Korean Journal of Veterinary Research 1993;33(4):719-734.
 Studies on electrocardiogram of the normal Korean native cattle I. Standard limb leads In-hyuk Choi1, In-sung Jung1, Nam-soo Kim1, Doo-seok Suh2 1College of Chonbuk National University2College of Chonnam National University 정상적(正常的)인 한우(韓牛)의 심전도(心電圖)에 관(關)한 연구(硏究) I. 표준지유도(標準肢誘導) 최인혁1, 정인성1, 김남수1, 서두석2 1전북대학교 수의과대학2전남대학교 수의과대학 Abstract The electrocardiographic(ECG) parameters on the standard limb leads in the normal Korean native cattle have been measured with a 3 channel Electrocardiograph built in a computed analysis. The study was conducted on the animals 98 heads of mean age of 17.7 months. Conduction parameters, waves, intervals and segments have been recorded. The recordings were analyzed as to shape and amplitude of the P and T waves and the components of the QRS complex. Heart rate was recorded by the Electrocardiogram which were a mean of $80.4{pm}11.6beats/min$. And the younger had a higher heart rate than the older one. Average conduction times in the RP, the QRS complex and the QTc interval recorded $166.7{pm}23.1msec.$, $79.7{pm}8.8msec.$ and $395.5{pm}30.4msec.$, in the P and T wave duration recorded $70.1{pm}13.5msec.$ and $97.6{pm}16.9msec.$, and in the PR and ST segment duration recorded $97.9{pm}23.5msec.$ and $173.9{pm}40.3msec.$, respectively. The wave forms in each lead observed various types. The amplitudes of wave type showed the highest frequency in each lead that were analyzed as follow : 1. In P wave, amplitudes of the positive type showed the frequency of 65.3%, 82.7% and 52.0% in leads I, II and III that were $103.1{pm}47.8{mu}V$, $115.2{pm}37.3{mu}V$ and $67.4{pm}26.9{mu}V$, and it showed the frequency of 54.1% and 85.7% in the leads aVL and aVF that were $63.7{pm}23.0{mu}V$, $88.0{pm}83.6{mu}V$, respectively. Average amplitude of the negative type showed the frequency of 78.6% in lead aVR which was $99.3{pm}38.0{mu}V$. 2. Average amplitude of the QRS complex were from $362.8{pm}177.7{mu}V$ to $532.8{pm}253.9{mu}V$(mean of $449.1{pm}57.2{mu}V$) that in all leads except lead I were manifested the Low-Voltage QRS complex(below 0.5mV). Average amplitudes of each wave type in the QRS complex aere $-50.2.4{pm}258.2{mu}V$ and $-428.6{pm}195.1{mu}V$ in the QS groups type that showed a frequency of 66.3%, 70.4% in the leads I and aVL, were $451.1{pm}20.4.0{mu}V$, $387.6{pm}175.8{mu}V$ and $299.3{pm}146.5{mu}V$ in the R groups type that showed a frequency of 48.0%, 53.1% and 34.7% in the leads III, aVR and aVF, and were $-307.5{pm}180.3{mu}V$, $201.4{pm}77.2{mu}V$ in the QR wave type which showed a frequency of 39.8% in lead II, respectively. 3. In T wave, amplitude of the positive type showed the frequency of 50.0%, 82.7%, 51.0% and 57.1% in leads II, III aVR and aVF which were $214.9{pm}115.6{mu}V$, $188.5{pm}119.3{mu}V$, $191.0{pm}93.7{mu}V$ and $165.7{pm}91.9{mu}V$, and the negative type showed a frequecny of 66.3% and 72.5% in leads I and aVL. that were $221.3{pm}112.5{mu}V$, $-173.6{pm}86.7{mu}V$, respectively. 4. Amplitude of ST segment in leads I, II and III were a mean of $-12.2{pm}37.2{mu}V$, $17.5{pm}42.6{mu}V$ and $28.3{pm}40.4{mu}V$, in leads aVR, aVL and aVF were $-3.9{pm}32.5{mu}V$, $-15.9{pm}35.6{mu}V$ and $26.2{pm}37.5{mu}V$, respectively. Key Words: Korean native cattle, electrocardiogram, standard limb leads