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ELECTROCARDIOGRAPHYHilton M Kaplan, MD

ELECTROCARDIOGRAPHYHilton M Kaplan, MD

University of Southern CaliforniaUniversity of Southern California

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R. ½

R. R. ½½ L. L. ½½

2 pumps in series2 pumps in series

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fetal circulationfetal circulation

cardiac cyclecardiac cycle

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intrinsic properties of myocardiumintrinsic properties of myocardium

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Starling’s Curves (Force-Volume)Starling’s Curves (Force-Volume)

↓

energyenergy

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electrical pathways in the heartelectrical pathways in the heart

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!!!!!!

conducting system of the heartconducting system of the heart

∞

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→ →

→ ↑

pacemaker hierarchypacemaker hierarchy

cardiac action potentialscardiac action potentials

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contractile mechanismscontractile mechanisms

stimulation, propagation, refractorinessstimulation, propagation, refractoriness

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↑ Ω

stimulation, propagation, refractorinessstimulation, propagation, refractoriness

refractorinessrefractoriness

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∝

' '

refractorinessrefractoriness

↑

↓

→

refractorinessrefractoriness

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intrinsic pacemakersintrinsic pacemakers

↑↑↑

• • ↑• ↓

↑↑↑ ↓

→ →

what we see … the ECGwhat we see … the ECG

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• • • • ↓

← →

↑

↓

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cardiac axiscardiac axis

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'

∠∠

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∠∠

∠∠

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∆ ∆

∆ ∆ ∆ ∆

∆ ∆ ∆ ∆

∆ ∆ ∆

∆

∆ ∆ ∆ ∆ ∆ ∆

∠∠

ECG analysisECG analysis

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