Analysis On Effect Of Blood Potassium Disorders On Cardiac Imaging Structure And Function In Dogs Based On Cardiac Ultrasound

The normal reference range of blood potassium concentration in dogs is generally considered to be 3.5-5.5mmol/L.If the blood potassium concentration is not within the normal range,it is called blood potassium disorder,which is divided into hypokalemia and hyperkalemia.Cardiomyocytes are very sensitive to changes in the concentration of potassium ions,so when blood potassium disorder occurs,it will first affect cardiac function.Long-term hyperkalemia can cause irreversible damage to the structure and function of the heart,and even cause cardiac arrest.The most commonly used diagnostic and monitoring methods for serum potassium disorders are electrocardiogram（ECG）and serum potassium biochemical testing.In order to evaluate the application value of echocardiography in the examination of canine heart structure and function,to explore the influence of blood potassium disorder on cardiac structure and function,and to provide experimental basis for clinical diagnosis,treatment and medical tests of canine blood potassium disorder.In this study,B-mode ultrasonography,M-mode ultrasonography and pulsed Doppler ultrasonography（PW）combined with electrocardiogram and canine N-terminal probrain sodium（NT-pro BNP）were used to explore the effect of serum potassium disturbance on cardiac structure and function.Hypokalemia model was established by intramuscular injection of furosemide combined with intravenous infusion of 25%glucose insulin solution（200 m L of 25%glucose solution:protamine zinc recombinant human insulin 20U）;hyperkalemia model was established by intravenous infusion of 3%potassium chloride glucose solution.The experiment was carried out in two stages:hyperkalemia and hypokalemia.6 experimental dogs were used each time,and each experimental dog was repeated 3 times,with an interval of more than 1 week between each repetition.An electrocardiograph was used to monitor the changes of NT-pro BNP and canine ECG waveforms under different blood potassium concentrations,and B-mode ultrasound,M-mode ultrasound,and pulsed Doppler ultrasound（PW）of veterinary color Doppler ultrasound were used at the same time to measure or calculate the changes in different sections.selected parameters.Cardiac structural parameters:ventricular septal end-diastolic thickness（IVSd）,left ventricular end-diastolic inner diameter（LVIDd）,end-diastolic left ventricular posterior wall thickness（LVPWd）,ventricular septal end-systolic thickness（IVSs）,left ventricular end-systolic inner diameter（LVIDs）,end-systolic left ventricular posterior wall thickness（LVPWs）,aortic diameter（Ao D）,left atrial diameter（LAD）,LA/Ao;systolic function parameters:end-diastolic volume（EDV）,end-systolic volume（ESV）,stroke Volume（SV）,ejection fraction（EF）,short-axis fractional shortening（FS）;diastolic function parameters:left ventricular maximum early diastolic blood flow（E peak）,mitral atrial systolic maximum blood flow（A peak）,Isovolumic relaxation period（IVRT）,E/A.Experimental results:（1）During the establishment of the serum potassium disorder model,only K⁺had extremely significant changes beyond the normal range,and the changes of Ca²⁺,Na⁺,and Cl^-did not exceed the normal range.Before and after the establishment of the serum potassium disorder model,the hematocrit（HCT）did not cause significant changes.difference.（2）Structural changes:in the case of hypokalemia,the IVS changes in the opposite trend in diastole and systole.In diastole,the thickness of IVS decreases with the decrease of serum potassium concentration;during systole,IVS decreases with the decrease of serum potassium concentration.rise.During hyperkalemia,the IVS is more sensitive to changes in serum potassium during diastole,and its thickness decreases with the increase in serum potassium,but during systole,the thickness of IVS is less sensitive to changes in serum potassium.There was no significant change in thickness.When the serum potassium concentration reached severe hypokalemia,the thickness of the interventricular septum decreased rapidly and became lower than the normal value.（3）Changes in systolic function:EF and FS have the same trend of change.In the case of hypokalemia,it increases with the decrease of blood potassium,mild hyperkalemia increases slowly with the increase of blood potassium concentration,and severe hyperkalemia increases gradually.Potassium drops suddenly and sharply.In hypokalemia,EDV and ESV decreased with the decrease of serum potassium concentration;in mild hyperkalemia,it slowly increased with the increase of serum potassium,and in severe hyperkalemia,it decreased with the increase of serum potassium concentration.（4）Changes in diastolic function:E/A fluctuated between 1-1.5 in mild hypokalemia and mild hyperkalemia,and E/A<1 in severe hypokalemia and severe hyperkalemia appear.IVRT is prolonged with decreasing serum potassium concentration during hypokalemia and prolonged during severe hyperkalemia.Conclusion:（1）The hypokalemia model was successfully established by injecting furosemide and insulin glucose solution;the hyperkalemia model was successfully established by intravenous infusion of potassium chloride glucose solution.（2）The changes of cardiac imaging structure and function with blood potassium disorder were successfully monitored by cardiac ultrasound.（3）Severe hypokalemia causes abnormal thickening of systolic IVS,abnormal reduction of diastolic and systolic LVID,and severe hyperkalemia causes diastolic LVID expansion.（4）When hypokalemia is present,cardiac systolic function is enhanced and diastolic function is decreased;when hyperkalemia is present,cardiac systolic and diastolic functions are decreased.