Anti-Arrhythmia Agents ; Brugada Syndrome/complications* ; Bundle-Branch Block/complications* ; Electrocardiography ; Humans ; Quinidine ; Ventricular Fibrillation

In order to assess the diagnostic value of invasive electrophysiologic study (EPS) in the patients with unexplained syncope, the electrophysiologic findings of 268 patients with unexplained syncope despite a complete clinical evaluation were analyzed. Results showed positive EPS finding was 38% in total patients and 50% in the patients aged > 70 years. With increasing age, the diagnostic yield of EPS also increased. No significant differences of complication rate were found among the different age groups. It was concluded that EPS have high diagnostic value in the patients with unexplained syncope. Its complications are few and mild. EPS may be recommended in elderly patients with unexplained syncope.
Age Factors ; Arrhythmia/complications ; Arrhythmia/*diagnosis ; Diagnosis, Differential ; *Electrocardiography ; Electrophysiology ; Follow-Up Studies ; Monitoring, Physiologic ; Retrospective Studies ; Syncope/diagnosis ; Syncope/*etiology ; Tachycardia/complications ; Tachycardia/diagnosis

OBJECTIVES: Dyspnea and palpitation are common features of pregnancy. While several theories have been put forward to explain the etiology of gestational dyspnea and palpitation, there have been few systemic studies of its incidence, severity and time-course in a group of normal women. METHODS: We interviewed postpartum women, within 3 days after delivery, about dyspnea and palpitation. Separately from this interview, we performed 24-hour ECG monitoring for obstetric patients with palpitation before delivery. RESULTS: The subjects interviewed were 261 women, of whom 37.5 percent and 11.5 percent experienced dyspnea and palpitation, respectively. These symptoms had a tendency to increase to term. The presence of arrhythmias could be documented in only 22% of patients having 24-hour Holter monitoring. CONCLUSION: Dyspnea and palpitation were common among normal pregnant women and had a tendency to increase to term.
Adult ; Arrhythmia/*physiopathology ; Dyspnea/*physiopathology ; Electrocardiography, Ambulatory ; Female ; Human ; Pregnancy ; Pregnancy Complications/*physiopathology ; Time Factors

Humans ; COVID-19/complications* ; Arrhythmias, Cardiac/diagnosis* ; Anti-Arrhythmia Agents/therapeutic use*

In order to assess the clinical manifestations and electrocardiogram (ECG) characteristics of Chinese long QT syndrome (LQTS) patients and describe the phenotype-genotype correlation, the subjects from 5 congenital LQTS families underwent clinical detailed examination including resting body surface ECG. QT interval and transmural dispersion of repolarization (TDR) were manually measured. Five families were genotyped by linkage analysis (polymerase chain reacting-short tandem repeat, PCR-STR). The phenotype-genotype correlation was analyzed. Four families were LQT2, 1 family was LQT3. Twenty-eight gene carriers were (14 males and 14 females) identified from 5 families. The mean QTc and TDRc were 0.56 +/- 0.04 s (range 0.42 to 0.63) and 0.16 +/- 0.04 s (range 0.09 to 0.24) respectively. 35.7% (10/28) had normal to borderline QTc (< or = 0.460 s). There was significant difference in QTc and TDRc between the patients with symptomatic LQTS and those with asymptomatic LQTS, and there was significant difference in TDRc between the asymptomatic patients and normal people also. A history of cardiac events was present in 50% (14/28), including 9 with syncope, 2 with sudden death (SD) and occurred in the absence of beta-blocker. Three SDs occurred prior to the diagnosis of LQTS and had no ECG record. Two out of 5 SDs (40%) occurred as the first symptom. Typical LQT2 T wave pattern were found in 40% (6/15) of all affected members. The appearing-normal T wave was found in one LQT3 family. Low penetrance of QTc and symptoms resulted in diagnostic challenge. ECG patterns and repolarization parameters may be used to predict the genotype in most families. Genetic test is very important for identification of gene carriers.
Arrhythmia/etiology ; Arrhythmia/genetics ; Asian Continental Ancestry Group ; Electrocardiography ; Genotype ; Long QT Syndrome/complications ; Long QT Syndrome/congenital ; Long QT Syndrome/*genetics ; Pedigree ; *Phenotype

AIMTo establish a novel arrhythmia model in rats.

METHODSCoronary artery occlusion was produced in hyperlipidemic rats after the animals were fed a high fat and cholesterol chow for 15 days. The incidence, duration and score of arrhythmias were determined 1 hour after coronary occlusion.

RESULTSThe incidence, duration and score of arrhythmia induced by coronary artery occlusion increased significantly in hyperlipidemic rats compared with those in normal rats (P < 0.05). In normal rats, pretreatment with amiodarone 60 mg x kg(-1) or verapamil 25 mg x kg(-1) 3 days before coronary artery occlusion did not influence the incidence, duration and score of arrhythmia (P > 0.05). In hyperlipidemic rats, amiodarone 60 mg x kg(-1) decreased the incidence, duration and score of arrhythmia (P < 0.05), but not verapamil 25 mg x kg(-1) (P > 0.05).

CONCLUSIONThe novel arrhythmia model induced by coronary artery occlusion in hyperlipidemic rats is reliable and similar to the pathophysiological state in human being.

Amiodarone ; pharmacology ; Animals ; Anti-Arrhythmia Agents ; pharmacology ; Arrhythmias, Cardiac ; etiology ; physiopathology ; Coronary Disease ; complications ; Disease Models, Animal ; Hyperlipidemias ; complications ; Male ; Rats ; Rats, Wistar

Anti-Arrhythmia Agents ; therapeutic use ; Cardiomyopathies ; drug therapy ; etiology ; Child, Preschool ; Female ; Humans ; Moricizine ; therapeutic use ; Tachycardia ; complications ; drug therapy ; Treatment Outcome

Adolescent ; Amiodarone ; therapeutic use ; Anti-Arrhythmia Agents ; therapeutic use ; Child ; Child, Preschool ; Emergency Medical Services ; Female ; Humans ; Infant ; Male ; Prognosis ; Tachycardia, Ventricular ; complications ; pathology ; therapy ; Treatment Outcome

To elucidate the mechanism of arrhythmia in healed myocardial infarction (HMI), the changes of action potential duration (APD), transient outward potassium current (Ito), delayed rectifier potassium current (IK) and inward rectifier potassium current (IK1) of left ventricular myocytes in non-infarcted zone of HMI were investigated. Rabbits were randomly assigned into two groups: HMI group, in which animals were subjected to thoracotomy and ligation of the circumflex coronary and sham-operated group, in which rabbits underwent thoracotomy but no conorary ligation. 3 months after the operation, the whole myocyte patch clamp technique was used to record APD, Ito, IK, and IK1 of ventricular myocytes in non-infarcted zone. Our results showed that the membrane capacitance was larger in HMI group than in sham-operated group. Action potential duration was significantly lengthened in HMI group and early afterdepolarization (EAD) appeared in HMI group. The densities of Ito, I(K, tail), and IK1 were reduced significantly in HMI group, from 6.72 +/- 0.42 pA/pF, 1.54 +/- 0.13 pA/pF and 25.6 +/- 2.6 pA/pF in sham-operated group to 4.03 +/- 0.33 pA/pF, 1.14 +/- 0.11 pA/pF and 17.6 +/- 2.3 pA/pF, respectively. It is concluded that the reduced densities of Ito, I(K, tail) and IK1 in ventricular myocytes of non-infarcted zone in HMI were responsible for the prolongation of APD and the presentation of EAD which played important roles in the development of malignant arrhythmia in HMI.
Action Potentials ; Arrhythmia/*etiology ; Heart Ventricles/metabolism ; Myocardial Infarction/complications ; Myocardial Infarction/metabolism ; Myocardial Infarction/*pathology ; Myocytes, Cardiac/*cytology ; Patch-Clamp Techniques ; Potassium Channels/*metabolism

Adolescent ; Anti-Arrhythmia Agents ; therapeutic use ; Atrial Fibrillation ; drug therapy ; Child ; Female ; Follow-Up Studies ; Heart Valve Diseases ; complications ; Humans ; Male ; Quinidine ; adverse effects ; therapeutic use ; Rheumatic Heart Disease ; complications