Bradyarrhythmias Flashcards
Sinus bradycardia
- narrow QRS
- HR <60bpm
- cause: damage to the heard, congenital condition, inflammation around the heart, electrolyte imbalance, hypothyroidism, obstructive sleep apnea, certain medications:
Sinus bradycardia
-symptoms
- dizziness, lightheaded
- fatigue
- shortness of breath
- chest pain
- being confused
- fainting
Sinus bradycardia
-diagnosis
- ECG
- stress test
- CBC
- electrolyte balance
Sinus bradycardia
-treatment
- treat underlying conditions
- pacemaker
AV blocks
-causes
- structural heart disease
- neurocardiogenic
- toxic/metabolic
- infectious - bacterial endocarditis, lyme carditis, rheumatic fever
- endocrine - thyroid, adrenal disease
- neuromuscular - myotonic dystrophy
AV blocks
-clinical features
- asymptomatic - especially 1st degree and Mobitz type 1
- fatigue, exercise intolerance, dyspnea, dizziness, syncope –> features of end-organ hypoperfusion
- irregular rhythms,: palpitations
- loss of atrioventricular synchrony –> feeling of pulsations in the neck or chest, symptoms of heart failure
1st degree AV block
- PR interval >200ms
- no interruption in atrial to ventricular conduction
- often discovered accidently
- risk of progression to complete heart block –> low
2nd degree AV block
-Mobitz type I
- progressive lengthening of the PR interval until a beat is dropped
- regular rhythm separated by short pauses –> bradycardia
- risk of progression to complete heart block –> low
2nd degree AV block
-Mobitz type II
- PR interval constant
- Single or intermittent non-conducted P waves without QRS complexes
- risk of progression to complete heart block –> high
3rd AV block - complete heart block
- complete block with no conduction
- P waves and QRS complexes have no relationship with each other
- risk of progression to cardiogenic shock or cardiac arrest –> high
Management of AV blocks
-ECG
Unstable patients
-atropine, transvenous pacing, transcutaneous pacing, inotropic medications
Stable patients
- identify and treat the underlying causes
- check serum electrolytes
Management of AV blocks
- 1° AV block
- Mobitz I
- 2:1 AV block thought to be at the AV nodal level
- no specific treatment if asymptomatic
- outpatient screening
Management of AV blocks -Mobitz II -2:1 AV block due to infranodal block -High-grade AV block 3° AV block
- continuous cardiac monitoring
- admission for temporary pacing
- permanent pacemaker for all patient with irreversible blocks
Left bundle branch block
- causes: cardiac (coronary artery disease, MI…) hyperkalemia, digoxin toxicity, degenerative disease of conduction tissue
- treatment: cardiac resynchronization therapy (biventricular pacing).
Right bundle branch block
- causes: cardiac (MI, coronary artery disease, mitral stenosis…), pulmonary (hypertension, embolism, COPD), congenital heart defects, Brugada syndrome, degenerative disease of the conduction tissue
- treatment: cardiac resynchronization therapy (biventricular pacing).
Digitalis effect
- digoxin overdose
- hypokalemia
- volume depletion
-symptoms: nausea, vomiting, diarrhea, abdominal pain, anorexia, photophobia, blurry vision with a yellow tint and halos, disorientations, palpitations
Digitalis effect
- diagnostics
- treatment
- diagnostics: ECG
- treatment: digoxin-specific antibody, atropine, magnesium, class IB anti-arrhythmias, temporary cardiac pacing
