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Ojective: To establish individualized virtual interventional system for tachyarrhythmia to evaluate its location the surgical target and analyze its clinical application value. Methods: A total of 120 patients with premature ventricular beats and atrioventricular reentrant tachycardia (including 40 cases of premature ventricular beats and 80 cases of atrioventricular reentrant tachycardia) underwent radiofrequency ablation in our hospital from January 2011 to January 2013, with an average age of 40.6± 9.7 years. New digital motor was used to record 18 conductor surface electrocardiogram (ECG), digital esophageal pacing map, raw data of cardiac CT imaging and surgical targets. All collected ECG and CT data were processed by computer aided diagnosis (CAD) of multi-pattern sequence recognition system, and then the processed data were analyzed. Two cardiologists analyzed and positioned the ECG artificially without informing the clinical data and the final target location results of radiofrequency ablation. They diagnosed the ECG according to the diagnostic and positioning criteria of premature ventricular beats and atrioventricular bypass. Then two physicians diagnosed the treated ECG and got the diagnostic results again. The gold standard was the successful target positioning diagnosis during the operation. The specificity, sensitivity, positive predictive value and negative predictive value of this method were obtained to evaluate the clinical value of individualized virtual interventional system for tachyarrhythmia. Results: The diagnostic accuracy of ECG+CAD group was higher than that of ECG group alone, the area under ROC curve (Az) = 0.742, 95% confidence interval [0.652-0.832]; ECG+CAD group: Az = 0.934, 95% confidence interval [0.882-0.985]; ECG+CAD group: accuracy 0.908; sensitivity: 0.913; specificity: 0.905; positive predictive value: 0.818; negative predictive value: 0.934, significantly higher than that of ECG group alone. Conclusion: Compared with body surface electrocardiogram alone, virtual interventional surgery system significantly improves the accuracy of target location and diagnosis of tachyarrhythmia, it has higher clinical application value. [ABSTRACT FROM AUTHOR]

Norepinephrine (NE) can raise blood pressure and speed up heart rate. However, because its effect of raising heart rate is less than that of reflex reduction of heart rate caused by the increase of blood pressure, NE causes more heart rate decrease in patients. A case of tachyarrhythmia caused by low dose NE was admitted to department of intensive care unit (ICU) of Shijiazhuang Third Hospital. The heart rate of the patient increased with the elevation of NE application dose. A variety of antiarrhythmic drugs was invalid. The related examination was prescribed to eliminate the cause of arrhythmia caused by the disorder of electrolysis and thyroid function, and found that heart rate decreased as the dose of NE tapered. After NE was stopped, the patient recovered sinus rhythm. During one month of follow-up, the patient's heart rhythm was normal. Therefore, the occurrence of tachyarrhythmia is related to NE.

Objective: To explore the relationship between unexplained palpitation in children and head-up tilt test (HUTT).
 Methods: A total of 142 children with the main symptom of unexplained palpitation were admitted to the Specialist Out-Patient Clinic of Children's Cardiovascular Disease from Sept. 2008 to Feb. 2017 in the Second Xiangya Hospital, Central South University. Among them, 63 cases were male, 79 cases were female, with the mean age of (10.12±2.88) years old. The detailed history, physical examinations, conventional 12 electrocardiogram, chest X-ray, echocardiography, myocardial enzymes and thyroid function were all examined. The disorders of heart disease, systemic disease and drug effect were ruled out. The HUTT inspection was then given to them.
 Results: Among the 142 palpitation cases, 79 cases were HUTT positive (55.6%) and 63 cases were HUTT negative (44.4%). The age in HUTT positive patients was older than that in HUTT negative patients (P<0.05), with no significant difference in gender (P>0.05). There were three types of hemodynamic changes in HUTT positive patients. Among them, 38 cases were postural orthostatic tachycardia syndrome (48.1%), 36 cases were the vasovagal syncope vasodepressive type (45.6%) and 5 cases were the vasovagal syncope mixed type (6.3%). There were no hemodynamic types for vasovagal syncope cardioinhibitory type, orthostatic hypotension and orthostatic hypertension.
 Conclusion: Among the clinically unexplained palpitations children, more than half are caused by unbalanced autonomic nervous function. HUTT can help clear the cause of unexplained palpitations.

Objective: Tachycardia induced cardiomyopathy (TIC), secondary to various tachyarrhythmias, is a reversible condition which can lead to cardiac enlargement and heart failure. The impairment of both structure and function of heart can be reverted completely or partially if tachyarrhythmias are ceased without delay. This study aimed to explore the clinical characteristics, therapeutic regimen and outcome of TIC in children., Methods: Clinical data of 12 children with TIC, who came from Peking University First Hospital from Feb. 2003 to Jun. 2009, were retrospectively analyzed and followed up. The echocardiogram data on admission were compared with those from 12 homochronous cases with idiopathic dilated cardiomyopathy matched with 12 TIC cases in age and gender., Results: Atrial tachycardia is the commonest arrhythmia in 12 TIC cases (75%). Four cases underwent catheterization for radiofrequency ablation and all succeeded. The cardiac rhythm of 6 out of 8 cases treated with drugs became sinus rhythm after 3 days to 2 weeks antiarrhythmic drugs treatment. The remaining 2 cases still retained atrial rhythm, but the ventricular heart rates declined to normal. The left ventricular end-diastolic dimensions of the 12 cases were decreased compared with those of pretherapy [(37.5 ± 5.3) mm vs. (43.0 ± 5.7) mm, P < 0.01], and the left ventricular ejection fractions were increased [(60.5% ± 5.6%) vs. (33.7% ± 10.3%), P < 0.01], after (3.4 ± 2.3) months. In our (4.3 ± 2.4) year-follow-up, all cases were fine, except in one case the tachyarrhythmia relapsed because of discontinuation of the drug treatment by her parents. The left ventricular end-diastolic dimensions in 12 TIC cases were smaller than those of the 12 age- and gender-matched idiopathic dilated cardiomyopathy [(43.0 ± 5.7) mm vs. (54.8 ± 7.5) mm, t = 7.9, P < 0.01], and the ejection fractions were higher [(33.7% ± 10.3%) vs. (21.8% ± 7.5%), t = 3.7, P < 0.01]., Conclusion: The diagnosis of TIC should be considered for the children with tachycardia, cardiac enlargement and cardiac insufficiency. The degree of cardiac enlargement and cardiac insufficiency might be of value for the differential diagnosis between TIC and idiopathic dilated cardiomyopathy. The rhythm control and ventricular rates control could all result in a favorite therapeutic efficacy.

A portable ECG monitor is introduced in the paper, which has a temporary intravenous and transesophageal fixable rate pacing function. During the PSVT attack, the tachyarrythmia can be stopped by the transesophageal cardiac pacing while the ECG signals are monitored. The instrument has some advantages such as small size, low price and good practicality. It is worth while introducing and popularizing it to all hospitals.

Late potentials (VLP) are high frequency-low amplitude electrical potentials that appear at late ventricular depolarization. A multilead method of detection (method M) was adopted in the present study. This study was designed to compare method M with composite XYZ lead method (method C) by analysis of signals recorded from the same hardware system. The purpose was to find out relations of the directions of MI Q vector and peri-infarction block to the recording lead axes of VLP. In 44 MI patients the results of VLP detection indicated that: (1) The positive incidence of VLP detection was 55% with method M which was significantly higher than that with method C (25%, P less than 0.01) especially in patients with ventricular tachycardia and/or ventricular fibrillation and ventricular premature contractions. The sensitivity of VLP with method M (75-88%) was apparently higher than that with method C (38%). (2) The direction of Q vector in MI was closely correlated with that of recording lead axes of VLP. (3) The positive VLP were found around peri-infarction block in patients with MI. The direction of peri-infarction block was mostly in line with that of lead axes with positive VLP, that is, the positive rate of VLP detection was the highest when ever the vector of MI and peri-infarction block were parallel to the recording lead axes of method M.

Quantitative analysis of the high frequency components of the terminal portion of the high-resolution surface QRS was performed in 119 normal subjects (N), 62 patients with ventricular tachycardia (VT) including 20 patients with sustained VT or VF (VTs/VF) and in 565 ischemic and nonischemic cardiac patients (NO-VT). High-resolution surface ECG (SAECG) was obtained during sinus rhythm with noise level below 0.4 microV by ART-1200EPX. The vector magnitude of the filtered and signal-averaged standard bipolar orthogonal leads X, Y, Z (V = square root of X2 + Y2 + Z2) were used for analysis. Total duration of the QRS (QRST), the duration of the low amplitude (40 microV) signals in the terminal portion of the QRS (D40) and the amplitude of the signals in the last 40 ms (V40) were measured at filter settings of both 25Hz and 40Hz by the computer. Specific values for each of the indices were identified at both 25Hz and 40Hz filterings, which could separate N as well as NO-VT from VTs/VF. They were greater than or equal to 120 ms for QRST, greater than or equal to 34 ms for D40 and less than or equal to 25 microV for V40 at 25Hz, greater than or equal to 120 ms for QRST, greater than or equal to 39 ms for D40 and less than or equal to 20 microV for V40 at 40 Hz filtering.(ABSTRACT TRUNCATED AT 250 WORDS)

Two hundred cases of acute myocardial infarction (AMI) who had survived for 2 or more weeks were studied consecutively. 96.5% had been followed up for 0.5-27 (average 13) months. Signal averaging with filter corner frequencies of 40-250Hz were used to record ventricular late potentials (VLP). During hospitalization, 26.5% had at least one positive VLP. There were no statistical differences in age, gender, CK-peak value, or LVEF prior to the discharge between positive and negative VLP groups. However, there were more positive cases in inferior wall infarction and Killip's grade II or above (P less than 0.05). More VT/VF cases in VLP positive group, but no statistical correlation between the VLP and ventricular arrhythmias in Holter recording. On follow-up, 2/3 positive cases turned out negative, but greater part in these with continuous positive VLP had obvious cardiac dysfunction and reinfarction.