{
  "scope": "Independent AI-assisted educational reference notes; not clinician certification or official examination scoring",
  "recording": 267,
  "clinicalApproval": false,
  "keyVersion": "1-full89-ai-reviewed-20261031-source73-current",
  "fullSourceSHA256": "ceb9c4e1de74dd0abff5aaee6f7abde162a46cbf960fb475199fa567084989f8",
  "sourceTitle": "ABIM_ECG_Complete_531_Case_Master.pdf",
  "sourceAccess": "Source document is not distributed here. No promise of public access or rights clearance.",
  "source73Page": 232,
  "findings": [
    {
      "optionId": "ecg-normal-ecg",
      "sourceCode": 1,
      "classification": "incorrect",
      "rationale": "Premature atrial beats and anterior inverted T waves preclude normal ECG."
    },
    {
      "optionId": "ecg-normal-variant",
      "sourceCode": 2,
      "classification": "incorrect",
      "rationale": "At age82, anterior T inversion with premature atrial beats is not established as a listed benign variant; no narrow rSRprime or early-repolarization pattern."
    },
    {
      "optionId": "ecg-electrode-placement-error",
      "sourceCode": 3,
      "classification": "incorrect",
      "rationale": "Positive I P/QRS and preserved precordial progression do not show limb reversal or precordial transposition."
    },
    {
      "optionId": "ecg-artifact",
      "sourceCode": 4,
      "classification": "required",
      "rationale": "Full raw/native trace has abrupt non-QRS limb notches and steps, e.g. II/III near3.62 and5.94s, with much cleaner precordial baselines; real acquisition/movement noise, not flutter or pacing. Terminal export hold is separately censored."
    },
    {
      "optionId": "ecg-right-atrial-abnormality",
      "sourceCode": 5,
      "classification": "neutral",
      "rationale": "Premature P near4.70s reaches about3.2mm in III on paired references, while II is1.66\u20132.48mm and aVF2.38\u20132.69mm across actual preP/latePR references. Source inferior-lead distribution and aVF threshold are uncertain; no ectopic-inferior exclusion invented. V1/V2 premature P overlaps prior T and is not a reliable RA amplitude baseline. Full PDFp2014 additionally excludes RA based on ectopic V1 P specifically; not extended to inferior leads or source6."
    },
    {
      "optionId": "ecg-left-atrial-abnormality",
      "sourceCode": 6,
      "classification": "neutral",
      "rationale": "V1 sinus terminal negative lobes are generally0.5\u20130.9mm deep; beat4 approaches0.99mm on latePR with baseline/noise sensitivity, not a robust >1mm result. PAC preP overlaps previous T and is not usable terminal-P proof. Inferior notching is noisy, with no secure >120ms notched P. Neutral rather than false certainty near boundary."
    },
    {
      "optionId": "ecg-sinus-rhythm",
      "sourceCode": 7,
      "classification": "required",
      "rationale": "Actual V2 atrial apices establish underlying sinus PP mostly.618\u2013.656s (91.5\u201397.1/min), with corresponding positive I/II P; two different premature P and post-PAC reset intervals are reported separately. No RR surrogate used."
    },
    {
      "optionId": "ecg-sinus-arrhythmia",
      "sourceCode": 8,
      "classification": "neutral",
      "rationale": "Ordinary sinus PP variation is below10%, but premature atrial/reset intervals markedly alter total PP. Low-amplitude atrial onset/apex uncertainty and ectopic-reset attribution prevent assigning independent sinus-arrhythmia credit; no persistence requirement imposed."
    },
    {
      "optionId": "ecg-sinus-bradycardia",
      "sourceCode": 9,
      "classification": "incorrect",
      "rationale": "Underlying actual sinus PP rate about92\u201397/min, not<60."
    },
    {
      "optionId": "ecg-sinus-tachycardia",
      "sourceCode": 10,
      "classification": "incorrect",
      "rationale": "Underlying sinus PP is not>100/min; short coupling intervals belong to two differently shaped premature P, not sinus tachycardia."
    },
    {
      "optionId": "ecg-sinus-pause-arrest",
      "sourceCode": 11,
      "classification": "incorrect",
      "rationale": "No >2s observed P-free pause. Terminal small P is followed by export hold, not proof of arrest."
    },
    {
      "optionId": "ecg-sinoatrial-exit-block",
      "sourceCode": 12,
      "classification": "incorrect",
      "rationale": "No PP-multiple dropped-P pauses or grouped SA-exit-block pattern; isolated premature atrial/reset events account for timing changes."
    },
    {
      "optionId": "ecg-premature-atrial-complexes",
      "sourceCode": 13,
      "classification": "required",
      "rationale": "Premature altered P in II/III/aVF/V1/V2 near4.70 and9.10s precedes unchanged narrow QRS at4.834 and9.218s. Coupling RR.434 and.484s is shorter than ordinary.618\u2013.634s; first is followed by.760s reset interval."
    },
    {
      "optionId": "ecg-atrial-tachycardia",
      "sourceCode": 14,
      "classification": "incorrect",
      "rationale": "Two isolated premature P, not at least three successive ectopic atrial beats."
    },
    {
      "optionId": "ecg-multifocal-atrial-tachycardia",
      "sourceCode": 15,
      "classification": "incorrect",
      "rationale": "No three established P morphologies with sustained atrial rate>100; recorded sequence is mainly sinus with two similar premature atrial events."
    },
    {
      "optionId": "ecg-supraventricular-tachycardia",
      "sourceCode": 16,
      "classification": "incorrect",
      "rationale": "Ordinary ventricular rhythm is below100/min; two isolated shortened coupling intervals do not form the source regular rhythm>100. No invented nonsinus or persistence prerequisite."
    },
    {
      "optionId": "ecg-atrial-flutter",
      "sourceCode": 17,
      "classification": "incorrect",
      "rationale": "Discrete low-amplitude P separated by quiet segments rather than organized continuous flutter activity; no typical240\u2013340/min atrial train."
    },
    {
      "optionId": "ecg-atrial-fibrillation",
      "sourceCode": 18,
      "classification": "incorrect",
      "rationale": "Organized P precedes each fully acquired QRS, including premature P, not absent-P fibrillation."
    },
    {
      "optionId": "ecg-premature-junctional-complexes",
      "sourceCode": null,
      "classification": "neutral",
      "rationale": "Null source mapping preserved; no invented golden criterion or point. Neutral0/0."
    },
    {
      "optionId": "ecg-junctional-escape-complexes",
      "sourceCode": 20,
      "classification": "incorrect",
      "rationale": "No late junctional escape after pause or block; premature complexes have antecedent ectopic P."
    },
    {
      "optionId": "ecg-junctional-rhythm-tachycardia",
      "sourceCode": 21,
      "classification": "incorrect",
      "rationale": "Sinus-axis P before ordinary QRS, not retrograde/junctional train."
    },
    {
      "optionId": "ecg-premature-ventricular-complexes",
      "sourceCode": 22,
      "classification": "incorrect",
      "rationale": "Premature complexes are preceded by altered P and retain native QRS morphology; no premature ventricular-origin wide complex."
    },
    {
      "optionId": "ecg-ventricular-parasystole",
      "sourceCode": null,
      "classification": "neutral",
      "rationale": "Null source mapping preserved; no invented golden criterion or point. Neutral0/0."
    },
    {
      "optionId": "ecg-ventricular-tachycardia",
      "sourceCode": 24,
      "classification": "incorrect",
      "rationale": "No three consecutive ventricular-origin premature beats>100/min."
    },
    {
      "optionId": "ecg-accelerated-idioventricular-rhythm",
      "sourceCode": 25,
      "classification": "incorrect",
      "rationale": "Linked P/QRS sequence and unchanged narrow morphology, not ventricular-origin rhythm; rate in90s alone does not establish AIVR."
    },
    {
      "optionId": "ecg-ventricular-escape",
      "sourceCode": 26,
      "classification": "incorrect",
      "rationale": "No20\u201340/min ventricular escape train."
    },
    {
      "optionId": "ecg-ventricular-fibrillation",
      "sourceCode": null,
      "classification": "neutral",
      "rationale": "Null source mapping preserved; no invented golden criterion or point. Neutral0/0."
    },
    {
      "optionId": "ecg-first-degree-av-block",
      "sourceCode": 28,
      "classification": "incorrect",
      "rationale": "Measured global P/QRS envelopes give PR98\u2013172ms, well below200ms; lead-specific P feet measured rather than formula offsets."
    },
    {
      "optionId": "ecg-mobitz-one-av-block",
      "sourceCode": 29,
      "classification": "incorrect",
      "rationale": "No progressivePR followed by nonconducted acquired P. Terminal expected beat lies in censored export hold."
    },
    {
      "optionId": "ecg-mobitz-two-av-block",
      "sourceCode": 30,
      "classification": "incorrect",
      "rationale": "No intermittent nonconducted P with PP-multipleRR; premature P is present at short intervals."
    },
    {
      "optionId": "ecg-two-to-one-av-block",
      "sourceCode": 31,
      "classification": "incorrect",
      "rationale": "One observed P per acquired QRS, not twoP perQRS."
    },
    {
      "optionId": "ecg-third-degree-av-block",
      "sourceCode": 32,
      "classification": "incorrect",
      "rationale": "P and QRS linked rather than independently marching atrial/ventricular clocks."
    },
    {
      "optionId": "ecg-wpw-pattern",
      "sourceCode": 33,
      "classification": "incorrect",
      "rationale": "Some PR bounds are short, but there is no delta-wave slurred upstroke with adult QRS>120ms; short PR alone is insufficient."
    },
    {
      "optionId": "ecg-av-dissociation",
      "sourceCode": 34,
      "classification": "incorrect",
      "rationale": "Recorded P-to-QRS associations persist, not AV dissociation."
    },
    {
      "optionId": "ecg-low-limb-voltage",
      "sourceCode": 35,
      "classification": "incorrect",
      "rationale": "II and I QRS excursions exceed5mm, contradicting all-limb low voltage."
    },
    {
      "optionId": "ecg-low-precordial-voltage",
      "sourceCode": 36,
      "classification": "incorrect",
      "rationale": "V3\u2013V6 QRS excursions exceed10mm, contradicting all-precordial low voltage."
    },
    {
      "optionId": "ecg-left-axis-deviation",
      "sourceCode": 37,
      "classification": "incorrect",
      "rationale": "Frontal peak-net and integrated methods span+12\u2026+69degrees across paired baselines, not\u221230\u2026\u221290."
    },
    {
      "optionId": "ecg-right-axis-deviation",
      "sourceCode": 38,
      "classification": "incorrect",
      "rationale": "Both axis methods remain far below source100degree right-axis boundary."
    },
    {
      "optionId": "ecg-electrical-alternans",
      "sourceCode": 39,
      "classification": "required",
      "rationale": "Paired-baseline III R varies.183\u2013.637mV and ordinary-beat variation also exceeds local quiet noise; V5 amplitudes vary as well. Full source permits broad beat-to-beat amplitude/direction variability, not mandatory alternating big/small pattern. Noise and ectopy separately documented; no effusion causal credit."
    },
    {
      "optionId": "ecg-left-ventricular-hypertrophy",
      "sourceCode": 40,
      "classification": "incorrect",
      "rationale": "Female82 Cornell12.8\u201314.6mm below20, Sokolow maximum25.2mm below35, and aVL R below11mm; no source LVH voltage route."
    },
    {
      "optionId": "ecg-right-ventricular-hypertrophy",
      "sourceCode": 41,
      "classification": "incorrect",
      "rationale": "No right axis and lateralR remains dominant; right-precordial T inversion alone does not establish RVH."
    },
    {
      "optionId": "ecg-combined-ventricular-hypertrophy",
      "sourceCode": null,
      "classification": "neutral",
      "rationale": "Null source mapping preserved; no invented golden criterion or point. Neutral0/0."
    },
    {
      "optionId": "ecg-complete-rbbb",
      "sourceCode": 43,
      "classification": "incorrect",
      "rationale": "No complete RBBB morphology: V1 terminal forces negative and lateral terminalS is not broad>40ms; adult global duration envelope does not establish\u2265120ms."
    },
    {
      "optionId": "ecg-incomplete-rbbb",
      "sourceCode": 44,
      "classification": "incorrect",
      "rationale": "Specific RBBB morphology not met, regardless of near110ms conservative duration bounds."
    },
    {
      "optionId": "ecg-left-anterior-fascicular-block",
      "sourceCode": 45,
      "classification": "incorrect",
      "rationale": "Axis is positive, not\u221245\u2026\u221290; no LAFB pattern."
    },
    {
      "optionId": "ecg-left-posterior-fascicular-block",
      "sourceCode": 46,
      "classification": "incorrect",
      "rationale": "Axis is not90\u2026180 and I/aVL not predominantlyrS; no width-only exclusion used."
    },
    {
      "optionId": "ecg-complete-lbbb",
      "sourceCode": 47,
      "classification": "incorrect",
      "rationale": "No broad notched lateralR with delayed>60ms intrinsicoid deflection or meanQRS\u2265120ms."
    },
    {
      "optionId": "ecg-incomplete-lbbb",
      "sourceCode": null,
      "classification": "neutral",
      "rationale": "Null source mapping preserved; no invented golden criterion or point. Neutral0/0."
    },
    {
      "optionId": "ecg-aberrant-conduction",
      "sourceCode": 50,
      "classification": "incorrect",
      "rationale": "No rapid-rate QRS>120ms normalizing at slower rate; premature atrial QRS retain morphology."
    },
    {
      "optionId": "ecg-nonspecific-intraventricular-conduction",
      "sourceCode": 49,
      "classification": "neutral",
      "rationale": "Manual global QRS mean envelope78.7\u2013109.7ms approaches strict>110ms within sampling/endpoint uncertainty. No specificBBB; neutral rather than pretending endpoint precision rules out every borderline estimate."
    },
    {
      "optionId": "ecg-mi-anterolateral-recent-probably-acute",
      "sourceCode": 51,
      "classification": "incorrect",
      "rationale": "No contiguous anterolateral qualifying pathologicalQ/QS or truepostJ injury elevation."
    },
    {
      "optionId": "ecg-mi-anterolateral-indeterminate-probably-old",
      "sourceCode": null,
      "classification": "neutral",
      "rationale": "Null source mapping preserved; no invented golden criterion or point. Neutral0/0."
    },
    {
      "optionId": "ecg-mi-anterior-anteroseptal-recent-probably-acute",
      "sourceCode": 53,
      "classification": "incorrect",
      "rationale": "Anterior smallinitialR precedesS and no contiguous female1.5mm truepostJ elevation."
    },
    {
      "optionId": "ecg-mi-anterior-anteroseptal-indeterminate-probably-old",
      "sourceCode": 54,
      "classification": "incorrect",
      "rationale": "Preserved initialR inV1\u2013V4 rather than qualifying contiguous pathologicalQ/QS."
    },
    {
      "optionId": "ecg-mi-lateral-recent-probably-acute",
      "sourceCode": 55,
      "classification": "incorrect",
      "rationale": "No qualifying lateralQ pairs or contiguous truepostJ lateral injury elevation."
    },
    {
      "optionId": "ecg-mi-lateral-indeterminate-probably-old",
      "sourceCode": 56,
      "classification": "incorrect",
      "rationale": "I/aVL initialnegative deflections are not paired qualifying\u226530ms/.1mV pathologicalQ."
    },
    {
      "optionId": "ecg-mi-inferior-recent-probably-acute",
      "sourceCode": 57,
      "classification": "incorrect",
      "rationale": "No contiguous inferior truepostJ elevation; III earlynegative deflection alone is not acute inferior injury."
    },
    {
      "optionId": "ecg-mi-inferior-indeterminate-probably-old",
      "sourceCode": 58,
      "classification": "incorrect",
      "rationale": "III initialnegative deflections occur, but no second inferior lead has qualifying\u226530ms/.1mV pathologicalQ; II predominantly initialR."
    },
    {
      "optionId": "ecg-mi-posterior-recent-probably-acute",
      "sourceCode": 59,
      "classification": "incorrect",
      "rationale": "V1 initialR is small with terminalS and invertedT; no pairedV1/V2 broad dominantinitialR with concordantpositiveT."
    },
    {
      "optionId": "ecg-mi-posterior-indeterminate-probably-old",
      "sourceCode": 60,
      "classification": "incorrect",
      "rationale": "No pairedV1/V2 posterior-infarct broadinitialR/concordantpositiveT morphology."
    },
    {
      "optionId": "ecg-early-repolarization",
      "sourceCode": 61,
      "classification": "incorrect",
      "rationale": "No elevated concaveJ takeoff with uprightT/notchedR; anteriorT inversion is not earlyrepolarization."
    },
    {
      "optionId": "ecg-juvenile-t-wave-variant",
      "sourceCode": null,
      "classification": "neutral",
      "rationale": "Null source mapping preserved; no invented golden criterion or point. Neutral0/0."
    },
    {
      "optionId": "ecg-nonspecific-st-t-changes",
      "sourceCode": 63,
      "classification": "required",
      "rationale": "V3/V4 mildly inverted or flattenedT and mild postJ displacement meet nonspecific morphology. Supported descriptive alternatives63/64/66 count once."
    },
    {
      "optionId": "ecg-ischemic-st-t-changes",
      "sourceCode": 64,
      "classification": "required",
      "rationale": "V1 negative T on beat11 is2.06\u20132.30mm across preP/latePR/postT references, and beat13 is2.02\u20132.21mm; meets\u22652mm inversion criterion without adding lead restrictions. Other beats straddlethreshold because baseline evolves. Educational ischemia-suggesting morphology only, not coronary cause confirmation. OR63/64/66 once."
    },
    {
      "optionId": "ecg-injury-st-t-changes",
      "sourceCode": null,
      "classification": "neutral",
      "rationale": "Null source mapping preserved; no invented golden criterion or point. Neutral0/0."
    },
    {
      "optionId": "ecg-electrolyte-st-t-changes",
      "sourceCode": 66,
      "classification": "required",
      "rationale": "FlattenedT and mildST depression meet complete source descriptive electrolyte-associated pattern without mandatoryU or lab proof. No biochemical diagnosis; OR63/64/66 once."
    },
    {
      "optionId": "ecg-hypertrophy-st-t-changes",
      "sourceCode": 67,
      "classification": "incorrect",
      "rationale": "Neither LVH nor RVH source criteria met; repolarization changes not credited as hypertrophy-associated."
    },
    {
      "optionId": "ecg-prolonged-qt",
      "sourceCode": 68,
      "classification": "neutral",
      "rationale": "Earliest global QRS foot and pairedRR give PAC8 early anterior QTc440\u2013510ms, but V5 later component if terminalT gives683\u2013768ms. Its first valley is not a proven isoelectric plateau. Similar V4/V6 late small humps support possible smallU/evolvingbaseline, not definitive exclusion of terminalT. Source68 is neutral on actual T-vs-U/baseline ambiguity, not ectopic-beat exclusion, persistence, or an assertion that allboundsstraddle460. PAC15 early candidate446\u2013497ms also remains documented."
    },
    {
      "optionId": "ecg-prominent-u-waves",
      "sourceCode": 69,
      "classification": "incorrect",
      "rationale": "No distinct U>1.5mm. A smaller late component near5.12\u20135.16s could be U versus fused/bifid terminalT or evolvingbaseline; it is not the nextP, whose globalfoot is5.428s. No prominentU credit, and no claim that everylatewaveisP."
    },
    {
      "optionId": "ecg-brugada-syndrome",
      "sourceCode": 70,
      "classification": "incorrect",
      "rationale": "No pseudoRBBB with coved/saddleback persistentV1\u2013V3 ST elevation."
    },
    {
      "optionId": "ecg-digitalis-toxicity",
      "sourceCode": 71,
      "classification": "incorrect",
      "rationale": "No\u22653beat atrialtachycardia, AFcompleteblock, advancedAVblock orbidirectionalVT. Atrialtachycardia would not requireAVblock under source."
    },
    {
      "optionId": "ecg-torsades-de-pointes",
      "sourceCode": null,
      "classification": "neutral",
      "rationale": "Null source mapping preserved; no invented golden criterion or point. Neutral0/0."
    },
    {
      "optionId": "ecg-hyperkalemia",
      "sourceCode": 73,
      "classification": "incorrect",
      "rationale": "Incorrect for the recorded ECG pattern after morphology review. Native and focused QRS9\u201312 show compact main QRS with small initial/terminal deflections, not convincing generalized widening or BBB; upper uncertainty bounds116\u2013120ms alone do not establish the separate widening component. Anterior T waves are broadly inverted and laterals low/broad, not tall narrow peaks; actual longest-T/PAC alternatives are normal-to-long or unresolved later termination, not convincing short QT combined with ST-T depression. Underlying sinus92\u201397/min with atrial premature beats has no bradycardia/arrest or ventricular tachyarrhythmia. Isolated ST depression is insufficient. No numeric short-QT cutoff or all-features-mandatory rule is used; this does not exclude biochemical hyperkalemia."
    },
    {
      "optionId": "ecg-hypokalemia",
      "sourceCode": 74,
      "classification": "neutral",
      "rationale": "FlattenedT/STdepression overlap fullsource hypokalemia; no mandatoryU or lab prerequisite, but biochemical cause unestablished."
    },
    {
      "optionId": "ecg-hypercalcemia",
      "sourceCode": 75,
      "classification": "incorrect",
      "rationale": "QT is not demonstrably shortened; some Bazett envelopes are prolonged-borderline, not hypercalcemicshortQT."
    },
    {
      "optionId": "ecg-hypocalcemia",
      "sourceCode": 76,
      "classification": "neutral",
      "rationale": "SomeQT envelopes crossprolonged boundary, but no certain interval or biochemicalcause; neutral0/0."
    },
    {
      "optionId": "ecg-mirror-image-dextrocardia",
      "sourceCode": 77,
      "classification": "incorrect",
      "rationale": "PositiveI P/QRS and preserved precordial progression contradict mirror-imagedextrocardia."
    },
    {
      "optionId": "ecg-acute-cor-pulmonale",
      "sourceCode": 78,
      "classification": "neutral",
      "rationale": "NonspecificSTT is an overlapping listed pulmonaryembolus manifestation; no acute pulmonarycause established, no mandatoryS1Q3T3 requirement."
    },
    {
      "optionId": "ecg-pericardial-effusion",
      "sourceCode": 79,
      "classification": "neutral",
      "rationale": "Broadsource39 amplitudevariation overlaps sourceeffusion and/or criterion, but does not identify pericardialcause; highvoltage doesnot itselfexcludeeffusion."
    },
    {
      "optionId": "ecg-acute-pericarditis",
      "sourceCode": 80,
      "classification": "incorrect",
      "rationale": "No diffuseST elevation with aVRPRelevation/otherlimbPRdepression pattern."
    },
    {
      "optionId": "ecg-hypertrophic-cardiomyopathy",
      "sourceCode": 81,
      "classification": "neutral",
      "rationale": "NonspecificSTT overlapfullHCMsource; noLVH/Q/RVHpattern and no apicalV4\u2013V6 deepT morphology. No invented giantTthreshold or HCM causalcredit."
    },
    {
      "optionId": "ecg-central-nervous-system-disorder",
      "sourceCode": 82,
      "classification": "neutral",
      "rationale": "AnteriorT inversion and uncertainQT overlap portions of fullCNSsource; not proof of CNSdisease. No requirement that all listed manifestations coexist."
    },
    {
      "optionId": "ecg-hypothermia",
      "sourceCode": 83,
      "classification": "neutral",
      "rationale": "QT-duration uncertainty overlaps one sourcehypothermia manifestation, without establishedbrady/AF orOsbornJ. No temperaturecause credited."
    },
    {
      "optionId": "ecg-atrial-coronary-sinus-pacing",
      "sourceCode": 84,
      "classification": "incorrect",
      "rationale": "No trueatrial pacingstimuli; limbnotches are noncardiactransients."
    },
    {
      "optionId": "ecg-normal-vvi-pacing",
      "sourceCode": 85,
      "classification": "incorrect",
      "rationale": "No ventricular pacingstimulus/different pacedQRS."
    },
    {
      "optionId": "ecg-normal-ddd-pacing",
      "sourceCode": 86,
      "classification": "incorrect",
      "rationale": "No pairedatrial/ventricularstimulus DDDpattern."
    },
    {
      "optionId": "ecg-pacing-capture-failure",
      "sourceCode": 87,
      "classification": "incorrect",
      "rationale": "No actualpacingstimulus withoutcapture; terminalexporthold is notpacingfailure."
    },
    {
      "optionId": "ecg-pacing-sensing-failure",
      "sourceCode": 88,
      "classification": "incorrect",
      "rationale": "No truepacemaker firing at inappropriate intervals."
    },
    {
      "optionId": "ecg-biventricular-paced-morphology",
      "sourceCode": 89,
      "classification": "incorrect",
      "rationale": "No dualventricularstimuli within80ms orCRT morphology."
    }
  ],
  "units": [
    {
      "id": "unit-1",
      "label": "Artifact",
      "acceptedCombinations": [
        [
          "ecg-artifact"
        ]
      ],
      "weight": 1,
      "rationale": "Supported educational morphology; alternatives counted once. Editorial weights, not official ABIM.",
      "evidenceRefs": [
        "finding:ecg-artifact"
      ]
    },
    {
      "id": "unit-2",
      "label": "Sinus rhythm",
      "acceptedCombinations": [
        [
          "ecg-sinus-rhythm"
        ]
      ],
      "weight": 1,
      "rationale": "Supported educational morphology; alternatives counted once. Editorial weights, not official ABIM.",
      "evidenceRefs": [
        "finding:ecg-sinus-rhythm"
      ]
    },
    {
      "id": "unit-3",
      "label": "Premature atrial complexes",
      "acceptedCombinations": [
        [
          "ecg-premature-atrial-complexes"
        ]
      ],
      "weight": 1,
      "rationale": "Supported educational morphology; alternatives counted once. Editorial weights, not official ABIM.",
      "evidenceRefs": [
        "finding:ecg-premature-atrial-complexes"
      ]
    },
    {
      "id": "unit-4",
      "label": "Electrical alternans",
      "acceptedCombinations": [
        [
          "ecg-electrical-alternans"
        ]
      ],
      "weight": 1,
      "rationale": "Supported educational morphology; alternatives counted once. Editorial weights, not official ABIM.",
      "evidenceRefs": [
        "finding:ecg-electrical-alternans"
      ]
    },
    {
      "id": "unit-5",
      "label": "Nonspecific ST or T-wave changes OR ST or T-wave changes suggesting ischemia OR ST or T-wave changes suggesting an electrolyte disturbance",
      "acceptedCombinations": [
        [
          "ecg-nonspecific-st-t-changes"
        ],
        [
          "ecg-ischemic-st-t-changes"
        ],
        [
          "ecg-electrolyte-st-t-changes"
        ]
      ],
      "weight": 1,
      "rationale": "Supported educational morphology; alternatives counted once. Editorial weights, not official ABIM.",
      "evidenceRefs": [
        "finding:ecg-nonspecific-st-t-changes",
        "finding:ecg-ischemic-st-t-changes",
        "finding:ecg-electrolyte-st-t-changes"
      ]
    }
  ],
  "contradictions": []
}