# Brugada 1991 Wide-QRS Tachycardia Algorithm (VT vs SVT)

> Brugada 1991 Wide-QRS Tachycardia Algorithm (VT vs SVT) is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-13).

Applies the Brugada 1991 four-step algorithm to distinguish ventricular tachycardia (VT) from supraventricular tachycardia (SVT) in a regular wide-QRS tachycardia, returning a diagnosis and the step at which the algorithm stopped.

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/brugada
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/brugada-1991-wide-qrs-tachycardia-algorithm-vt-vs-svt-94ab49ae
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_AV091wPc6izRfwDqHbLCL

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability brugada-1991-wide-qrs-tachycardia-algorithm-vt-vs-svt-94ab49ae
```

Example prompt: Run the Brugada 1991 four-step VT/SVT algorithm for a patient with regular wide-QRS tachycardia: no RS complex in any precordial lead is true, RS interval >100 ms is false, AV dissociation is false, and morphology criteria for VT in V1–V2 and V6 is false — what's the diagnosis and at which step did it stop?

## When to prefer this

Choose this endpoint when you need to programmatically apply the original Brugada 1991 four-step decision tree for differentiating VT from SVT in a regular wide-QRS tachycardia, and the caller has already assessed the four Boolean criteria from the ECG. Prefer this over manual lookup when building clinical decision-support workflows, educational tools, or audit trails that require a documented algorithmic step. Do not use for Brugada syndrome screening, Vereckei aVR algorithm, RWPT, Sgarbossa criteria, or when an actual ECG tracing needs to be machine-read.

## Known failure modes

- Missing required query parameters (no_rs_precordial, rs_interval_gt_100, av_dissociation, morphology_vt) returns a 400 error
- Invalid non-boolean values for any of the four step parameters cause a validation error
- Payment failure or missing x402 payment header results in a 402 response
- Network timeout or upstream unavailability returns a 5xx error

## How this service works

Brugada 1991 four-step algorithm for a regular tachycardia with a wide QRS complex. Caller assigns absence of an RS complex in all precordial leads, RS interval >100 ms in one precordial lead, AV dissociation, and VT morphology in V1–V2 and V6. Returns diagnosis vt or svt and the stopping step. magent does not interpret ECGs. Not Brugada syndrome, not Vereckei aVR, not RWPT, not Sgarbossa, and not a cardioversion order. Not a medical device.

## Output

Returns a JSON object containing the diagnosis field ('vt' or 'svt') and the stopping_step field (1–4) indicating which step of the Brugada 1991 algorithm produced the final classification. No ECG tracing is interpreted by the service; all Boolean inputs are caller-assigned.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "headers": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    },
    "queryParams": {
     "type": "object",
     "required": [
      "no_rs_precordial",
      "rs_interval_gt_100",
      "av_dissociation",
      "morphology_vt"
     ],
     "properties": {
      "morphology_vt": {
       "type": "boolean",
       "description": "Step 4: both V1–V2 and V6 morphology criteria for VT as in Brugada 1991. true or false as assigned by the caller. Evaluated only when steps 1–3 are false. magent does not interpret ECGs."
      },
      "av_dissociation": {
       "type": "boolean",
       "description": "Step 3: atrioventricular dissociation (Brugada 1991). true or false as assigned by the caller. Evaluated only when steps 1 and 2 are false. magent does not interpret ECGs."
      },
      "no_rs_precordial": {
       "type": "boolean",
       "description": "Step 1: absence of an RS complex in all precordial leads (Brugada 1991). true or false as assigned by the caller. true diagnoses VT and stops the tree. magent does not interpret ECGs."
      },
      "rs_interval_gt_100": {
       "type": "boolean",
       "description": "Step 2: RS interval >100 ms in one precordial lead (Brugada 1991). true or false as assigned by the caller. Evaluated only when step 1 is false. magent does not measure the tracing."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/brugada-1991-wide-qrs-tachycardia-algorithm-vt-vs-svt-94ab49ae/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.magentlab.com](https://www.zero.xyz/host/api.magentlab.com/llms.txt)