# Clinical Cases: Cardiac Cycle

## Case 1: Aortic Stenosis with Classic Physical Findings

### Patient Presentation
**Demographics:** 78-year-old male

**Chief Complaint:** Exertional chest pain and dyspnea for 3 months

**History of Present Illness:**
A 78-year-old male with history of hypertension presents with progressive exertional chest pain and shortness of breath over the past 3 months. He reports symptoms when climbing one flight of stairs. He also experienced a near-syncopal episode last week while walking uphill. He denies symptoms at rest. He has a known bicuspid aortic valve diagnosed incidentally 10 years ago.

**Physical Examination:**
- Vital Signs: BP 125/85 mmHg, HR 72 bpm, RR 16/min, SpO2 97% on room air
- General: Well-appearing elderly male
- Cardiovascular:
  - Carotid pulse: Parvus et tardus (small and slow-rising)
  - PMI: Sustained, laterally displaced
  - Auscultation: Harsh crescendo-decrescendo systolic murmur at right upper sternal border radiating to carotids
  - S2: Single or paradoxically split (delayed A2)
  - S4 gallop present
- Lungs: Clear bilaterally

### Workup
- **ECG:** Left ventricular hypertrophy with strain pattern, left atrial enlargement
- **Echocardiogram:**
  - Severely calcified bicuspid aortic valve
  - Aortic valve area: 0.7 cm² (severe stenosis <1.0 cm²)
  - Mean gradient: 52 mmHg (severe >40 mmHg)
  - Peak velocity: 4.8 m/s (severe >4.0 m/s)
  - LVEF: 55% with concentric LVH
- **Cardiac catheterization:** Confirmed severe AS, mild CAD

### Diagnosis
**Severe symptomatic aortic stenosis with classic triad of angina, syncope, and dyspnea**

*Cardiac Cycle Correlation:*
- **Systolic murmur timing:** The murmur occurs during ventricular ejection (systole) as blood is forced through the stenotic aortic valve
- **Crescendo-decrescendo pattern:** Reflects pressure gradient peaking in mid-systole then declining as ejection ends
- **S4 gallop:** Indicates atrial contraction against stiff, hypertrophied LV (presystolic/late diastolic)
- **Parvus et tardus:** Delayed upstroke and reduced amplitude of carotid pulse due to obstruction
- **Prolonged ejection time:** Extends A2, causing single or paradoxically split S2
- **Wiggers diagram correlation:** The stenotic valve creates a large pressure gradient between LV and aorta during ejection phase

### Treatment
1. **Urgent surgical aortic valve replacement (SAVR)** or **transcatheter aortic valve replacement (TAVR)**
2. Avoid strenuous activity until valve replacement
3. Symptomatic patients with severe AS have poor prognosis without intervention (survival ~2-3 years with angina, ~3 years with syncope, ~1-2 years with heart failure)
4. Beta-blockers cautiously if needed for angina (avoid vasodilators)

### Clinical Image
![Aortic Stenosis Echocardiogram](case_01_image.jpg)

**Image Description:** Echocardiogram demonstrating severely calcified aortic valve with restricted leaflet motion and continuous wave Doppler showing elevated transvalvular gradient consistent with severe aortic stenosis.

**Source:** Radiopaedia - Aortic stenosis
**License:** CC BY-NC-SA 3.0
**URL:** https://radiopaedia.org/cases/aortic-valve-stenosis-echocardiography

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## Case 2: Mitral Regurgitation with S3 Gallop

### Patient Presentation
**Demographics:** 55-year-old female

**Chief Complaint:** Progressive shortness of breath and leg swelling for 2 months

**History of Present Illness:**
A 55-year-old female with history of rheumatic fever as a child presents with 2 months of progressive dyspnea, now occurring with minimal exertion. She also notes orthopnea (sleeps with 3 pillows), paroxysmal nocturnal dyspnea, and bilateral leg swelling. She has experienced fatigue and decreased exercise tolerance.

**Physical Examination:**
- Vital Signs: BP 118/68 mmHg, HR 92 bpm (irregular), RR 22/min, SpO2 94% on room air
- General: Appears fatigued, mild respiratory distress
- Cardiovascular:
  - JVP elevated to 14 cm
  - PMI: Diffuse, laterally displaced, hyperdynamic
  - Auscultation: Holosystolic (pansystolic) murmur at apex radiating to axilla
  - S1: Diminished
  - S3 gallop present (low-pitched sound in early diastole)
  - Irregularly irregular rhythm (atrial fibrillation)
- Lungs: Bibasilar crackles
- Extremities: 2+ bilateral pitting edema

### Workup
- **ECG:** Atrial fibrillation with LVH, left atrial abnormality
- **Chest X-ray:** Cardiomegaly, pulmonary vascular congestion, Kerley B lines
- **Echocardiogram:**
  - Severe mitral regurgitation (rheumatic etiology with leaflet thickening and restriction)
  - Dilated left atrium (5.8 cm)
  - Dilated left ventricle (LVEDD 6.5 cm)
  - LVEF: 50% (may be falsely preserved due to unloading into LA)
  - Moderate pulmonary hypertension

### Diagnosis
**Severe chronic mitral regurgitation (rheumatic) with heart failure and atrial fibrillation**

*Cardiac Cycle Correlation:*
- **Holosystolic murmur:** Occurs throughout systole because the pressure gradient between LV and LA exists from mitral valve closure to opening
- **S3 gallop (ventricular gallop):** Occurs during rapid ventricular filling phase of diastole; indicates volume overload and dilated, compliant LV
- **Diminished S1:** Due to incomplete mitral valve closure
- **Hyperdynamic PMI:** Reflects volume-overloaded LV
- **Wiggers diagram correlation:** During systole, blood regurgitates into LA (normally at low pressure), creating a large v-wave in LA pressure tracing

S3 timing: Occurs 120-180 ms after S2, during the rapid filling phase when blood rushes into the dilated ventricle

### Treatment
1. Diuretics for volume overload (furosemide)
2. ACE inhibitor or ARB for afterload reduction
3. Rate control for atrial fibrillation (beta-blocker or digoxin)
4. Anticoagulation for atrial fibrillation (warfarin or DOAC)
5. **Surgical mitral valve repair or replacement** indicated for severe symptomatic MR
6. Referral to cardiac surgery

### Clinical Image
![Mitral Regurgitation Echocardiogram](case_02_image.jpg)

**Image Description:** Color Doppler echocardiogram showing severe mitral regurgitation with a large regurgitant jet extending deep into the left atrium during systole. The jet represents abnormal blood flow from left ventricle to left atrium through the incompetent mitral valve.

**Source:** Wikimedia Commons - Mitral regurgitation echocardiogram
**License:** CC BY-SA 4.0
**URL:** https://commons.wikimedia.org/wiki/File:Mitral_regurgitation_color_doppler.jpg

---

## Case 3: Hypertrophic Cardiomyopathy with Dynamic Outflow Obstruction

### Patient Presentation
**Demographics:** 28-year-old male

**Chief Complaint:** Exertional dyspnea and near-syncope

**History of Present Illness:**
A 28-year-old male athlete presents with exertional shortness of breath and two episodes of near-syncope during basketball games over the past 6 months. He describes lightheadedness and "graying out" of vision during intense exertion. He has also noticed occasional palpitations. His father died suddenly at age 42 while jogging. No prior cardiac history.

**Physical Examination:**
- Vital Signs: BP 125/78 mmHg, HR 70 bpm, RR 14/min, SpO2 99% on room air
- General: Muscular, athletic male in no acute distress
- Cardiovascular:
  - Carotid pulse: Brisk, bifid (spike and dome)
  - PMI: Sustained, double impulse
  - Auscultation: Harsh crescendo-decrescendo systolic murmur at left lower sternal border
  - **Murmur increases with Valsalva and standing** (decreased preload)
  - **Murmur decreases with squatting and passive leg raise** (increased preload)
  - S4 gallop present

### Workup
- **ECG:** LVH with deep, narrow Q waves in lateral leads (septal hypertrophy), T-wave inversions
- **Echocardiogram:**
  - Asymmetric septal hypertrophy (septal wall 24 mm, posterior wall 11 mm)
  - Systolic anterior motion (SAM) of mitral valve
  - LVOT gradient: 65 mmHg at rest, 110 mmHg with Valsalva
  - Hyperdynamic LV function (EF 75%)
  - Mild mitral regurgitation
- **Genetic testing:** MYH7 mutation (beta-myosin heavy chain)

### Diagnosis
**Hypertrophic obstructive cardiomyopathy (HOCM) with dynamic left ventricular outflow tract obstruction**

*Cardiac Cycle Correlation:*
- **Dynamic obstruction:** LVOT obstruction worsens during systole as the hypertrophied septum and SAM of mitral valve narrow the outflow tract
- **Murmur characteristics:**
  - Increased with Valsalva/standing: Decreased preload → smaller LV cavity → more obstruction → louder murmur
  - Decreased with squatting: Increased preload → larger LV cavity → less obstruction → softer murmur
- **Bifid carotid pulse:** Initial rapid ejection (spike) followed by obstruction then continued ejection (dome)
- **S4 gallop:** Atrial contraction against stiff, hypertrophied LV
- **PV loop:** Shows mid-systolic obstruction with pressure spike after initial ejection

### Treatment
1. **Avoid strenuous competitive athletics** (risk of sudden cardiac death)
2. Beta-blockers (first-line therapy to reduce obstruction)
3. Disopyramide (negative inotrope, reduces SAM)
4. Avoid dehydration, vasodilators, high-dose diuretics
5. **ICD implantation** indicated for high-risk features (family history of sudden death, massive LVH, unexplained syncope)
6. Consider septal myectomy or alcohol septal ablation if refractory

### Clinical Image
![HCM Echocardiogram](case_03_image.jpg)

**Image Description:** Echocardiogram demonstrating hypertrophic cardiomyopathy with asymmetric septal hypertrophy and systolic anterior motion (SAM) of the mitral valve causing left ventricular outflow tract obstruction.

**Source:** Radiopaedia - Hypertrophic cardiomyopathy
**License:** CC BY-NC-SA 3.0
**URL:** https://radiopaedia.org/cases/hypertrophic-cardiomyopathy-hcm