Basic Electrophysiology Quiz Questions And Answers

A tall peaked "T" wave on an electrocardiogram (ECG) is often seen in hyperkalemia, which is an elevated level of potassium in the blood. Hyperkalemia can cause changes in the electrical activity of the heart, leading to abnormal ECG findings. The high potassium levels affect the repolarization phase of the cardiac action potential, resulting in a tall and peaked T wave. This abnormality is important to recognize as it can be associated with life-threatening arrhythmias. Hypoxia, hypercalcemia, and hypokalemia may cause different ECG findings, but they are not typically associated with a tall peaked T wave.

Left atrial enlargement can be seen as a wide or biphasic P wave on an electrocardiogram (ECG). This is because an enlarged left atrium can cause delayed conduction of electrical impulses, resulting in a prolonged and widened P wave. The biphasic P wave occurs when there is a combination of positive and negative deflections, indicating abnormal electrical activity in the left atrium. Therefore, the presence of a wide or biphasic P wave on an ECG can suggest left atrial enlargement.

A block in the left or right bundle branch can disrupt the normal conduction of electrical signals in the heart. This can lead to a delay or blockage in the activation of the ventricles, resulting in a prolonged QRS width on an electrocardiogram (ECG). The QRS complex represents the depolarization of the ventricles, so any interruption in the normal conduction pathway can cause a delay in this process and subsequently prolong the QRS width.

A first-degree AV block with a prolonged PR interval of .32 seconds is not an immediately life-threatening condition. While it may indicate a conduction abnormality in the heart, it does not require urgent intervention. The other options, such as symptomatic ventricular tachycardia, dissociated rhythm with a slow ventricular response, and symptomatic supraventricular tachycardia, all have the potential for hemodynamic compromise and would necessitate an immediate call to notify the physician.

Atrial 'no capture' refers to the absence of atrial depolarization, indicating that the atrial myocardium has reached its effective refractory period (ERP). This means that the atrial muscle cells are unable to initiate another action potential and contract.

The CS catheter would record the earliest A wave in a patient with left atrial arrhythmia. The CS catheter is positioned in the coronary sinus, which receives blood from the left atrium. Therefore, it would be able to record the earliest atrial contraction (A wave) originating from the left atrium. The other catheters (RVA, His, and HRA) are not specifically positioned to record atrial activity and would not be able to capture the earliest A wave.

Left anterior hemiblock is not a cause of wide complex tachycardia. Wide complex tachycardia refers to a rapid heart rhythm with a widened QRS complex on an electrocardiogram (ECG). The most common cause of wide complex tachycardia is ventricular tachycardia (VT), which originates from the ventricles. Other causes include supraventricular tachycardia (SVT) with aberrancy, which occurs when a rapid heart rhythm from the atria conducts abnormally through the ventricles, and pre-excitation, which is a condition where there is an accessory pathway in the heart. Paced rhythm refers to a rhythm that is artificially generated by a pacemaker. Left anterior hemiblock, on the other hand, is a specific type of heart block that affects the electrical conduction in the left anterior fascicle of the bundle branch system, but it does not cause wide complex tachycardia.

Intracardiac high pass filters are usually set to 30 Hertz (Hz). High pass filters allow frequencies above a certain cutoff point to pass through while attenuating frequencies below that point. In the case of intracardiac high pass filters, they are used to eliminate low-frequency noise and interference, allowing only higher frequency signals related to cardiac activity to be recorded. Setting the filter to 30 Hz ensures that the filter removes any unwanted noise below that frequency, providing a cleaner and more accurate recording of cardiac signals.

The EP lab evaluates the main properties of cardiac muscle, which are conduction velocity and refractory period. Conduction velocity refers to the speed at which electrical impulses travel through the heart, while refractory period refers to the period of time during which the cardiac muscle is unable to respond to another stimulus. These properties are important in assessing the electrical activity and function of the heart, and can help diagnose and manage various cardiac conditions.

Incremental pacing and extra-stimulus pacing are both pacing protocols used to evaluate conduction velocity and refractory periods. Incremental pacing involves gradually increasing the pacing rate to assess the conduction velocity and refractory periods at different levels of stimulation. Extra-stimulus pacing involves delivering an additional stimulus after a normal pacing stimulus to assess the refractory period. Both protocols are commonly used in electrophysiology studies to evaluate the electrical properties of the heart and identify any abnormalities in conduction or refractoriness.

Isuprel, also known as isoproterenol, is a medication that acts as a beta-adrenergic agonist. It stimulates beta receptors in the heart, leading to an increase in heart rate and contractility. By administering Isuprel during an EP (electrophysiology) study, it can alter the automatic tone of the AV (atrioventricular) node. This means that it can affect the electrical conduction between the atria and ventricles, potentially increasing or decreasing the AV node's sensitivity to electrical signals. This alteration in AV node function can be useful in diagnosing and treating certain heart rhythm abnormalities.

Ectopic rhythms occur when there is an abnormal electrical impulse in the heart that originates from a location other than the sinus node. These rhythms can occur in various situations, such as when the normal sinus depolarization is blocked through the AV node, when the rate of ectopic depolarization is higher than the rate of the SA node, or when ischemic myocardium causes spontaneous depolarizations. However, they do not occur when the normal sinus depolarization is accelerated through the AV node. This means that if the electrical impulse follows the normal conduction pathway and is accelerated through the AV node, ectopic rhythms are less likely to occur.

Intracardiac signals are typically filtered to remove unwanted noise and artifacts. The high pass filter is set at 30 to eliminate low-frequency noise and baseline drift, while the low pass filter is set at 500 to remove high-frequency noise and muscle artifact. This combination of filters helps to enhance the clarity and accuracy of the intracardiac signals, allowing for better analysis and interpretation of the data.

The surface ECG has high pass and low pass filters set at 0.5 and 100. High pass filters remove low frequency noise and baseline wander, allowing only the higher frequency components of the ECG signal to pass through. Low pass filters remove high frequency noise and muscle artifact, allowing only the lower frequency components of the ECG signal to pass through. Therefore, a high pass filter of 0.5 and a low pass filter of 100 are used to ensure that the ECG signal is free from noise and artifacts while preserving the important frequency components of the signal.

The correct answer is "After the RVA deflection." This means that the HIS "V" deflection occurs after the RVA deflection.