Arrhythmias Flashcards
Normal heart rate
60-100 bpm
where do electrical impulses originate
Sinoatrial node (SA)
sinus tachycardia
NSR > 100 bpm
What med can be used for sinus tachycardia in the setting of acute coronary artery syndrome
beta blockers
sinus bradycardia
NSR < 60 bpm
first line for sx or unstable sinus bradycardia – and what does it do
atropine (anticholinergic drug that decreases vagal tone)
second line for sx or unstable sinus bradycardia if unresponsive to atropine
epinephrine or transcutaneous pacing
definitive management of sinus bradycardia
permanent pacemaker
what is the most common cause of narrow QRS complex tachycardia in paroxysmal supra ventricular tachycardia
reentry - AV nodal reentry MC
paroxysmal A-fib
self-terminating within 7 days (usually < 24 hours) +/- recurrent
persistent A-fib
fails to self-terminate, lasts > 7 days. requires termination (medical or electrical)
permanent A-fib
persistent A-fib > 1 year (refractory to cardio version or cardio version never tried)
lone a-fib
paroxysmal, persistent or permanent without evidence of heart disease
risk factors for Afib
HTN
valvular heart disease
heart failure ischemia
advanced age
obstructive sleep apnea
pulmonary embolism
obesity
chronic kidney disease
electrolyte imbalance (hypomagnesemia, hypokalemia)
diabetes
hyperthyroidism
pheochromocytoma
alcohol consumption
omega-3 fatty acid use
inflammation
what percent of Afib episodes are asx
90%
sx Afib
palpitations
dizziness
fatigue
generalized weakness
poor exercise tolerance
mild dyspnea
presyncope
unstable afib
sx are due to hypo perfusion and can include significant hypotension (systolic BP in double digits)
altered mental status
refractory chest pain (uncontrolled angina or ischemia)
decompensated congestive heart failure
what can be used to diagnose afib
EKG
cardiac monitoring
what will EKG show for Afib
irregularly irregular rhythm w fibrillary waves
no discrete P waves
often atrial rate > 250 bpm
the AV nodal refractory period determines the ventricular rate
cardiac monitoring for afib
a holter monitor or telemetry can be used if afib is not seen on an EKG but is suspected
tx for stable afib
rate control - Beta blockers (metoprolol, Atenolol, esmolol) OR non-dihydropyridine calcium channel blockers (Diltiazem, Verapamil) to slow AV node conduction
when is digoxin used in Afib
this is another option for rate control but is usually reserved for patients in whole beta blockers or CCBs are contraindicated (severe heart failure [NYHA class III or IV], hypotension)
tx for unstable afib
direct current (synchronized) cardioversion
is rate control or rhythm control preferred for long-term management of afib
rate control
long term therapy for afib
rate control
direct current (synchronized cardio version) or pharmacologic cardio version
radio frequency catheter ablation or surgical ‘MAZE’ procedure
CHA2DS2-VASc criteria for nonvalvular Afib to determine patients yearly thromboembolic risk in order to select appropriate anticoagulation regimen
in patients w AFib, what CHA2DS2-VASc score for oral anticoagulation
2 or more
when is cardio version most successful in afib
performed within 7 days after onset of Afib
what is done prior to cardio version in patients w Afib
transesophageal echocardiogram
If Afib > 48 hours — anticoagulation therapy
initiate anticoagulation therapy for at least 3 weeks before and at least 4 weeks after cardio version
If Afib < 48 hours — anticoagulation therapy
cardio version may be attempted as soon as possible often without coagulation
how long must anticoagulation be continued after cardio version in Afib
for 4 weeks after cardio version
CHA2DS2-VASc criteria
Congestive heart failure (1)
HTN (1)
Age >/= 75 (2)
DM (1)
Stroke, TIA, thrombus (2)
Vascular disease (prior MI, aortic plaque, peripheral arterial disease) (1)
Age 65-74 (1)
Sex (female) 1
recommended therapy for CHA2DS2-VASc 2 or more
moderate to high risk
chronic oral anticoagulation therapy recommended
recommended therapy for CHA2DS2-VASc 1
low risk
anticoagulation may be recommended in some cases
recommended therapy for CHA2DS2-VASc 0
no anticoagulation needed
tx for afib in stable patient
anticoagulation - warfarin, apixaban, rivaroxaban, edoxaban, heparin, dabigatran
tx for afib in the presence of heart failure
digoxin
amiodarone
dronedarone
tx for afib for RATE control
BB or CCB
metoprolol
esmolol
diltiazem
verapamil
atrial flutter
rapid, regular atrial depolarizations at a characteristic rate around 300 bpm due to 1 single irritable atrial focus firing at a fast rate w some degree of AV node conduction block
what percent of pts w atrial flutter have coronary artery disease or hypertensive heart disease
60%
what is the range for bpm in atrial flutter
240 - 400 bpm
characteristically around 300 bpm
sx atrial flutter
palpitations
dizziness
fatigue
poor exercise tolerance
mild dyspnea
pre syncope
unstable atrial flutter
sx are due to HYPOPERFUSION
systolic BP in double digits
altered mental status
refractory chest pain
diagnosis of atrial flutter
EKG
transthoracic echocardiography
what will EKG show for atrial flutter
flutter “sawtooth” atrial waves usually ~300 bpm (atrial rate usually 240-400 bpm) but no discernible P waves
what is the preferred initial imaging modality for evaluating atrial flutter
transthoracic echocardiography
what will transthoracic echocardiography show for aflutter
can evaluate right and left atrial size, size and fin of right and left ventricles, assess for valvular heart disease, LVH, pericardial disease
tx for stable aflutter
vagal maneuvers
rate control w beta blockers (metoprolol, atenolol, esmolol) or non-dihydropyridine calcium channel blockers (Verapamil, Diltiazem)
when is Digoxin used for aflutter
another option for rate control but usually reserved for pts in whole beta blockers or CCBs are contraindicated (severe heart failure class III or IV,) hypotension – due to ADE and toxicity
tx for unstable aflutter
direct current (synchronized) cardio version
definitive management for aflutter
radiofrequency catheter ablation
PVC
premature beat originating in the ventricle –> wide, bizarre QRS occurring earlier than expected
With a PVC, the T wave is in the opposite direction of the QRS usually
Associated w a compensatory pause = overall rhythm is unchanged (AV node prevents retrograde conduction)
tx for PVC
asx –> no tx
sx –> beta blockers (MC) or non-dihydropyridime CCB
radio frequency catheter ablation if refractory
ventricular tachycardia
3 or more consecutive PVCs (Wide complex QRS duration > 120 ms) at a rate > 100 BPM (usually between 120 and 300 bpm)
what can sustained vtach lead to
Vfib
what is sustained vtach
duration at least 30 seconds or cause hemodynamic collapse in < 30 seconds
causes of vtach
underlying heart dz: ischemic heart dz MC (post MI 70%), structural heart defects, cardiomyopathies
Prolonged QT interval
Electrolyte abnormalities (hypomagnesemia, hypokalemia, hypocalcemia)
Digoxin toxicity
sx vtach
palpitations
dizziness
fatigue
dyspnea
chest pain
unstable vtach
hypo perfusion can cause hypotension (systolic BP in double digits), altered mental status, refractory chest pain, acute pulmonary edema
what will EKG show for vtach
regular, wide complex tachycardia w no discernible P waves
tx for stable vtach
Amiodarone
Procainamide
tx for unstable vtach
direct current (synchronized) cardio version
tx for pulseless vtach
unsynchronized cardio version (defibrillation) + CPR
chronic therapy for Vtach
beta blockers
torsades de pointes and what will EKG show
variant of polymorphic Vtach
polymorphic Vtach (cyclic alterations of the QRS amplitude around the isoelectric line) aka sinusoidal waveform
what labs should you do when someone has torsades
rule out hypomagnesemia and hypokalemia
tx for recurrent TdP
IV magnesium sulfate
Isoproterenol or Transvenous overdrive pacing if refractory
Tx for congenital TdP
beta blockers
Avoid Isoproterenol
Tx for hemodynamically unstable TdP
synchronized cardio version
tx for pulseless TdP
prompt defibrillation (unsynchronized) cardio version
Vfib
a type of sudden cardiac arrest or sudden cardiac death with ineffective ventricular contraction
RF for Vfib
Ischemic heart disease (MC)
structural heart defects
Sustained Vtah
electrolyte abnormalities - hypokalemia, hyperkalemia, hypomagnesemia, acidosis, hypoxia
what will EKG show for vfib
disorganized high frequency undulations w erratic pattern of electrical impulses, fibrillation waves of varying amplitude, shape, and periodicity, occurring at a rate above 320 bpm
No identifiable P waves, QRS complexes, or T waves
tx for vfib
Unsynchronized cardioversion (defibrillation) + CPR
Epi and Amiodarone per ACLS protocol
prevention for Vfib
secondary prevention - implantable cardioverter-defibrillator placement in people w prior VF and sustained VT
primary prevention - ICD placement (pts w left ventricular ejection fraction < 35%)
First degree AV block
PR internal > 0.2
second degree AV block MOBITZ 1
progressive PRI lengthening until occasionally non-conducted atrial beats (one or more P waves without corresponding QRS)
second degree AV block MOBITZ 2
constant PRI length occasionally non-conducted atrial beats
third degree AV block
AV dissociation - normal P-P and R-R - atrial beats are not related to ventricular beats
aortic dissection
hx of uncontrolled HTN
sudden onset severe chest pain that radiates to back
pericarditis
hx of viral infection
retrosternal stabbing, chest pain that improves when leaning forward, worsens w deep inspiration
congestive heart failure
sx - cough exacerbated by lying down at night and improved by propping with pillows, exertion dyspnea
costochondritis
hx of viral infeciton
sx - stabbing chest pain that worsens w deep inspiration, relieved by aspirin
chest wall tenderness
pulmonary embolism
hx of recent immobilization
sx - acute onset SOB at rest and pleuritic chest pain, tachycardia, hypotension, tachypnea, fever
pulmonary edema
sx worsening dyspnea of 6 hours + cough w pink, frothy sputum
GERD
retrosternal burning sensation that occurs after heavy meals and when lying down; relieved by antacids
sickle cell disease - acute chest syndrome
sx - acute onset severe chest pain w hx of sickle cell disease
what murmur might people w Afib have
mitral stenosis