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Correct CHOICE is (a) Apexcardiograph

To explain I WOULD say: An apexcardiograph records the chest-wall movements over the APEX of the heart. These movements are in the FORM of vibrations having a frequency RANGE of 0.1 to about 20 Hz.

Right answer is (C) PCG

Easy explanation: The phonocardiograph is an instrument used for RECORDING the sounds connected with the pumping action of the heart. These sounds provide an indication of the heart rate and its rhythmicity. They also give USEFUL INFORMATION regarding the effectiveness of blood pumping and VALVE action.

Right answer is (a) Baseline wander

The BEST I can explain: AZTEC contains digital logic, which is able to detect base line wander. Also, the sum of ABSOLUTE VALUES of all slopes is used for noise DETECTION, but sudden bursts of muscle artifact or an excursion from baseline are distinguishable from an ECG wave only if the condition PERSISTS.

The correct OPTION is (B) 0.05 to 150 Hz

Explanation: Although the electric field GENERATED by the heart can be best characterized by vector quantities, it is generally convenient to DIRECTLY measure only scalar quantities, i.e. a voltage difference of mV order between the given points of the body. The diagnostically useful frequency range is usually accepted as 0.05 to 150 Hz (GOLDEN et al 1973).

Correct choice is (b) ECG

To elaborate: ECG provides VALUABLE information about a wide RANGE of cardiac disorders such as the presence of an inactive part (INFARCTION) or an enlargement (cardiac HYPERTROPHY) of the heart muscle.

The CORRECT option is (a) P WAVE

Explanation: P wave detection is USED to DIFFERENTIATE between a Sinus RHYTHM and a SupraventricularRhythm.

The correct ANSWER is (a) True

To ELABORATE: Yes, EEG signals picked up by the surface electrodes are usually SMALL as compared with the ECG signals. They may be several hundred microvolts, but 50 microvolts peak-to-peak is the most TYPICAL.

The correct CHOICE is (c) 50

Easiest explanation: EEG machines have a notch filter sharply tuned at 50 Hz so as to eliminate mains frequency interference. These however have the undesirable property of ‘ringing’ i.e. they produce a damped oscillatory response to a square wave CALIBRATION waveform or a muscle POTENTIAL. The use of notch filters should preferably be restricted to exceptional circumstances when all other METHODS of eliminating interference have been found to be ineffective.

Correct option is (a) True

For explanation I would SAY: The contribution from each ECG lead to the QRS DETECTION signal is proportional to its measured quality based on the waveform amplitude, and the amount of muscle and baseline noise. The weighting factors are updated every 200 ms to ALLOW for a quick adaption to signal quality changes.

Right answer is (b) HIGH pass FILTER

Easy explanation: High pass filter amplifies signal above a certain frequency. LOW pass filter amplifies signals below a certain frequency. Band pass filter amplifies frequencies within a certain band. Band stop filter amplifies all the frequencies EXCEPT those in a certain band.

Correct choice is (b) neuromuscular function

To explain I WOULD say: The instrument is useful for making a study of several aspects of neuromuscular function, neuromuscular condition, EXTENT of NERVE lesion, reflex responses, etc.

Correct option is (b) Position of electrode

Explanation: The amplitude of the EMG signals depends upon various factors, e.g. the type and placement of ELECTRODES used and the degree of muscular exertions. The needle electrode in contact with a SINGLE muscle fibre will pick up spike type voltages WHEREAS a surface electrode PICKS up many overlapping spikes and therefore produces an average voltage effect.

Right answer is (B) 30 to 100 Hz

To elaborate: The closure of the mitral and tricuspid VALVE contributes LARGELY to the first sound. The FREQUENCIES of these sounds are GENERALLY in the range of 30 to 100 Hz and the duration is between 50 to 100 ms.

Right CHOICE is (a) True

Explanation: True, electrocardiographs are used in catheterization LABORATORIES, coronary care units and for routine DIAGNOSTIC applications in CARDIOLOGY.

Correct CHOICE is (d) Kassal et al

Explanation: A new acoustic sensor, which enhances the audibility of heart SOUNDS and enables recording of quantitative acoustic spectral DATA is DESCRIBED by Kassal et al, 1994. This device is a polymer based adherent differential-output sensor, which is only 1.0 mm thick.

Correct answer is (b) FALSE

For explanation: False, The transducer required for recording these movements in apexcardiograph is similar to that employed for a phonocardiograph (PCG) but which has a FREQUENCY response much below the audio range. It can be an aircoupled microphone or a contact microphone. They are further categorized into crystal type or dynamic type based on their principle of operation. The crystal microphone contains a wafer of piezo-electric material, which generates potentials when subjected to mechanical stresses due to heart sounds. The dynamic type microphone consists of a moving coil having a FIXED magnetic core INSIDE it. The coil moves with the heart sounds and produces a voltage because of its INTERACTION with the magnetic flux.

Right choice is (B) Sensing device

Explanation: In BCG, the patient is made to lie on a table top which is spring suspended or otherwise mounted to respond to very slight MOVEMENTS along the head axis. Sensing devices are mounted on the table to CONVERT these movements into corresponding electrical signals. The sensors usually are piezo-electric crystals, resistive elements or permanent magnets, moving with respect to fixed COILS.

The correct choice is (b) ground electrode

Best EXPLANATION: A ground electrode is necessary for providing a common reference for measurement. These electrodes pick up the potentials produced by the contracting muscle fibres. The signal can then be amplified and displayed on the SCREEN of a cathode ray TUBE. It is also applied to an AUDIO amplifier CONNECTED to a loudspeaker.

The correct option is (d) above 100 Hz

Easiest EXPLANATION: The second sound is higher in pitch than the first, with frequencies above 100 Hz and the duration between 25 to 50 ms. This sound is produced by the slight back FLOW of blood into the heart before the valves close and then by the closure of the valves in the ARTERIES leading out of the ventricles. This means that it occurs at the closure of aortic and the pulmonic valves.

Right option is (C) 0.1 to 70 Hz

Explanation: The typical frequency range of standard EEG machines is from 0.1 Hz to 70 Hz, THOUGH newer machines allow the DETECTION and filtering of frequencies up to several hundred Hertz. This may be of importance in some INTRACRANIAL recordings.

Correct answer is (b) Amplitude ZONE Time EPOCH Coding

To elaborate: Cox and Nolle suggested AZTEC (Amplitude-Zone-Time-Epoch-Coding) a pre-processing program for real-time ECG RHYTHM analysis at an approximate data reduction rate of 10:1.

The correct choice is (C) Frequency domain

To EXPLAIN: Several ECG compression techniques have been proposed in the last few decades. These techniques can be CLASSIFIED into three major categories: i) TIME domain ii) Transformation domain iii) Parameter Extraction.

Right ANSWER is (c) Amplitude Measurements

Easy explanation: Electrocardiograms are almost invariably RECORDED on graph paper with horizontal and vertical lines at 1 mm intervals with a thicker line at 5 mm intervals. Time measurements and heart rate measurements are MADE horizontally on the electrocardiogram. Amplitude measurements are made VERTICALLY in millivolts.The sensitivity of an ELECTROCARDIOGRAPH is typically set at 10 mm/mV.

Right option is (d) 32X

The explanation is: To be accepted as a P WAVE, it must be at LEAST 1/32 of the R wave height and the P-R INTERVAL must be CLOSE to the average P-R interval.

So, P=R/32

If P=X then, X = R/32

R = 32X.

Correct choice is (b) For Stabilizing effect

Easiest explanation: The preamplifier is usually a three or four stage DIFFERENTIAL AMPLIFIER having a sufficiently LARGE negative CURRENT FEEDBACK, from the end stage to the first stage, which gives a stabilizing effect.

Right answer is (a) Power Amplifier

Best explanation: The preamplifier is usually a three or four stage differential amplifier having a SUFFICIENTLY LARGE negative current feedback, from the end stage to the FIRST stage, which GIVES a stabilizing effect. The amplified output signal is picked up single-ended and is given to the power amplifier. The power amplifier is GENERALLY of the push-pull differentical type.

Right option is (d) Electro-retinography

For explanation: It is found that an electrical potential EXISTS between the CORNEA and the BACK of the eye. This potential CHANGES when the eye is illuminated. The process of recording the change in potential when LIGHT falls on the eye is called electroretinography.

Correct OPTION is (C) Al-Ajlouni

The explanation is: Various Wavelet-based ECG compression TECHNIQUES have been found to give lower distortion for the same compression ratios. A new discrete wavelet transform has been SUGGESTED by Al-Ajlouni for compression ECG signals with minimum LOSS of diagnostic information.

Right choice is (C) Detection of VENTRICULAR fibrillation

Easiest explanation: The detection of ventricular fibrillation is BASED on TWO criteria:

i)The frequency of the sinusoid

ii) The filter leakage fraction.

The CORRECT choice is (b) 12 R-R intervals

To explain: Normally, the heart rate is COMPUTED by averaging the most recent 12 R-R intervals. This AVERAGE gives a stable ESTIMATE of the heart rate even when the rhythm is irregular.

Right choice is (b) bone

Easiest explanation: Hard tissue, MINERALIZED tissue, and calcified tissue are often used as synonyms for bone when describing the structure and properties of bone or tooth. Biological soft tissues are nonlinear, anisotropic, fibrous composites, and a detailed description of their behavior is the subject of active research. One can separate these tissues based on their MODE of loading: cartilage is generally loaded in compression; tendons and ligaments are loaded in tension, and muscles GENERATE active tension.

Right answer is (a) 10 mm/mV

To explain: Electrocardiograms are ALMOST invariably RECORDED on graph paper with horizontal and vertical lines at 1 mm intervals with a THICKER line at 5 mm intervals. Time measurements and heart rate measurements are made HORIZONTALLY on the electrocardiogram. Amplitude measurements are made vertically in millivolts. The sensitivity of an ELECTROCARDIOGRAPH is typically set at 10 mm/mV.

Right option is (C) ECG(Electrocardiograph)

Explanation: The electrocardiograph (ECG) is an instrument, which records the electrical ACTIVITY of the heart. Electrical signals from the heart characteristically precede the normal mechanical FUNCTION and monitoring of these signals has GREAT clinical significance.

The CORRECT answer is (C) three

The best explanation: The major information that it PROVIDES is the direction of depolarization and repolarization of the atria and the VENTRICLES. Each vectorcardiogram exhibits three loops, showing the VECTOR orientation of the P wave, the QRSaxis and the T wave.

The correct answer is (c) PVDF(Poly-vinylidene fluoride)

The explanation is: Its principle sensing components is PVDF (poly-vinylidene fluoride), which is a piezo-electric polymer. It PRODUCES CHARGES of equal magnitude and OPPOSITE polarity on opposite surfaces when a MECHANICAL strain is imposed on the material.

Right option is (b) False

Explanation: Several TYPES of electrodes may be used to RECORD EEG. These INCLUDE: Peel and Stick electrodes, Silver PLATED cup electrodes and Needle electrodes. EEG electrodes are SMALLER in size than ECG electrodes.

The correct OPTION is (d) connective and soft tissue

Explanation: Connective and soft tissue says BLOOD is soft and connective tissue.Soft tissues include tendon, ligament, blood vessels etc. HARD tissues include BONES.

The correct choice is (b) Electro-oculography

The best explanation: Electro-oculography is the recording of the bio-potentials GENERATED by the MOVEMENT of the EYEBALL. The EOG potentials are picked up by small surface electrodes placed on the skin NEAR the eye.

Correct ANSWER is (d) EMG

The explanation is: EMG measurements are also important for the myoelectric CONTROL of prosthetic devices (artificial limbs). This use involves PICKING up EMG signals from the muscles at the terminated nerve endings of the REMAINING limb and using the signals to activate a mechanical arm. This is the most demanding REQUIREMENT from an EMG since it depends on the working of the prosthetic device.

The correct option is (a) True

To ELABORATE: True, ERG potentials can be recorded with a PAIR of electrodes. One of the electrodes is mounted on a contact lens and is in DIRECT contact with the cornea and the other electrode is placed on the skin adjacent to the outer corner of the eye as it is found that an electrical POTENTIAL exists between the cornea and the back of the eye. This potential changes when the eye is illuminated. A reference electrode MAY be placed on the forehead.

Correct choice is (a) VCG

Explanation: Vectorcardiography is the technique of analyzing the electrical activity of the heart by obtaining ECG’s ALONG THREE axes at right angles to one another and DISPLAYING any two of these ECGS as a vector display on an X-Y oscilloscope.

Correct choice is (c) 50 uV/cm

Explanation: A CALIBRATING SIGNAL is used for CONTROLLING and documenting the SENSITIVITY of the amplifier channels. This supplies a voltage step of adequate amplitude to the INPUT of the channels. A typical value of the calibration signal is 50 uV/cm.

Right answer is (c) It occurs within a 200 ms interval

Explanation: AT wave following a QRS is also searched. A wave is CONSIDERED as a T wave if (i) it occurs within a 200 ms interval, (ii) its peak occurred within 1/3rd the R–R interval +80 ms or within 240 ms whichever is greater, following the preceding R wave, and (III) its HEIGHT is half the height of a NORMAL R wave.

Right option is (b) Electrode JELLY

Best explanation: Electrode jelly or PASTE is USED to IMPROVE the electrical contact. If the electrodes are intended to be used under the skin of the scalp, NEEDLE electrodes are used. They offer the advantage of reducing movement artefacts.

The correct answer is (d) Combine discrete cosine and Fourier TRANSFORM

The explanation: In the transformation domain category, ECG SAMPLES are transformed to another domain. Examples INCLUDE Fourier descriptors, discrete cosine transform, wavelet transform and combine discrete cosine and wavelet transform.