Cardiac Rhythm disturbances- Johnston Flashcards
What are some signs and symptoms of arrhythmias?
- palpitations
- Lightheadedness - faint like
- Syncope or near syncope
- Chest pain
- Dyspnea
- Sudden death
What are some common etiology of cardiac arrhythmias?
- Stress
- Ischemia (CAD, MI, HF)
- Metabolic acidosis
- infection
- cardiomyopathy/alcohol; chemo
- Electrolyte imbalance
- Drugs (caffeine, nicotine, thyroid, aminophylline, OTC)
- HTN
What are some causes of sinus tachycardia?
- can be physiologic or pathologic
- Emotion, anxiety, fear, drugs, hyperthyroid
- fever, pregnancy, anemia, CHF
- hypovolemia
_ is the dominant cardiac pacemaker and has it’s own intrinsic discharge rate
Sinus node
when Lifting heavy objects, would you expect bradycardia or tachycardia?
Bradycardia. This is the valsalva maneuver which is a vagal stimuli.
A patient presents with alternating tachycardia and bradycardia and was diagnosed with sick sinus syndrome. What is the likely treatment option?
- pacemaker to treat the bradycardia and pharmacologic intervention for the tachycardia.
A pt presents with heightened vagal tone–vomiting nausea– and chest pain. On EKG, bradycardia, 2ndary mobitz type I AV block, ST elevation were noted. Lab shows elevated cardiac enzymes. Pt’s MI was most likely on what area of the heart?
Inferior MI.
Non conducted atrial bigeminy has been implicated in _ (brady or tachycardia)
Bradycardia
what are the criteria needed to diagnose a sinus bradycardia on EKG?
- P wave followed by a ventricular beat with rate <60.
- Normal axis
- constant and normal PR interval
- Constant P wave configuration in each lead
- regular or slightly irregular P-P cycle or R-R cycle
Atrial fibrillation causes can be remembered by the acronym PIRATES which stands for _
- Pulmonary disease
- Ishchemia
- Rheumatic heart dz
- Anemia
- Thyrotoxicosis
- Ethanol
- Sepsis
What is the most common cause of unexplained pause on an EKG?
A pauce is defined as a missing QRS complex on an EKG. It is often due to nonconducted premature atrial contraction (PAC)
What is a nonconducted atrial bigeminy and how can it be recognized on an EKG?
PAC occurs when a focus in the atrium (not the SA node), generates an AP before the next scheduled SA node AP. When this occurs prior to the AV node recovering (the AV node is still refractory), a non-sinus P wave will be seen that is not followed by a QRS complex (non-conducted). When every other QRS complex is a PAC, then the rhythm is referred to as “atrial bigeminy”
On EKG:
- Occurs early
- P wave would different from normal P wave shape (since this P wave is not from the SA node) and usually narrow and biphasic
- There is a compensatory pause after the PAC. The extra atrial action potential causes the SA node to become refractory to generating its next scheduled beat. Thus it must “skip a beat” and it will resume exactly 2 P to P intervals after the last normal sinus beat.
what are some causes, signs and symptoms of sick sinus syndrome (SSS)?
Causes: ischemia, sclerotic, inflammatory changes in SAN
signs and symptoms: nonspecific such as syncope, dizziness, fatigue, heart failure
How is SSS recognized on an EKG?
Period of tachycardia followed by a long pause and bradycardia and then back to tachy cardia.
Sinus bradycardia in a lot of cases may not need treatment. Treatment is indicated only when HR? 45-50 and/or they become symptomatic which would include _1_and often are treated with with 2 as first line option, side effects of which commonly includes urinary retention and abd distention.
- decreased BP, CO, SV, renal perfusion; SOB, decreased cerebral perfusion (confusion), CP, cool, clammy, diaphoretic, syncope, dizziness
- Atropine. Other treatment, if atropine does not work, includes epi, isoproterenol and a pacemaker.
Bradycardia is often associated with _ MI and lesion of the _ artery
inferior wall MI
RCA
which phase of the cardiac AP is most prone to arrhythmia?
Phase 4
_ is the property of a cardiac cell to depolarize spontaneously during phase 4 of an AP/leads to generation of an impulse
Automaticity
Ventricular beats appearing in groups of 2 or 3 with the last one early and a different wave is characterized as _
Atrial bigeminy or trigeminy (ectopic focus tied to SA rhythm)
what are some common causes of atrial premature beats?
- epi
- increased sympathetic
- caffeine, amphatamines, cocaine,
- excess digitalis, ethanol
- hyperthyroidism
- stretch
- hypoxia
How is a premature atrial beat recognized on EKG?
- an early P wave that sometimes can be masked within the T wave in which case it’ll appear as a too-tall T wave (taller than the other T waves in the same lead)
- can be conducted (QRS present) or nonconducted (no accompnaying QRS)
How is premature atrial complexes treated?
Treat only if symptomatic, give beta blocker such as metoprolol
_ is a sudden heart rate greater than 100 (commonly 150-250/min), impulses which are not coming from SA node, bother some other foci, commonly irritable focus P wave is seen.
Paroxysmal Atrial tachycardia.
How is Paroxysmal arial tachycardia (PAT) recognized on an EKG?
tachycardia with P’ waves that do not look like sinus-generated P waves.
- you’ll see a normal run followed by an irritable foci that starts a round of tachycardia. In between the tachycardic QRS, the P and T waves are superimposed on each other.
How is a PAT with AV block recognized on a EKG?
- Rapid rate, spiked P’ waves 2:1 ratio of P’: QRS.
- atrial ectopic beats that appear within the QRS complex.
PAT with AV block is often associated with toxicity with what drug?
digitalis
how is multifocal atrial tachycardia recognized on a EKG?
- 3 or more different P waves
- PR interval varies
- irregular ventricular rhythm
- atrial rate > 100
Multifocal atrial tachycardia is associated with what pathologies?
- lung disease (among others but lung disease/abnormalities is the main one)
what are some drugs of choice to treat MAT?
MAT is most likely due to lung disease and thus you’d treat the lung first. then to treat the tachycardia you can give DC theophylline, Verapamil (be cautious if pt has EF impairment cuz it can make HF worse), magnesium sulfate.
- be cautious with beta blockers since it can make pulmonary problems worse
_ is associated with atrial rate >350-600/min, undulating baseline, no discernible P waves, irregular RR interval with irregularly irregular ventricular rhythm. Multiple atrial foci.
afib
when pt presents with irregular heart beating, and has DJD, HTN, or HF, EKG shows irregularly irregular waves, most likely _
Afib
Beats of 250-350/min; Saw tooth appearance in leads II, III, avF, V is characteristic of _
Atrial flutter
A fib is associated with what risk factors?
- pulmonary disease
- Ischemia (cardiomyopathy, pericarditis, HTN, ASD)
- RHD (mitral or aortic valve abnormalities)
- Atrial myxoma
- Thyrotoxicosis (hyperthryoidism)
- Ethanol
- Sepsis
How do pts with a-fib usually present?
- often asymptomatic
- may present with SOB, palpitation, chest pain, syncope
- On PE: thready pulse, hypotensive and tremor may be noted
what is the prognosis and complication of a flutter and afib?
- increased risk of stroke
- atrial mural thrombi emboli to cerebral vassels causing TIA or CVA
How is pericarditis recognized on a EKG?
diffuse ST elevation on multiple leads
what is the drug of choice to treat supraventicular tachycardia?
adenosine
HOw is junctional (nodal) tachycardia recognized on a EKG?
- rate 150-250
- non discernible P wave
- T waves are tall
- QRS are narrow
what is the rate of junctional foci?
40-60/min
what are some causes of premature ventricular contractions (PVC)?
- normal heart
- CAD, MI, HF, ischemia, hypoxia,
- valvular disease
- congenital
- Acid/base imbal
- Hyperthyroid
- drugs
what is the difference in the appearance of the QRS complex in Nodal/junctional tachycardia vs a ventricular tachycardia?
Junctional/Nodal = narrow QRS
Ventricular = wide QRS
How is PVC’s recongnized on EKG?
- premature, bizzarre, wide QRS
- No preceding P wave; may produce a retrograde P wave in ST segment
- ST-T wave moves in opposite direction of QRS
- usually full compensatory pause
EKG changes seen after a person takes thrombolytic agent is known as _
accelerated idoventricular rhythm
what is the treatment for PVC?
- if stable no Rx; if symptomatic or in setting of ACS- metoprolol
- if Unstable - amiodarone, lidocaine, procainamide
_ is described as 3 or more consecutive bizzare QRS complexes ventricular rate 120-200 - wide QRS - p wave often lost (AV disassocation) - lasts longer than 30 seconds
V tach
whats the treatment for V tach?
Cardioversion
what is the treatment for Vfib?
defibrillate
_ is characterized by QRS swings from positive to negative direction, can be seen in Prolonged QT syndrome, antiarrhythmias, alcohol, TCA, electrolyte imbalance
Torsades de Pointes
If you suspect someone with Torsades what ion levels should you check?
K, Ca, Mg. Also check what meds he’s taking
what is the first line treatment for Torsade?
MgSO4
others include: overdrive pacing; isoproternol
Explain what EKG changes are seen with changes in levels of each of the these ions:
A. K+
B. Ca++
C. Mg+
A. Prominent U waves, prolonged QT interval, flat or inverted T waves
B. Low: prolongs QT interval; trigers arrhythmias (torsades). High: shortens QT interval
C. Low: prolongs QT (torsades); high: shortens QT
how is hypokalemia recognized on EKG?
- prominent U wave
- prolonged QT interval
- flat or inverted T wave
how is hyperkalemia recognized on EKG?
Peaked T wave,
- wide QRS
- prolonged PR interval
- loss of P wave
How is hypocalcemia recognized on EKG?
Prolongation of QT interval
How is hypercalcemia recognized on EKG?
- Short QT interval
- Short ST segment
How is hypomagnesemia recognized on EKG and what is hypomagnesemia associated with?
Prolonged PR, wide QRS, prolonged QT, dec Twave.
- associated with poor nutrition, alcoholism, decrease absorption, renal magnesium loss, diuretics
What is hypothermia recognized on EKG?
- bradycardia
- J wave (osborne wave )
how is pulmonary embolism recognized on EKG?
- T wave inversion V1-V4
- Transient RBBB
- tachycardia
How is cerebral hemorrhage recognized on an EKG?
- ST-T changes
How is hypothyroidism recognized on a EKG?
- Widespread flattening or mild inversion of T waves without associated ST segment displacement
How is Wolff-Parkinson White syndrome recognized on an EKG?
Short P-R interval
- Slurred upstroke (delta wave) of QRS complex
- accessory AV conduction pathway (Bundle of Kent)
How is supraventricular tachycardia associated with wolf-parkinson-white syndrome treated?
Procainamide or amiodarone for afib with rapid ventricular response
-synchonized cardioversion for severely syptomatic
What drugs are contraindicated in supraventricular tachycardia associated with wolf-parkinson-white syndrome
Drugs that delay AV node conduction (BB, CCB, and adenosine
An 18-year-old male reports to his physician that he is having repeated episodes of a “racing heart beat”. He believes these episodes are occurring completely at random. He is experiencing approximately 2 episodes each week, each lasting for only a few minutes. During the episodes he feels palpitations and shortness of breath, then nervous and uncomfortable, but these feelings resolve in a matter of minutes. He is otherwise well. Vital signs are as follows: T 98.8F, HR 60 bpm, BP 110/80 mmHg, RR 12. EKG shows a wide QRS (> 0.12 second) with initial slurring (delta wave), sinus rhythm, and a short PR (< 0.12 second). What is the likely diagnosis?
- Paroxysmal atrial fibrillation
- Panic attacks
- Ventricular tachycardia
- Atrioventricular reentrant tachycardia
- Atrioventricular block, Mobitz Type II
- AV reentrant tachycardia
Episodes of recurrent palpitations and EKG findings revealing a pre-excitation are consistent with a diagnosis of Wolff-Parkinson-White Syndrome (WPW), an atrioventricular reciprocating tachycardia.
A 52-year-old patient with a complicated past medical history becomes unstable in the intensive care unit. His monitor depicts the rhythm that shows patterns consistent with Torsades. Which of the following electrolyte disturbances may have contributed to his current arrhythmia?
- Hyperchloremia
- Hypophosphatemia
- Hyperkalemia
- Hypercalcemia
- Hypomagnesemia
- Hypomagnesemia
Conditions that predispose patients to TdP include hypomagnesemia, hypokalemia, hypocalcemia, long QT interval. First-line treatment includes a magnesium (magnesium sulfate) bolus and sometimes exogenously increasing the heart rate (i.e isoproterenol or pacing). Defibrillation is indicated in patients who are hemodynamically unstable.
57 year old woman presents to ER after fainting. She complained of a rapid heartbeat to her co worker just before she passed out. EKG was performed and showed wide QRS with rate of 200/min (monomorphic ventricular tachycardia). Pt has a history of CAD. what is the most appropriate treatment?
Pt has ventricular tachycardia. Immediate CPR and defibrillation or chemical cardioversion (if hemodynamically stable with lidocaine, amiodarone, or procainamide)
How is atrial fibrillation treated?
rate control: BB or CCB
prevention of stroke: warfarin or aspirin
how is atrial flutter treated?
Class IA, IC, or III antiarrhythmics
A 28-year-old woman presents to the urgent care center complaining of weakness, confusion, and that her heart is “racing and flopping” in her chest. She has no significant past medical history. She denies any previous episodes of anxiety attacks or heart issues. She smokes 1/2 of a pack of cigarettes per day and is a social drinker. She denies the use of any illicit drugs. She has no known drug allergies, and she does not take any medications on a daily basis. An EKG shows irregularly irregular pattern and lack of p wave. This patient’s ventricular contraction rate is determined by which
- SA node refractory period
- AV node refractory period
- Bundle of His conduction speed
- Purkinje fiber conduction speed
- Purkinje fiber refractory period the following?
- AV node refractory period
This patient is experiencing an episode of atrial fibrillation as determined by her EKG findings. In atrial fibrillation, the ventricular rate is determined by the AV node refractory period.
A 60-year-old male presents with palpitations. He reports drinking many glasses of wine over several hours at a family wedding the previous evening. An EKG reveals absent P waves and irregularly irregular rhythm. He does not take any medications. Which is most likely responsible for the patient’s symptoms?
- Atrial fibrillation
- Transmural myocardial infarction
- Untreated hypertension
- Torsades de pointes
- Ventricular hypertrophy
- A fib
How is atrial escape rhythm recognized on EKG?
sinus arrest leading to 60-80 beats/min, no P waves or inverted P waves after QRS
How is junctional escape rhythm recognized on EKG?
40-60 beat/min, no P waves or inverted P waves after QRS
How is ventricular escape rhythm recognized on EKG?
20-40 beats/min, no P waves
What drugs should be avoided with ectopic ventricular beats?
SNS stimulants or K wasting drugs
What is barlow syndrome?
Mitral valve prolapse producing multifocal PVC’s
_ is a good diagnostic tool for atrial flutter which can be best seen in leads 2, 3 and avF
Vagal maneuver (valsalva)