This set of Biomedical Instrumentation Multiple Choice Questions & Answers (MCQs) focuses on “Phonocardiography (PCG)”.
1. An arrhythmia monitor is basically a ______
a) Sophisticated monitoring system
b) Sophisticated alarm system
c) Patient monitoring system
d) ECG interpretation system
Explanation: An arrhythmia monitor is basically a sophisticated alarm system. It is not an ECG interpretation system. It constantly scans ECG rhythm patterns and issues alarms to events that may be premonitory or life threatening.
2. In arrhythmia monitoring system, it gives alarm light signals whenever the prematured or widened ectopic beats exist up to the rate of ___________
a) 6/min to 10/min
b) 6/min to 12/min
c) 6/min or 10/min
d) 6/min or 12/min
Explanation: In arrhythmia monitoring instrument, it gives alarm light signals whenever the prematured or widened ectopic beat exist up to the rate of 6/min or 12/min.It is one of the operating sequences of the arrhythmia monitoring instrument.
3. In automated arrhythmia monitoring system, which task is performed after the Ventricular fibrillation detection?
a) Rhythm definition
b) Beat labeling
c) Atrial fibrillation detection
d) Noise detection
Explanation: In automated arrhythmia monitoring system, Rhythm definition is performed after the Ventricular fibrillation detection. Rhythm definition is also performed after the beat labeling and atrial fibrillation detection in automated arrhythmia monitoring and analysis system.
4. In signal conditioning, ECG signal is amplified, filtered with 0.05-100 Hz for monitoring purposes and 1-40 Hz for diagnostic purposes.
Explanation: ECG signal is amplified and filtered with 0.05-100 Hz for diagnostic purposes and 1-40 Hz for monitoring purposes in signal conditioning.
5. Which analog-to-digital converter is used in the digitization of ECG signal in signal conditioning?
a) 16 bit
b) 12 bit
c) 32 bit
d) 64 bit
Explanation: In signal conditioning, ECG signal is amplified, filtered and digitized using an 8 or 12 bit analog-to-digital converter with a typical sampling rate of 250 Hz.
6. By using a _________ rather than a _________ the amplitude of low frequency noise as well as the low frequency components of the ECG will be reduced without affecting the QRS.
a) High-pass filter, Band-pass filter
b) Low-pass filter, Band-pass filter
c) Band-pass filter, Low-pass filter
d) Band-pass filter, High-pass filter
Explanation: The maximum of the QRS energy spectrum is in the vicinity of 10 Hz, the filter is designed to have a bandwidth of about 15 Hz with a centre frequency of 10-12 Hz. By using a bandpass filter rather than a low-pass filter, the amplitude of low frequency noise as well as the low frequency components of the ECG will be reduced without affecting the QRS.
7. The steep, large amplitude variation of the QRS complex is the obvious characteristics to use and this is the function of the R wave detector.
Explanation: Arrhythmia monitors require reliable R wave detectors as a prerequisite for subsequent analysis. The steep, large amplitude variation of the QRS complex is the obvious characteristics to use and this is the function of the R wave detector.
8. In the process of the ECG waveform, the detection filter removes _______ and _______
a) Baseline wander, motion noise
b) Muscle artifact, motion noise
c) Low frequency noise, motion noise
d) Baseline wander, muscle artifact
Explanation: The ECG waveform is processed by two digital filters: a detection filter and a classification filter. The detection filter removes low frequency noise (baseline wander) and muscle artifact. P waves and T waves are diminished.
9. How many steps are there in QRS detection?
a) Three steps
b) Two steps
c) Four steps
d) One step
Explanation: QRS detection is now almost universally performed digitally in a two-step process. The ECG is first preprocessed to enhance the QRS complex while suppressing noise, artifact and non-QRS portions of the ECG. The output of the preprocessor stage is subjected to a decision rule that confirms the detection of QRS if the processor output exceeds a threshold.
10. _________ is based on analyzing the shape of the QRS complexes and separating beats into groups or clusters.
a) Timing classification
b) Morphology characterization
c) Beat labeling
d) Noise detection
Explanation: Morphology characterization is based on analyzing the shape of the QRS complexes and separating beats into groups or clusters of similar morphology. Most algorithms for real time arrhythmia analysis maintain no more than 10-20 clusters at a time, order to limit the amount of computation needed to assign a QRS complex to a cluster.
11. When will be R-R interval declared premature?
a) If it is greater than 85% of the predicted interval
b) If it is less than 85% of the predicted interval
c) If it is greater than 75% of the predicted interval
d) If it is less than 75% of the predicted interval
Explanation: In timing classification, the observed R-R interval is compared to an estimate of the expected R-R interval. An R-R interval will be declared premature if it is less than 85% of the predicted interval. Similarly, an R-R interval is long if it is greater than 110% of the predicted value.
12. Which is the final stage in arrhythmia analysis?
a) Beat labeling
c) Rhythm labeling
d) Summary statistics
Explanation: Rhythm labeling is the final stage in arrhythmia analysis. It is based on defined sequences of QRS complexes. The analysis systems are heavily oriented towards detecting ventricular arrhythmias, particularly single PVCs.
13. Ventricular Fibrillation is detected by _________
a) Shape of the QRS complexes
b) Difference of the R-R interval
c) Timing sequence of QRS complexes
d) Frequency domain analysis
Explanation: Ventricular fibrillation is usually detected by frequency domain analysis. The system is characterized as a narrow-band, low frequency signal with energy concentrated in a band around 5-6 Hz. It can be distinguished from noise by appropriately designing band-pass filters.
14. Which techniques are used in a new algorithm proposed by Jen and Hwang to obtain the long term ECG signal feature and extract the meaningful information hiding in the QRS complex?
a) Cepstrum time warping and Dynamic coefficient
b) Cepstrum coefficient and Dynamic time warping
c) QRS detection and Dynamic coefficient
d) QRS detection and Cepstrum time warping
Explanation: Jen and Hwang proposed a new algorithm using cepstrum coefficient and the dynamic time warping techniques to obtain the long term ECG signal feature and extract the meaningful information hiding in the QRS complex. This algorithm may also be used for arrhythmia detection by simply checking the difference of R-R wave intervals through signal feature extraction comparison for a certain period of time.
15. What is the sampling rate of the analog-to-digital converter in digitizing of ECG signal in signal conditioning?
a) 250 Hz
b) 215 Hz
c) 40-100 Hz
d) 200-215 Hz
Explanation: In signal conditioning, ECG signal is amplified, filtered (0.05-100 Hz for diagnostic purposes, 1-40 Hz for monitoring purposes) and digitized using an 8 or 12-bit analog-to-digital converter with a typical sampling rate of 250 Hz.
Sanfoundry Global Education & Learning Series – Biomedical Instrumentation.
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