Evaluation of the thoracodorsal artery as an alternative conduit for coronary bypass.

Complete coronary revascularization using arterial grafts has been performed recently because of their improved patency rates. However, as the need to repeat coronary bypass surgery has become more frequent, it can be difficult to find adequate conduits for further bypass surgery. Therefore, we investigated the use of the left thoracodorsal artery (LTDA) as an alternative bypass conduit. The length from its origin, internal diameter, and number and location of branches were angiographically measured in 16 patients, and in situ blood flow volume and external diameter were intraoperatively measured in 8. Moreover, each specimen of the LTDA, the internal thoracic artery (ITA), and the inferior epigastric artery (IEA) were evaluated histologically. We found that the thoracodorsal artery has the same diameter as the ITA angiographically, and the same histological findings as the IEA. In conclusion, the thoracodorsal artery may be useful as a coronary arterial graft.

[A cross-sectional study on relationships between daily physical activity and concentration of serum cholesterol and body mass index in fifth grade elementary schoolchildren and their parents].

The purpose of this study was to estimate the effects of daily physical activity on serum total cholesterol (TC) and high density lipoprotein cholesterol (HDL-C), body mass index (BMI) and atherogenic index (AI) in 240 fifth grade schoolchildren, their 174 fathers and 212 mothers. Information on daily physical activity was obtained by inquiry with a questionnaire and was also measured directly with a device sensing acceleration of physical movement. In schoolchildren, effect of physical activity on TC, HDL-C and AI was not apparent, but that on BMI was shown. In adult men, HDL-C differed by job classification and increased as the degree of physical labor increased from desk work to light and heavy work. Strength of physical activity using the quotient of total amount of measured physical activity divided by body weight had a significant positive correlation with serum HDL-C (r = 0.20, p < 0.05) and significant negative correlation with AI (r = -0.18, p < 0.05) in adult men. In adult women, daily physical activity did not have a significant correlation to TC, HDL-C, AI or BMI. These results appear to suggest that the effect of daily physical activity on serum cholesterol, AI, BMI of schoolchildren and adult women was smaller than that for adult men.

[Effects of smoking and drinking habits and vitamin A intake on serum concentrations of beta-carotene and retinol].

Serum samples from 341 males aged 10 to 59 years were obtained and stored at -40 degrees C until examined for retinol and beta-carotene concentrations by HPLC, and their relationships to smoking habit, alcohol drinking habit and vitamin A intake were studied. In univariate analysis the serum beta-carotene level was significantly lower in the smokers than in the non-smokers (smokers: 4.6 micrograms/dl, non-smokers: 7.1 micrograms/dl, p less than 0.01) and lower in the drinkers than in the non-drinkers (drinkers: 4.6 micrograms/dl, non-drinkers: 7.3 micrograms/dl, p less than 0.01). The serum retinol level was not different by smoking habit but was higher in the drinkers than in the non-drinkers (drinkers: 80.4 micrograms/dl, non-drinkers: 67.0 micrograms/dl, p less than 0.01). Serum beta-carotene was higher in the group with a greater intake of vitamin A of vegetable origin (6.1 micrograms/dl) than in the group with a smaller intake of it (4.7 micrograms/dl) (p less than 0.01), but serum retinol was not different by the amount of vitamin A intake of animal food origin. To estimate the respective effects and interactions of the above factors on serum beta-carotene and retinol levels by adjusting for the confounding effects of age, serum total cholesterol, HDL-cholesterol and triglyceride, analysis of covariance was performed. For serum beta-carotene, smoking habit (p less than 0.01), drinking habit (p less than 0.01) and the amount of vitamin A intake of vegetable food origin (p less than 0.05) had significant main effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Frequency and output-dependent change in conduction over slow pathways in a patient with sustained ventricular tachycardia unrelated to coronary artery disease.

In a patient with sustained ventricular tachycardia, we obtained two different paced QRS morphologies from a single pacing site. In one QRS morphology the stimulus to the QRS complex was long, 150 msec, and in the other it was 100 msec. At the paced cycle length of 600 msec and the stimulus output of 4 V, one QRS morphology with the stimulus to the onset of QRS activation (St-QRS) interval of 150 msec was observed. At the paced cycle length of 400 msec, the other QRS morphology with a St-QRS interval of 100 msec was observed alternatively with the former. At the paced cycle length of 353 msec or 316 msec, the latter with a shorter St-QRS interval was exclusively observed. When the stimulus output was increased from 4 to 10 V, keeping with the paced cycle length at 400 msec, the St-QRS interval was shortened from 100 to 80 msec. For the two QRS morphologies with two St-QRS intervals, two slowly conducting pathways would be responsible. The site of the block in the faster pathway must be located at the proximity of the pacing site and the conduction at a shorter paced cycle length would be explained by "supernormal conduction."

[Circadian variations of sudden death].

Characteristics of the circadian variation for sudden death (SD), were studied by analyzing summary death certificates for the period of 1984 to 1986 in Niigata prefecture. SD was defined as death within 2 hours of onset of underlying cause (n = 4,362), and the time of onset of the cause was determined by subtracting the "time elapsed until death" from the "time of death." The periodicity for time of onset of the cause was analyzed in groups stratified by year, season, sex and age with Rogers' method utilized to check the statistical significance of the periodicity. SD, as a whole, showed a statistically significant circadian variation with a low incidence during 0 to 4 A.M. and a high incidence during 6 to 8 A.M. and 6 to 8 P.M. By season, no significant circadian variation was seen in the summer unlike for other seasons. When analyzed by age group, no significant circadian variation in SD was seen for the young to middle aged group (15-54 years old). On the other hand, there was a significant circadian variation for the senior (55 to 74 years old) and the elderly group (75 years old or older) with a low incidence during 0 to 4 A.M. and high incidence during 6 to 12 A.M. and 6 to 8 P.M.. For the old age group, the number of the cases increased so remarkably as to form an evening peak. The percentage of SD for young to middle cases was higher in the summer than in the other seasons which may be the reason for absence of significant circadian variation in the summer.

Entrainment of ventricular tachycardia in arrhythmogenic right ventricular tachycardia.

In two patients with arrhythmogenic right ventricular dysplasia (ARVD), sustained ventricular tachycardia (VT) was induced by programmed stimulations during serial drug testings. One patient had five and the other had two VT morphologies, and the sites of origin were determined by endocardial catheter mappings. When overdrive pacing was performed, constant fusion in the QRS complex was observed in the two patients. Constant fusion of a different degree was also observed at different paced cycle lengths. Both patients had dilated right ventricles and wall-motion abnormality, and the diagnosis of ARVD was further confirmed by the specimen resected at the site of origin of VT. Therefore, VT in ARVD can be entrained and reentry is the most likely mechanism of such VT.

Experimental study about removal of the implanted tined polyurethane ventricular lead by radiofrequency waves through the lead.

Polyurethane pacemaker leads are widely used nowadays. However, only a few studies have been done to investigate the fixation mechanism of polyurethane leads. To elucidate how pacemaker leads are fixed at the early phase after implantation, polyurethane-insulated tined ventricular leads were implanted in seven mongrel dogs. One to 4 months later, tips of the leads were anchored among the trabeculae and the distal part of the leads were encapsulated by whitish fibrous tissue. It was found that not organized thrombi, but cell reaction with various stages of inflammatory cells was responsible for forming the fibrous tissue. We attempted to remove the lead by delivering radiofrequency wave through the lead. However, no lead could be removed.

Aortitis syndrome, coronary artery ectasia, and mid-ventricular obstruction.

A 46-year-old Japanese woman, who had been diagnosed as having aortitis syndrome 4 years earlier, was admitted to our hospital in May 1989. The diagnosis of aortitis syndrome was confirmed by intravenous digital subtraction angiography which showed stenotic lesions in each subclavian artery, the left common carotid artery, and the descending aorta. Coronary arteriography revealed diffuse and prominent dilatation of entire coronary artery segments. Moreover, a left ventriculogram showed complete obstruction of the mid-ventricle during systole. Thus, we diagnosed this case as aortitis syndrome complicated by coronary artery ectasia and mid-ventricular obstruction. The causal relations of these findings are discussed.

Proarrhythmic effects of antiarrhythmic drugs assessed by electrophysiologic study in recurrent sustained ventricular tachycardia.

Proarrhythmic responses were evaluated in repeated electrophysiologic studies (EPS) in 27 patients with inducible ventricular tachycardia (VT). Class Ia drugs were administered to 23, Ib to 6, Ic to 4, III to 5 and IV to 9 patients. The mean age was 53 years, and 18 patients had structural heart diseases. Pleomorphism was observed in 11 patients. In 4 patients (15%), the VT cycle length (CL) shortened by 50 ms or more in EPS during the administration of antiarrhythmic drugs. VT was inducible by a less aggressive induction mode than the control study in 9 patients (33%). In 4 patients (15%), the induced VT changed to the incessant form, and the other 2 patients (7%) required DC shocks due to hemodynamic deterioration. Patients with pleomorphic VT and/or structural heart diseases seemed to develop proarrhythmia more frequently. In total, some proarrhythmic response was observed in 13 (48%) of the 27 patients. Therefore, it should be kept in mind that proarrhythmic effects are frequently observed during antiarrhythmic therapy in patients with sustained VT. The action of the drugs on the slow conduction zone may vary, which may provide a basis for the development of proarrhythmia.

[Past histories of sudden death without specific underlying disease].

To study past histories of patients who died suddenly, we selected cases from all the summary death certificates in which death occurred within 24 hours from the onset of symptoms spanning 1984 to 1986 in Niigata prefecture with a population of 2.5 million. We then re-examined all information on the death certificates to determine the underlying causes. Sudden deaths due to cardiovascular diseases other than acute myocardial infarction and cerebrovascular accident (OCD) accounted for the largest proportion (51.4%). The proportion of death of unknown etiology increased with the decrease in age in both sexes aged 15 to 54 years, accounting for 67.8% in males and 51.1% in females. The number of cases with histories of diseases related to atherosclerosis (e.g. hypertension, old cerebrovascular accident, etc) increased with age in both sexes, accounting for 38.5% in males and 36.4% in females, both aged 75 years old and over. Except diseases related to atherosclerosis, the past histories accounted for 2.5% or greater were as follows: alcoholism (4.1%), psychiatric disorder (PSY, 2.9%) and valvular heart diseases (VD, 2.6%) in 15-54-year-old males; ischemic heart diseases (IHD, 9.4%), arrhythmia without organic heart diseases (ARR, 2.5%) and VD (2.5%) in 55-74-year-old male; IHD (11.4%), bronchial asthma (3.7%), common cold within one month (CC, 3.6%), cor pulmonale or its related diseases (3.0%) and ARR (2.6%) in male of 75 years old and over; PSY (8.7%), IHD (5.8%), VD (5.1%), pregnancy, delivery or related diseases (4.4%), chronic renal failure (3.6%) and CC (2.9%) in 15-54-year-old females; IHD (10.2%), VD (3.2%) and ARR (2.6%) in 55-74-year-old females; and IHD (11.8%) in females of 75 years old and over. When diseases related to atherosclerosis were included, half of the sudden death cases due to OCD had past histories of underlying cause. As descriptions of past histories are often incomplete, there were probably more cases with past histories. The results of this study indicate that investigation of past histories may aid in elucidating and preventing sudden death.

Requirements of non-pharmacologic interventions in the treatment of recurrent sustained ventricular tachycardia.

Sixty-five patients (pts) with sustained ventricular tachycardia (VT) and 1 patient with symptomatic nonsustained VT were included in this study. Of these, 5 had died before electrophysiologic study (EPS) or determination of effective antiarrhythmic drugs. Inducibility of VT by our protocol varied from 69 to 100% according to underlying diseases. Drug efficacy was evaluated by using conventional drugs in all and using flecainide and amiodarone in some. However, more than 50% of pts with inducible VT were found to be resistant to pharmacological therapy. Fourteen of 26 pts with drug-refractory VT, underwent surgical therapy. In all pts, the site of VT origin was determined and VT was either eradicated or clinically controlled in 86% of the patients. Catheter ablation was tried in 9 pts at the earliest activation site of VT or at the site where pace-mapping produced the best result in configuration in the QRS complex as the clinical VT. Prophylactic effect was confirmed in 60% but VT recurred in 3 pts. These VT became responsive to anti-arrhythmic drugs in 2 pts. In thirteen pts who died suddenly during the follow up period, none had adequate antiarrhythmic drugs. One patient died after operation because of residual VT among four different QRS morphologies found preoperatively. In conclusion, the success rate antiarrhythmic drug prophylaxis against VT induction or recurrence did not exceed 50%, therefore non-pharmacological interventions such as surgery or catheter ablation may be required.

Electrical catheter ablation for drug-refractory sustained ventricular tachycardia with old myocardial infarction--a case report.

We performed electrical catheter ablation (ECA) in a patient who had old myocardial infarction and drug-refractory sustained ventricular tachycardia (VT). ECA using 100J to the earliest activation site and the pace-mapping site failed to prevent the VT. ECA using the same energy to the site at which mid-diastolic potential was recorded during tachycardia could successfully ablate the VT. Therefore the site of energy delivery was important in VT with old myocardial infarction.

Ventricular tachycardia with two possible exits from one re-entrant circuit.

A case of sustained ventricular tachycardia (VT) with two possible exits from one re-entrant circuit is described in this paper. The patient was a 27-year-old female who had undergone corrective surgery for tetralogy of Fallot at the age of 8, and developed VT of distinctly different QRS configurations. The exit of one VT was at the right ventricular (RV) outflow tract and the other at the RV apex as determined by endocardial and pace-mapping. Continuous and split activities were observed at the RV outflow tract during both types of VT. One VT was entrained by rapid pacings, and the causal mechanism was thought to be re-entry and common re-entrant circuit was established for two QRS configurations of VTs. A discrepancy was observed between the site of the earliest activation and the site of the pace-mapping which resulted in QRS configuration of VT of the RV apex origin. The findings in this paper should be considered when contemplating aggressive therapy such as electrical ablation.

[Abnormal local ventricular electrogram and its relation to induction of ventricular tachycardia in patients with hypertrophic cardiomyopathy].

To investigate the mechanism of induction of ventricular tachycardia (VT) in patients with hypertrophic cardiomyopathy (HCM), we reviewed and analyzed the local ventricular electrograms (LVE) at the pacing sites in 15 patients with HCM and 52 control subjects. Each patient had a clinical history of nonsustained VT or syncope. The results were as follows: 1. Rapid and polymorphic VT was induced in six of the 15 patients with HCM and in 10 of the 52 control subjects. 2. The duration of the LVE at the pacing site was progressively prolonged as the number of extrastimuli were increased or the premature intervals were shortened. Compared with the controls, patients with HCM had longer durations of the LVE by basic drive, single extrastimulus, and by double extrastimuli: 113 +/- 31 vs 95 +/- 16 ms (p less than 0.005), 156 +/- 35 vs 109 +/- 17 ms (p less than 0.001), and 220 +/- 88 vs 133 +/- 25 ms (p less than 0.001), respectively. 3. In the HCM group, the maximum duration of the LVE by double ventricular extrastimuli was significantly longer in patients with inducible VT compared with those with non-inducible VT: 287 +/- 95 vs 183 +/- 56 ms (p less than 0.05). 4. Induction of VT in the HCM group was accompanied by the critical prolongation of the LVE at the pacing site. In two of the six patients with HCM, the LVE at the pacing site spanned the entire cardiac cycle at the time of the initiation of VT.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrophysiologic evaluation of asymptomatic patients with the Wolff-Parkinson-White pattern.

In the past 4 years, 34 asymptomatic patients with the Wolff-Parkinson-White (WPW) pattern underwent electrophysiologic study. The effective refractory period (ERP) of antegrade conduction over the accessory pathway was 288 +/- 29 msec. In three asymptomatic patients (9%), the antegrade ERP of the accessory pathway was shorter than 250 msec. The antegrade ERP of the accessory pathway became shorter than 250 msec in an additional 12 of 22 (55%) patients after isoproterenol administration. Nineteen (56%) of the asymptomatic patients showed the absence of retrograde conduction over the accessory pathway even after isoproterenol administration. The rate of induction of orthodromic reciprocating tachycardia in the asymptomatic WPW patients was 15% (5/34), which was significantly lower than that in the symptomatic patients. These data suggest that in the asymptomatic patients, the absence of retrograde conduction over the accessory pathway is the reason they remained asymptomatic, free of reciprocating tachycardia. However, even in the asymptomatic patients, some had the accessory pathway in which antegrade ERP was shorter than 250 msec. They may result in rapid ventricular conduction over the accessory pathway when atrial fibrillation develops.

[Association of sustained ventricular tachycardia and a mid-systolic click: a case report].

A 27-year-old woman had a history of palpitation at the age of nine. Ventricular tachycardia (VT) was detected four years ago and treatment with procainamide was started. Physical examination disclosed nothing abnormal other than an apical mid-systolic click. Electrocardiogram and chest radiograph were normal, and echocardiogram disclosed borderline mitral valve prolapse (MVP). VT was not provoked by exercise, and Holter monitorings of electrocardiogram were always within a normal limit. Angiography was normal. Electrophysiological study disclosed VT by left ventricular stimulation and the earliest activation was at the apex, VT was abolished by early stimulation from the right ventricular apex. The association of a mid-systolic click and VT was interesting in this case. When the patient had a systolic click at the outpatient clinic, VT frequently occurred within a month (six of seven times), while VT did not occur without an audible systolic click (three of four times). Although it is uncertain whether VT of this patient has any relationship to MVP or to the click, these problems remain to be solved in the future.

[Evaluation of therapeutic interventions of sustained monomorphic ventricular tachycardia guided by an electrophysiologic study: a case report].

Therapeutic evaluation of sustained monomorphic ventricular tachycardia (VT) using electrophysiologic study (EPS) is presented in a case of refractory VT. A 54-year-old man with a history of recurring syncope underwent coronary angiography which revealed total occlusion of the posterior descending branch of the right coronary artery. Left ventriculography showed a left ventricular aneurysm at the cardiac apex. Ejection fraction of the left ventricle was 36%. He had four VTs of different QRS morphologies in 12 lead electrocardiograms. According to our programmed ventricular stimulations, single or double, and rarely triple, extra stimuli were administered after eight basic stimuli at two basic cycle lengths. Rapid ventricular pacing, up to 210 bpm, was then added. The stimuli were delivered to two different sites in the right ventricle and to at least one site in the left ventricle. When the entire protocol could not induce VT, isoproterenol was given intravenously, and the same protocol was repeated. No drug could prevent VT attacks, even after the surgical resection of two VT foci, VT was still inducible. Postoperative drug therapy could not prevent VT induction in EPS. However, changes in the mode required for VT induction were observed. Among 47 patients with sustained monomorphic VT treated in our hospital, 24 had EPS to evaluate the efficacies of therapeutic interventions, such as drugs and surgery. In 14 patients, no VT was induced by the entire VT induction protocol. Among the remaining 10 patients, four showed changes in the VT induction mode, but VT recurred in their clinical courses even after their treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrophysiologic study of patients with ventricular dysrhythmias during long-term follow-up after repair of tetralogy of Fallot.

We performed an electrophysiologic study (EPS) in 8 patients who had received corrective surgery for tetralogy of Fallot. The mean age was 30 years. An average of 15 years had elapsed after corrective surgery. Two patients had episodes of syncope. ECG showed normal sinus rhythm in 7 patients and atrial fibrillation in 1, and all had complete right bundle branch block. All patients had ventricular premature beats of grade 3 or higher of Lown's classification. Overdrive suppression test was performed in 6 patients. Corrected sinus node recovery time (CSNRT) ranged from 230 msec to 510 msec. Wenckebach block of atrioventricular nodal conduction occurred at rates of 130 to 170 bpm during atrial pacing. The H-V interval was prolonged to 60 msec in 1 patient, but was below 55 msec in the others. Programmed stimulation induced ventricular tachycardia (VT) in 3 patients, nonsustained VT in 2 and sustained VT in 1. In 2 of 3 patients, delayed potential or fragmentations were recorded in the outflow tract of the right ventricle. During the follow-up period of 20 months, 2 patients died suddenly. Their CSNRTs and H-V intervals were normal. Ventricular tachyarrhythmia seems to be important as a cause of late sudden death after repair of tetralogy of Fallot.

Potency and receptors involved in coronary vasoconstriction caused by neuropeptide Y(NPY).

Using anesthetized dogs, the coronary vascular effects of neuropeptide Y (NPY) were studied and the action of alpha- or serotonergic receptor blockade on the action of NPY was evaluated. To demonstrate the biological significance of the action of NPY, the vasoconstrictor potencies of NPY and norepinephrine were compared. One to 5 nmol of intracoronary NPY reduced coronary flow in a dose-dependent manner. The action started rather gradually and lasted for 10 min or more. Since perfusion pressure and central venous pressure were unchanged, the decrease in coronary flow should be a result of coronary vasoconstriction. Intracoronary norepinephrine infusion caused vasodilatation but when dogs were pretreated with 0.5 to 1.0 mg/kg of systemic propranolol, a vasoconstrictor effect was observed at a 5 times higher dose than with NPY. Furthermore, the action of NE was only transient, lasting for 30 sec or less. The vasoconstrictor action of NPY was not antagonized by phentolamine or by ketanserin. Since NPY is an endogenous polypeptide found in the sympathetic nerve terminals around coronary arteries, it may participate in the regulation of coronary flow.