# HEAR Score Calculator (No Troponin)

> HEAR Score Calculator (No Troponin) is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Computes the HEAR score (0–8) for emergency chest pain risk stratification using age, caller-assigned history, ECG, and risk factors — without troponin.

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/hear
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/hear-score-calculator-no-troponin-5be7cb29
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_UOL0ojlbjdJLYUiZuVQNz

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 hear-score-calculator-no-troponin-5be7cb29
```

Example prompt: Calculate the HEAR score for a 67-year-old patient presenting with highly suspicious chest pain history (score 2), an ECG showing significant ST depression (score 2), and 3 or more risk factors (score 2).

## When to prefer this

Use this endpoint when you need a fast, deterministic HEAR score for emergency chest pain triage and troponin results are not yet available or not included in the workflow. Prefer it over full HEART score calculators when troponin is intentionally omitted. Ideal for ED clinical decision support pipelines that require a citable, published rule (Smith 2020 / Six 2008 HEART age cutoffs) rather than a probabilistic model.

## Known failure modes

- Missing required query parameters (age, history, ecg, risk_factors) returns an error
- Age out of range (below 18 or above 120) may return a validation error
- Integer inputs outside 0–2 for history, ecg, or risk_factors return a validation error
- Payment not included or insufficient USDC results in 402 Payment Required
- Caller-assigned scores that do not accurately reflect clinical findings will produce a valid but clinically misleading score — the API cannot verify inputs

## How this service works

HEAR score for emergency chest pain from age and caller-assigned history, ECG, and risk factors (each 0-2, max 8). No troponin. Smith 2020 very-low-risk group is scores 0 and 1 (MACE ~0.9% in that paper). Deterministic published score with citation; not a diagnosis or discharge protocol. magent does not interpret history, count risk factors, or read an ECG.

## Output

Returns the numeric HEAR score (integer 0–8) computed from the four caller-supplied components (age bracket, history, ECG, risk factors), plus an indication of whether the score falls in the Smith 2020 very-low-risk group (scores 0–1, associated with ~0.9% MACE). The score is deterministic and cites published methodology; it is not a diagnosis or discharge recommendation.

## 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": [
      "age",
      "history",
      "ecg",
      "risk_factors"
     ],
     "properties": {
      "age": {
       "type": "integer",
       "description": "Age in years (18-120). Younger than 45 scores 0; 45-64 scores 1; 65 or older scores 2 (same cuts as Six 2008 HEART)."
      },
      "ecg": {
       "type": "integer",
       "description": "Caller-assigned ECG. 0 normal; 1 repolarization without significant ST depression (including BBB, LVH, digoxin, or known unchanged); 2 significant ST depression or elevation without those confounders. magent does not read an ECG."
      },
      "history": {
       "type": "integer",
       "description": "Caller-assigned history. 0 nonspecific, 1 moderately suspicious, 2 highly suspicious. magent does not interpret the history."
      },
      "risk_factors": {
       "type": "integer",
       "description": "Caller-assigned risk-factor points. 0 none, 1 = 1-2 risk factors, 2 = ≥3 or atherosclerotic disease. magent does not count diabetes, smoking, or other factors."
      }
     }
    }
   },
   "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/hear-score-calculator-no-troponin-5be7cb29/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)