{"uid":"cap_SXt-ASid8VWSfCi2fiaru","slug":"qtc-calculator-bazett-fridericia-f7c91b02","name":"QTc Calculator (Bazett / Fridericia)","description":"Deterministic published-formula arithmetic plus ICD-10-CM, RxNorm, and LOINC. Pay in USDC on Base via x402.","url":"https://api.magentlab.com/api/calc/qtc?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"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":["qt_ms","heart_rate_bpm","formula"],"properties":{"qt_ms":{"type":"number","description":"Measured QT interval in milliseconds (200-800)."},"formula":{"enum":["bazett","fridericia"],"type":"string","description":"Correction formula. Required; magent does not pick one silently."},"heart_rate_bpm":{"type":"integer","description":"Heart rate in beats per minute (30-220). RR_s = 60 / HR."}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"path":"/api/calc/qtc","count":2,"items":[{"rr_s":0.75,"qt_ms":400,"qtc_ms":461.9,"formula":"bazett","citation":{"id":"bazett-1920","doi":null,"title":"An analysis of the time-relations of electrocardiograms","source":"Heart. 1920;7:353-370","authors":"Bazett HC"},"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.","heart_rate_bpm":80,"formula_expression":"QTc_ms = QT_ms / sqrt(RR_s)"},{"rr_s":0.75,"qt_ms":400,"qtc_ms":461.9,"formula":"bazett","citation":{"id":"bazett-1920","doi":null,"title":"An analysis of the time-relations of electrocardiograms","source":"Heart. 1920;7:353-370","authors":"Bazett HC"},"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.","heart_rate_bpm":80,"formula_expression":"QTc_ms = QT_ms / sqrt(RR_s)"}]}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.005","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.005/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_6O1T11od7Gfh_ZZhxNytH","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.005","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Calculates heart-rate-corrected QT interval (QTc) using either the Bazett or Fridericia formula, returning a deterministic result with citation.","exampleAgentPrompt":"Calculate the QTc for a patient with a measured QT of 420 ms and a heart rate of 65 bpm using the Bazett formula.","exampleUseCases":[{"title":"Drug-induced QT prolongation check","prompt":"A patient on sotalol has a QT of 480 ms and heart rate of 58 bpm — compute the QTc using the Fridericia formula so I can assess prolongation risk."},{"title":"Pre-discharge cardiology QTc review","prompt":"Before discharge, the ECG shows QT 390 ms at a heart rate of 88 bpm. Can you calculate the Bazett-corrected QTc for the chart?"},{"title":"Pharmacist medication safety screen","prompt":"I need the Fridericia QTc for a patient with QT interval 450 ms and heart rate of 110 bpm — they're starting azithromycin and I need to document this."}],"resultDescription":"Returns the QTc value computed by the chosen formula (Bazett: QTc = QT / √RR; Fridericia: QTc = QT / RR^(1/3)), along with the formula name and its published citation, given the raw QT interval in milliseconds and heart rate in beats per minute.","failureModes":["Missing required 'formula' parameter — endpoint does not default to either formula and returns an error","QT interval outside valid range (200–800 ms) rejected","Heart rate outside valid range (30–220 bpm) rejected","Invalid formula value (only 'bazett' or 'fridericia' accepted)","Payment failure or missing x402 payment header returns 402"],"whenToPreferThis":"Use this endpoint when you need a deterministic, citeable QTc calculation with explicit formula selection — ideal for clinical documentation, pharmacovigilance, and cardiology workflows where auditability and formula transparency are required. Prefer this over LLM-derived math or unattributed calculators.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-12T00:41:50.103Z","isFirstParty":false,"canonicalSlug":"qtc-calculator-bazett-fridericia-f7c91b02"}