This is done with Bascom IDE and not Arduino. The source code is in the attachment.

'------------------------------------------------------------------------------
' ECG Electro Cardio Gram
' 2021-07-01 (c)gammda
' Ver-1
' CardioGraph
' Use Arduino UNO analog input A1 (pinc.1) and AD8232 modul
' .-----------------------.
' |ATMEGA328              |
' |Clock 11.059200MHz     |
' |Baud:19200             |
' '-----------------------'
' 1.Install GUI-O application on smartphone
'   www.gui-o.com or https://play.google.com/store/apps/details?id=com.guio.guioapp
' 2.Start GUI-O and make Bluetooth connection with arduino board
' 3.Press on start GUI-O button
'------------------------------------------------------------------------------

$regfile = "m328pbdef.dat"
$crystal = 11059200
'$baud = 9600                                                'default baudrate for Bluetooth HC06
$baud = 19200                                               'NOTE!  For proper connection, it is necessary to set 19200 on the bluetooth module HC06.
                                                            'For first test you can use default baudrate 9600

Config Serialin = Buffered , Size = 120

Const Timer1reload = 43200
Config Timer1 = Timer , Prescale = 256
Load Timer1 , Timer1reload
On Ovf1 Timer1_isr
Enable Timer1
Start Timer1

Enable Interrupts


'-ADC--------------------------------------------------------------------------
Dim Channel As Byte                                         'A/D conversion
Channel = 1

Config Adc = Single , Prescaler = Auto , Reference = Avcc
Start Adc
Enable Interrupts
'------------------------------------------------------------------------------
$lib "GetToken.Lib"
$external Gettoken
Declare Function Gettoken(strinput As String , Byval Bseparator As Byte , Byval Bcount As Byte ) As String
Dim Sep As Byte
Dim Pozicija As Byte
'------------------------------------------------------------------------------

Dim Cardio As Integer
Dim Pulse As Byte
Dim Pulsex As Byte
Pulsex = 60

Dim Timx As Byte
Dim Timy As Byte
Dim Pul1 As Byte
Dim Soun_d As Bit
Soun_d = 0

Dim Flags As Bit
Flags = 0
Dim Data_key As Byte
Dim Znak As String * 15
Dim Rdata As String * 100
Dim Init As String * 4

Gosub Guio_ini                                              'start initalization procedure on GUI-O - write objects on screen of smart phone
'------------------------------------------------------------------------------
Main:
Do
  If Ischarwaiting() = 1 Then
   Gosub Read_data
  End If

     Cardio = Getadc(channel)                               'read walue of AD

     If Cardio > 740 Then                                   'sound if amplitude je more than 740
       If Soun_d = 1 Then
         Print "@ton1 EDUR:500"                             'sound appear on smart phone
       End If

       Pul1 = Pul1 + 1                                      'calculate pulse
       If Timy = 4 Then
         Pulse = Pul1 * 10
         Pul1 = 0
         Timy = 0
       End If

     End If

     Print "@ch1 PLI:" ; Chr(34) ; "pl1" ; Chr(34) ; " YP:" ; Chr(34) ; Cardio ; Chr(34)       ' write graph data (AD data) ECG to GUI-O

  If Timx > 1 Then

    Print "@ch0 PLI:" ; Chr(34) ; "pl0" ; Chr(34) ; " PLC:" ; Chr(34) ; "#000000" ; Chr(34) ; " YP:" ; Chr(34) ; Pulse ; Chr(34) ; " XP:" ; Chr(34) ; "0" ; Chr(34)       'Write graph pulse to GUI-O
    Print "@lbpulse TXT:" ; Chr(34) ; Pulse ; Chr(34)       'write numeric value on GUI-O

    Timx = 0
  End If

Loop
End                                                         'End of main cycle
'------------------------------------------------------------------------------
 Read_data:
 Reset Watchdog
 Data_key = Inkey()
 If Data_key = "@" Then Input Rdata Noecho


 Sep = &H20
 Pozicija = 1
 Znak = Gettoken(rdata , Sep , Pozicija)


If Znak = "btsound" Then
   Toggle Soun_d

   If Soun_d = 1 Then
    Print "@btsound BTH:0.25"                               'If sound is ON button outline appear
   Else
    Print "@btsound BTH:0"                                  'If sound is OFF button outline disappear
   End If

End If


Init = Mid(rdata , 1 , 4)
If Init = "init" Then                                       'reading "@init" from GUI-O
  Gosub Guio_ini
End If


Rdata = ""

Return
'-Initialization procedure GUI-O Objects-------------------------------------------------------

Guio_ini:

 Print "@sls 500"                                           'start writting objects
 Print "@cls"                                               'clear screen
 Print "@clh"                                               'clear HW components
 'Print "@clo"                                               'clear orientation
 Print "@guis BGC:#000000 ASR:0.449671"                     'bacground color X-Y ratio
 Print "|SORI UID:sori1 HID:sori ORI:2 SEN:0"
 Waitms 250
 Print "|IM UID:imx X:15 Y:50 W:100 H:100 ROT:0 SHE:0 VIS:1 OPA:1 SCM:2 IP:" ; Chr(34) ; "ECG.jpg" ; Chr(34)       'GUI-O Image ECG.jpg copy to smartphone \Phone\Android\data\com.guio.guioapp\files\Pictures\

 Print "|TON UID:ton1 HID:ton EDUR:1000 TONT:24"            'GUI-O define ton

 Print "|CH UID:ch0 X:65 Y:25 W:72 H:50 BTH:0.1 XTC:10 YTC:8 VIS:1 BSZ:5 DRA:0 BGC:#FFFFFF FGC:#900000 RAD:0 LT:0.15 XMA:5 YMA:8 SHVL:1 VLP:0 CHN:" ; Chr(34) ; "PULSE" ; Chr(34) ; " FFA:" ; Chr(34) ; "font6" ; Chr(34) ; " FSZ:4"
 Print "|CH UID:ch1 X:65 Y:75 W:72 H:50 BTH:0.1 XTC:10 YTC:8 VIS:1 BSZ:200 DRA:0 CHT:2 BMA:0.03 XLO:0 XHI:40000 BGC:#FFFFFF FGC:#900000 RAD:0 LT:0.15 XMA:5 YMA:8 SHVL:1 VLP:0 CHN:" ; Chr(34) ; "ELECTRO CARDIOGRAM" ; Chr(34) ; " FFA:" ; Chr(34) ; "font6" ; Chr(34) ; " FSZ:4"
 'GUI-O graph for pulse and Cardio

 Print "|LB UID:lbpulse X:87 Y:35 ALP:1 ROT:0 SHE:1 FGC:#000000 FFA:" ; Chr(34) ; "font6" ; Chr(34) ; " FSZ:16 TXT:" ; Chr(34) ; "---" ; Chr(34)       'Label for number-pulse
 Print "|LB UID:lbpname X:85 Y:23 ALP:1 ROT:0 SHE:1 FGC:#000000 FFA:" ; Chr(34) ; "font8" ; Chr(34) ; " FSZ:4 TXT:" ; Chr(34) ; "PULSE BMP" ; Chr(34)       'Label for name

 Print "|LB UID:lbname X:2 Y:92 ALP:1 ROT:0 SHE:1 FGC:#FFFFFF FFA:" ; Chr(34) ; "font7" ; Chr(34) ; " FSZ:10 TXT:" ; Chr(34) ; "ECG" ; Chr(34)       'Label general name


 Print "|BT UID:btsound X:22 Y:92 W:10 H:10 ROT:0 RAD:1 SHVR:0.8 SHE:1 SHC:#404040 BGC:#808B96 SBGC:#808B96 FGC:#FFFFFF FSZ:6 BTH:0 FFA:" ; Chr(34) ; "font6" ; Chr(34) ; " TXT:" ; Chr(34) ; "Sound" ; Chr(34) ; " SVAL:" ; Chr(34) ; "Stop" ; Chr(34)
 'Button for sound ON/OFF

 Print "@ch1 PLI:" ; Chr(34) ; "pl1" ; Chr(34) ; " PLC:" ; Chr(34) ; "#000000" ; Chr(34) ; " YP:" ; Chr(34) ; Cardio ; Chr(34) ; " XP:" ; Chr(34) ; "0" ; Chr(34)
 'write data for cardio
 Print "@hls 250"                                           'end writting objects

Return



'-Timer_ISR--------------------------------------------------------------------------------

 Timer1_isr:
   Timx = Timx + 1
   Timy = Timy + 1


  Return

'------------------------------------------------------------------------------------------