From Skillstat Flashcards
Characteristics of Normal Sinus Rhythm
- Rate between 60-100
- Narrow QRS
- Upright P waves in II
Characteristics of Sinus Bradycardia?
- Rate under 50 bpm
- Narrow QRS
- Upright P waves in II
- Can be normal baseline for jacked bros.
Characteristics of Sinus Tachycardia?
- Rate above 100, usually under 150
- Narrow QRS
- Often due to sympathetic stimulation, eg pain, fever, increased O2 demand, hypovolemia)
Sinus Arrhythmia?
- Irregular rhythm which fluctuates with inspiration (HR increases) and expiration (HR decreases).
- Narrow QRS and upright P waves
- Common in children
- Usually benign
Sinus Exit Block
- P wave absent
- Mostly flat line in II between complexes
- Pause is equal to a multiple of previous P-P intervals
- P cells in sinus node are firing on schedule; surrounding T (transmission) cells are not.
Sinus Arrest? Aka Sinus Pause?
- Pause in electrical activity that is not equal to a multiple of P-P intervals
- Failure of SA node to fire
- An escape pacemaker such as AV junction will provide impulse
NSR with Premature Atrial Complexes?
- Atria initiate an impulse earlier than expected from SA node
- Narrow QRS
- Flattened, noticed, peaked, or biphasic P waves for the PAC
Characteristics of Supraventricular Tachycardia?
- Rhythm between 170-230/minute.
- Narrow QRS
- Regular, rapid pattern.
- When at rest, narrow QRS tachycardia over 150/minute are most often SVT
Characteristics of atrial fibrillation?
- Chaotic baseline with recognizable QRS complexes.
Characteristics of atrial flutter?
- Sawtooth pattern on the baseline.
- QRS complex every 2nd or fourth impulse (former is 150/min, latter is 75/min).
- Caused by a recently circuit within the atria generating a loop.
Characteristics of Paced Atrial rhythm?
- vertical spike before the P wave
Characteristics of NSR with 1 degree AV Block?
- Prolonged PR interval, greater than .20 seconds.
- Underlying rhythm should be identified, and then “with a first degree AV block” is added to the end.
- Results from a prolonged transmission of electrical impulse through AV junction (AV node and the bundle of His).
What is a Wenckebach block otherwise known as?
Mobitz Type I Second Degree AV Block.
Characteristics of a Second Degree AV Block Type I
- cyclical lengthening of the PR interval followed by a dropped QRS
- QRS complexes yield an irregular rhythm
- Caused by cyclical and progressive delay through AV junction
Characteristics of a Second Degree AV Block Type II?
- One or more QRS complexes are dropped
- PR intervals do not change (fixed PR intervals)
- Caused by an intermittent block below the AV node
- Low cardiac output when there are multiple dropped QRS complexes
- Can progress to 3rd degree AVB.
Characteristics of Second Degree AV Block with 2:1 Conduction?
- Each alternative P wave is NOT paired with a QRS complex.
- PR interval is constant.
- Can be associated with low cardiac output, can progress to a 3rd degree AV block.
Characteristics of a 3rd degree AV block?
- Lonely P waves (P wave without an accompanied QRS complex)
- Chaotic PR intervals.
- Narrow QRS denotes a higher junction at block
- Wide QRS points toward a sub oval block high in bundle branches.
Characteristics of Normal Sinus Rhythm with Premature Junctional Complex?
- Absent or inverted P wave in lead II
- shortened PR interval (less than .12 seconds)
- complex comes early or premature
- Occurs due to an irritable focus within the AV junction.
Characteristics of a Junctional Rhythm?
- Expected rate is 40-60 BPM
- Inverted or absent P waves in lead II.
- Originates from AV junction (between AV node and Bundle of His)
- Absent P wave in junctional rhythm is associated with loss of atrial kick.
What are the characteristics of an accelerated junctional rhythm?
- Rate between 60-100/minute
- Inverted or absent P waves in lead II
- Shortened PR interval
- Narrow QRS complexes
- Due to increased automaticity, increased sympathetic system activity, or ischemia.
Characteristics of a Junctional Tachycardia Rhythm?
- Rate over 100 BPM
- Inverted or absent P waves in lead II
- Shortened PR interval
- QRS complexes that are usually narrow
- One presentation includes an inverted P wave buried in each QRS complex
Characteristics of a wandering pacemaker?
- Rhythm with 3 or more different P wave morphology (absent counts as one).
- Narrow QRS complex
Characteristics of Normal Sinus Rhythm with Premature Ventricular Complex?
- Complex arrives earlier than expected
- Complex is usually wide (.12 seconds or more)
- T wave often points in opposite direction from QRS complex.
- often represent increased ventricular automaticity or re-entry phenomenon.
PVC every second complex is called ventricular bigeminy, every third is ventricular trigeminy
Characteristics of Idioventricular Rhythm?
- Anticipated rate of 20-40/minute
- Occurs when SA and AV nodes are not firing or are slower than the ventricular pacemaker rate.
- Rate is often not sufficient to sustain an adequate cardiac output.
Characteristics of an Accelerated Idioventricular Rhythm?
- Rate between 41-100 beats per minute
- Wide complexes
- Can progress rapidly to asystole or VTach.
- Due to hypoxia or excessive sympathetic stimulation
Characteristics of Ventricular Tachycardia?
- Looks like big waves
- Non-sustained VT (a group of 3 or more PVCs) is a run of VT)
- Can be caused by myocardial ischemia, a PVC landing on a T-wave (R-on-T), cardiac drug toxicity, or electrolyte imbalance.
Characteristics of Ventricular Fibrillation?
- Chaotic electrical activity originating in ventricles
- Coarse VFib has amplitude equal to our greater than 3 mm, Fine VFib is less than 3mm in height, and suggests less electrical energy in myocardium (less opportunity for defibrillation success)
- No cardiac output with this rhythm.
Characteristics of Paced Ventricular Rate?
- Vertical spike before the QRS complex.
What effect do sodium imbalances have on ECG?
Sodium imbalances are not apparent on ECG.
How does Hypercalcemia prevent on an ECG?
- Shortened QT interval
- Widened QRS Complex
- Possible bradycardia
How does hypocalcemia present on an ECG?
- Lengthened QT interval
- Shortened QRS duration
How does Hyperkalemia present on an ECG?
Mild Hyper K - Pointed T-waves, most pronounced in precordial leads. - Patients with LVH may instead display normalization of T-wave inversions in V5, V6, aVL, I) Moderate Hyper K - Exacerbation of Mild Hyper K changes - Widening, lower amplitude P waves - Prolonged PR interval - Possible loss of delta wave in WPW patients - ST elevation in V1-V3 possible Severe HyperK - Exacerbation of previous changes - Widening QRS complex.
ECQ changes due to Hypokalemia?
- T waves become wider with lower amplitudes
- T wave inversion may occur in severe HypoK
- ST segment depression develops
- P wave amplitude, P wave duration, and PR interval may all increase
- U waves emerge, best seen in V2&V3.
How would Hypermagnesmia (rare) present on an ECG?
- May cause atrioventricular and intraventricular conduction disturbances.
- May culminate in 3rd degree AV block or asystole
