The Normal Electrocardiogram

What causes the P wave in a normal electrocardiogram (ECG)?

The QRS complex in a normal electrocardiogram (ECG) is caused by which electrical event in the heart?

Which electrical event is responsible for generating the T wave in a normal electrocardiogram (ECG)?

In a normal electrocardiogram (ECG), which components are classified as depolarization waves?

What is the normal duration of the monophasic action potential of ventricular muscle?

In a simultaneous recording of a monophasic action potential from a ventricular muscle fiber and an ECG, when do the QRS waves typically appear?

Under what condition is no potential recorded in the ECG when measuring ventricular electrical activity?

Why is the atrial T wave, representing atrial repolarization, seldom observed on a normal ECG?

What is the approximate duration of the ventricular repolarization process, which corresponds to the T wave?

In a standard ECG display, what electrical potential is represented by 10 small horizontal line divisions in the vertical direction?

On a standard ECG running at 25 millimeters per second, what time duration does each 5-millimeter segment, indicated by dark vertical lines, represent?

When ECGs are recorded from electrodes on the two arms or on one arm and one leg, what is the usual voltage of the QRS complex from the top of the R wave to the bottom of the S wave?

What is the normal voltage range for the P wave in a standard electrocardiogram?

According to the text, what is the normal voltage range for the T wave when recorded from limb leads?

What is the normal duration of the P-Q interval in an electrocardiogram?

What does the P-Q interval on an electrocardiogram represent?

What is the ordinary duration of the Q-T interval in a normal electrocardiogram?

The Q-T interval on an ECG corresponds to what physiological event?

What is the normal time interval between two successive QRS complexes in an adult, corresponding to a heart rate of 72 beats per minute?

How is the heart rate determined from an electrocardiogram?

During most of the cycle of ventricular depolarization in a normal heart, in which primary direction does the current flow?

What does the term 'bipolar' mean in the context of standard bipolar limb leads?

For recording limb lead I, how are the terminals of the electrocardiograph connected?

To record limb lead II, how are the negative and positive terminals of the electrocardiograph connected to the patient's limbs?

What are the correct electrical connections for recording limb lead III?

What does Einthoven's law state regarding the potentials recorded in the three standard bipolar limb leads?

If at a given moment the potential on the right arm is negative 0.2 millivolts, the left arm is positive 0.3 millivolts, and the left leg is positive 1.0 millivolts, what will the potential recorded in lead II be, according to Einthoven's law?

When recording precordial (chest) leads, how is the negative electrode, known as the indifferent electrode, connected?

In a normal heart, why are the QRS recordings in precordial leads V1 and V2 mainly negative?

Why are the QRS complexes in precordial leads V4, V5, and V6 mainly positive in a healthy heart?

What is the setup for an augmented limb lead recording?

What is the primary reason the aVR lead recording is inverted in a normal ECG?

What is the typical speed at which a standard ECG is run?

On a standard ECG, what is the time value represented by the smallest interval marked by thin vertical lines?

How does the voltage of a QRS complex recorded on a limb lead ECG compare to the voltage of a monophasic action potential recorded directly at the heart muscle membrane?

Approximately how long after the termination of the P wave does atrial repolarization occur?

What is a primary reason that the voltage of the T wave is considerably less than the voltage of the QRS complex?

During depolarization of a cardiac muscle fiber, what change occurs to the electrical charge on the outside of the fiber membrane?

Immediately before ventricular depolarization is complete, the average direction of current flow reverses for about 0.01 second. Why does this occur?

In the context of precordial leads, what is the 'indifferent electrode' or 'Wilson central terminal'?

When recording the augmented limb lead aVF, which limb is connected to the positive terminal of the electrocardiograph?

What is the term for extending ECG assessment to record cardiac electrical events while the patient is ambulating during normal daily activities?

What is the typical use for a continuous recorder like a Holter monitor in ambulatory electrocardiography?

What is the function of an implantable loop recorder?

The QRS complex is often composed of three separate waves. What do these waves (Q, R, and S) collectively represent?

What is the general term for the electrical potential differences that can be recorded from a partially depolarized mass of syncytial cardiac muscle?

Besides the P wave and QRS complex, are there any other depolarization waves in a standard ECG?

If the P-Q interval is measured to be 0.16 second and the Q wave is absent, what is the P-R interval?

What happens to the potential recorded by an ECG when a cardiac muscle fiber has completely repolarized?

What is the primary reason that it does not matter greatly which bipolar limb lead is recorded when one wants to diagnose different cardiac arrhythmias?