# HEART Pathway HEART Pathway Status: LIVE Price: $0.005 USDC `GET /api/calc/heart_pathway` HTML: https://magentlab.com/docs/heart-pathway Markdown: https://magentlab.com/docs/heart-pathway.md Not a medical device. Not a diagnosis, dose, or listing recommendation. ## What it computes Apply the Mahler 2015 HEART Pathway and return whether a caller-assigned HEART score plus 0-hour and 3-hour troponin flags meet the published early-discharge rule. ## When to use When an agent already has a caller-assigned Six 2008 HEART total (0-10) and caller-assigned 0-hour and 3-hour troponin elevation flags and needs the published Mahler 2015 early-discharge candidate result. magent does not assign HEART items, read an ECG, or assay a troponin. ## When not to use - Not a medical device and not a diagnosis of ACS or of discharge safety. - heart_score is the caller-assigned Six 2008 HEART total (0-10). magent does not assign history, ECG, age, risk-factor, or troponin HEART items. - troponin_0_elevated and troponin_3h_elevated are caller-assigned flags for a value above the 99th percentile. magent does not assay a troponin or read an ECG. - This tool does not order a stress test or angiogram. Presence of high-risk features does not mandate a test. - This is the Mahler 2015 HEART Pathway (HEART 0-3 plus serial 0h/3h troponin), not the Six 2008 HEART score alone. ## Formula ``` early_discharge_candidate iff heart_score <= 3 and troponin_0_elevated is false and troponin_3h_elevated is false; heart_score is the caller-assigned Six 2008 HEART total 0-10; troponin flags are caller-assigned above the 99th percentile at 0 and 3 hours (Mahler 2015) ``` ## Citation [The HEART Pathway randomized trial: identifying emergency department patients with acute chest pain for early discharge](https://doi.org/10.1161/CIRCOUTCOMES.114.001384) Mahler SA, Riley RF, Hiestand BC, Russell GB, Hoekstra JW, Lefebvre CW, Nicks BA, Cline DM, Askew KL, Elliott SB, Herrington DM, Burke GL, Miller CD Circ Cardiovasc Qual Outcomes. 2015;8(2):195-203 DOI: [10.1161/CIRCOUTCOMES.114.001384](https://doi.org/10.1161/CIRCOUTCOMES.114.001384) ## Worked example ### HEART 2, both serial troponins not elevated Given: `heart_score=2, troponin_0_elevated=false, troponin_3h_elevated=false` 1. heart_score 2 is <= 3 2. troponin_0_elevated is false and troponin_3h_elevated is false 3. early_discharge_candidate is true ## Also searched as - HEART Pathway - Mahler HEART Pathway - HEART Pathway early discharge - HEART 0-3 serial troponin - Mahler 2015 chest pain - low-risk HEART Pathway - HEART Pathway randomized trial ## Parameters - `heart_score` (integer, required): Caller-assigned HEART score integer 0-10 (Six 2008 components already summed by the caller). magent does not assign history, ECG, age, risk-factor, or troponin HEART items. Early discharge requires 0-3 when both serial troponin flags are false. - `troponin_0_elevated` (boolean, required): 0-hour troponin above the 99th percentile threshold as assigned by the caller. true or false. true blocks early discharge. magent does not assay a troponin. - `troponin_3h_elevated` (boolean, required): 3-hour troponin above the 99th percentile threshold as assigned by the caller. true or false. true blocks early discharge. magent does not assay a troponin. ## Bulk (POST) POST the same path with a JSON items array. The first item is the GET unit; each additional item is $0.002. Invalid items return HTTP 400 before settlement. Method: `POST /api/calc/heart_pathway` Max items: 25 Price: unit_amount + extra_item_amount * (n - 1) (unit 5000 atomic, extra 2000 atomic) Status: PREVIEW - 1 to 25 items. Each item uses the same keys as the GET query parameters. - POST of 1 item costs the same as GET. Lists longer than 25: chunk into multiple POSTs. Extra items still execute; do not pad dummy rows. - The first invalid item fails the whole request (index in the 400 JSON). You are not charged. - HTTP 200 is {count, path, items}. Each items[i] is the GET 200 body for that row. - Catalog misses (empty matches, found=false) stay paid 200s inside that slot. - x402 resource URL is this path plus n and body_sha256. Browsers that prefer text/html get the same paywall as GET; Pay retries POST with the same items. Example request: ```json { "items": [ { "heart_score": "2", "troponin_0_elevated": "false", "troponin_3h_elevated": "false" }, { "heart_score": "2", "troponin_0_elevated": "false", "troponin_3h_elevated": "false" } ] } ``` Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/heart-pathway Example 200: ```json { "count": 2, "path": "/api/calc/heart_pathway", "items": [ { "components": [ { "value": 2, "factor": "heart_score_le_3", "met": true }, { "value": false, "factor": "trop0_not_elevated", "met": true }, { "value": false, "factor": "trop3h_not_elevated", "met": true } ], "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.", "citation": { "authors": "Mahler SA, Riley RF, Hiestand BC, Russell GB, Hoekstra JW, Lefebvre CW, Nicks BA, Cline DM, Askew KL, Elliott SB, Herrington DM, Burke GL, Miller CD", "doi": "10.1161/CIRCOUTCOMES.114.001384", "id": "mahler-2015", "pmid": "25737484", "source": "Circ Cardiovasc Qual Outcomes. 2015;8(2):195-203", "title": "The HEART Pathway randomized trial: identifying emergency department patients with acute chest pain for early discharge" }, "formula": "heart_pathway", "formula_expression": "early_discharge_candidate iff heart_score <= 3 and troponin_0_elevated is false and troponin_3h_elevated is false; heart_score is the caller-assigned Six 2008 HEART total 0-10; troponin flags are caller-assigned above the 99th percentile at 0 and 3 hours (Mahler 2015)", "early_discharge_candidate": true, "heart_score": 2, "troponin_0_elevated": false, "troponin_3h_elevated": false }, { "components": [ { "value": 2, "factor": "heart_score_le_3", "met": true }, { "value": false, "factor": "trop0_not_elevated", "met": true }, { "value": false, "factor": "trop3h_not_elevated", "met": true } ], "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.", "citation": { "authors": "Mahler SA, Riley RF, Hiestand BC, Russell GB, Hoekstra JW, Lefebvre CW, Nicks BA, Cline DM, Askew KL, Elliott SB, Herrington DM, Burke GL, Miller CD", "doi": "10.1161/CIRCOUTCOMES.114.001384", "id": "mahler-2015", "pmid": "25737484", "source": "Circ Cardiovasc Qual Outcomes. 2015;8(2):195-203", "title": "The HEART Pathway randomized trial: identifying emergency department patients with acute chest pain for early discharge" }, "formula": "heart_pathway", "formula_expression": "early_discharge_candidate iff heart_score <= 3 and troponin_0_elevated is false and troponin_3h_elevated is false; heart_score is the caller-assigned Six 2008 HEART total 0-10; troponin flags are caller-assigned above the 99th percentile at 0 and 3 hours (Mahler 2015)", "early_discharge_candidate": true, "heart_score": 2, "troponin_0_elevated": false, "troponin_3h_elevated": false } ] } ``` ## Response fields - `formula` (string): heart_pathway - `formula_expression` (string): Mahler 2015 HEART Pathway early-discharge rule - `heart_score` (integer): Echo of the caller-assigned HEART total 0-10 - `troponin_0_elevated` (boolean): Echo of the caller-assigned 0-hour 99th-percentile flag - `troponin_3h_elevated` (boolean): Echo of the caller-assigned 3-hour 99th-percentile flag - `early_discharge_candidate` (boolean): true only when heart_score is 0-3 and both serial troponin flags are false. Not a discharge order or diagnosis. - `components` (array): Rows for heart_score_le_3, trop0_not_elevated, and trop3h_not_elevated with factor, met, and value - `citation` (object): Mahler 2015 Circ Cardiovasc Qual Outcomes citation - `disclaimer` (string): Not-a-device notice ## Example JSON Frozen fixture. Not a live lookup. ```json { "components": [ { "value": 2, "factor": "heart_score_le_3", "met": true }, { "value": false, "factor": "trop0_not_elevated", "met": true }, { "value": false, "factor": "trop3h_not_elevated", "met": true } ], "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.", "citation": { "authors": "Mahler SA, Riley RF, Hiestand BC, Russell GB, Hoekstra JW, Lefebvre CW, Nicks BA, Cline DM, Askew KL, Elliott SB, Herrington DM, Burke GL, Miller CD", "doi": "10.1161/CIRCOUTCOMES.114.001384", "id": "mahler-2015", "pmid": "25737484", "source": "Circ Cardiovasc Qual Outcomes. 2015;8(2):195-203", "title": "The HEART Pathway randomized trial: identifying emergency department patients with acute chest pain for early discharge" }, "formula": "heart_pathway", "formula_expression": "early_discharge_candidate iff heart_score <= 3 and troponin_0_elevated is false and troponin_3h_elevated is false; heart_score is the caller-assigned Six 2008 HEART total 0-10; troponin flags are caller-assigned above the 99th percentile at 0 and 3 hours (Mahler 2015)", "early_discharge_candidate": true, "heart_score": 2, "troponin_0_elevated": false, "troponin_3h_elevated": false } ``` ## Errors - HTTP 400 `invalid_heart_score`: heart_score must be an integer from 0 to 10. Returned before settlement; you are not charged. - HTTP 400 `invalid_flag`: boolean clinical flags must be true or false Returned before settlement; you are not charged. - HTTP 400 `invalid_items`: POST body must be a JSON object with only an items array Returned before settlement; you are not charged. - HTTP 400 `invalid_item_count`: items must be an array of 1 to 25 objects Returned before settlement; you are not charged. - HTTP 400 `invalid_item`: each items entry must be a JSON object Returned before settlement; you are not charged. Shared HTTP 402 and 503: https://magentlab.com/docs/payments ## Related tools - [HEART score](https://magentlab.com/docs/heart) — Compute the HEART score as age points plus caller-assigned history, ECG, risk factors, and troponin (each 0-2). - [EDACS](https://magentlab.com/docs/edacs) — Compute the Than 2014 Emergency Department Assessment of Chest pain Score from age, sex, and caller-assigned flags. - [TIMI UA/NSTEMI](https://magentlab.com/docs/timi-ua-nstemi) — Compute the TIMI risk score for unstable angina / NSTEMI from age and six caller-assigned flags. ## Payment Unpaid requests return HTTP 402 even if query parameters or POST items are missing or invalid, so CDP and agents can index the path. After a PAYMENT-SIGNATURE, invalid params return HTTP 400 JSON before settlement. magent does not charge. Fix the params, then request a new 402 quote for that complete URL. Catalog misses (empty matches, found=false) are valid paid 200s. - GET the tool with Accept: application/json (do not send Accept: text/html unless you want the human paywall). - HTTP 402 means you have not paid. Decode the base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote. - Sign accepts[0] (exact, EIP-3009) with validBefore = now + maxTimeoutSeconds (600 seconds), or accepts[1] (batch-settlement deposit/voucher) on product GET. Ping and POST {items} stay exact. Magent retries transient facilitator 429/5xx before answering. - Retry the same URL with PAYMENT-SIGNATURE (base64 JSON of accepted and payload). Magent attaches canonical extensions.bazaar on CDP verify/settle; echoing 402 bazaar is optional. - Success is HTTP 200 JSON plus PAYMENT-RESPONSE. exact settles before the tool. batch-settlement verifies (and deposit-settles) before the tool and commits the charge after HTTP 2xx. HTTP 503: retry the same PAYMENT-SIGNATURE. Mint a new exact nonce only after a new HTTP 402. - offered `exact` on eip155:8453: Fixed-price USDC on Base. The buyer authorizes the advertised amount (EIP-3009). magent settles before the tool runs (paymentFlow upfront). extra.assetTransferMethod=eip3009 extra.paymentFlow=upfront. - offered `batch-settlement` on eip155:8453: Payment-channel vouchers claimed later in batches. Exact stays accepts[0]. Same-path POST {items} is still exact. extra.assetTransferMethod=eip3009 extra.paymentFlow=authorization. - not offered `upto`: Not offered. Usage-based: buyer authorizes a ceiling, seller settles the actual amount after work. Reserved for a future metered tool. Not for current calculators or code search. Same-path POST {items} is still scheme exact: one EIP-3009 authorization for GET unit plus $0.002 per extra item. That is not x402 batch-settlement (payment channels / vouchers). Shared HTTP 402 and 503 table: https://magentlab.com/docs/payments Stdio MCP (one process per host): https://magentlab.com/docs/mcp ## Guarantees - HTTP 402 is unpaid, including a missing query. After PAYMENT-SIGNATURE, invalid parameters return HTTP 400 before settlement. You are not charged. HTTP 402 never includes the tool JSON. - exact: settlement finishes before the tool (paymentFlow upfront). batch-settlement: verify/deposit before the tool; chargedCumulativeAmount commits after HTTP 2xx. Uncertain or failed settlement fails closed (HTTP 503). Retry the same PAYMENT-SIGNATURE. - HTTP 402 is unpaid only. Do not sign a second authorization because of a 503. - Execution is timeout-bounded and concurrency-capped. - Calculator inputs are stored encrypted for allowlisted operators (Magent Console). They are not in public logs, SSH lookups, catalog, or rollups. Request logs store path without query.