Cardiac arrhythmias Flashcards
what is brady and tachyarrhythmias?
bradyarrhythmia- < 60/min
tachy: > 100/min
what is supraventricular arrhythima?
arrhythmias that originate in the sinoatrial node, atrial myocardium, or atrioventricular node (regular QRS complex)
what is ventricular arrhythmia ?
Definition: arrhythmias that originate below the atrioventricular node (wide QRS complex)
what are the arrhythmias of sinus origin?
sinus tachycardia: physiological in excercise and pathological in HF, MI, Pulmo emb, SMN stimulation.
sinus bradycardia: physiological in athletes and sleep.
pathological: hypothyroidism, anorexia nervosa, inferior MI, Cushing reflex, BB or CCB or opiate use. treatment: iv atropine or pacemaker
sinus arrhythmia: naturally in inspiration (HR INCREASES) and expiration (HR DECREASES)
Sinus arrest or exit block: sinus node fails to fire
what are the re-entrant arrhythmias?
- PSVT: re-entrant circuits that loops within the AV node. can happen from alcohol and coffee consumption. they could have a regular rhythm and HR:150-250.RP interval is shorter than PR interval. absence of normal p waves or depressed p waves. T: carotid massage or adenosine
1b. AV nodal reentry tachycardia (AVNRT)
A form of paroxysmal supraventricular tachycardia
A dysfunctional AV node that contains two electrical pathways
Regular rhythm
Rate: 150–250
P waves occur during (i.e. are not visible) or after the QRS complex
RP interval is shorter than PR interval
Narrow QRS complex
1c. Junctional tachycardia The AV node takes over the pacemaker function Digitalis toxicity Myocarditis Myocardial infarction Regular rhythm Rate: 100–130 P waves occur before, during, or after the QRS complex P waves are inverted AV dissociation may occur Narrow QRS complex
- atrial flutter: caused by a single re-entrant circuit that runs around the annulus of the tricuspid valve. regular rhythm and HR of 150-250bpm. some get through and some don’t. p waves with saw tooth appearance. AV node conduction ratio of 2:1 T: meds or cardioversion. definitive treatment: catheter ablation.
- A FIB: hundreds of re-entrant circuits scattered around Atria. HR: >500BPM. no P waves seen. Irregularly irregular rhythm. Absence of true contraction means stasis of blood in heart thus more likely to have thrombus formation esp in left atrial appendage, resulting in stroke, central retinal artery and limb occlusion etc. T: bb and ccb or cardioversion for a fib and anticoagulants for thrombus
what are the ectopic arrhythmias?
1.Focal atrial tachycardia:
Discharge from a single ectopic focus in the atrium
Very abrupt onset
Regular rhythm
Rate: 150–250
P wave: morphology varies depending on the site of the ectopic focus
Occurs before the QRS complex
Narrow QRS complex
2. multifocal atrial tachycardia (MAT): from multiple ectopic foci firing from atrium. associated with lung diseases like asthma and COPD. irregularly irregular rhythm, HR:100-200bpm. Like A fib but P waves are present but vary in shape and PR intervals are irregular. 3 different P wave morphology to diagnose.
what is preexcitation syndrome?
lead to PSVT and it is an accessory pathway that acts as a shortcut to normal electrical circuits. ventricles are excited earlier than usual. seen in Wolf Parkinsons white syndrome- they have an extra pathway called Bundle of kent that came from a mutated autodominant PRKAG 2 gene. presented as shortening PR intervals, widening QRS complex and presence of delta wave.
what are the clinical features of arhythmia?
Palpitations, altered cardiac output: signs of hypotention and low brain perfusion: dizziness, syncope, altered mental status.
people with underlying heart disease: arhythmia can lead to acute heart failure
what are the types of ventricular arrhythmias ?
- ventricular tachycardia
2. ventricular fibrillation
what is ventricular tachycardia?
originates from ectopic focus of the ventricle. wide qrs
2 types: monomorphic (QRS complexes are the same and it is a complication of myocardial scarring.) and polymorphic (Complexes are different- not assiciated with myocardial scarring)
what are the causes of Polymorphic Ventricular tachycardia?
- Brugada synd: AD mutation hitting cardiac Na channels.. male asian descent. it shows with pseudo R bundle branch block, widened QRS, RSR configuration, ST elevation. T: prevention w/ implantable cardioverter defib.
- Torsades de pointes:Polymorphic ventricular tachycardia with QRS complexes that appear to twist around the isoelectric line.
anything that prolong QT interval- diseases with genetic mutations hitting ion channels (K channels) like jervell lange nelsen synd or romano- ward synd or electrolyte abnormality: hypo kalemia, calcemia and magnesemia (diarrhea).
other: medication: ABCDE
A- antiarhythmics like type 1a and 1c and type 3
B: aB
C:antipsyCotics
D:antiDepressants
E:antiEmetics
Treatment: MgSO4 as it can rapidly lead to Afic
what is V fib
VT can lead to V fib.
Triggers: AMI, HF, shock, hypoxemia/hype. muscle fibers start quiverring b/c not contracting at the same time. PQRST pattern breaks down. no CO and cardiac arrest.
T: CPR and D fib
