Study Notes on Syncope by Dr. Pierre Tian

Speaker: Dr. Pierre Tian, Cardiologist at Westmead Hospital
Topic: Syncope
- Overview of syncope
- Discussion of its causes, history taking, physical examinations, investigations, management, and case studies.

Syncope: A transient loss of consciousness due to systemic hypoperfusion (low blood flow to the brain).
- It resolves spontaneously without medical intervention.

Various etiologies including:
- Cardiovascular issues (arrhythmias, structural heart disease)
- Neurological causes (seizure disorders)
- Metabolic issues (hypoglycemia, dehydration)
- Situational factors (vasovagal responses)

Important to gather a detailed medical history to differentiate between types of syncopal events.

Presentation:
- Symptoms: Fatigue and loss of consciousness during ambulation (walking to toilet), lasting minutes.
- Asymptomatic upon examination in the emergency department (ED).
Examination Findings:
- ECG: Sinus rhythm with more P waves than QRS complexes.
- PR interval noted to be normal.
- Appearance of additional P waves indicating two-to-one AV block.
Diagnosis Discussion:
- Secondary heart block, likely due to significant disease in the AV node or the His bundle.
- Explanation of the conduction system and sympathetic tone in the context of cardiac rhythm.
Management Techniques:
- Carotid sinus massage to differentiate block levels.
- Considerations of AV nodal disease management based on hemodynamic stability.
- Interventions may include beta agonists or pacing if compromised.
Escalation of Care:
- It’s critical to monitor the patient's responsiveness during physical activity and manage any hypotension as indicated.

Types of block:
- AV nodal level block: Narrow QRS complexes.
- Infra-nodal level block: Broad QRS complexes indicative of His bundle or bundle branch block.
Exploring management possibilities based on the level of block and patient symptoms.
- Temporary pacing may be necessary in symptomatic patients unlikely to respond to medications.

Presentation:
- History of recurrent syncope associated with specific triggers (blood drawing, choir singing).
Diagnostic Findings:
- ECG monitoring reveals profound bradycardia and possible sinus arrest contributing to her symptoms.
Mechanism Explanation:
- Increased vagal tone affecting both SA and AV nodes resulting in significant bradycardia.
Management:
- Non-pharmacological approaches (increased fluid and salt intake).
- If conservative measures fail, medications like Midodrine and fludrocortisone may be prescribed.
- Most cases do not warrant pacemaker insertion, especially in young patients.

Presentation:
- Syncope while playing squash, exertional chest pain, lightheadedness.
Important Examination Findings:
- Blood pressure: 180/80 with low volume carotid pulse.
- ECG: Evidence of LV hypertrophy (LVH) and sinus rhythm with conduction abnormality.
Diagnostic Investigation:
- Transesophageal echocardiogram (TEE) reveals severe aortic stenosis (50 mmHg gradient) with a bicuspid aortic valve.
Implications for Treatment:
- Risk assessment for associated conditions like ascending aortic aneurysm and coarctation.
Management Strategies:
- Surgical intervention may be necessary for aortic valve repair due to associated comorbidities.

Syncope can have various underlying causes and requires an extensive history and physical examination for accurate diagnosis.
Investigations include ECG and potential monitoring to capture arrhythmias during syncopal episodes.
Treatment depends significantly on the etiology identified and may require the use of pacemakers or defibrillators in rhythmogenic cases.
Non-invasive management techniques are often the first line for potentially benign causes of syncope.