# Canadian Syncope Risk Score CSRS Status: LIVE Price: $0.005 USDC `GET /api/calc/csrs` HTML: https://magentlab.com/docs/csrs Markdown: https://magentlab.com/docs/csrs.md Not a medical device. Not a diagnosis, dose, or listing recommendation. ## What it computes Compute the Thiruganasambandamoorthy 2016 Canadian Syncope Risk Score from caller-assigned ED clinical flags and ECG numbers. ## When to use When an agent needs the published CSRS arithmetic after ED syncope assessment and must not invent a disposition or 30-day percent from a narrative. ## When not to use - Not a medical device. Not a disposition protocol and not a syncope diagnosis. - Derivation enrolled adults ≥16 years presenting within 24 hours of syncope. Age is not a CSRS component. - Abstract and Figure 2 score QRS axis < −30° or >100°. Some reprints of Table 3 list >110°. magent uses the Figure 2 / abstract cutoff (>100°). Axis −30° and 100° do not score; −31° and 101° do. - Caller assigns clinical flags and supplies ECG numbers. magent does not read an ECG tracing. - QRS duration 130 ms does not score; 131 ms does. QTc 480 ms does not score; 481 ms does. SBP 90 and 180 mm Hg are not out of range (the paper is <90 or >180); that criterion is a caller-assigned boolean. - This tool does not return 30-day percents or later five-tier labels. ## Formula ``` CSRS = predisposition_vasovagal(-1) + heart_disease(1) + sbp_lt_90_or_gt_180(2) + elevated_troponin(2) + (qrs_axis < -30 or > 100)(1) + (qrs_duration > 130)(1) + (qtc > 480)(2) + ed_vasovagal_syncope(-2) + ed_cardiac_syncope(2); range -3 to 11; max 11; Figure 2 / abstract (axis >100, not table 110) ``` ## Citation [Development of the Canadian Syncope Risk Score to predict serious adverse events after emergency department assessment of syncope.](https://doi.org/10.1503/cmaj.151469) Thiruganasambandamoorthy V, Kwong K, Wells GA, et al. CMAJ. 2016;188(12):E289-E298 DOI: [10.1503/cmaj.151469](https://doi.org/10.1503/cmaj.151469) ## Worked example ### All flags false, non-scoring ECG Given: `ed_cardiac_syncope=false, ed_vasovagal_syncope=false, elevated_troponin=false, heart_disease=false, predisposition_vasovagal=false, qrs_axis_deg=0, qrs_duration_ms=80, qtc_ms=400, sbp_lt_90_or_gt_180=false` 1. All clinical flags false; QRS axis 0° (not < −30 or >100); QRS duration 80 ms (not >130); QTc 400 ms (not >480) 2. Score = 0 (max 11) ### Vasovagal predisposition and ED vasovagal diagnosis Given: `ed_cardiac_syncope=false, ed_vasovagal_syncope=true, elevated_troponin=false, heart_disease=false, predisposition_vasovagal=true, qrs_axis_deg=0, qrs_duration_ms=80, qtc_ms=400, sbp_lt_90_or_gt_180=false` 1. predisposition_vasovagal → -1; ed_vasovagal_syncope → -2; remaining flags and ECG cutoffs false 2. Score = -3 (max 11) ## Also searched as - Canadian Syncope Risk Score - CSRS syncope - Thiruganasambandamoorthy syncope - ED syncope risk score - Canadian syncope score - CSRS ECG syncope ## Parameters - `predisposition_vasovagal` (boolean, required): Predisposition to vasovagal syncope (Thiruganasambandamoorthy 2016). true or false. Scores -1 if true. - `heart_disease` (boolean, required): History of heart disease (Thiruganasambandamoorthy 2016). true or false. Scores 1 if true. - `sbp_lt_90_or_gt_180` (boolean, required): Any ED systolic BP <90 or >180 mm Hg (caller-assigned; SBP 90 and 180 are not out of range). true or false. Scores 2 if true. magent does not take a numeric SBP. - `elevated_troponin` (boolean, required): Troponin above the 99th percentile (Thiruganasambandamoorthy 2016). true or false. Scores 2 if true. - `qrs_axis_deg` (number, required): QRS axis in degrees (-180 to 180). Scores 1 when < -30 or > 100 (Figure 2 / abstract; not table 110). -30 and 100 do not score; -31 and 101 do. - `qrs_duration_ms` (number, required): QRS duration in milliseconds (40-300). Scores 1 when >130. 130 does not score; 131 does. - `qtc_ms` (number, required): QTc in milliseconds (200-800). Scores 2 when >480. 480 does not score; 481 does. - `ed_vasovagal_syncope` (boolean, required): ED diagnosis of vasovagal syncope (Thiruganasambandamoorthy 2016). true or false. Scores -2 if true. Cannot be true together with ed_cardiac_syncope. - `ed_cardiac_syncope` (boolean, required): ED diagnosis of cardiac syncope (Thiruganasambandamoorthy 2016). true or false. Scores 2 if true. Cannot be true together with ed_vasovagal_syncope. ## 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/csrs` 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": [ { "ed_cardiac_syncope": "false", "ed_vasovagal_syncope": "false", "elevated_troponin": "false", "heart_disease": "false", "predisposition_vasovagal": "false", "qrs_axis_deg": "0", "qrs_duration_ms": "80", "qtc_ms": "400", "sbp_lt_90_or_gt_180": "false" }, { "ed_cardiac_syncope": "false", "ed_vasovagal_syncope": "false", "elevated_troponin": "false", "heart_disease": "false", "predisposition_vasovagal": "false", "qrs_axis_deg": "0", "qrs_duration_ms": "80", "qtc_ms": "400", "sbp_lt_90_or_gt_180": "false" } ] } ``` Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/csrs Example 200: ```json { "count": 2, "path": "/api/calc/csrs", "items": [ { "components": [ { "factor": "predisposition_vasovagal", "points": 0, "present": false }, { "factor": "heart_disease", "points": 0, "present": false }, { "factor": "sbp_lt_90_or_gt_180", "points": 0, "present": false }, { "factor": "elevated_troponin", "points": 0, "present": false }, { "value": 0.0, "factor": "qrs_axis", "points": 0, "present": false }, { "value": 80.0, "factor": "qrs_duration", "points": 0, "present": false }, { "value": 400.0, "factor": "qtc", "points": 0, "present": false }, { "factor": "ed_vasovagal_syncope", "points": 0, "present": false }, { "factor": "ed_cardiac_syncope", "points": 0, "present": false } ], "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": "Thiruganasambandamoorthy V, Kwong K, Wells GA, et al.", "doi": "10.1503/cmaj.151469", "id": "thiruganasambandamoorthy-2016", "pmid": "27378464", "source": "CMAJ. 2016;188(12):E289-E298", "title": "Development of the Canadian Syncope Risk Score to predict serious adverse events after emergency department assessment of syncope." }, "formula": "csrs", "formula_expression": "CSRS = predisposition_vasovagal(-1) + heart_disease(1) + sbp_lt_90_or_gt_180(2) + elevated_troponin(2) + (qrs_axis < -30 or > 100)(1) + (qrs_duration > 130)(1) + (qtc > 480)(2) + ed_vasovagal_syncope(-2) + ed_cardiac_syncope(2); range -3 to 11; max 11; Figure 2 / abstract (axis >100, not table 110)", "max_score": 11, "score": 0, "qrs_axis_deg": 0.0, "qrs_duration_ms": 80.0, "qtc_ms": 400.0 }, { "components": [ { "factor": "predisposition_vasovagal", "points": 0, "present": false }, { "factor": "heart_disease", "points": 0, "present": false }, { "factor": "sbp_lt_90_or_gt_180", "points": 0, "present": false }, { "factor": "elevated_troponin", "points": 0, "present": false }, { "value": 0.0, "factor": "qrs_axis", "points": 0, "present": false }, { "value": 80.0, "factor": "qrs_duration", "points": 0, "present": false }, { "value": 400.0, "factor": "qtc", "points": 0, "present": false }, { "factor": "ed_vasovagal_syncope", "points": 0, "present": false }, { "factor": "ed_cardiac_syncope", "points": 0, "present": false } ], "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": "Thiruganasambandamoorthy V, Kwong K, Wells GA, et al.", "doi": "10.1503/cmaj.151469", "id": "thiruganasambandamoorthy-2016", "pmid": "27378464", "source": "CMAJ. 2016;188(12):E289-E298", "title": "Development of the Canadian Syncope Risk Score to predict serious adverse events after emergency department assessment of syncope." }, "formula": "csrs", "formula_expression": "CSRS = predisposition_vasovagal(-1) + heart_disease(1) + sbp_lt_90_or_gt_180(2) + elevated_troponin(2) + (qrs_axis < -30 or > 100)(1) + (qrs_duration > 130)(1) + (qtc > 480)(2) + ed_vasovagal_syncope(-2) + ed_cardiac_syncope(2); range -3 to 11; max 11; Figure 2 / abstract (axis >100, not table 110)", "max_score": 11, "score": 0, "qrs_axis_deg": 0.0, "qrs_duration_ms": 80.0, "qtc_ms": 400.0 } ] } ``` ## Response fields - `formula` (string): csrs - `formula_expression` (string): Exact expression used - `score` (integer): CSRS points from -3 to 11 - `max_score` (integer): 11 - `qrs_axis_deg` (number): QRS axis in degrees used for the < -30 or > 100 cutoff - `qrs_duration_ms` (number): QRS duration in ms used for the >130 cutoff - `qtc_ms` (number): QTc in ms used for the >480 cutoff - `components` (array): Per-factor points - `citation` (object): Thiruganasambandamoorthy 2016 CMAJ citation - `disclaimer` (string): Not-a-device notice ## Example JSON Frozen fixture. Not a live lookup. ```json { "components": [ { "factor": "predisposition_vasovagal", "points": 0, "present": false }, { "factor": "heart_disease", "points": 0, "present": false }, { "factor": "sbp_lt_90_or_gt_180", "points": 0, "present": false }, { "factor": "elevated_troponin", "points": 0, "present": false }, { "value": 0.0, "factor": "qrs_axis", "points": 0, "present": false }, { "value": 80.0, "factor": "qrs_duration", "points": 0, "present": false }, { "value": 400.0, "factor": "qtc", "points": 0, "present": false }, { "factor": "ed_vasovagal_syncope", "points": 0, "present": false }, { "factor": "ed_cardiac_syncope", "points": 0, "present": false } ], "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": "Thiruganasambandamoorthy V, Kwong K, Wells GA, et al.", "doi": "10.1503/cmaj.151469", "id": "thiruganasambandamoorthy-2016", "pmid": "27378464", "source": "CMAJ. 2016;188(12):E289-E298", "title": "Development of the Canadian Syncope Risk Score to predict serious adverse events after emergency department assessment of syncope." }, "formula": "csrs", "formula_expression": "CSRS = predisposition_vasovagal(-1) + heart_disease(1) + sbp_lt_90_or_gt_180(2) + elevated_troponin(2) + (qrs_axis < -30 or > 100)(1) + (qrs_duration > 130)(1) + (qtc > 480)(2) + ed_vasovagal_syncope(-2) + ed_cardiac_syncope(2); range -3 to 11; max 11; Figure 2 / abstract (axis >100, not table 110)", "max_score": 11, "score": 0, "qrs_axis_deg": 0.0, "qrs_duration_ms": 80.0, "qtc_ms": 400.0 } ``` ## Errors - HTTP 400 `invalid_flag`: boolean clinical flags must be true or false Returned before settlement; you are not charged. - HTTP 400 `invalid_qrs_axis`: qrs_axis_deg must be a number from -180 to 180 (Thiruganasambandamoorthy 2016 CSRS). Returned before settlement; you are not charged. - HTTP 400 `invalid_qrs_duration`: qrs_duration_ms must be a number from 40 to 300 (Thiruganasambandamoorthy 2016 CSRS). Returned before settlement; you are not charged. - HTTP 400 `invalid_qtc_ms`: qtc_ms must be a number from 200 to 800 (Thiruganasambandamoorthy 2016 CSRS). Returned before settlement; you are not charged. - HTTP 400 `invalid_csrs_ed_diagnosis`: ed_vasovagal_syncope and ed_cardiac_syncope cannot both be true (Thiruganasambandamoorthy 2016 CSRS). 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 - [San Francisco Syncope Rule](https://magentlab.com/docs/sf-syncope) — Compute the San Francisco Syncope Rule (CHESS) criterion count and rule-positive flag from published cutoffs. ## 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 echoing accepted, payload, and extensions when present). - 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. - 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.