Explanation:
In standard calibration ECG graph paper, each large box represents 0.5 millivolts (mV) of electrical activity. So, a deflection of the tracing upward or downward by one large box from the baseline represents a change of 0.5 millivolts in electrical potential.
Explanation:
Each small box represents 0.04 seconds, and since there are five small boxes between the flutter waves, the total time for five small boxes is 0.20 seconds. To convert this to beats per minute (BPM), you invert the time interval (1/0.20) which equals 5, then multiply by 60 to convert seconds to minutes, resulting in 300 beats per minute (BPM).
Explanation:
In a normal sinus rhythm, the sinus node fires at a rate of 60 to 100 times per minute, which represents the normal range for heart rate in adults.
Explanation:
If the electrocardiograph is not properly grounded, it can pick up interference from the electrical system, including the 60-cycle electrical interference, which can distort the ECG signal and lead to inaccurate interpretations.
Explanation:
The first negative deflection noted in the QRS complex is the Q wave. It represents the initial depolarization of the interventricular septum.
Explanation:
To calculate the ventricular rate when the R-R intervals are regular, divide 300 by the number of large boxes between two consecutive R waves on the ECG strip. This method provides an estimate of the heart rate in beats per minute (bpm).
Explanation:
To measure the duration of the QRS complex accurately, it's typically measured from the beginning of the Q wave to the end of the S wave, representing the total time for ventricular depolarization. This method provides a consistent and reliable measurement of the QRS complex duration.
Explanation:
The P wave on an electrocardiogram represents the electrical impulse spreading through the atria, signaling atrial depolarization, which initiates atrial contraction.
Explanation:
Lead II on an ECG strip typically shows both atrial and ventricular activity. It is commonly used to monitor both atrial and ventricular sensing, allowing for the assessment of both chambers' electrical activity.
Explanation:
Regularly assessing the regularity of the rhythm, followed by determining the rate, and then evaluating the P wave, PR interval, and QRS complex can be an effective sequence for ECG analysis. This approach allows for a systematic evaluation of both rhythm and conduction abnormalities, ensuring comprehensive interpretation.
Explanation:
The T wave on an ECG represents ventricular repolarization, which is the phase of the cardiac cycle when the ventricles reset their electrical state in preparation for the next contraction.
