Objective To explore the causes of short P R interval syndrome.Methods 15 patients of short P R interval syndrome were tested with transesophageal atrial pacing (TEAP),and then the results and the parameters of TEAP were analyzed.Results The detection rates of dual atrioventricular nodal pathways(DAVNP),L G L syndrome and latent preexcitation syndrome were 66.67%(10/15),26.67%(4/15)and 6.67%(1/15)respectively.Conclusion The most common causes of short P R interval syndrome are DAVNP and the L G L syndrome

Objective To evaluate the accuracy and feasibility of 64-slice spiral CT (64SCT) in assessing coronary artery disease.Methods A total of 30 suspected patients (male 21 cases, female 9 cases, and mean age of 54.6 years) were undergone both 64SCT and selective coronary angiography (SCA). Volume redering (VR) ,multiplanar reconstruction (MPR), maximum intensity projection (MIP) and transverse section were reconstructed. The results of coronary reconstructions were compared with SCA to analyze the accuracy of the 64SCT in detecting coronary artery stenoses.Results In the 396 segments of coronary artery(diameter≥2 mm)of 30 patients, 385 were judged to be evaluable by 64SCT. The evaluable rate was 97.2%. The sensitivity, specificity, positive predictive value and negative predictive value of the 64SCT in detecting coronary artery stenoses(≥50% of stenosis) were 96.22%, 94.56%, 89.44% and 96.88%. The accuracy rate of 64SCT in detecting ≥50% stenosis of coronary artery was 95.90%.Conclusion 64SCT has high accuracy in detecting coronary artery stenoses, as a noninvasive method,it can be used for screening patients with known or coronary artery diseases.

Objective To evaluate the robustness of body mass index (BMI) adapted tube current selection method for obtaining consistent image quality in MSCT coronary artery imaging Methods Initially one hundred patients in the control group ( C group) underwent cardiac scans using GE 64-row VCT with standard scan protocol (640 mA, 120 kV, 0.35 see, body bewtie, C2 filter). Noise measurement was obtained for each patient using the average of three consecutive slices in the ascending aorta with ROI of 10 mm×10 mm to establish the relationship between BMI, desired image noise (IN) and required mA. An excel table was established to predict the required mA to achieve a desired IN for each patient with different BMI. A second group of one hundred cardiac patients (L group) was scanned with BMI-aclapted mA from the table to evaluate the practicability of this method. BMI, IN, CT dose index(CTDI),effective dose (ED) were all recorded. Results For the control group of 100 patients, the mean values and standard deviations of image quality score (IQS), BMI, IN and ED were 3.71±0.54, 25.08±2.63, 24.56±5.03 and (17.63±1.68 ) mSv (with range of 15-22 msy). Regression analysis indicated linear relationship between BMI and image noise with fixed mA. Using the relationship between tube current and image noise and noise ratio between large bowtie and cardiac bowtie, the following equation for the required tube current Xma to achieve present image noise of Ins for patient with certain BMI value when using cardiac bowtie could be then obtained: Xma = Fma×( k1 x BMI + c1 )/Ina]2, where Fma = 640 mA, k1 = 1. 033, c1 = - 3.2, Ins = 27 in the study. (2) For the patients in L group, the mean values and standard deviations of IQS, BMI, and IN were 3.69±0.53, 25.07±2.91, and 26.61±3.44, respectively. The average tube current used was (469.95±113.45) mA, depending on patient's BMI values. The average effectively dose was(9.08±2.25) mSv. There was no statistically difference between the two groups in image quality( F= 0.068,P=0.794). Conclusions In 64-MSCT cardiac imaging, the use of BMI dependent tube current selection method, in conjunction with dose reduction techniques, can provide individualized scan protocol to obtain consistent image quality across patient population and to optimize dose delivery to patients.

Objective To investigate the diagnostic value of head-up tilt test (HUT) in cough syncope (CS).Methods Forty-seven outpatients or inpatients with CS and 79 patients with suspected vasovagal syncope(SVVS) due to syncope history in our hospital from January 2011 to May 2015 served as the observation group and control group respectively.HUT was performed in the two groups.The cough response during HUT,changes of systolic pressure and diastolic pressure caused by cough,HUT positive results and hemodynamic type were observed,Results In the observation group,4 cases(8.51％) were cough caused syncope,26 cases (55.32 ％) were presyncope and 17 cases (36.17 ％) had no symptoms,while 79 cases in the control group had no symptoms,the differences were statistically significant (P＜ 0.05).The total positive rate of cough response in the observation group was 63.83％,and the specificity was 100.00％.The systolic blood pressure had statistical difference between the two groups(.P＜0.05).The diastolic pressure had statistical difference between the cases of non-symptoms with the cases of syncope and cases of presyncope in the observation group (P＜0.05),but had no statistical difference compared with the cases of non-symptoms in the control group(P＞0.05).The heart rate(HR) had no statistical difference among various groups(P＞0.05).The HUT positive rate in the observation group was lower than that in the control group(P＜0.05).The hemodynamic type had no statistical difference between the two groups(P＞0.05).Conclusion Severe coughing during HUT may cause the blood pressure decrease,induces syncope or presyncope,can increase the diagnostic sensitivity of CS patients,which is very useful in the suspected diagnosis of CS patients,especially for CS patients with a unclear history.

Objective To investigate the intra- and interobserver repeatability of coronary artery disease (CAD) diagnosis based on invasive coronary angiography (ICA) and CT coronary angiography (CTCA).Methods Two readers with comparable experience ( over 10 years) independently evaluated ICA results of 42 consecutive patients with a blind method. After 30 days,one of them reviewed the same patients again.Another two comparable-experience (over 10 years) readers evaluated the results of CTCA (prospectively ECG-triggering) from the same 42 patients in the same way.The inter-reader and intra-reader repeatability of ICA and CTCA were analyzed by performing Kappa test and calculating the percentage of the segments with agreement on stenotic degree.Using ICA as reference,the accuracy of CTCA in diagnosing CAD was studied by comparing the area under ROC. Results The Kappa between readers for ICA and CTCA were 0.91 and 0.81.Intra-reader Kappa were 0.92 and 0.83 respectively (x2 =509.4 and 432.5,all P ＜0.01 ).The percentage of the segments with agreement between readers on the degree of stenosis were 80.8％ (494/611) in ICA and 75.2％ (469/624) in CTCA ( x2 =2.75,P =0.10),and within the same reader,86.9％ (531/611)in ICA and 81.9％ (511/624) in CTCA(x2 =3.76,P =0.053).With≥ 50％narrowing as a CAD diagnosis criterion,the agreement rates for two readers were 96.6％ (590/611 ) in ICA and 94.4％ (589/624) in CTCA( x2 =3.36,P =0.07),and for the same reader,97.4％ (595/611) in ICA,95.4％ (595/624) in CTCA ( x2 =3.62,P =0.06).Using ICA as reference,two readers of CTCA results achieved a sensitivity and specificity of 84.9％ (530/624)and 98.1％ (612/624).The area under ROC was 0.94 (95％ CI 0.91-0.97).Conclusions Both ICA and CTCA demonstrate good repeatability in diagnosing CAD.The repeatability of ICA is superior to that of CTCA.A certain discrepancy exists in two readings from the same reader or two readers.