Cardiac Arrhythmias and Their Electrocardiographic Interpretation

What heart rate is generally defined as tachycardia in an adult?

What is the term for a slow heart rate, usually defined as fewer than 60 beats/min?

The respiratory type of sinus arrhythmia is primarily caused by a spillover of signals from the medullary respiratory center into which adjacent center?

In a sinoatrial (SA) block, what happens to the P waves and what part of the heart typically picks up a new rhythm?

What is the threshold for a P-R interval to be considered prolonged, diagnosing a first-degree incomplete heart block?

Which type of second-degree A-V block is characterized by a progressive prolongation of the P-R interval until a ventricular beat is dropped?

In complete A-V block (third-degree block), what is the relationship between the P waves and the QRS-T complexes?

In Stokes-Adams syndrome, what is the typical rate of the ventricular pacemaker that emerges after overdrive suppression?

What is the condition known as electrical alternans, which results from partial intraventricular block every other heartbeat?

What is the term for a contraction of the heart that occurs before the time that a normal contraction would have been expected?

Which of the following is NOT listed as a possible cause of ectopic foci leading to premature contractions?

What is a 'pulse deficit' in the context of premature contractions?

In an A-V nodal premature contraction, why is the P wave often missing from the electrocardiogram?

What are two characteristic ECG effects of premature ventricular contractions (PVCs)?

Delayed repolarization of ventricular muscle, leading to a long Q-T interval, increases a person's susceptibility to developing which specific type of ventricular arrhythmia?

What is the most frequent underlying cause of paroxysmal tachycardia, according to the text?

In the example of paroxysmal atrial tachycardia shown in Figure 13-13, what feature of the P wave indicates the origin is in the atrium but not near the sinus node?

What are the two primary reasons ventricular tachycardia is considered a serious condition?

If not stopped, how long does it typically take for ventricular fibrillation to become fatal?

What are the three conditions listed that can cause an impulse to continue to travel around a circular pathway (circus movement)?

What happens to the ECG during the first few seconds of ventricular fibrillation, and how does it change afterward?

What is the primary purpose of ventricular defibrillation using a strong electrical current?

Why is atrial fibrillation generally not as immediately lethal as ventricular fibrillation?

During atrial fibrillation, what causes the ventricular rhythm to be very irregular?

How is atrial flutter different from atrial fibrillation in terms of the electrical signal's movement?

What is the typical atrial contraction rate during atrial flutter?

What is cardiac arrest defined as in the text?

Fever causes tachycardia because an increased temperature increases the rate of metabolism of what specific part of the heart's conduction system?

In patients with carotid sinus syndrome, even mild external pressure on the neck can cause extreme bradycardia due to what effect?

In third-degree (complete) A-V block, the ventricular rate is typically less than how many beats per minute?

The delay in the ventricles starting their own beat during Stokes-Adams syndrome, which can last 5 to 30 seconds, is due to a phenomenon called:

In a premature ventricular contraction (PVC), why is the QRS complex considerably prolonged?

What is the term for the pattern of a premature ventricular contraction (PVC) alternating with a normal contraction?

Which of the following is NOT listed as an acquired cause of Long QT Syndrome (LQTS)?

In a normal heart, when the cardiac impulse has traveled through the ventricles, why does it die out instead of continuing in a circus movement?

What are the two changes in cardiac muscle that rapid stimulation, such as with a 60-cycle current, causes that predispose to circus movement?

After successful defibrillation, the heart remains quiescent for 3 to 5 seconds before it begins to beat again. Why does this pause occur?

What is a major risk for patients with atrial fibrillation due to the reduced atrial contractile function?

In atrial fibrillation, what is the minimum time that must typically elapse between one ventricular contraction and the next, due to the properties of the A-V node?

What is the typical ventricular rate driven by the fibrillatory impulses in atrial fibrillation?

In Mobitz type II second-degree block, what is a key feature that distinguishes it from type I?

In a person fainting from vasovagal syncope, what two primary nervous system actions cause the rapid fall in arterial pressure?

What is the typical Q-T interval in a normal ECG?

What is the primary mechanism by which the drug lidocaine can treat ventricular tachycardia?

What does a 2:1 block imply in the context of Mobitz type II second-degree A-V block?

How long can a person typically live with atrial fibrillation, in contrast to the lethality of ventricular fibrillation?

During hand pumping of the heart (CPR), how long have fibrillating hearts been successfully pumped by hand followed by successful defibrillation?

What is the typical voltage of the ECG waves when ventricular fibrillation first begins?

What is the primary reason that a long conductive pathway, such as in a dilated heart, can cause re-entry?

Unconsciousness occurs within how many seconds after the beginning of ventricular fibrillation due to lack of blood flow to the brain?