Arrhythmia Recognition, Anatomy, and Physiology Flashcards

Which of the following rhythms may be characterized by regular P-P and regular R-R intervals occurring at different rates?

Answer: Complete heart block

Explanation: In a complete heart block, there is a dissociation between the atrial and ventricular rates, resulting in regular P-P intervals (atrial rate) and regular R-R intervals (ventricular rate), but occurring at different rates due to the interruption in the electrical conduction between the atria and ventricles.

If a dual chamber pacemaker ventricular lead senses a non-cardiac signal, what is MOST LIKELY to occur?

Answer: Failure to ventricular pace

Explanation: If a dual chamber pacemaker's ventricular lead senses a non-cardiac signal, it may incorrectly interpret it as a heartbeat, leading to a failure to deliver the appropriate pacing stimulus to the ventricle. This can result in a failure to ventricular pace, meaning the ventricle does not receive the necessary pacing impulse, potentially leading to symptoms related to bradycardia or other rhythm disturbances.

What cardiac rhythm is shown in this presenting rhythm strip from a trans telephonic pacemaker check?

Answer: Paced atrial rhythm

Explanation: In a paced atrial rhythm, regular spikes are seen representing the pacing of the atria by the pacemaker. This is characterized by consistent atrial pacing spikes followed by atrial depolarization.

A characteristic of a third-degree AVB is:

Answer: The conduction of the atrial impulse failing to reach the ventricle

Explanation: In third-degree atrioventricular block (AVB), also known as complete heart block, the atrial electrical impulses fail to conduct to the ventricles. This results in an independent rhythm between the atria and ventricles, leading to the characteristic dissociation between P waves and QRS complexes on an ECG.

A PVC that occurs during the relative refractory period is referred to as:

Answer: R-on-T

Explanation: A PVC (Premature Ventricular Contraction) that occurs during the relative refractory period, where the ventricles are still in a vulnerable state, is referred to as the R-on-T phenomenon. It's called so because the PVC occurs on the peak of the T wave of the preceding beat, potentially leading to dangerous arrhythmias like ventricular tachycardia or ventricular fibrillation.

Which of these rates could be considered a junctional tachycardia?

Answer: 130 bpm

Explanation: Junctional tachycardia is a type of arrhythmia where the heart rate is typically between 100 to 140 beats per minute (bpm), with rates exceeding the normal range for the junctional pacemaker. Therefore, a rate of 130 bpm could be considered within the range of junctional tachycardia.

A regular rhythm with a narrow QRS complex with no notes P wave and rates between 40-6- bpm is known as:

Answer: Junctional escape rhythm

Explanation: A junctional escape rhythm is characterized by a regular rhythm, narrow QRS complexes, and rates typically between 40 to 60 bpm. In this rhythm, the electrical impulses originate from the atrioventricular junction (AV node or His-Purkinje system) as a backup pacemaker when the normal pacemaker fails to function.

Atrial flutter is best described as a rapid atrial depolarization of:

Answer: A single reentry focus

Explanation: Atrial flutter is characterized by a rapid, regular atrial depolarization originating from a single reentrant circuit within the atria. This single reentry focus leads to the characteristic sawtooth pattern on an ECG.

Which valves prevent the back flow of blood from the aorta and pulmonary arteries into the ventricles during diastole?

Answer: Semilunar

Explanation: Semilunar valves, including the aortic and pulmonary valves, prevent the back flow of blood from the aorta and pulmonary arteries into the ventricles during diastole by closing when the ventricles relax, thus maintaining one-way blood flow through the heart.

The conduction system terminates with the:

Answer: Purkinje Network

Explanation: The conduction system of the heart terminates with the Purkinje network, which consists of specialized fibers responsible for rapidly conducting the electrical impulses to the myocardium, triggering ventricular contraction.

Which cardiac chamber contains MOST of the muscle mass of the heart?

Answer: Left ventricle

Explanation: The left ventricle contains the most muscle mass of the heart because it is responsible for pumping oxygenated blood throughout the entire body, requiring significant muscular force.