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MODULE 15: THE HEART
PART 3 OF 7
Stina’s ER ECG showed widespread, concave ST changes across many leads — diffuse, not confined to the territory of a single artery, exactly the pattern expected in pericarditis rather than a heart attack.
Slide 1 Transcript
PATIENT CHART
STINA
THIS PART
Age 44
PRESENTING WITH
Chest Pain, mildly raised HR
TESTS ORDERED
Echcardiogram, ECG,
DIAGNOSIS
Acute pericarditis — not myocardial infarction or anxiety.
CHART CLUES
COLLECTED AS YOU GO
Sharp, Pleuritic, Positional Chest Pain With a Friction Rub
Structurally Normal Chambers and Valves on Echo
Diffuse, Concave ST Changes Across Nearly All Leads
Normal S1 and S2 With a Superimposed Friction Rub
A Steady, Un-Tetanizable Rhythm Throughout the Flare
An Inflamed Serous Sac — Friction Rub Plus Small Effusion
Recurrent Pericarditis as FMF Serositis Reaching the Heart
Put your money down: Her ECG is abnormal in almost every lead — one blocked artery, or something wrapped around the whole heart?
A heart attack starves the territory of a single coronary artery, so its ECG changes cluster in a few leads; an inflamed sac irritates the whole surface at once. Before the videos, predict what ‘abnormal everywhere’ means about where Stina’s problem lives.
Pick the answer you believe now. We’ll come back to it later!
A Second Confirmation
The ER team ran an ECG within minutes of Stina’s arrival. To her, the tracing was a jagged ribbon; to the physician, it was a second confirmation. The ST-segment changes were spread diffusely across nearly all the leads instead of clustering in the few leads that watch one coronary artery’s territory. That pattern told them the irritation was wrapped around the whole heart — a sac problem, not a blocked-pipe problem — and it matched the rub they had already heard.
Electricity First
No nerve required — the heart starts its own beat.
Slide 2 Transcript
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Single Choice: Which statement about electricity First is correct?
The Pacemaker
One patch of cellsThe basic structural and functional units of life. sets the pace for everything.
Slide 3 Transcript
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Drag the Words: Match each term to its role in the Pacemaker.
The Spark and Its Map
Every heartbeat begins as electricity. The sinoatrial (SA) node in the right atrium fires spontaneously — the heart’s natural pacemaker — and the impulse spreads across both atria to make them contract. It then reaches the atrioventricular (AV) node, which deliberately delays the signal so the atria can finish topping off the ventricles, then races down the bundle of His, the right and left bundle branches, and out through the Purkinje fibers, so the ventricles contract from the apex up in a coordinated squeeze. The ECG records this as the P wave (atrial depolarizationThe loss of electrical charge across a membrane, triggering an action potential.), the QRS complex (ventricular depolarization), and the T wave (ventricular repolarizationThe return of membrane potential to a negative value after depolarization.). Because pericarditis irritates the surface of the entire heart evenly, its ECG changes are diffuse; because a heart attack starves one arterial territory, its changes are focal. Reading where the changes sit on the heart is how Stina’s clinicians separated her inflamed sac from a clogged artery.
The AV Node Delay
A deliberate pause so the ventricles fill.
Slide 4 Transcript
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A deliberate pause so the ventricles fill.
Down the Fast Wires
From the AV node, the signal sprints.
Slide 5 Transcript
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Mark the Words: Mark the words that describe down the Fast Wires.
Diffuse, Not Focal
For Stina, the ECG is the wiring telling the same story the stethoscope told. Because pericarditis irritates the entire surface of the heart evenly, its ST changes are diffuse, spread across nearly all the leads; because a heart attack starves one artery’s territory, its changes are focal. Her tracing was diffuse — a whole-surface problem, not a blocked pipe — and it matched the friction rub the team had already heard. Two independent readings of the same inflamed sac, arriving at the same answer.
Backups All the Way Down
Every level can pace — just slower.
Slide 6 Transcript
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Multiple Choice: Choose the best answer about backups All the Way Down.
Autonomic Tuning
The nerves that can’t start the beat, but shape it.
Slide 7 Transcript
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Sort the Paragraphs: Put the steps of autonomic Tuning in the right order.
The Rhythm Section
A self-firing circuit with a deliberate pause.
Slide 7 Transcript
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Dialog Cards: Flip the cards to review the Rhythm Section.
Reading the Electricity
The heart’s wiring, drawn on paper from the skinThe body’s largest organ, providing protection and regulation..
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Summary: Pick the true statement about reading the Electricity.
The Three Waves
P, QRS, T — depolarize, depolarize, reset.
Slide 7 Transcript
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Drag and Drop: Drag each label onto the Three Waves.
Intervals and Timing
The gaps between waves are measurements, not pauses.
Slide 7 Transcript
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Image Hotspots: Tap the labelled parts of intervals and Timing.
A Normal Tracing
Regular, evenly spaced, 60 to 100 a minute.
Slide 7 Transcript
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Single Choice: Which statement about A Normal Tracing is correct?
When It Goes Wrong
A few classic ways the rhythm misbehaves.
Slide 7 Transcript
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Drag the Words: Match each term to its role in when It Goes Wrong.
Diffuse Versus Focal
The pattern that solved Stina’s case.
Slide 7 Transcript
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Fill in the Blanks: Complete the key terms for diffuse Versus Focal.
The Heart, Drawn
Waves, intervals, and a telltale pattern.
Slide 7 Transcript
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Mark the Words: Mark the words that describe the Heart, Drawn.
FINDING!
Diffuse, Concave ST Changes Across Nearly All Leads
The sign is the distribution: widespread, concave ST-segment changes spread diffusely across the ECG rather than confined to the leads watching one coronary artery’s territory. Because different leads watch different regions, a whole-surface (diffuse) pattern points to pericardial inflammation, while a focal pattern points to ischemia. Chart entry: diffuse ECG changes consistent with pericarditis, not a regional myocardial infarction.
Confirm or refute your bet: Her ECG is abnormal in almost every lead — one blocked artery, or something wrapped around the whole heart?
Stina’s diffuse ST changes are the electrical signature of a pericardiumThe membrane surrounding the heart. inflamed evenly around the entire heart, and they agree with the friction rub already heard on exam. Two independent findings — the rub and the diffuse ECG — point to the same inflamed sac.
Slide 7 Transcript
NEXT PART
Electricity is only the trigger; the payoff is movementA fundamental property of life involving motion of the body or its parts.. The next page turns one spark into one complete heartbeat — pressures, valves, and the sounds you can hear.
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All Modules
- Anatomical Language, Membranes & Homeostasis
- Just Enough Chemistry
- The Cell & Its Transport
- Making Cells & Proteins
- The Integumentary System
- The Skeletal System
- The Muscular System
- Nervous Tissue & the Senses
- The Spinal Cord
- The Brain & the Blood–Brain Barrier
- The Autonomic Nervous System
- Special Senses (in developmentThe process of growth and differentiation.)
- The Endocrine System
- Blood
- The Heart
- Blood Vessels
- The Digestive System
- The Respiratory System
- The Urinary System
- Fluids, Electrolytes & Acid–Base Balance
- The Reproductive System
- The Immune System
List of terms
- cells
- depolarization
- repolarization
- skin
- pericardium
- movement
- development