood of cardiac involvement and may necessitate more aggressive monitoring and treatmen
T1/T2 Mapping Ratio in Myocarditis: Explanation and Clinical Context T1/T2 mapping ratio is a non-invasive CMR-based metric used to quantify myocardial tissue changes in suspected myocarditis. T1 relaxation time reflects myocardial fibrosis and edema, while T2 relaxation time predominantly reflects myocardial water content and inflammation. The ratio of T1/T2 helps to stratify the likelihood of active myocardial infl
Takotsubo (InterTAK) Prognostic Score: Explanation and Clinical Context The InterTAK Prognostic Score is a validated tool derived from the International Takotsubo Registry to estimate the risk of in-hospital complications and adverse events in patients with Takotsubo syndrome. It incorporates clinical and demographic variables including gender, emotional and physical triggers, ST-segment elevation, QTc prolongation,