Prolongation Of PQ Interval Research Articles

Experience of using propafenone in newborns and young children with arrhythmias

Aim. To evaluate the efficacy and safety of propafenone therapy in newborns and young children, including children with congenital heart defects (CHD). Material and methods . The study included 65 children with initiation of propafenone therapy at the age of 0-5 years. For diagnosis of arrhythmias and treatment control, electrocardiography (ECG), 24-hour Holter monitoring and echocardiography were performed. The initial dose of propafenone was 5-7 mg/kg/ day; the maximum dose — 15 mg/kg/day. The dose was titrated to effective with clinical and ECG control. It was considered acceptable to increase the duration of PQ interval and QRS complex by no more than 25% of the baseline value. The adverse and arrhythmogenic effects of the drug were evaluated. Results. Indications for propafenone administration were atrial tachycardia in 29 (44,61%) children, frequent premature ventricular contractions and ventricular tachycardia in 13 (20%) children, Wolff-Parkinson-White syndrome in 13 (20%) children, and other types of supraventricular tachycardia in 10 (15,39%) children. Sixteen (24,62%) children had CHD. In 20 (30,77%) children, propafenone was administrated in the neonatal period. The duration of propafenone therapy was 17,3±15,16 months. The drug was effective in 39 (60%) children (81,25% with CHD and 53,06% without CHD), not effective enough in 14 (21,54%) children, ineffective in 12 (18,46%) children. There was no association of the effectiveness/inefficiency of propafenone depending on the age, sex and the type of arrhythmia. Five (7,69%) children had prolongation of PQ interval and/or QRS by more than 25%. Arrhythmogenic effect of propafenone was observed in 1 (1,54%) child, noncardiac adverse effects — in 3 (4,62%) children. There were no cases of sudden cardiac death. Conclusion. Propafenone is an effective antiarrhythmic drug in newborns and young children with supraventricular and ventricular arrhythmias, including children with CHD. Using propafenone may be accompanied with adverse and arrhythmogenic effects, which were observed in 6% of children and were not associated with CHD.

ATRIAL LEAD LOCATION PLAYS AN IMPORTANT ROLE TO AVOID UNNECESSARY VENTRICULAR PACING NOT ONLY DURING ATRIAL PACING BUT ALSO DURING ATRIAL SENSING

It is important to avoid unnecessary ventricular pacing (VP) to prevent adverse cardiac events in patients undergoing pacemaker implantation. However, Right atrial (RA) pacing sometimes causes prolongation of PQ interval leading to increase of VP frequency. The purpose of this study was to determine

Sa1480 Prolonged Severe Hypercalcemia Induces an Acute Pancreatitis in Rats, and Shortening of QTc Interval and Prolongation of Pq Interval. the Effect of the Therapy With Stable Gastric Pentadecapeptide BPC 157 (PL 14736)

Sa1480 Prolonged Severe Hypercalcemia Induces an Acute Pancreatitis in Rats, and Shortening of QTc Interval and Prolongation of Pq Interval. the Effect of the Therapy With Stable Gastric Pentadecapeptide BPC 157 (PL 14736)

Recovery from arrhythmias in lambs infected with Strongyloides papillosus following worm elimination.

Calves and lambs heavily infected with Strongyloides papillosus develop cardiac arrest by ventricular fibrillation which is preceded by continuous sinus tachycardia and prolongation of the PQ interval during the patent infection. In the present study, cardiac rhythms following anthelmintic treatment were investigated in lambs infected with S. papillosus to ascertain whether cardiac disorders due to the infection are based on a reversible and curable change. Eight lambs were given a lethal dose of S. papillosus. Five of the animals were injected with ivermectin when they developed continuous sinus tachycardia and prolongation of the PQ interval. The other three animals served as untreated controls. In the treated animals, elevated heart rates and PQ intervals began to decrease between 10 and 21 h, then continuous sinus tachycardia and prolongation of PQ interval disappeared within 39 h of treatment. No arrhythmias were detected after the disappearance of sinus tachycardia. Faecal egg counts became negative within 61 h of treatment. Only a few worms were collected from the small intestine at necropsy. The control animals developed ventricular fibrillation by 349 h after infection, having high faecal egg counts and intestinal worm burdens. These results indicate that cardiac disorders generated by S. papillosus infection are reversible and curable following worm elimination.

Antianginal effects of YM-16151-4 in various experimental angina models.

The antianginal effects of YM-16151-4, a combined calcium entry blocking and beta 1-adrenoceptor blocking agent, were evaluated in various experimental angina models and compared with those of nifedipine and propranolol. In anesthetized dogs, YM-16151-4 (0.3 and 1 mg/kg intravenously, i.v.) increased coronary blood flow and reduced myocardial oxygen consumption (MVO2). In isolated dog coronary arteries, YM-16151-4 concentration-dependently inhibited 3,4-diaminopyridine-induced rhythmic contractions with an IC50 value of 91 nM. In anesthetized rats, YM-16151-4 also inhibited the ST-segment depression induced by vasopressin (0.5 U/kg i.v.) with an ED50 value of 29 mg/kg orally, (p.o.). Nifedipine was also effective in these models, but propranolol was not. In addition, YM-16151-4 (0.3 mg/kg i.v.) inhibited the ST-segment elevation in the epicardial ECG induced by coronary artery occlusion in anesthetized dogs. Propranolol (1 mg/kg i.v.) also inhibited this elevation, but nifedipine (0.003 mg/kg i.v.) did not. In anesthetized dogs, furthermore, the prolongation of PQ-interval induced by YM-16151-4 was almost the same as that induced by propranolol. These results demonstrate that YM-16151-4, in contrast to nifedipine and propranolol, is fully effective in these various types of angina models. Thus, YM-16151-4 is expected to prove a valuable antianginal agent in treatment of various types of angina pectoris, with these antianginal effects resulting from the sum of its calcium entry blocking and beta 1-adrenoceptor blocking activities.

The applicability of noninvasive His bundle electrogram to assessing the effect of digitalis on atrioventricular conduction.

His bundle electrograms were recorded by a signal averaging technique using the Takayasu vectorial lead system, and effects of ouabain on the atrioventricular conduction were investigated using Wistar rats. Ouabain was given intraperitoneally at 30 min intervals in doses of 1-40 mg/kg. When ouabain dosage was increased to 20 mg/kg, the prolongation of PQ interval became prominent and P waves were hidden on the preceding T waves. Dose-related prolongation of PQ and AH intervals was observed in the 1-15 mg/kg dosages. Ouabain-induced ventricular arrhythmias occurred in the 30 mg/kg dosage. Dose-related prolongation of QRS duration and HV interval was observed in the 1-25 mg/kg dosages. These prolongations were significant by the analysis of variance (p less than 0.01). Prolongation of PQ and AH intervals is probably due to a digitalis-induced increase in parasympathetic nerve activity. However, the reason for the prolongation of HV interval and QRS duration was uncertain. Direct effects of ouabain on the conduction system, or central nervous system effects of ouabain on cardiovascular function were speculated. These results suggest the applicability of the noninvasive record of His bundle electrogram to assessing the digitalis effect even on the human atrioventricular conduction.

冠状動脈疾患に関する研究(第1報) : 冠状動脈疾患に関する集団検診とその予後について

The mass survey on coronary artery disease (CAD) was perfomed during the period of 1956 to 1958 in Tokyo. This study was concerned with the incidence and grade of CAD in four male populations aged above 40, and the methods of laboratory examination and the criteria of clinical diagnosis of CAD were also discussed.Inquiry of detailed medical history and physical examination including blood pressure measurement were carried out by physician. In addition, height and Weight were measured, and ECG and chest X-ray film were examined.Total number studied at initial examination was 1122 cases which were classified into four populations, namely, officers, clerks, professors and medical practitioners.Of these cases, 487 were reexamined in 1 to 2 years follow-up period.The classification of CAD was based upon the criteaia shown below : GROUR I : Infarction.GROUP A : 1) Coronary T 2) Positive exercise test 3) Abnormal S-T deviation (over 0.05 mV.) with B. P. under 179/99 mmHg.GROUP B : Abnormal ST-T deviation and/or significant cardiac enlargement with B. P. over 180/100 mmHg.GROUP C : 1) Low voltage 2) Prolongation of PQ interval (over 0.20") 3) Bundle-branch block 4) Prolongation of QRS complex (over 0.01") 5) Abnormal ST-T deviation (under 0.05 mV.) with B. P. under 179/99mmHg. 6) Significant cardiac enlargement with B. P. under 179/99 mmHg. 7) Arrhythmia beginning after middle age.GROUP D* : Hypertension (over 160/90 mmHg.) without electrocardiographic. and roentgenologic abnormalities GROUP E* : No abnormalities.(*Group D and E are not CAD.)1) In 32.8 per cent of all cases, hypertension over 160/90 mmHg. was found, and prevalence rate of hypertension showed a positive correlation with age and relative weight. But there were no differences in prevalence of hypertension between four populations.2) There were no cases with myocardial infarction, but group A was found in 2 to 3 per cent, group B in 9.3 per cent and group C in 24.8 per cent of apparently healthy indiviauals.3) Diagnosis of group A was made in 1.0 per cent of cases aged 40 to 49 years, in 3.8 per cent of 50 to 59, in 7.7 per cent of above 60. The prevalence rate of CAD was increased with age.4) The prevalence of CAD was higher in cases with high levels of blood pressure and/or relative weight than those with normal or low levels.5) Significant relationship of CAD to diet, smoking and alcohol intake was not demonstrated.6) The incidence of myocardial infarction or sudden death among 487 cases, which were reexamined at 1 to 2 years' follow-up survey, was 0.4 per cent (2 cases) and that of group A was 1.0 per cent (5 cases). All these cases showed some abnormal findings at the initial examination.7) In 1 to 2 years' follow-up period, no incidence of myocardial infarction or angina pectoris was seen in the group which was diagnosed as group A, suggesting the necessity of health control by mass survey.