10 common ecg related disease

Reading File

Searching the Web

10 common ECG diseases EKG findings diagnosis

Finding Sources

Reading File

Finding Sources

I now have comprehensive information from authoritative medical textbooks. Here is the full, detailed answer:

10 Common ECG-Related Diseases

1. Atrial Fibrillation (AF)

ECG Features:

Absent P waves (replaced by chaotic fibrillatory baseline)
Irregularly irregular ventricular response
Narrow QRS complexes (unless aberrant conduction)
Ventricular rate typically 100-160 bpm (uncontrolled)

Key Points: AF is the most common sustained arrhythmia. It reduces left atrial contribution to cardiac output and increases stroke risk due to LA thrombus formation. Rate control plus anticoagulation are mainstays of management. (Braunwald's Heart Disease)

2. ST-Elevation Myocardial Infarction (STEMI)

ECG Features:

ST segment elevation ≥1 mm in 2+ contiguous leads
Reciprocal ST depression in opposing leads
Pathological Q waves (develop hours to days later)
T-wave inversions (evolving pattern)
ST elevation in lead V4R suggests right ventricular infarction

Key Points: STEMI diagnosis depends on ECG in the setting of ischemic symptoms. Emergent coronary reperfusion (PCI or thrombolysis) is required. (Tintinalli's Emergency Medicine; Goldman-Cecil Medicine)

3. Atrioventricular (AV) Heart Block

ECG Features:

Type	ECG Finding
1st degree	PR interval >200 ms, all beats conducted
2nd degree - Mobitz I (Wenckebach)	Progressive PR prolongation until a QRS is dropped
2nd degree - Mobitz II	Fixed PR, sudden non-conducted P wave (infranodal)
3rd degree (complete)	P-QRS dissociation, escape rhythm

Key Points: Mobitz II and complete heart block carry risk of hemodynamic compromise and may require pacing. In 2:1 AV block, ECG differentiation of type I vs II is not always possible; a PR <160 ms with wide QRS suggests infranodal (type II) block. (Harrison's Principles; Washington Manual; Fuster & Hurst's The Heart)

4. Ventricular Tachycardia (VT)

ECG Features:

Wide QRS complex tachycardia (QRS ≥120 ms, often >160 ms)
Rate >100 bpm (typically 150-250 bpm)
AV dissociation (P waves independent of QRS) - pathognomonic
Fusion beats and capture beats
QRS concordance across precordial leads

Key Points: Extreme QRS durations >160 ms strongly favor VT over SVT with aberrancy. AV dissociation during wide-complex tachycardia is the strongest ECG criterion for VT. (Goldman-Cecil Medicine; Tintinalli's Emergency Medicine)

5. Bundle Branch Block (BBB)

ECG Features:

Type	QRS	Lead V1	Lead I / V6
RBBB	≥120 ms	rSR' ("rabbit ears")	Wide, slurred S wave
LBBB	≥120 ms	Broad rS or QS	Tall, notched R wave

Key Points: New LBBB with chest pain is treated as STEMI equivalent. RBBB is commonly seen in PE, right heart strain, and congenital heart disease. A wide QRS with narrow-complex origin points to aberrant conduction rather than VT. (Washington Manual; Goldman-Cecil Medicine)

6. Wolff-Parkinson-White (WPW) Syndrome

ECG Features:

Short PR interval (<120 ms)
Delta wave (slurred initial upstroke of QRS)
Widened QRS complex
Secondary ST-T changes
With AF: pre-excited AF with rapid, irregular, wide-complex tachycardia (can degenerate to VF)

Key Points: WPW involves a congenital accessory AV pathway bypassing the AV node, causing ventricular preexcitation. AV reentrant tachycardia (AVRT) is the most common arrhythmia. Definitive treatment is radiofrequency ablation of the accessory pathway. (Miller's Anesthesia; Tintinalli's Emergency Medicine)

7. Congenital Long QT Syndrome (LQTS)

ECG Features:

Prolonged QTc interval: ≥480 ms in females, ≥470 ms in males (diagnostic threshold)
Abnormal T-wave morphology (bifid, notched, or late-peaking T waves)
Torsades de pointes (TdP): polymorphic VT with characteristic "twisting" around the isoelectric line

Key Points: LQTS is a repolarization disorder caused by ion channel mutations. Risk triggers include catecholamine surges, QT-prolonging drugs, and electrolyte abnormalities. Management: beta-blockers, avoidance of QT-prolonging drugs, and ICD in high-risk patients. (Miller's Anesthesia)

8. Brugada Syndrome

ECG Features:

Coved-type ST-segment elevation in right precordial leads (V1-V3) - "type 1 pattern" is diagnostic
Pseudo-right bundle branch block (RBBB) pattern
Pattern may be concealed and unmasked by fever, sodium channel blockers, or certain drugs
Risk of VT/VF and sudden cardiac death

Key Points: Caused by sodium channel gene mutations (SCN5A). May be unmasked by fever or medications. The website brugadadrugs.org lists drugs to avoid. Definitive treatment is an ICD. (Miller's Anesthesia)

9. Pulmonary Embolism (PE)

ECG Features:

Sinus tachycardia (most common finding)
S1Q3T3 pattern: deep S in lead I, Q wave + T-wave inversion in lead III
Right bundle branch block (new or incomplete RBBB)
Right axis deviation
T-wave inversions in V1-V4 (right heart strain)
P pulmonale (tall peaked P waves)

Key Points: ECG changes in PE reflect acute right heart strain and pressure overload. The S1Q3T3 pattern is classic but present in only ~20-26% of cases. Sinus tachycardia is the most sensitive (though non-specific) ECG finding. (Creasy & Resnik's Maternal-Fetal Medicine)

10. Pericarditis

ECG Features:

Diffuse ST elevation (saddle-shaped / concave upward) in most leads except aVR and V1
PR segment depression (hallmark - especially in lead II)
PR elevation in aVR
T-wave inversions develop in later stages (after ST normalization)
Electrical alternans if large pericardial effusion present

Key Points: Unlike STEMI, ST changes in pericarditis are diffuse (not in a coronary territory) and concave. The evolution through 4 stages (ST elevation → ST normalization → T inversion → T wave normalization) helps distinguish it from MI.

Quick Reference Summary Table

#	Disease	Key ECG Pattern	Danger Sign
1	Atrial Fibrillation	No P waves, irregular RR	Pre-excited AF in WPW
2	STEMI	ST elevation + Q waves	Complete occlusion
3	AV Heart Block	PR prolongation / dropped beats	Complete dissociation
4	Ventricular Tachycardia	Wide complex, AV dissociation	Pulseless VT → VF
5	Bundle Branch Block	Wide QRS, rSR' or LBBB morphology	New LBBB = STEMI equivalent
6	WPW	Delta wave, short PR	Rapid pre-excited AF → VF
7	Long QT Syndrome	Prolonged QTc ≥470-480 ms	Torsades de pointes
8	Brugada Syndrome	Coved ST elevation V1-V3	Sudden cardiac death
9	Pulmonary Embolism	S1Q3T3, sinus tachycardia, RBBB	Massive PE with RV failure
10	Pericarditis	Diffuse saddle ST, PR depression	Cardiac tamponade

Sources: Braunwald's Heart Disease, Tintinalli's Emergency Medicine, Harrison's Principles of Internal Medicine, Goldman-Cecil Medicine, Miller's Anesthesia, Washington Manual of Medical Therapeutics, Fuster & Hurst's The Heart.

This is a shared conversation. Sign in to Orris to start your own chat.