PubMed Health⌕ Search

Biomedical subjects

M Fukatani

Publications and source records attributed to M Fukatani.

31 records · Page 2Linked to original sources
PubMed1989

Intra-atrial conduction delay and fragmented atrial activity in patients with paroxysmal atrial fibrillation.

To examine the electrophysiologic characteristics of paroxysmal atrial fibrillation (PAF), we studied intra-atrial conduction delay and fragmented atrial activity during premature stimulation of high right atrium in the following four groups: Group I (n = 25), patients without PAF and without sick sinus syndrome (SSS); Group II (n = 22), patients with PAF but without SSS; Group III (n = 10), patients without PAF and with SSS; Group IV (n = 6), patients with PAF and SSS. Intra-atrial conduction delay was the increase in the interval (from the stimuli to the coronary sinus electrogram) observed with early premature beats greater than or equal to 20 ms compared with that of basic rhythm. Fragmented atrial activity was defined as disorganized atrial activity greater than or equal to 150% of the duration of high atrial activity of basic beats recorded. The conduction delay zone (CDZ) and fragmented atrial activity zone (FAZ) were significantly wider in Groups II, III and IV than in Group I. There were no significant differences in either CDZs or FAZs among Groups II, III and IV. Thus, the widening of CDZs and/or FAZs are characteristic of PAF and SSS. CDZ and FAZ may be good indices of development of PAF in patients without SSS.

Adolescent↗
PubMed1988

The total heart beats per 24 hours by ambulatory electrocardiography and the changes of heart rate by treadmill exercise test in sick sinus syndrome.

To study the clinical implications of the total number of heart beats per 24 hours (THB), 24 hour ambulatory electrocardiography and treadmill test were performed by sixty patients with sick sinus syndrome (SSS, 58 +/- 12 years old) who underwent overdrive suppression test. Results were compared with thirty control subjects (58 +/- 12 years old). The THB was 74 +/- 11 thousand beats in the SSS group and 99 +/- 10 thousand beats in the control group. The THB and the maximal heart rate (MHR) achieved during the treadmill test were significantly lower in the SSS group than in the control group. However, the exercise duration in patients with SSS was similar to that of the control subjects. The exercise duration and the MHR were correlated to age, but not to the THB in the patients with SSS. There was no significant relationship between the total heart beats per 24 hours and the maximal sinus node recovery time (max. SNRT). We conclude that the THB, independent of the max. SNRT, can be a useful index in diagnosing and assessing the quantity of bradycardia in patients with SSS. The tolerance of exercise and the MHR were not correlated with the THB, in patients with SSS.

Adult↗
PubMed1987

Periodic occurrence of premature atrial beats inducing alternation during supraventricular tachycardia in a case of pre-excitation syndrome.

During orthodromic atrioventricular reciprocating tachycardia (AVRT) in a patient with pre-excitation syndrome, 2:1 to 9:1 cycle length alternation was observed. The alternation was induced by the development of premature atrial beats (PABs) recurring in every three to ten AVRT beats. An electrophysiologic study revealed that: 1) PAB developed periodically during atrial/ventricular tachy-pacing (at a rate of 140-170 times/min), during atrial/ventricular extrastimulus study, and during electrically induced AVRT. 2) The PAB had a constant coupling interval to the preceding atrial complex, probably an atrial echo beat, and was associated with no His bundle or ventricular deflection. 3) An intensive search failed to reveal any third ventriculo-atrial conduction pathway. The PABs may have been induced by intra-atrial reentry or by triggered activity in the atrium.

Anti-Arrhythmia Agents↗
PubMed1986

Sinus node function after selective elimination of sympathetic influences on the sinus node area of the dog.

Six-hydroxydopamine (6OHDA) was injected directly into the subepicardium of the sinus node area in an attempt to damage sympathetic nerve terminals in the sinus node. The changes in sinus node function were observed for 4 weeks. The predominant rhythm was of sinus origin throughout the observation period. The sinus rate progressively decreased from 145.1 +/- 14.2 to 76.2 +/- 12.1 beats/min during the first week after injection of 6OHDA. The sinus rate remained at this level for 2 weeks, followed by a gradual increase to 89.3 +/- 18.2 beats/min 4 weeks after injection of 6OHDA. These sinus rates were only significantly different from control dogs through the 14th postoperative day. The sinus rate was considerably increased by intravenous atropine injections 5 to 7 days after the injection of 6OHDA into the sinus node area. The sinus node recovery time was much longer in dogs with an injection of 6OHDA than that in the control dogs throughout the observed period. These results suggest that elimination of the sympathetic influences on the sinus node can be achieved by direct injection of 6OHDA into the sinus node area in the dog, and that sinus node function can be depressed by decreasing sympathetic tone alone, in the absence of an intrinsic dysfunction of the sinus node.

Animals↗
PubMed1978

Long-term follow-up after cardiac pacing in bradyarrhythmias.

Fifty-nine patients aged 39-80 years underwent implantation of a cardiac pacemaker and were followed for up to 9 years (average duration of pacing 39 months). Atrioventricular conduction disturbances (complete atrioventricular block, 2 : 1 atrioventricular block, bifascicular block, and atrial fibrillation with slow ventricular rate) were present in 49 patients and sick sinus syndrome (sinus arrest or sino-atrial block, and bradycardia-tachycardia syndrome) in 10. Pacing was required because of Adams-Stokes attacks in 41 patients, 2 of whom also had congestive heart failure. It was required in 6 because of frequent dizziness, in 10 because of congestive heart failure, and in 2 because of low cardiac output. The symptomatic improvement after cardiac pacing was well recognized in most of our patients, and 32 (54 percent) of the 59 patients pursued normal physical and daily activity. Although the efficacy of pacemaker therapy was of limited value in some patients with congestive heart failure or underlying or coexisting diseases, the beneficial effects following pacemaker implantation were: (1) abolishment of transient neurologic symptoms such as Adams-Stokes attack, (2) relief from a constant fear of a recurrence of an Adams-Stokes attack or sudden cardiac death, and (3) improvement in restricted physical activity due to low cardiac output. Thus, we conclude that pacemaker implantation in most patients with bradyarrhythmias is beneficial not only for the treatment of the acute problem but also because it prolongs life and greatly enhances its quality. However, in spite of the beneficial effects after pacemaker implantation, we still observe a number of complications connected with the use of a permanent pacemaker. Therefore, our policy is to implant a permanent pacemaker following the execution of sufficient studies of the bradyarrhythmia and the etiology of symptoms, and then under taking long-term follow-up of the patients.

Adult↗
PubMedDate not supplied

Effect of verapamil directly administered into A-V node artery on A-V junctional automaticity and A-V conduction in dogs.

We investigated the direct effects verapamil, which was infused into the A-V node artery at two doses of 0.01 and 0.1 microgram/kg/min on the A-V conduction and the A-V junctional automaticity in the dog with experimentally induced A-V junctional rhythm. Verapamil significantly prolonged the A-H interval, but not the H-V interval, in the His bundle electrogram during atrial pacing at a rate of 100 beats/min. Effective and functional refractory periods of the A-V node also were prolonged significantly by verapamil. On the other hand, verapamil showed less propensity to decrease the spontaneous A-V junctional rate and to prolong the A-V junctional recovery time after atrial overdrive at a rate of 100 beats/min for 60 s. These results indicate that suppressive effects of verapamil on the A-V junctional automaticity are much weaker when compared with that on the A-V conduction.

Animals↗