Canadian Syncope Risk Score

CSRS

Compute the Thiruganasambandamoorthy 2016 Canadian Syncope Risk Score from caller-assigned ED clinical flags and ECG numbers.

LIVE $0.005 USDC GET /api/calc/csrs

Markdown: /docs/csrs.md · Canonical: https://magentlab.com/docs/csrs

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

Title: Development of the Canadian Syncope Risk Score to predict serious adverse events after emergency department assessment of syncope.
Authors: Thiruganasambandamoorthy V, Kwong K, Wells GA, et al.
Source: CMAJ. 2016;188(12):E289-E298
DOI: 10.1503/cmaj.151469

Worked example

All flags false, non-scoring ECG

Given: ed_cardiac_syncope=falseed_vasovagal_syncope=falseelevated_troponin=falseheart_disease=falsepredisposition_vasovagal=falseqrs_axis_deg=0qrs_duration_ms=80qtc_ms=400sbp_lt_90_or_gt_180=false

All clinical flags false; QRS axis 0° (not < −30 or >100); QRS duration 80 ms (not >130); QTc 400 ms (not >480)
Score = 0 (max 11)

Vasovagal predisposition and ED vasovagal diagnosis

Given: ed_cardiac_syncope=falseed_vasovagal_syncope=trueelevated_troponin=falseheart_disease=falsepredisposition_vasovagal=trueqrs_axis_deg=0qrs_duration_ms=80qtc_ms=400sbp_lt_90_or_gt_180=false

predisposition_vasovagal → -1; ed_vasovagal_syncope → -2; remaining flags and ECG cutoffs false
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

Try

Opens the live endpoint. Unpaid browser requests show the paywall; agents should send Accept: application/json.

/api/calc/csrs?predisposition_vasovagal=false&heart_disease=false&sbp_lt_90_or_gt_180=false&elevated_troponin=false&qrs_axis_deg=0&qrs_duration_ms=80&qtc_ms=400&ed_vasovagal_syncope=false&ed_cardiac_syncope=false

Full URL: https://api.magentlab.com/api/calc/csrs?predisposition_vasovagal=false&heart_disease=false&sbp_lt_90_or_gt_180=false&elevated_troponin=false&qrs_axis_deg=0&qrs_duration_ms=80&qtc_ms=400&ed_vasovagal_syncope=false&ed_cardiac_syncope=false

Call

Expect HTTP 402 until you retry with PAYMENT-SIGNATURE. Incomplete query params return HTTP 400 before any quote or charge.

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/calc/csrs?predisposition_vasovagal=false&heart_disease=false&sbp_lt_90_or_gt_180=false&elevated_troponin=false&qrs_axis_deg=0&qrs_duration_ms=80&qtc_ms=400&ed_vasovagal_syncope=false&ed_cardiac_syncope=false"

Parameters

Name	Type	Required	Description
`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.

POST /api/calc/csrs Max 25 unit_amount + extra_item_amount * (n - 1) extra $0.002 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 (fixture)

{
  "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"
    }
  ]
}

Open bulk paywall →

Opens a two-item fixture on the API host. Unpaid browsers get the same MetaMask paywall as GET; Pay retries POST with those items.

Example 200 (fixture)

{
  "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

Field	Type	Description
`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

Machine form of the same example. Frozen fixture. Not a live lookup.

{
  "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
}

Client errors (HTTP 400)

Invalid params return 400 without charge. Shared HTTP 402 and 503 meanings: Payments.

HTTP	Code	When
400	`invalid_flag`	boolean clinical flags must be true or false Returned before settlement; you are not charged.
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.
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.
400	`invalid_qtc_ms`	qtc_ms must be a number from 200 to 800 (Thiruganasambandamoorthy 2016 CSRS). Returned before settlement; you are not charged.
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.
400	`invalid_items`	POST body must be a JSON object with only an items array Returned before settlement; you are not charged.
400	`invalid_item_count`	items must be an array of 1 to 25 objects Returned before settlement; you are not charged.
400	`invalid_item`	each items entry must be a JSON object Returned before settlement; you are not charged.

Related tools

San Francisco Syncope Rule — 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. Unpaid valid requests return HTTP 402 with a base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote: retry the same PAYMENT-SIGNATURE. Full handshake and shared payment errors: Payments. Stdio MCP: /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.