Monitoring And Analysis Of Serum Digoxin Concentration And Its Effect On Arrhythmia

Part 1:Monitoring and analysis of serum digoxin concentration in 2064 hospitalized patientsObjectives:To retrospectively analyze of 2064 cases of serum digoxin concentration in Shunde Hospital of Southern Medical University in order to provide reference for the clinical safe,rational and effective use of digoxin.Methods:According to the inclusion and exclusion criteria,serum digoxin concentrations(SDCs)of 2064 inpatients from January 2013 to December 2017 in Shunde Hospital of Southern Medical University were collected.The blood concentration of digoxin was determined by chemiluminescence immunoassay.The comparisons were made on the basis of age,gender,blood concentration and departments.Results:(i)There were 500(24.2%)patients with the reference range of SDC recommended by the ACC/AHA guidelines.669(32.4%)cases reported below the lower limit,528(25.5%)of which were lower than the lower limit of the instrument monitoring range.There were 895(43.4%)cases above the upper limit,33(1.6%)cases above the upper limit of instrument monitoring.Incidence of digoxin toxicity was 6.6%(137 cases)in total.(ii)With a mean age of 72.16±13.75 years old,589(28.5%)patients were<65 years old and 1475(71.5%)patients were>65 years old.Compared with the two groups,patients>65 years old had higher SDCs and more toxic patients(P<0.05).(iii)1044(50.6%)males and 1020(49.4%)females included in the study,there was no significant difference in SDCs between gender(P=0.178).Using 1.0μg/L as the cut point,there was no difference in the ratio of male to female(P=0.066).There were statistical differences between male and female at the cut point of 1.2μg/L(P=0.026).Compared with males,there were more cases of digoxin toxicity in females(P<0.001),but there was no significant difference in all-cause mortality between males and females(P=0.394).(iv)All SDC cases were collected from 20 departments.Numbers of SDC cases monitored by cardiology(42.3%),intensive care unit(13.5%),neurology(10.3%)and pneumology department(9.7%)ranked the top four in the hospital.(v)Among the SDCs monitored by the cardiovascular department,there were 304(34.8%)patients with their SDCs below 0.5μg/L,121(22.5%)patients with SDCs in the range of 0.5-1.0μg/L,373(42.7%)patients with SDCs over 1.0μg/L and 121 patients(13.8%)with SDCs over 2.0μg/L.57 patients were diagnosed with digoxin toxicity.Conclusion:(i)The serum digoxin concentration of 0.5-1.0μg/L accounts for 24.2%,1.0-1.2μg/L accounts for 7.3%,1.2-2.0μg/L accounts for 21.2%,>2.0μg/L accounts for 14.8%.(ii)Serum digoxin concentrations and poisoning events were higher in elderly patients(>65 years old).(iii)The number of female patients in the SDC>1.2μg/L group and the mumber of poisoning cases were higher than that of male.Part 2:The influence of serum digoxin concentration on arrhythmiaObjectives:To compare the differences in electrocardiogram(ECG)between different groups of SDCs and try to analyze the effect of different digoxin concentration on arrhythmia.Methods:A retrospective analysis was conducted to analyze medical information of 370 inpatients who received digoxin use and performed a 24-hour Holter electrocardiographic recording when the SDC was at the presumed steady-state bood concentration in the Shunde Hospital of Southern Medical University between January 1,2013 to March 31,2018.Patients were divided into 2 groups based on SDCs--normal SDC group(SDC<1.2μg/L)and elevated SDC group(SDC>1.2μg/L),270 patients with SDC<1.2μg/L and 100 patients with SDC>1.2μg/L.The influence factors,such as baseline characteristics,laboratory findings,disease and combined medications were collected.The blood concentration of digoxin was monitored by chemiluminescence immunoassay.ECG findings of patients were recorded by 24-hour Holter Recorder.The differences in ECGs between 2 groups were analyzed.Results:(i)Compared with the normal SDC group,the proportion of female patients in the elevated SDC group was higher.The NYHA-IV class patients were more common,and the Cr and BUN concentrations were higher(P<0.05).(ii)Most patients had concomitant disease in this study.Heart failure(97.8%),heart valve disease(41.4%),diabetes(33.0%)and renal failure(31.1%)were most common.Patients with renal failure accounted for a greater proportion in the elevated SDC group(P<0.05).The incidence of myocardiopathy was higher in the normal SDC group(P<0.05).(iii)The patients used spironolactone,furosemide,beta blockers,statins was 81.8%,80.8%,55.9%,52.4%respectively.Furosemide,nitrates,amiodarone,potassium chloride sustained release tablets were more commomly used in patients with elevated SDC(P<0.05).(iv)The outcome results of 24-hour Holter showed that 168(45.4%)had sinus rhythm;240(64.9%)had atrial fibrillation,including 52(14.1%)with paroxysmal atrial fibrillation;8(2.2%)had pacemaker rhythm.Premature ventricular contraction(PVC)(76.5%),atrial fibrillation(64.9%),and premature atrial contraction(36.2%)were the most common arrhythmias.The incidence of ventricular tachycardia in the elevated SDC group was significantly higher than that in normal SDC group(P=0.010).(v)The frequent PVCs group patients were more common with SDC>1.2μg/L and NYHA-IV class and cardiomyopathy,a lower LVEF,slower resting heart rate and higher use of spironolactone(P<0.05).(vi)Multivariate regression analysis indicated that SDC>1.2μg/L and EF reduction were independent risk factors for frequent PVCs.Conclusion:(i)In this study,the incidence of ventricular tachycardia events was significantly increased in the SDC>1.2μg/L group.(ii)The increase of SDC is an independent risk factor for frequent PVCs.