Cardiology Flashcards
Sinus Bradycardia: Description/Common Causes/Presentation/Dx/Treatment
Description:Regular, sinus, slower than normal heart rate for age
Common Causes:Sleep, athletic habitus, anorexia, breath-holding spells, hypothyroidism, medications, steroids, elevated intracranial pressure, severe hypoxia, sinus node dysfunction
Presentation:Can be asymptomatic in athletic individuals
If significant can have fatigue, exercise intolerance, and syncope
dx: ascultation and ECS
Treatment: May not require treatment
Reversible causes should be treated individually
Bradycardic arrest: CPR and atropine
Sinus node dysfunction can be treated with pacemaker
Sinus Arrhythmia: Description/Common Causes/Presentation/Diagnosis/Treatment
Description: Irregular, sinus, varying distance between QRS complexes
(Fig. 8.2)
Common Causes: Respirophasic variation: heart rate increases with inspiration, decreases with expiration
Presentation
▪ Usually asymptomatic
Diagnosis
Auscultation and ECG
Treatment
▪ No treatment required
Sinus Arrhythmia: Second-Degre heart Block (Wenckebach/Mobitz I): Description/Common Causes/Presentation/Diagnosis/Treatment
Description Gradual PR interval prolongation followed by dropped QRS complex
Common Causes: Occur during times of high vagal tone, often during sleep, athletic habitus, AV node dysfunction
Presentation
▪ Usually asymptomatic
Diagnosis
ECG
Treatment
▪ Usually transient and does not require treatment
Second-Degree Heart Block (Mobitz II)
Description Constant PR interval with abrupt dropped QRS complex
Common causes: Most common cause of myocarditis, postsurgical complications, AV node dysfunction, Lyme disease
Presentation
▪ Can be asymptomatic
▪ Can also have fatigue
Diagnosis
ECG
Treatment
▪ Always pathologic
▪ Treat reversible cause if present
▪ Pacemaker placement if no treatable cause
Third-Degree Heart Block or Complete Heart Block
Description: AV dissociation with constant P wave faster than QRS rate
(Fig. 8.3)
Common Causes
Congenital (maternal autoimmune disorders), structural heart disease, postsurgical, Lyme disease
Presentation
▪ Can be asymptomatic
▪ Fatigue
▪ Syncope
Diagnosis
ECG, Holter, exercise test, echocardiogram
Treatment
▪ If reversible, can treat
▪ If symptomatic or hemodynamic compromise, will need pacemaker
Sinus Tachycardia
Description: Regular, sinus, faster than normal heart rate for age
Common Causes: Anemia, dehydration, pain/agitation, hyperthyroidism
Presentation:
▪ Usually symptomatic from other causes
▪ May have “palpitations”
Diagnosis:
Auscultation and ECG
Treatment:
▪ Treat reversible causes, rare in isolation
Supraventricular Tachycardia (SVT) and Wolff-Parkinson-White (WPW)
Description:
Baseline: sinus, WPW has delta wave causing slurring of P wave into QRS
(Fig. 8.4)
In SVT: narrow QRS complex, much faster than normal heart rate, P waves may not be visible
(Fig. 8.5)
Common Causes:
Accessory conduction pathway
Presentation:
▪ At baseline, may not have any symptoms
▪ Will feel palpitations during tachycardia
▪ Can have syncope and sudden cardiac death (high-risk WPW)
Diagnosis
Baseline ECG,
Holter, Exercise test to determine if high risk for sudden death,
SVT ECG
Treatment
▪ Acute treatment of SVT: breath-holding, adenosine, direct cardioversion
▪ Long-term treatment: beta- blockers, catheter ablation
Atrial Flutter
Description: Regular, “sawtooth pattern” with atrial rates faster than QRS waves
Common CausesUncommon in children, can be seen in neonates with no other associations
Presentation:
▪ Can be asymptomatic
▪ If rhythm is very fast, can show hemodynamic compromise
Diagnosis
ECG, Holter, echocardiogram to rule out structural heart disease
Treatment
▪ Direct synchronized cardioversion
▪ Usually neonates do not require further therapy
Atrial Fibrillation
Description: Irregularly irregular, P waves are abnormal and different morphologies, QRS similar to sinus rhythm
Common Causes: Very uncommon in children, can occur in patients with WPW who have SVT that degenerates into atrial fibrillation, postsurgical
Presentation
▪ Palpitations
▪ Can be at risk of stroke due to left atrial thrombus formation
Diagnosis
ECG, Holter, echocardiogram to rule out structural heart disease
Treatment
▪ Direct cardioversion (must be anticoagulated first due to risk of stroke)
Ventricular Tachycardia
Description: Regular, wide complex, QRS different from baseline
(Fig. 8.6)
Common Causes: Structural heart disease, postsurgical, myocarditis, long QT, medication overdose, cardiomyopathy
Presentation
▪ May be asymptomatic
▪ Palpitations
▪ Fatigue
▪ Syncope
▪ Sudden death
Diagnosis
ECG, Holter, exercise test, echocardiogram to rule out structural heart disease
Treatment
▪ If asymptomatic, can consider medical management with beta-blockers
▪ If syncope or aborted sudden cardiac arrest, implantable cardiac defibrillator (ICD) placement
Torsades de Pointes
Description Irregular, fast, wide complex, sinusoidal pattern along baseline
Common Causes
Hypokalemia, hypomagnesemia
Prolonged QTc, Brugada
Presentation
▪ Palpitations
▪ Syncope
▪ Sudden death
Diagnosis
ECG
Treatment
▪ Correct if reversible cause
▪ If progresses to ventricular fibrillation, defibrillate!
▪ May respond to magnesium
Ventricular Fibrillation
Description: Irregular, wide complex, can be disorganized
Common Causes: Electrolyte abnormalities, channelopathies, postsurgical
Presentation
▪ Palpitations
▪ Syncope
▪ Sudden death
Diagnosis
ECG
Treatment
▪ Correct if reversible cause
▪ Defibrillate!
Premature Atrial Complex (PAC)
Description: Single, early, narrow complex beat
(Fig. 8.7)
Common cause:
Abnormal focus in atria, electrolyte abnormalities, can be normal finding
Presentation
▪ Likely asymptomatic if isolated
Diagnosis
ECG, Holter, electrolytes, echocardiogram if frequent PACs
Treatment
▪ No treatment necessary in isolation
▪ Can treat reversible causes
Premature Ventricular Complex
Description: Single, early, wide complex beat, different QRS than baseline
(Fig. 8.8)
Common Cause:
Abnormal focus in ventricle, electrolyte abnormalities, Long QT syndrome, myocarditis, HCM, structural heart disease, can be normal finding
Presentation
▪ Likely asymptomatic if isolated
Diagnosis
ECG, Holter, electrolytes, echocardiogram if frequent PVCs
Treatment
▪ No treatment necessary in isolation
▪ Can treat reversible causes
First Degree Heart Block
Description: PR interval prolonged beyond normal for age
Common Causes:
AV node dysfunction, increased vagal tone (e.g., sleep), rheumatic fever, Ebstein’s anomaly, Atrial septal defect (ASDs), AV canal defects, hypocalcemia medications
Presentation:
▪ Likely asymptomatic
Diagnosis
ECG, Holter, echocardiogram if persistent
Treatment
▪ Usually benign and no treatment required
Prolonged QT
Description: QT interval is corrected (QTc) for heart rate and is prolonged beyond normal for age
(Fig. 8.9)
Common Causes:
Congenital: familial or de novo genetic mutation
Acquired: electrolyte abnormalities, medications, postsurgical, myocarditis, infections
Presentation
▪ At baseline, likely asymptomatic
▪ Predisposes to ventricular fibrillation and can cause syncope or sudden death
Diagnosis
ECG, Holter, exercise test, echocardiogram to rule out structural heart disease, genetic testing
Treatment
▪ Avoid QTc- prolonging medications
▪ Beta-blocker for genetic cause
▪ ICD if history of syncope or aborted sudden cardiac arrest
