# HeartCalc

> Pediatric cardiology and neonatal hemodynamics calculators and references for clinicians: cath hemodynamics, congenital heart surgery risk (STAT 2020), HCM sudden cardiac death risk, neonatal blood pressure, bedside guideline references (athlete pre-participation screening, pediatric ICD indications), and experimental prototypes for ICU, echo, neonatal, fetal, ECG and clinic use. Every page computes in the browser; nothing entered in a calculator is stored or sent, and the optional "Report a problem" form sends only what the reader types into it. By Piyawat Arichai, MD, FAAP (pediatric cardiology).

Verified tools have been checked against their primary references. Experimental prototypes are built from published sources but are not independently verified and are not for clinical decisions. Each tool page states its population, its guards and its equations and sources (the "Model, equations and sources" section, at #method).

## Verified tools

- [Cath Hemodynamics](https://heartcalc.doctorarichai.com/cath): Fick flows and resistances from cath saturations and pressures.
- [Surgical Mortality Risk](https://stat.doctorarichai.com): STAT Score, Category and model-based operative mortality for congenital heart surgery procedures.
- [Sudden Cardiac Death Risk (HCM)](https://heartcalc.doctorarichai.com/scd): 5-year risk of sudden cardiac death in hypertrophic cardiomyopathy, with the model chosen by age.
- [Neonatal Blood Pressure](https://heartcalc.doctorarichai.com/neonatal-bp): Systolic BP centile for babies born at 23 to 41 weeks, from birth through the first year (NNNI 1999).
- [CCHD Pulse-Ox Screen](https://heartcalc.doctorarichai.com/cchd-screen): Newborn critical congenital heart disease screening with the updated AAP algorithm: right hand and foot SpO2 for up to two screens.
- [Fetal Echo](https://heartcalc.doctorarichai.com/fetal): Fetal cardiac Z scores by gestational age or femur length and the 10-point Cardiovascular Profile Score.
- [Cath Extensions](https://heartcalc.doctorarichai.com/cath-plus): Glenn/Fontan PVRi from Qp, Nakata and McGoon PA indices, Gorlin valve area, and AHA/ATS 2015 vasoreactivity response.
- [Echo Z-Scores](https://heartcalc.doctorarichai.com/echo-z): Pediatric Heart Network (Lopez 2017) Z scores for 35 2D echo measurements, with expected mean and normal range, and Detroit alongside.
- [LV Mass and LVH](https://heartcalc.doctorarichai.com/lv-mass): PHN 2D LV mass, volume and wall Z scores, plus M-mode LV mass indexed to height^2.7 against the Khoury 2009 cutoffs.
- [Aortic Root and Ghent](https://heartcalc.doctorarichai.com/aortic-root): Aortic root Z scores (PHN, with Detroit alongside) and the revised Ghent systemic score and rules as a reference checklist.
- [Turner Syndrome Aortic Z-Scores](https://heartcalc.doctorarichai.com/turner): Aortic size compared with healthy girls and women with Turner syndrome (Quezada 2015), with the aortic size index.
- [Kawasaki Coronary Z-Scores](https://heartcalc.doctorarichai.com/kawasaki): Coronary artery z scores from four published models side by side, with the AHA 2024 classification and risk level on Boston z, its long-term management (Table 2), a model-disagreement flag and the Son 2019 aneurysm risk score.
- [CICU Severity Panel](https://heartcalc.doctorarichai.com/cicu): Vasoactive-inotropic score, vasoactive-ventilation-renal score, oxygenation index and oxygen saturation index after cardiac surgery.
- [Pediatric Blood Pressure](https://heartcalc.doctorarichai.com/bp): AAP 2017 category and stage for one reading from the child's table percentiles (1 to <13 y) or fixed thresholds (13 to <18 y), with a four-limb gradient helper.
- [QTc and LQTS Score](https://heartcalc.doctorarichai.com/qtc): QTc by Bazett, Fridericia, Framingham and Hodges from QT (ms) and heart rate or RR, with pediatric +2 SD context and the Schwartz 1993-2011 LQTS points score.

## Experimental tools

- [Neonatal Echo Hemodynamics](https://heartcalc.doctorarichai.com/neonatal-echo): Targeted neonatal echo: LV and RV output, SVC flow, the El-Khuffash PDA severity score and the Iowa PDA score, with gestational and postnatal age guards. Experimental prototype, not independently verified.
- [Neonatal Echo Reference Values](https://heartcalc.doctorarichai.com/neonatal-echo-ref): Published preterm and term echo reference ranges and cut-offs, each with population, method and citation, searchable by parameter. Experimental prototype, not independently verified.
- [Borderline LV Scores](https://heartcalc.doctorarichai.com/borderline-lv): What the Rhodes 1991 and Colan 2006 discriminant scores and the Cohen AV valve index say about biventricular candidacy, with an automatic measurement sensitivity band. Experimental prototype, not independently verified.
- [PRAiS2 Surgical Risk](https://heartcalc.doctorarichai.com/prais2): What the UK PRAiS2 model for 30-day mortality after pediatric cardiac surgery is, why it is not reproduced here, where to run it, and observed/expected arithmetic for its outputs. Research and audit use only. Experimental prototype, not independently verified.
- [PH Echo Estimator](https://heartcalc.doctorarichai.com/ph-echo): Pediatric pulmonary hypertension echo screening markers: RVSP, PA acceleration time, eccentricity index and TAPSE. Experimental prototype, not independently verified.
- [Single-Ventricle O2 Explorer](https://heartcalc.doctorarichai.com/sv-o2): Educational model of a parallel circulation: Qp:Qs from saturations and systemic oxygen delivery across Qp:Qs, after Barnea 1994. Experimental prototype, not independently verified.
- [Pediatric Heart Failure](https://heartcalc.doctorarichai.com/hf): NT-proBNP compared with age- and sex-specific upper reference limits for ages 1 to 19 (NHANES, Mu 2023), with the Ross 2012 and NYU PHFI scores described and linked. Experimental prototype, not independently verified.
- [Pediatric CPET](https://heartcalc.doctorarichai.com/cpet): Where pediatric exercise reference values come from (Burstein 2021 and others, explained and linked) and percent predicted peak VO2 from a predicted value you bring from a named reference. Experimental prototype, not independently verified.

## Bedside references

Guideline recommendations and checklists, condensed from the source with class and level of evidence kept. No calculation; each page cites its documents (#method).

- [Bedside References](https://heartcalc.doctorarichai.com/refs): High-yield bedside references for pediatric cardiology: guideline recommendations and checklists, condensed from the source with class and level of evidence, each page cited.
- [Echocardiogram Calculators and References](https://heartcalc.doctorarichai.com/refs/echo): Echo references for pediatric cardiology, organised like an echo report: ventricular function, chambers, valves, great arteries and coronaries, pressures and shunts. Jump straight to a measurement.
- [Pre-participation Screening (Athletes)](https://heartcalc.doctorarichai.com/refs/preparticipation): AHA 14-element pre-participation cardiovascular screening checklist for young athletes, with the AHA/ACC recommendations on ECG screening (2014, 2015) and the 2025 AHA/ACC update.
- [ICD Indications (Pediatric)](https://heartcalc.doctorarichai.com/refs/icd): ICD indications in children and young people with heart disease (21 years and under): the 2021 PACES expert consensus by condition and class of recommendation, with the 2024 AHA/ACC rows for HCM.
- [Pacemaker Indications (Pediatric)](https://heartcalc.doctorarichai.com/refs/pacemaker): Permanent pacemaker indications in children and young people (21 years and under): every 2021 PACES pacemaker recommendation (Section 2) by condition and class, with the 2023 HRS rows on pacing site and resynchronization in pediatric and congenital heart disease.
- [Cardiomyopathy in Children: Diagnosis and Management](https://heartcalc.doctorarichai.com/refs/cardiomyopathy): Cardiomyopathy in children, with adult values labelled: phenotypes as the 2023 ESC guideline defines them (HCM, DCM, NDLVC, ARVC, RCM; LVNC as each source treats it), diagnostic cut-offs, work-up and red flags, graded management, family screening and genetic testing, follow-up, and a finder for late gadolinium enhancement (LGE) patterns on cardiac MRI.
- [Antithrombotic Therapy in Pediatric Heart Disease](https://heartcalc.doctorarichai.com/refs/antithrombotics): Antithrombotic therapy in pediatric heart disease by lesion and procedure: systemic-to-PA shunt and Norwood, RV-PA conduit, ductal or RVOT stent, Glenn, Fontan, mechanical and bioprosthetic valves, endovascular stents and devices, and catheter-related thrombosis. Agent, start, target, duration and monitoring, with every graded row by source as printed: AATS 2026 (neonates and infants), AHA 2013, CHEST 2012, ASH 2018, and ACHD 2025 (adult, labelled). UFH and LMWH anti-Xa ranges, INR targets and aspirin dose ranges as printed.
- [Myocarditis: Diagnosis and Imaging](https://heartcalc.doctorarichai.com/refs/myocarditis): Myocarditis in children, neonates and adults: when to suspect it, diagnostic certainty (AHA 2021 strata, ESC 2025 definite and possible), graded tests (JCS 2023 pediatric and neonatal, ESC 2025), labs, ECG, echo, the updated Lake Louise Criteria for CMR, other imaging, biopsy and red flags for fulminant myocarditis.
- [Aortopathy (All Ages)](https://heartcalc.doctorarichai.com/refs/aortopathy): Aortopathy from fetus to adult: how aortic size is indexed by age, rapid-growth definitions, and surgical thresholds for Marfan, Loeys-Dietz by gene, vascular EDS, other heritable thoracic aortic disease genes, bicuspid aortic valve, Turner and repaired congenital heart disease, from the AHA 2024 pediatric statement and the ACC/AHA 2022 and ESC 2024 guidelines (adult, labelled), with classes of recommendation.
- [Repaired Tetralogy of Fallot](https://heartcalc.doctorarichai.com/refs/tof): Repaired tetralogy of Fallot: how often to repeat echo, CMR, exercise testing, ECG and Holter by age, the CMR and echo thresholds that matter (PR fraction, RVESVi, RVEDVi, RVEF, LVEF, RV pressure, QRS, TR, branch PAs), and pulmonary valve replacement indications: the AHA 2024 framework (no class), STS 2026 and AHA 2011 rows, and the adult ACHD 2025 and ESC 2020 guidelines with class and level (adult, labelled). Imaging schedules from AHA 2024, ASE 2014 and ACHD 2025.
- [Anomalous Aortic Origin of a Coronary Artery (AAOCA)](https://heartcalc.doctorarichai.com/refs/aaoca): Anomalous aortic origin of a coronary artery (AAOCA), right (AAORCA) and left (AAOLCA): high-risk anatomy as each source defines it, how to image (echo views, CT, CMR), ischemia testing, surgery indications with class and level (AATS 2017; adult ACHD 2025 and ESC 2020, labelled), sports participation and return to play (AHA/ACC 2025, AATS 2017, ESC 2020), and follow-up after repair.
- [Genetic Testing in Congenital Heart Disease](https://heartcalc.doctorarichai.com/refs/genetics-chd): Genetic testing in congenital heart disease: which test to send for each lesion (CMA, 22q11.2 deletion, karyotype, gene panels, exome or genome sequencing), how often each lesion carries a 22q11.2 deletion or aneuploidy, when to refer to genetics, recurrence risk by affected relative (AHA 2018 Table 10), and the cardiac screening sources state for trisomy 21, Noonan, Holt-Oram and other syndromes. AHA 2018, NSGC 2021, ACMG 2021, AHA 2021, AHA 2014 fetal, AAP 2022, AHA 2024; adult rows from ACHD 2025 labelled.
- [Echo: LV and RV Systolic Function](https://heartcalc.doctorarichai.com/refs/echo-systolic): Echo assessment of LV and RV systolic function in neonates and children: how ASE recommends measuring EF, fractional shortening, GLS, TAPSE, FAC, s′, RV strain and RIMP, with pediatric and neonatal reference values and adult ASE cut-offs.
- [Echo: Diastolic Function](https://heartcalc.doctorarichai.com/refs/echo-diastolic): Echo assessment of diastolic function in neonates and children: what the ASE pediatric and neonatal guidelines recommend, preterm and term reference values, pediatric left atrial volume indexing, filling-pressure studies, and the adult ASE 2025 algorithm for comparison.
- [Echo: Valve Regurgitation](https://heartcalc.doctorarichai.com/refs/echo-regurgitation): Grading mitral, aortic, tricuspid and pulmonary regurgitation by echo in children: the ASE pediatric approach, pediatric study cut-offs, the adult ASE 2017 grading tables labelled as adult, and how to tell physiologic from pathologic regurgitation.
- [Echo: Valve Stenosis and Coarctation](https://heartcalc.doctorarichai.com/refs/echo-stenosis): Grading aortic, pulmonary, mitral and tricuspid stenosis and coarctation by echo in children: Doppler versus catheter gradients, pediatric pitfalls, AHA 2011 pediatric intervention thresholds, and the adult ASE/EACVI grading tables labelled as adult.
- [Echo: Prosthetic Valves](https://heartcalc.doctorarichai.com/refs/echo-prosthetic): Prosthetic valve echo: the ASE 2024 criteria for normal function, possible and significant stenosis and prosthesis-patient mismatch in the pulmonary, aortic, mitral and tricuspid positions, and every normal Doppler value by valve model and size (Appendix Tables A1-A9), adult-derived tables labelled.
- [Echo: Strain Normal Values](https://heartcalc.doctorarichai.com/refs/echo-strain): Normal LV, RV and LA strain by speckle tracking from preterm infants to 21 years: age-band values by platform (Philips QLAB 10.8, TomTec AutoSTRAIN), neonatal reference intervals, pediatric LA strain by age, z-score sources and adult ASE/EACVI limits.
- [Echo: Pulmonary Hypertension](https://heartcalc.doctorarichai.com/refs/echo-ph): Echo assessment of pulmonary hypertension in neonates, infants and children: neonatal signs, pressure estimates, eccentricity index and RV/LV ratio centiles, PAAT and TAPSE normal values by age, cut-offs, risk tables, screening recommendations, and the adult ESC/ASE approach for comparison.
- [Echo: Single Ventricle](https://heartcalc.doctorarichai.com/refs/echo-single-ventricle): Echo measurements in single-ventricle patients from neonate to Fontan: short-axis and RV fractional area change, area-length volumes, dP/dt, MPI, arch Doppler after Norwood, Fontan fenestration gradient and AV-valve regurgitation, with published single-ventricle cohort values (SVR trial, PHN Fontan studies) and the AHA and ACHD surveillance intervals.
- [Echo: PDA Assessment](https://heartcalc.doctorarichai.com/refs/echo-pda): Echo assessment of the patent ductus arteriosus in preterm infants: the AAP 2025 suggested hsPDA definition, small/moderate/large shunt markers, the El-Khuffash and Iowa scores, how to measure, and what is known beyond the neonatal period.

## For AI agents

- [OpenAPI](https://heartcalc.doctorarichai.com/openapi.json): JSON API for the verified calculators, /api/v1/cath, /api/v1/scd, /api/v1/neonatal-bp. Parameter names equal the page's form control ids.
- [tools.json](https://heartcalc.doctorarichai.com/tools.json): machine-readable registry of every tool: inputs (names, units, options, required), population, outputs, sources, method link and a prefill example.
- [llms-full.txt](https://heartcalc.doctorarichai.com/llms-full.txt): this file plus every tool's inputs and its model, equations and sources as text.
- Prefill links hand a calculation to a clinician, who sees the filled page and checks it:
  - Pattern: <tool url>?<input name>=<value>&<input name>=<value>... Input names are the form control ids and radio-group names listed in each tool's inputs.
  - Radio groups and selects take an option value (case-insensitive; an option label also works). Checkboxes take 1, true, yes or on (0, false, no or off to clear). Dates take YYYY-MM-DD. Numbers use a dot for decimals.
  - Mode-setting radios are applied first, then everything else, so the page shows the right fields.
  - The page shows a caution notice, "Filled from a link.", listing every field it set, asking the clinician to check each value against the patient, and listing parameters it ignored or found invalid. Unknown parameters fill nothing.
  - Query-string values reach the web host's request logs like any URL. The same parameters after # instead of ? never leave the browser.
- Prefill examples:
  - Cath Hemodynamics: https://heartcalc.doctorarichai.com/cath?ageY=0&ageM=6&sex=M&ht=68&wt=7.5&hgb=11.5&vo2Method=seckeler&hr=140&sao2=97&mvDirect=71&pa=85&mAo=55&mRA=6&mPA=28&mLA=8
  - Sudden Cardiac Death Risk (HCM): https://heartcalc.doctorarichai.com/scd?ageY=12&sex=male&wt=40&mwtMm=17&laMm=29&lvot=24&syncope=no&nsvt=no&fh50=no&massive=no&aneur=no&lvef=no&lge=notdone
  - Neonatal Blood Pressure: https://heartcalc.doctorarichai.com/neonatal-bp?gaW=26&gaD=3&mode=pna&pna=5&sbp=46
  - CCHD Pulse-Ox Screen: https://heartcalc.doctorarichai.com/cchd-screen?ageH=26&rh1=97&foot1=93&rh2=98&foot2=96
  - Fetal Echo: https://heartcalc.doctorarichai.com/fetal?mode=ga&gaW=24&gaD=0&m_mv=6&m_tv=7&m_av=4&m_pv=5&m_aao=4.5&m_mpa=5.5&m_isth3=3.2&m_duct3=4&hydrops=effusion&venous=normal&ctar=0.38&fn=mild&arterial=normal
  - Cath Extensions: https://heartcalc.doctorarichai.com/cath-plus?mod=cavo&circ=glenn&qpMode=fick&cMPA=13&cMAtr=6&cVo2i=150&cVo2Src=measured&cHgb=15&cPv=97&cPvSrc=assumed&cPa=65
  - Echo Z-Scores: https://heartcalc.doctorarichai.com/echo-z?ageY=10&ht=140&wt=35&unit=mm&v_ANN=18&v_ROOT=25&v_STJ=20&v_AAO=21&v_MVLAT=25&v_LVEDD=42&v_LVST=7&v_LVPWT=7&v_LMCA=3
  - LV Mass and LVH: https://heartcalc.doctorarichai.com/lv-mass?ageY=12&sex=male&ht=150&wt=40&unit=mm&LVEDA=14&LVEDAEPI=25&LVEDL=68&LVEDLEPI=76&LVST=9&LVPWT=9&LVEDD=44&ivs=9&lvid=44&pw=9
  - Aortic Root and Ghent: https://heartcalc.doctorarichai.com/aortic-root?ageY=14&ht=165&wt=50&unit=mm&ANN=22&ROOT=34&STJ=27&AAO=27&el=no&fh=no&wristThumb=both&pectus=excavatum&foot=flat&myopia=1&mvp=1
  - Turner Syndrome Aortic Z-Scores: https://heartcalc.doctorarichai.com/turner?ageY=14&ht=145&wt=42&bav=no&unit=mm&AR=27&STJ=22&AAO=25
  - Kawasaki Coronary Z-Scores: https://heartcalc.doctorarichai.com/kawasaki?age=3&ageUnit=years&sex=male&wt=14&ht=95&dUnit=mm&dLMCA=2.6&dLAD=2.4&dRCA=2.5&rlMode=echo&isMax=no&maxZ=6.1&max8=no&baseline=yes&asian=no&crp=15&crpUnit=mg%2FdL
  - CICU Severity Panel: https://heartcalc.doctorarichai.com/cicu?dopa=5&epi=0.05&milri=0.5&vaso=0.5&vasoUnit=mU&population=infantCpb&window=h0_24&vent=conv&rr=20&pip=25&peep=5&paco2=45&map=12&fio2=50&pao2=80&spo2=95&mixing=no&crUnit=mgdl&crBase=0.3&crNow=0.6
  - Pediatric Blood Pressure: https://heartcalc.doctorarichai.com/bp?ageY=10&sex=male&sbp=114&dbp=70&sbp90=112&sbp95=116&dbp90=74&dbp95=77&ra=114&la=112&leg=92
  - QTc and LQTS Score: https://heartcalc.doctorarichai.com/qtc?ageY=4&sex=male&qt=320&rateMode=hr&hr=115&syncope=stress

### Rules

- Cite the source: name the model or reference the tool uses (its sources list) next to any number you report.
- Report guard and not-applicable messages as the tool states them (for example "No model applies under 1 year of age"); never compute around a guard or extrapolate beyond a stated population.
- Label experimental tools as "experimental prototype, not independently verified" wherever you use them.
- Decision support only: results inform a clinician; they are not a diagnosis, an order or a treatment decision.
- Never send identifiers. No names, record numbers, dates of birth, exact dates of service, addresses or free text about a patient in API calls or links. Use age (ageY) rather than a date of birth.
- Hand off with a prefill link so the clinician sees the page, its notices and its sources, and checks every value against the patient.

## About

- Author: [Piyawat Arichai, MD, FAAP](https://doctorarichai.com), pediatric cardiology.
- HeartCalc is a personal set of clinician tools. It is not an official site of any hospital.
- Privacy: Every HeartCalc page computes in the browser: nothing entered into a calculator is stored or sent anywhere. The optional "Report a problem" form sends only what is typed into it, the page and the section; calculator inputs are never included. A prefill link carries its values in the URL; values after ? reach the web host's request logs like any URL, values after # stay in the browser. Never put identifiers in a link.