What criteria should the nurse use to determine normal sinus rhythm for a client on a cardiac monitor? Select all that apply.

Choice A rationale:

Ventricular Fibrillation (VF) is a chaotic, disorganized rhythm that arises from the ventricles of the heart. It is characterized by the absence of distinct QRS complexes, P waves, and T waves on the ECG. Instead, the ECG shows a rapid, irregular pattern of waveforms that vary in amplitude and frequency. This indicates that the electrical activity in the ventricles is completely disorganized, preventing effective contraction of the heart muscle and leading to a lack of cardiac output. VF is a lifethreatening emergency that requires immediate defibrillation to restore a normal heart rhythm.

Key features of VF on ECG:

Absence of distinct QRS complexes

Absence of P waves

Absence of T waves

Rapid, irregular pattern of waveforms Varying amplitude and frequency of waveforms Pathophysiology of VF:

VF occurs when multiple ectopic foci in the ventricles fire rapidly and asynchronously, leading to disorganized electrical activity. This can be caused by a variety of factors, including:

Acute myocardial infarction (heart attack)

Myocardial ischemia (reduced blood flow to the heart muscle)

Electrolyte imbalances (such as low potassium or magnesium)

Electrical shock

Certain medications

Drug overdoses

Clinical manifestations of VF:

Loss of consciousness

Absence of pulse

Apnea (absence of breathing)

Cardiac arrest

Treatment of VF:

Immediate defibrillation

CPR

Advanced cardiac life support (ACLS) medications Choice B rationale:

Atrial Flutter is a rapid, regular atrial rhythm that is characterized by a sawtooth pattern on the ECG. It is caused by a reentrant circuit in the atria, which leads to a rapid firing of atrial impulses. Atrial flutter can sometimes be difficult to distinguish from VF on ECG, but it is important to differentiate between the two rhythms because the treatment is different.

Choice C rationale:

Ventricular Tachycardia (VT) is a rapid, regular ventricular rhythm that is characterized by wide QRS complexes on the ECG. It is caused by an abnormal focus of electrical activity in the ventricles. VT can be life-threatening, but it is not as immediately life-threatening as VF.

Choice D rationale:

Asystole is the absence of any electrical activity in the heart. It is a form of cardiac arrest and is characterized by a flat line on the ECG. Asystole is a life-threatening emergency that requires immediate CPR and advanced cardiac life support (ACLS) measures.

Choice A rationale:

Atrial flutter is characterized by a rapid, regular atrial rate of around 250-350 beats per minute with a "sawtooth" pattern on the ECG. It typically presents with a 2:1 or 4:1 atrioventricular (AV) block, resulting in a ventricular rate of around 150 beats per minute or less. However, the rhythm in question does not exhibit the characteristic sawtooth pattern or rapid atrial rate of atrial flutter.

Choice B rationale:

Normal Sinus Rhythm (NSR) is the typical heart rhythm in healthy individuals. It is characterized by the following features on the ECG:

Regular rhythm: The R-R intervals (the distance between consecutive QRS complexes) are relatively constant.

Rate: The heart rate is typically between 60-100 beats per minute.

P waves: Each QRS complex is preceded by a P wave, representing atrial depolarization.

PR interval: The PR interval (the distance between the P wave and the QRS complex) is normal, measuring between 0.12-0.20 seconds.

QRS complex: The QRS complex is narrow (less than 0.12 seconds), representing normal ventricular depolarization.

ST segment: The ST segment is usually isoelectric (flat).

T wave: The T wave is typically upright, representing ventricular repolarization.

Choice C rationale:

Atrial Fibrillation (AFib) is characterized by a rapid, irregular atrial rate (usually over 400 beats per minute) with no discernible P waves on the ECG. The ventricular rate is also irregular, often ranging between 100-175 beats per minute.

However, the rhythm in question does not exhibit the characteristic irregular pattern of AFib.

Choice D rationale:

Ventricular Tachycardia (VT) is a rapid heart rhythm originating from the ventricles. It is characterized by a wide QRS complex (greater than 0.12 seconds) and a rate typically over 100 beats per minute. However, the rhythm in question does not exhibit the wide QRS complex characteristic of VT.