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A Nogami

Publications and source records attributed to A Nogami.

At least 55 records · Page 3Linked to original sources
PubMed1997

Longitudinal dissociation in the his bundle: a possible mechanism of two distinct cycle lengths in atrioventricular reentrant tachycardia.

Two wide QRS tachycardias with identical morphology but different cycle lengths (CLs) developed in a 63-year-old man. Electrophysiological study demonstrated inducible atrioventricular reentrant tachycardia (AVRT) due to a concealed left posterior accessory pathway (AP), which was successfully ablated by radiofrequency application. Neither dual AV nodal pathways nor other APs were documented. Splitting of the His-bundle electrogram was shown, and programmed stimulation induced sudden prolongation of intra-hisian conduction time. These results suggest longitudinal dissociation in the His bundle may be responsible for two distinct CLs in AVRT without dual AV nodal physiology.

Bundle of His↗
PubMed1997

Adenosine-sensitive atrial reentrant tachycardia originating from the atrioventricular nodal transitional area.

INTRODUCTION: Atrial tachycardia shows wide variations in its electrophysiologic properties and sites of origin. We report an atrial tachycardia with ECG manifestations and electrophysiologic characteristics similar to an atypical form of AV nodal reentrant tachycardia (AVNRT). METHODS AND RESULTS: This supraventricular tachycardia was observed in 11 patients. It was initiated by atrial extrastimulation with an inverse relationship between the coupling interval of an extrastimulus and the postextrastimulus interval. Its induction was not related to a jump in the AH interval, and its perpetuation was independent of conduction block in AV node. Ventricular pacing during tachycardia demonstrated AV dissociation without affecting the atrial cycle length. A very small dose of adenosine triphosphate (mean 3.9 +/- 1.2 mg) could terminate the tachycardia. The earliest atrial activation during tachycardia was recorded at the low anteroseptal right atrium with a different intra-atrial activation sequence from that recorded during ventricular pacing, where the tachycardia was successfully ablated in 9 of 10 attempted patients. Bidirectional AV nodal conduction remained unaffected after successful ablation. CONCLUSION: There may be an entity of adenosine-sensitive atrial tachycardia probably due to focal reentry within the AV node or its transitional tissues without involvement of the AV nodal pathways. This tachycardia can be ablated without disturbing AV nodal conduction from the right atrial septum.

Adenosine↗
PubMed1997

Retrograde supernormal conduction in concealed accessory atrioventricular pathway following catheter ablation.

A case is presented of a 63-year-old woman with a concealed accessory pathway that exhibited retrograde supernormal conduction after radiofrequency catheter ablation. Although ventricular pacing at a slow rate revealed no retrograde conduction over the accessory pathway following ablation, the tachycardia recurred 15 months later. During ventricular pacing there was retrograde 1:1 conduction over the accessory pathway at a fast rate while there was intermittent VA dissociation with rare retrograde conduction at the slower rate. Ventricular extrastimulus testing demonstrated a supernormal conduction zone of the coupling interval. Thus, accessory pathways may exhibit supernormal conduction after catheter ablation. Pacing should be performed at both slow and fast rates to confirm the presence of conduction block following ablation.

Cardiac Pacing, Artificial↗
PubMed1997

Radiofrequency catheter ablation of posteroseptal atrioventricular accessory pathways--location-specific electrographic characteristics of successful ablation sites.

The electrographic features of successful sites of radiofrequency catheter ablation were analyzed in 33 cases of posteroseptal accessory pathways and compared with those from 155 cases of free wall accessory pathways. The atrioventricular intervals in the posteroseptal cases were significantly longer than in the free wall cases (posteroseptal vs left and right free wall; 38 vs 33 and 26 msec, respectively; p < 0.05), and the incidences of continuous electrograms (42 vs 63 and 79%; p < 0.01) and PQS-pattern unipolar electrograms (50 vs 76 and 78%; p < 0.05) were significantly lower in the posteroseptal cases. The V-delta intervals in the posteroseptal cases were significantly longer than in the left free wall cases (17 vs 13 msec; p < 0.05), but shorter than in the right free wall cases (17 vs 23 msec; p < 0.05). No statistically significant difference in the incidence of Kent potentials among the 3 groups was observed. In radiofrequency ablation of posteroseptal pathways, the length of the atrioventricular interval and the incidences of continuous electrograms and PQS-pattern unipolar electrograms may be unsatisfactory even at the appropriate target site, but the V-delta interval and Kent potential are good indicators of suitable target sites.

Adolescent↗
PubMed1997

Cardiomyopathy in a case of Crow-Fukase syndrome.

Crow-Fukase syndrome or POEMS syndrome is a variant of plasma cell dyscrasia that is characterized by polyneuropathy, organomegaly, endocrinopathy, the presence of M-protein in serum, and dermatological changes. A 60-year-old man presented with features of Crow-Fukase syndrome, such as the presence of M-protein in serum, dermatological changes, and osteosclerotic changes, but did not have polyneuropathy. To our knowledge, this is the first case of Crow-Fukase syndrome in which the presence of hypertrophic cardiomyopathy has been confirmed by a left endomyocardial biopsy. The findings suggest that hypertrophic cardiomyopathy may be a manifestation of organomegaly in patients with Crow-Fukase syndrome.

Cardiomyopathy, Hypertrophic↗
PubMed1997

Elevated serum lipoprotein (a) levels associated with ulcerative colitis in a young Japanese patient.

Thromboembolism has been shown to play a role in the pathogenesis of inflammatory bowel disease (IBD). A possibility exists that lipoprotein (a) [Lp(a)], a newly-discovered prothrombotic factor, also participates in the development of at least some cases of IBD. Marked elevation of serum Lp(a) levels was observed in a young patient with ulcerative colitis. A biopsy specimen of the rectal mucosa showed findings compatible with ulcerative colitis, as well as small vessel thrombus occurring within the muscularis mucosa in the rectum. Serum Lp(a) levels were markedly elevated on admission (71 mg/dl), with a gradual decrease to 46 mg/dl on discharge. Moreover, serum Lp(a) levels decreased in parallel with clinical improvement. In the quiescent clinical stage, no small vessel thrombus was observed in the mucosa on follow-up colonoscopy. The association between IBD and hyper-Lp(a)-emia would be presumable but it has been, to our knowledge, previously unreported. The case reported here would be the first young patient, suggesting the presence of hyper-Lp(a)-emia and small vessel thrombus formation occurring in association with the development of ulcerative colitis.

Adult↗
PubMed1996

Shortcut link between the fast and slow pathways and the mechanism of cure in atrioventricular nodal reentrant tachycardia by catheter ablation.

UNLABELLED: The mechanism of cure in AV nodal reentrant tachycardia (AVNRT) by catheter ablation has not been fully clarified. We hypothesized that disruption of a shortcut link between the fast and slow pathways is responsible for the elimination of tachycardia. RESULTS: AVNRT was eliminated in 20 patients by catheter ablation. In five patients (25%; group I) slow pathway conduction disappeared 1 week after ablation. In six patients (30%; group II), the effective refractory period of the slow pathway was prolonged by more than 50 ms (212 +/- 81 ms vs 340 +/- 81 ms; P < 0.05). In the remaining nine patients (45%; group III), there was no change in the refractory period (270 +/- 65 ms vs 273 +/- 74 ms), although tachycardia was not inducible. A shortcut link between the fast and slow pathways was examined by comparing the A-H intervals over the slow pathway during the tachycardia and during atrial pacing at the tachycardia cycle length. Prior to ablation, a shortcut link was assumed in 1 of group I patients, 2 of group II patients, and 8 of group III patients. Of the 9 patients in whom the slow pathway was not impaired after ablation (group III), 8 patients were found to have a shortcut link, while 8 of 11 patients with impairment of the slow pathway after ablation (groups I and II) had no shortcut link between the fast and slow pathways (P < 0.05). CONCLUSION: In patients with a shortcut link between the fast and slow pathways, slow pathway conduction itself does not need to be impaired to eliminate the AVNRT, whereas in patients without this shortcut link, slow pathway conduction must be impaired.

Adult↗
PubMed1996

Time- versus frequency-domain analysis in predicting cycle length of inducible ventricular tachycardia after myocardial infarction.

To determine whether time- and frequency-domain analyses differ in their ability to predict sustained ventricular tachycardia (VT) induced by programmed ventricular stimulation, 60 consecutive patients with myocardial infarction and 30 healthy control subjects were evaluated. Programmed ventricular stimulation using three extrastimuli and signal-averaged ECG recordings were performed in patients with myocardial infarction. Of the 60 patients, sustained monomorphic VT (SMVT) with cycle length (CL) > or = 250 ms (slow SMVT) was inducible in 9, and SMVT with CL < 250 ms (fast SMVT) was inducible in 9. The durations of the filtered QRS (f-QRS) at each high-pass filter (25, 40, and 80 Hz) and the low amplitude signal (LAS) at 25-Hz high-pass filtering were significantly longer in the slow SMVT group than in the fast SMVT, no VT, or normal control group. The root-mean-square voltages at 25-Hz and 80-Hz high-pass filters in the slow SMVT group were significantly lower than in the fast SMVT, no VT, or normal control group. There was no significant difference in time-domain variables among fast SMVT, no VT, and normal control groups. The CL of the induced sustained VT was significantly correlated with the durations of f-QRS and LAS. Concerning frequency-domain variables (area ratio and factor of normality), there was no significant difference between slow and fast SMVT groups. Both the slow and fast SMVT groups had a significantly higher area ratio and a significantly lower factor of normality than the group with no VT or the normal control subjects. In conclusion, there were significant correlations between time-domain variables and CL of SMVT, while there was no correlation when using frequency-domain parameters.

Cardiac Catheterization↗
PubMed1996

Selective radiofrequency catheter ablation of the slow pathway for common and uncommon atrioventricular nodal reentrant tachycardia.

The utility of selective radiofrequency catheter ablation of the slow pathway for the treatment of common and uncommon atrioventricular nodal reentrant tachycardia (AVNRT) was studied in 110 consecutive patients, 94 with slow-fast form common AVNRT, and 11 and 5, respectively, with the fast-slow and slow-slow forms of uncommon AVNRT. Ablation sites were determined by mapping a late and spiky "slow pathway potential" in the posterior right atrial septum in common AVNRT, and also the earliest retrograde atrial activation over the retrograde slow pathway in uncommon AVNRT. AVNRT was successfully eliminated in all patients with a mean number of radiofrequency pulses of 2.9 +/- 3.0 and a mean total energy applied of 3536 +/- 2996 joules. There were no early or late complications, except for transient AV block for 15 sec immediately after energy application in one common AVNRT patient, and no recurrence of AVNRT in a mean follow-up period of 24 +/- 13 months. There were no significant differences between common and uncommon AVNRT in success rate, mean application number and total energy applied. However, the AVN physiology post-ablation was different. Slow pathway conduction was eliminated in only 32% of the patients post-ablation in common AVNRT, while it was elininated in 100% in uncommon AVNRT. Selective radiofrequency catheter ablation of the slow pathway can cure common and uncommon AVNRT effectively and safely. Common AVNRT can be eliminated irrespective of the persistence of slow pathway conduction, while uncommon AVNRT can be eliminated by the eradication of slow pathway conduction.

Adolescent↗
PubMed1996

Evaluation of cardiac sympathetic nervous function by 123I-metaiodobenzylguanidine scintigraphy in insulin-treated non-insulin dependent diabetics with hypoglycemia unawareness.

The association between the lack of adrenergic symptoms during hypoglycemia and myocardial 123I-metaiodobenzylguanidine (MIBG) accumulation was investigated in 12 insulin-treated non-insulin-dependent diabetes mellitus (NIDDM) patients who had no evidence of heart disease. These patients were divided into 2 groups according to the presence (group A) or absence (group B) of adrenergic symptoms during hypoglycemia. Autonomic function tests revealed significantly severe autonomic dysfunction in group B compared to that in group A. Insulin infusion test indicated no significant difference in the catecholamine response between the two groups. 123I-MIBG scintigraphy showed that the heart/mediastinum ratio of MIBG uptake was significantly lower, and scintigraphic defect was greater in group B than in group A. There were no significant differences in the washout rate between the two groups. These results suggested that the lack of adrenergic symptoms during hypoglycemia may be associated with cardiac sympathetic nervous dysfunction in insulin-treated NIDDM patients, and this dysfunction is mainly due to cardiac sympathetic denervation.

3-Iodobenzylguanidine↗
PubMed1995

[Frequency versus time domain analysis in signal-averaged ECG: reproducibility and differences in predicting high risk patients with myocardial infarction].

Frequency domain analysis (FDA) and time domain analysis (TDA) are techniques for the diagnostic interpretation of signal averaged ECG. To overcome the limitations of TDA, such as noise and conduction disturbances, FDA has been developed. But the reproducibility of FDA, especially spectral temporal mapping analysis, results are significantly lower than that of TDA. We examine the difference of two methods, and the role in high risk patients with myocardial infarction. Low amplitude signal (LAS) and area ratio (AR) are independent predictors of inducible sustained monomorphic ventricular tachycardia (SMVT) by programmed ventricular stimulation. The combined use of TDA and FDA enhanced the accuracy in predicting inducible SMVT.

Body Surface Potential Mapping↗
PubMed1994

Atrioventricular nodal physiology after slow pathway ablation.

The AV nodal physiology before and 1 week after "slow pathway potential" guided catheter ablation was examined in 32 patients with AV nodal reentrant tachycardia. A mean of 4.9 applications of radiofrequency energy eliminated AV nodal reentrant tachycardia in all patients. There were no significant differences in sinus cycle length (815 +/- 159 msec vs 813 +/- 162 msec; P = NS) and fast pathway conduction properties before and 1 week after ablation. Slow pathway conduction was completely eliminated in 10 (31%) (group I) of 32 patients after ablation. In the remaining 22 patients residual slow pathway conduction associated with one AV node echo was observed. In 15 patients (47%) (group II), the effective refractory period of the slow pathway showed a change of < 30 msec (265 +/- 51 vs 266 +/- 51 msec; P = NS), and in 7 patients (22%) (group III), a prolongation of more than 80 msec (247 +/- 56 vs 340 +/- 42 msec; P = 0.0001) before and 1 week after ablation. Minimal and maximal A2-H2 interval over the slow pathway in group II was not significantly changed (Min A2-H2: 241 +/- 37 vs 247 +/- 40 msec; P = NS, Max A2-H2: 346 +/- 79 vs 350 +/- 60 msec; P = NS), while a significant prolongation was measured in group III (Min A2-H2: 261 +/- 53 vs 373 +/- 107 msec; P < 0.01, Max A2-H2: 359 +/- 41 vs 427 +/- 63 msec; P < 0.05) before and after ablation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Oxygen uptake kinetics are determined by cardiac function at onset of exercise rather than peak exercise in patients with prior myocardial infarction.

BACKGROUND: Resting cardiac function does not necessarily affect exercise capacity. However, to determine whether it affects early dynamics of oxygen uptake (VO2) during exercise, we measured VO2 during a constant work rate and during incremental exercise testing in patients with a history of myocardial infarction. VO2 kinetics and exercise capacity were compared between patients with relatively high left ventricular ejection fractions (LVEF > or = 35%, group 1) and those with lower ejection fractions (LVEF < 35%, group 2). METHODS AND RESULTS: Forty patients with a history of prior myocardial infarction (age, 57 +/- 10 years) were monitored during 6 minutes of moderate constant work rate testing (40 +/- 8 W) and during symptom-limited incremental exercise testing with a cycle ergometer. VO2 was calculated from respired gas analysis on a breath-by-breath basis. Cardiac output determinations were made with a computerized cadmium telluride detector every 10 seconds during exercise. The VO2 time constant during constant work rate exercise was slower in group 2 (58.0 +/- 7.6 seconds) compared with group 1 (45.8 +/- 10.5 seconds, P = .0002), indicating slower kinetics in group 2. The time constant for the rise in cardiac output during exercise was also slower in patients with lower EFs (63.0 +/- 12.8 versus 50.0 +/- 12.2 seconds). However, there were no differences in exercise capacity parameters, such as the VO2 or cardiac output at peak exercise, obtained during incremental exercise testing among the two groups. CONCLUSIONS: The prolonged time constant of VO2, which is primarily determined during early parts of exercise, reflects delayed cardiac output response in patients with severely impaired LV function. The time constant of VO2 during submaximal constant work rate exercise can be used as a sensitive and discriminant measure of impaired cardiac reserve in these patients.

Adult↗
PubMed1994

Radiofrequency catheter ablation of atrioventricular accessory pathways in Wolff-Parkinson-White syndrome with drug-refractory and symptomatic supraventricular tachycardia--its high effectiveness irrespective of accessory pathway location and properties.

Radiofrequency catheter ablation of atrioventricular accessory pathways was performed in 125 cases of the Wolff-Parkinson-White syndrome (type-A:54, type-B: 29, concealed: 42) complicated with drug-refractory and symptomatic atrioventricular reentrant tachycardia and/or paroxysmal atrial fibrillation. A total of 135 accessory pathways were identified: 50 left free-wall manifest, 34 left free-wall concealed, 21 right free-wall manifest, 2 right free-wall concealed, 15 posteroseptal manifest, 10 posteroseptal concealed, 2 right anteroseptal manifest and 1 right anteroseptal concealed. Accessory pathway conduction was successfully eliminated in 133 of these 135 accessory pathways (99%). Two right posteroseptal pathways were eventually ablated with direct current. Successful ablation required a mean 5.2 applications of radiofrequency current, a mean total energy of 2615 J and a mean fluoroscopic time of 52 min. The mean number of applications, applied energy and fluoroscopic time were greater in the right free-wall pathways than in the left free-wall pathways, and in the concealed pathways than in the manifest pathways. None of the procedures produced complications. During a mean follow-up period of 11.5 months, 1 right free-wall accessory pathway recurred and was ablated successfully in a repeat session. These results suggest that radiofrequency catheter ablation of accessory pathways is highly effective and safe irrespective of the accessory pathway location and properties, although these factors can affect the difficulty of this procedure. This technique may be an alternative to surgical therapy for Wolff-Parkinson-White syndrome with drug-refractory and symptomatic supraventricular tachyarrhythmias.

Adolescent↗
PubMed1994

Catheter ablation of atrioventricular accessory pathway with decremental properties connecting to the tricuspid annulus.

A 65-year-old male with Wolff-Parkinson-White syndrome presented with atrial fibrillation. The patient was found at the electrophysiological study to have two accessory pathways, a Kent fiber and an atrioventricular accessory pathway with decremental properties. The latter pathway conducted exclusively in the antegrade conduction and the ventricular insertion site was the tricuspid annulus. Both accessory pathways were successfully abolished by radiofrequency catheter ablations at the tricuspid annulus. We propose that an atrioventricular accessory pathway with decremental conduction may have various forms concerning not only sites of origin, but also sites of insertion.

Aged↗
PubMed1994

[A case of hypertrophic obstructive cardiomyopathy (HOCM) complicated by infective endocarditis (IE) and mitral regurgitation (MR)].

The case of a 56-year-old man who underwent mitral valve replacement due to HOCM complicated by IE and MR is reported. Preoperative 2D echocardiographic assessment of the mitral valve revealed systole anterior motion (SAM) and vegetation, and color flow Doppler echocardiographic examination revealed severe mitral regurgitation. The left ventricular out-flow tract gradient decreased from 140 mmHg preoperatively to 60 mmHg postoperatively. Mitral valve replacement should be considered in patients with associated IE and severe MR.

Cardiomyopathy, Hypertrophic↗
PubMed1993

Insulin-like growth factor-I induces hypertrophy with enhanced expression of muscle specific genes in cultured rat cardiomyocytes.

BACKGROUND: Cardiac hypertrophy is commonly observed in acromegalic patients, in whom serum insulin-like growth factor-I (IGF-I) levels are elevated. In the present study, we examined whether IGF-I induces hypertrophy in cultured neonatal rat cardiomyocytes through its specific receptor and whether IGF binding protein-3 (IGFBP-3), which is a major circulating carrier protein for IGF-I, inhibits IGF-I-induced cardiac hypertrophy in vitro. METHODS AND RESULTS: Because the response of cardiac hypertrophy is characterized by the induction of expression for muscle-specific genes, the effect of IGF-I on steady-state levels of mRNA for myosin light chain-2 (MLC-2) and troponin I and for skeletal and cardiac alpha-actin isoforms was evaluated by Northern blot analysis. IGF-I (10(-7) M) increased mRNA levels for MLC-2 and troponin I as early as 60 minutes with maximum levels by 6 hours, which were maintained for as long as 24 hours. IGF-I (10(-7) M) also increased transcripts for skeletal alpha-actin but not for cardiac alpha-actin. The cell size as evaluated morphometrically was almost doubled after 48-hour treatment with IGF-I. IGF-I induction of protein synthesis was dose dependent (10(-10) to 10(-7) M) with a maximal 2.2-fold increase seen at 10(-8) M. In contrast to the hypertrophic effect of IGF-I, growth hormone affected neither protein synthesis nor expression for muscle-specific genes. Binding study using 125I-IGF-I revealed the presence of specific binding sites for IGF-I in rat cardiomyocytes. IGFBP-3 induced a dose-dependent inhibition of protein synthesis stimulated by IGF-I; IGFBP-3 (10(-7) M) completely inhibited the [3H]leucine uptake stimulated by IGF-I (10(-8) M). IGFBP-3 similarly inhibited the IGF-I-stimulated gene expressions for MLC-2 and troponin I. CONCLUSIONS: These results suggest that IGF-I directly causes cardiac hypertrophy and that its effect can be blocked by IGFBP-3.

Actins↗