Nursing Management of Common Cardiac Dysrhythmias Flashcards

Vocabulary practice flashcards covering cardiac conduction, EKG components, sinus rhythms, atrial dysrhythmias, AV blocks, ventricular dysrhythmias, antiarrhythmic medications, and cardiac pacing interventions.

Sinoatrial (SA) Node

Pacemaker of the heart located in the right atrium that generates impulses at an intrinsic rate of 60-100 BPM.

The 1500 Method

The most accurate heart rate calculation method for regular rhythms, performed by counting the small boxes between two QRS complexes and dividing that number into 1500.

P Wave

The EKG waveform representing atrial depolarization.

PR Interval (PRI)

The measurement from the beginning of the P wave to the beginning of the QRS complex, normally lasting $< 0.20\,\text{seconds}$.

QRS Complex

The EKG waveform representing ventricular depolarization, with a normal duration of $< 0.12\,\text{seconds}$.

T Wave

The EKG waveform representing ventricular repolarization.

Normal Sinus Rhythm (NSR)

A regular cardiac rhythm originating from the SA node at a rate of 60-100 BPM, characterized by uniform P waves, a normal PR interval ($< 0.20\,\text{seconds}$), and a normal QRS complex ($\le 0.12\,\text{seconds}$).

Sinus Bradycardia

A sinus rhythm where the SA node fires at a rate of $< 60\,\text{BPM}$, meeting all other normal sinus rhythm criteria.

Atropine

An anticholinergic medication that blocks the vagus nerve to increase heart rate and inhibits acetylcholine, used to treat symptomatic sinus bradycardia.

Sinus Tachycardia

A sinus rhythm with a discharge rate from the SA node exceeding 100 BPM due to vagal inhibition, while meeting all other normal sinus rhythm criteria.

Supraventricular Tachycardia (SVT)

A rapid dysrhythmia originating above the ventricles at a rate of 150-250 BPM, featuring abnormal or hidden P waves and a normal QRS duration ($0.06-0.12\,\text{seconds}$).

Valsalva Maneuver

A vagal maneuver, such as bearing down or exhaling against resistance, that stimulates the vagus nerve in the parasympathetic nervous system to induce reflex bradycardia and slow the heart rate.

Adenosine

A Class V antiarrhythmic medication with a 3-second half-life that slows conduction through the AV node, administered as a rapid IV push (1-2 seconds) followed by a 20 mL normal saline flush.

Digoxin

A cardiac glycoside that acts as a positive inotrope, negative chronotrope, and negative dromotrope to improve cardiac output and slow AV node conduction, reversed by Digibind in toxicity.

Amiodarone

A potassium channel blocker with alpha- and beta-adrenergic blocking effects that delays repolarization, prolongs PR and QT intervals, and widens QRS to suppress atrial and ventricular dysrhythmias.

Synchronized Cardioversion

The delivery of a timed electrical shock programmed to coincide with the R wave (typically starting at 50-100 joules) to convert tachycardias with a pulse to sinus rhythm.

Defibrillation

An unsynchronized electrical shock at high energy levels (200-360 joules) used to treat life-threatening pulseless rhythms such as pulseless Ventricular Tachycardia and Ventricular Fibrillation.

Atrial Fibrillation (A-fib)

A dysrhythmia caused by total disorganization of atrial electrical activity from multiple ectopic foci, featuring an atrial rate over 400 BPM, fibrillation waves, loss of atrial kick, and an irregular ventricular response.

Atrial Flutter

An atrial tachydysrhythmia originating from a single ectopic focus in a reentry loop, identified by recurring, regular, sawtooth-shaped flutter waves and an atrial rate of 250-400 BPM.

Asystole

The complete lack of cardiac electrical activity resulting in a flat line on the EKG, requiring immediate high-quality CPR and Epinephrine administration.

Pulseless Electrical Activity (PEA)

A state of cardiac arrest in which the EKG displays organized electrical activity on the monitor but no mechanical ventricular contraction or palpable pulse is present.

5 H's and 5 T's

The mnemonic for reversible causes of PEA and Asystole: Hypovolemia, Hypoxia, Hydrogen ion (acidosis), Hypo/Hyperkalemia, Hypothermia, Tension pneumothorax, Toxins/Tablets, Tamponade, Pulmonary thrombosis, and Coronary thrombosis.

Ventricular Tachycardia (VT)

A ventricular rhythm with a rate of 150-250 BPM and wide, distorted QRS complexes ($> 0.12\,\text{seconds}$), occurring either with a pulse or pulseless.

Torsades de Pointes

A form of polymorphic Ventricular Tachycardia where QRS complexes twist around the isoelectric line, commonly treated with intravenous magnesium.

Lidocaine

An antiarrhythmic and local anesthetic that reduces myocardial irritability by decreasing ventricular depolarization, automaticity, and excitability.

Epinephrine

A catecholamine with alpha- and beta-adrenergic effects that increases heart rate, contractility, and peripheral vasoconstriction, given at 1 mg IVP every 3-5 minutes during cardiac arrest.

Ventricular Fibrillation (V-fib)

A lethal cardiac rhythm characterized by chaotic electrical activity without ventricular contractions, yielding zero cardiac output and absent P waves, PR intervals, and QRS complexes.

First-Degree AV Block

An AV conduction delay resulting in a prolonged PR interval constant at $> 0.20\,\text{seconds}$, where every P wave is followed by a normal QRS complex.

Second-Degree Type I AV Block (Wenckebach)

An AV conduction block where the PR interval progressively lengthens with each beat until a QRS complex is completely dropped, after which the cycle repeats.

Second-Degree Type II AV Block (Mobitz II)

An AV block characterized by constant PR intervals (normal or prolonged) with intermittent, unannounced dropped QRS complexes due to non-conducted P waves.

Third-Degree AV Block (Complete Heart Block)

A complete AV block with complete dissociation between atria and ventricles, where P waves and QRS complexes occur independently at their own intrinsic rates.

Artifact

EKG baseline distortion caused by non-cardiac interference such as patient movement, shivering, loose or dried leads, or external electrical appliances.

Transcutaneous Pacing

An emergency temporary pacing method that delivers electrical current to the heart via external pads attached to the patient's anterior chest and back.

Transvenous Pacing

A temporary pacing technique where a lead wire is inserted through the internal jugular or subclavian vein directly into the right ventricle and connected to an external generator.

Pacemaker Failure to Capture

A pacemaker malfunction in which the electrical output is insufficient to depolarize the myocardium, represented on EKG as a pacemaker spike not followed by a P wave or QRS complex.

Pacemaker Failure to Sense

A pacemaker malfunction occurring when the pacemaker fails to recognize spontaneous intrinsic electrical activity and delivers inappropriate electrical stimuli.

Implantable Cardioverter-Defibrillator (ICD)

An implanted electronic device capable of monitoring cardiac rhythms and delivering automatic pacing or defibrillation shocks to treat life-threatening ventricular dysrhythmias.