# 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, and experimental prototypes for ICU, echo, neonatal, fetal, ECG and clinic use. Every page computes in the browser; nothing entered is stored or sent. 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 Risk (STAT 2020)](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).

## 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.
- [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. 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.
- [Fetal Echo](https://heartcalc.doctorarichai.com/fetal): Fetal cardiac Z scores by gestational age or femur length and the 10-point Cardiovascular Profile Score. Experimental prototype, not independently verified.
- [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. 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.
- [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. Experimental prototype, not independently verified.
- [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. Experimental prototype, not independently verified.
- [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. Experimental prototype, not independently verified.
- [Kawasaki Coronary Z-Scores](https://heartcalc.doctorarichai.com/kawasaki): Coronary artery z scores from four published models side by side, with the AHA 2017 classification, a model-disagreement flag and the Son 2019 aneurysm risk score. 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.
- [CICU Severity Panel](https://heartcalc.doctorarichai.com/cicu): Vasoactive-inotropic score, vasoactive-ventilation-renal score, oxygenation index and oxygen saturation index after cardiac surgery. 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 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. Experimental prototype, not independently verified.
- [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 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.

## For AI agents

- [MCP server](https://heartcalc.doctorarichai.com/mcp): tools calculate_cath_hemodynamics (Cath Hemodynamics), calculate_hcm_scd_risk (Sudden Cardiac Death Risk (HCM)), calculate_neonatal_bp (Neonatal Blood Pressure).
- [OpenAPI](https://heartcalc.doctorarichai.com/openapi.json): JSON API for the same 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

### 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, MCP 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 on a page is stored or sent anywhere. 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.