ecg is used to measure the rate and regularity of heartbeats , the presence of any damage to the heart , and the effects of drugs or devices used to regulate the heart ( such as a pacemaker ) .
normally , the frequency range of ecg signal is 0.05100  hz and its dynamic range is 110  mv .
the ecg signal as depicted in figure 1 is characterized by five peaks and valleys labeled by the letters p , q , r , s , and t. the performance of ecg analyzing system depends mainly on the accurate and reliable detection of the qrs complex , as well as t- and p - waves .
the p - wave represents the activation of the upper chambers of the heart , the atria , while the qrs complex and t - wave represent the excitation of the ventricles or the lower chamber of the heart .
the detection of the qrs complex is the most important task in automatic ecg signal analysis .
once the qrs complex has been identified a more detailed examination of ecg signal including the heart rate and the st segment can be performed [ 1 , 2 ] .
most of the modern 12-lead ecg monitoring systems are based on einthoven 's triangle , wilson central terminal , and goldberger augmented leads .
the developed ecg device is implemented on the principle of einthoven 's triangle and used lead - ii configuration , as it is known as a monitoring lead , given in figure 2 . based on above facts ,
such efforts are primarily led by the academia but extending deeply into the industries . however , most research efforts have been focusing on either the vital sign monitoring aspect or the ecg feature extraction using standard databases both falling short of expectation .
having analyzed the existing solutions , this work vows to bridge the two major research efforts and bring out a more realizable product to directly benefit the consumers in the medical field .
this research work offers the following contributions to the produced system ; foremost is the portable ecg monitoring platform based on a 3-lead system and a design under the ni daq card ( 6008 ) .
the ecg data was collected through the daq card to the pc / laptop and then transmitted to the end user ( physician ) through smtp to analyze the patient condition .
the hardware part comprises instrumentation amplifier ( ad620 ) , some passive components , operational amplifier ( lm741 ) , daq card , and laptop whereas labview is used as software .
the software is used to exchange the data from analog to digital form , to perform the calculations , and to produce the ecg waveform onto the monitor .
each of the components in this block diagram is explained in detail in the following subsections .
the principle of the electrodes is to convert a physical parameter into an electrical output .
the function of the transducer is to convert biological information into a quantifiable electrical signal .
the most preferable electrode is ag / agcl , as it reduces the impedance while using it and the gel is used for the proper contact in between the surface of the skin and electrode . after receiving raw ecg signal from the subject through electrode
, it has to be processed in order to bring the signal in visible form and to limit the bandwidth of the signal .
to do so , the instrumentation amplifier was used to amplify the tiny signal whereas passive and active components are used to design filter and to amplify it . 

figure 4 illustrates the constructive circuit diagram of signal conditioning . the circuit has been designed and tested in multisims to get the appropriate output of signal .
the voltage gain of the instrumentation amplifier is calculated using the following equation:(1)g=1 + 49.4  krg , g=1 + 49.4  k1  k=1 + 49.4=50.4 .
the voltage gain of the operational amplifier is estimated using given formula as the used one is noninverting amplifier:(2)g=1+r3r2,g=1 + 200  k1  k=1 + 200=201 .
the output of the instrumentation amplifier is fed into the passive ac coupling with a cutoff frequency , as in ( 3 ) , of 0.02  hz such that high - pass filters ( 3)fhigh - pass12r1c1=123.145.61031000106,fhigh - pass53.1456,fhigh - pass0.02  hz . the second - stage amplified signal is fed into a low - pass filter with a cutoff frequency , as in ( 4 ) , of 160  hz for removing high frequency noise or movement artifacts : ( 4)flow - pass12r4c2=123.14101031106,flow - pass10006.28=159.2  hz .
the output of the signal conditioning circuit should be sent to the ni daq card for the conversion of signal from analog to digital as it has the inbuilt analog - to - digital converter .
the given figure ( figure 5 ) gives the idea about the block diagram of ni usb-6008 which is a simple and low - cost multifunction i / o device from national instruments .
the ni usb-6008 card has 8 differential analog input channels and 12-bit analog - to - digital converter running at a sampling frequency up to 300  hz , which can be increased up to 200 khz .
it is a software package developed to build programs with symbols ( icons ) rather than writing out lines and lines of programming text .
it uses symbols , terminology , and formats that are familiar to technicians , scientists , and engineers .
labview is programmed to act as an interface , helping pieces of hardware  communicate  with each other
. moreover , labview offers built - in libraries that allow the user to work over the internet and use different programming formats and systems . 

figure 6 shows the step of smtp of how the data is processed throughout the different stages and transferred to client .
it is a part of the application layer of the tcp / ip protocol . using a process called  store and forward , 
it works closely with something called the mail transfer agent ( mta ) to send your communication to the right computer and e - mail inbox [ http://support.aycontrol.com/ ] .
the approach that has been followed in the designing of device is included in figure 7 .
there were several stages like finding the appropriate electrodes to acquire the signal from body of the subject and analog signal conditioning circuit includes filtering and amplifying stage , daq card , and digital signal processing and display system .
the ecg system that has been developed is used for the continuous acquisition and chart recording of single input channels .
it allowed user to record and save buffered analog ecg data from one or more individuals , which is continuously acquired into a circular buffer at the same time in that data previously retrieved from the buffer is plotted [ 68 ] . a common reason to read data
while the acquisition is in progress is to process and display the data in virtual - real time .
the analog signal is acquired from the bread board and converted to the digital one through daq .
digital signal processing is done accurately as needed in order to produce high signal - to - noise ratio so that the heart diagnostic system is precise . here
, the digital filter is done to remove the power line interferences and other artifacts available in the signal .
the purpose of these indicators is to provide some feedback to the user ( i.e. , physician ) regarding the patient 's average heart rate . 

the first part shows how the data have been acquired using data acquisition card ( 6008 ) ; immediate in next step , the retrieved data has been processed by band pass filter as well as notch filter to remove the artifacts from the signal [ 9 , 10 ] .
the following given equation is used to calculate the heart rate and to identify the arrhythmia condition [ 11 , 12]:(5)heart rate=60t2t1,with t1 being occurrence of first r wave and t2 being occurrence of second r wave .
after processing raw ecg signal , the signal has been displayed onto the laptop as shown in figure 9 .
finally , the developed smtp tool is used to send image file of acquired ecg signal through email express vi , shown in figure 10 that represents the front panel and figure 11 that represents the block panel developed using labview which allows sending the data quickly through e - mails from labview to a health care centre or a physician .
the given system is based on the principle of heart rate monitoring ; it is able to produce the results shown in figure 12 , which show accurate ecg signals and the correct calculation of both a resting and an elevated heart rate .
initially , there was an issue with the system regarding doctor notification subsystem which has been short by validating the proposed concept by running the vi at home , which sent both text and e - mail to our  doctor  notifying them that there was a detected problem with the patient 's heart .
it brings the freedom for the physician as well as for the doctor to check up on patients hearts from time to time by seeing real - time waveforms as shown in figure 12 .
the proposed device is functioning well once all the hardware connected properly to meet the criteria for the proposed idea . as a whole
most of the work has been done based either on hardware or on software . in the case of hardware , to transmit the ecg data , transmitter and receiver had been used , which increases the cost of the device , whereas the developed one integrated with hardware along with software to transmit the data anywhere using smtp technology .
in this paper , the low - cost biomedical measurement system with the ability of storage in digital format as well as sending the data to the remote area has been presented .
the hardware implementations using commercially available devices and the software written in labview program for continuously monitoring ecg data have been described .
the proposed measurement system is also capable of sending the data through smtp to the physician or health care centre with no time .
 this paper leads to developing a labview based ecg patient monitoring system for cardiovascular patient using simple mail transfer protocol technology . 
 the designed device has been divided into three parts . 
 first part is ecg amplifier circuit , built using instrumentation amplifier ( ad620 ) followed by signal conditioning circuit with the operation amplifier ( lm741 ) . 
 secondly , the daq card is used to convert the analog signal into digital form for the further process . 
 furthermore , the data has been processed in labview where the digital filter techniques have been implemented to remove the noise from the acquired signal . after processing 
 , the algorithm was developed to calculate the heart rate and to analyze the arrhythmia condition . 
 finally , smtp technology has been added in our work to make device more communicative and much more cost - effective solution in telemedicine technology which has been key - problem to realize the telediagnosis and monitoring of ecg signals . 
 the technology also can be easily implemented over already existing internet . 
1. Introduction
2. Material and Method
3. Designing Strategies
4. Designed Labview Interface
5. Result
6. Discussion
7. Conclusion and Future Work