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Biomedical subjects

Haruhiko Abe

Publications and source records attributed to Haruhiko Abe.

At least 19 recordsLinked to original sources
PubMed2004

Cardiac autonomic balance and QT dispersion during head-up tilt testing in diabetics with and without sensory neuropathy.

BACKGROUND: Cardiovascular autonomic dysfunction is associated with higher mortality in diabetics. However, detection methods of early cardiac diabetic dysautonomia, and its correlation with severity of sensory neuropathy, have not been described. METHODS: We analyzed the heart rate variability (HRV) by spectral analysis and QT dispersion in 23 diabetics with and without sensory neuropathy, and in 5 age-matched controls, in the supine position and during head-up tilt testing (HUT). Diabetics were divided into 3 groups according to the degree of sensory neuropathy. RESULTS: In the spectral analysis of HRV, the high frequency components in the supine position decreased as a function of severity of the neuropathy. High frequency in diabetics was significantly decreased in the supine position, even in absence of sensory neuropathy. The low/high frequency ratio (L/H) in the supine position was similar among controls and the 3 patient groups. L/H in diabetics with moderate or severe neuropathy did not increase from the supine to the upright position. Baseline QT dispersion increased proportionally to the severity of sensory neuropathy and, in patients without apparent sensory neuropathy, QT dispersion increased significantly during HUT. CONCLUSIONS: The spectral analysis of HRV and measurements of QT dispersion, before and during HUT, were reliable detection methods of early abnormalities in autonomic balance and may predict a risk of sudden cardiac death in diabetics.

Aged↗
PubMed2004

Determination of baroreceptor-stroke volume reflex sensitivity by power spectral analysis: a quantitative probe of baroreceptor-cardiac reflex.

Baroreceptor-cardiac reflex, which consists of baroreceptor-induced chronotropic and inotropic actions, is a very useful index of cardiac sympathovagal balance. Baroreceptor-heart rate reflex sensitivity, which reflects baroreceptor-induced chronotropic action, has been used as a marker of baroreceptor-cardiac reflex. However, it cannot be used in patients with chronotropic incompetence and/or implanted cardiac pacemaker. We hypothesized that baroreceptor-stroke volume (SV) reflex sensitivity, which reflects baroreceptor-induced inotropic action, may also be a useful method for measurement of baroreceptor-cardiac reflex, similar to the baroreceptor-heart rate reflex sensitivity. To test this hypothesis, we measured baroreceptor-SV reflex sensitivity expressed as ratio of low frequency (LF) power to total power of SV fluctuation (LF/TP(SV): %/mmHg) by spectral analysis of mean blood pressure and SV fluctuations, the gain in low-frequency band between two signals in supine and 60 degrees upright positions, and compared these values to baroreceptor-heart rate reflex sensitivity in 14 healthy subjects. Baroreceptor-SV reflex sensitivity correlated significantly with baroreceptor-heart rate reflex sensitivity (r = 0.73, p < 0.0001). In addition, baroreceptor-SV reflex sensitivity correlated significantly and positively with high frequency (HF) power (r = 0.57, p < 0.005) and negatively with LF/HF ratio (r = -0.57, p < 0.005) in power spectral analysis of R-R interval variability. Moreover, baroreceptor-SV reflex sensitivity in LF/TP(SV) correlated positively with the R-R interval (r = 0.70, p < 0.0001) and negatively with diastolic blood pressure (r = -0.50, p < 0.01). We conclude that baroreceptor-SV reflex sensitivity in LF/TP(SV) can be used as a quantitative probe of baroreceptor-cardiac reflex, similar to the baroreceptor-heart rate reflex sensitivity in healthy subjects, and it may enable us to estimate inotropic aspect in baroreceptor-cardiac reflex in patients with chronotropic incompetence and/or implanted pacemaker.

Adult↗
PubMed2004

Twice-daily administration of a long-acting angiotensin-converting enzyme inhibitor has greater effects on neurohumoral factors than a once-daily regimen in patients with chronic congestive heart failure.

Although many clinical trials have evaluated the use of long-acting angiotensin-converting enzyme (ACE) inhibitors in patients with chronic congestive heart failure (CHF), there are no data regarding whether a once-daily or twice-daily regimen is preferable with respect to effects on the neuroendocrine system. To address this issue, the authors evaluated the comparative effects of the administration schedule on neurohumoral factors and autonomic nervous activity in patients with CHF. Thirty-two patients with mild compensated CHF received lisinopril (5-20 mg/d) orally either once a day (n = 17) or twice a day (n = 15) for more than 3 months. After this initial therapy, patients receiving a once-daily regimen switched to a twice-daily regimen and vice-versa, and patients were followed for an additional 3 months. Neurohumoral factors and the coefficient of variance in the electrocardiographic R-R interval (CVRR) were measured. Hemodynamic parameters, renal function, plasma concentrations of brain natriuretic peptide and aldosterone, and CVRR did not differ between the two regimens. However, the plasma concentration of norepinephrine was significantly lower, and plasma renin activity tended to be lower with the twice-daily regimen. These findings suggest that twice-daily administration of long-acting ACE inhibitors may have better effects on the neuroendocrine system than a once-daily regimen in patients with mild CHF.

Aged↗
PubMed2004

New onset of pacemaker dependency after permanent pacemaker implantation.

Pacemaker dependency has dangerous consequences under conditions of electromagnetic interference, unrecognized lead dysfunction, and battery depletion, and has been associated with cardiovascular and overall mortality. The aim of this study was to examine the incidence of new onset of pacemaker dependency during long-term follow-up after pacing system implantation. The study included 518 patients (mean age 72.9 +/- 10.4 years) who presented with intrinsic rhythms at the time of implantation. Indications for pacing were sick sinus syndrome (SSS) in 275 (53%) patients, AV block in 209 (40%), and AF with bradycardia in 34 (7%) patients. The mean follow-up was 3.7 +/- 2.7 years (range 1-17). Pacemaker dependency was defined as the absence of an intrinsic rhythm during backup pacing at 30 beats/min for 30 seconds. New onset of pacemaker dependency was observed in 23 (4.4%) of the 518 patients at a mean of 3.1 +/- 2.7 years of follow-up. Pacing indications were SSS in 6 (2.2%) of 275 patients, AV block in 15 (7.2%) of 209, and AF with bradycardia in 2 (5.9%) of 34. Patients with AV block had a significantly higher incidence of pacemaker dependency than patients with SSS (odds ratio 3.51; 95% CI 1.3 to 9.3; P = 0.012). The average annual rate of new pacemaker dependency was 1.6% during an 8-year follow-up. The incidence of new onset of pacemaker dependency varied among pacing indications, and was significantly higher in patients with AV block than patients with SSS.

Adolescent↗
PubMed2004

Alleviation of central sleep apnea by ventricular pacing in a patient with an implanted cardioverter defibrillator.

A 75-year-old man with a single chamber cardioverter defibrillator implanted for the management of sustained ventricular tachycardia developing after a healed myocardial infarction was admitted for evaluation of a sleep disorder. Polysomnography confirmed the presence of severe predominant central sleep apnea syndrome. The apnea-hypopnea index score decreased from 43.3 during spontaneous cardiac rhythm to 24.6 during VVI pacing at a rate of 70 beats/min. Ventricular pacing reduced the number of episodes of central sleep apnea/hypopnea without reducing the total sleep time, though it had no effect on episodes of obstructive sleep apnea/hypopnea.

Aged↗
PubMed2004

Anomalous right coronary artery originating from the distal left circumflex artery: single coronary artery with choronic atrial fibrillation.

This report describes a patient with a single coronary artery in whom the right coronary artery originated from the distal left circumflex artery. Single coronary artery is a rare congenital anomaly of the coronary circulation which is often associated with other congenital cardiac malformations. This anomaly is thought to be clinically significant especially in patients with atrial fibrillation, although no other associated cardiac anomaly was detected.

Angina Pectoris↗
PubMed2003

Successful treatment of radiation-induced brain necrosis by hyperbaric oxygen therapy.

We describe a 68-year-old man who underwent hyperbaric oxygen (HBO) therapy to manage radiation necrosis of the brain, which developed after two treatments with stereotactic radiosurgery (SRS) to the same lesion. The necrosis was subsequently treated with steroids alone for 2 months; however, he progressed clinically and radiographically. Improvement again was noted with the reinstitution of HBO therapy. This case suggests that HBO therapy is an important therapeutic option in the treatment of brain radiation necrosis caused by SRS.

Aged↗
PubMed2003

Clinical advantage of neutral anode positioning feature in recent pacemaker generator.

Recent advances in pacemaker technology such as a thinner lead body, smaller size of pacemaker generators and pacemaker pulse generators with the neutral anode positioning (NAP) feature, have made pacemaker implantation easier. To date, however, the clinical disadvantages of this NAP feature have not been investigated. We investigated whether there are any clinically disadvantages in pacing and sensing thresholds, myopotential tracking thresholds and myopotential inhibition thresholds in 62 pacemaker patients with the NAP feature. All measured data from the NAP devices when the pacemaker was set to the bipolar system were acceptable and normal. In the unipolar system with NAP feature, no differences were observed in the numerous parameters measured compared to previously reported measured data in the unipolar system without the NAP feature. We concluded that the physician can also benefit from this feature since any pulse generator with the NAP feature is suitable for implant on either side of the body, without any disadvantages. Therefore, left- or right-sided pacers need no longer be ordered, stocked, or specified at the time of implant.

Cardiac Pacing, Artificial↗
PubMed2003

Analysis of transmural trends in myocardial integrated backscatter in patients with progressive systemic sclerosis.

Cardiac involvement in progressive systemic sclerosis (PSS) is common and has a strong negative impact on the prognosis, especially when autoantibodies are present. To determine whether ultrasonic tissue characterization can detect early ultrastructural changes in the sclerodermal myocardium, we analyzed the transmural heterogeneity in myocardial integrated backscatter (THIB). "A-THIB" was defined as the absolute difference in integrated backscatter between the left (subendocardial) and right (subepicardial) ventricular halves of the myocardium in the septum and posterior wall, and was measured in 11 patients with PSS and 10 age- and sex-matched healthy participants. A-THIB in patients with PSS was higher than that in healthy participants (1.3 +/- 1.3 vs 4.0 +/- 1.4 dB for the septum and 1.1 +/- 0.7 dB vs 2.8 +/- 0.4 dB for the posterior wall; mean +/- SD, respectively, P <.0005). Septal A-THIB was higher in patients with PSS with than without anti-Scl70 or antinucleolar antibodies (3.2 +/- 1.1 vs 5.0 +/- 1.0 dB, P =.0165). Early changes in the myocardium of patients with PSS, possibly related to increased interstitial collagen deposition, can be detected by quantitative analysis of THIB.

Adult↗
PubMed2003

Successful treatment of severe orthostatic hypotension with erythropoietin.

A 71-year-old man, who was diagnosed with familial amyloidosis type I, was admitted for treatment of severe orthostatic hypotension associated with recurrent syncopal attacks. Head-up tilt testing demonstrated severe orthostatic hypotension (114/72 mmHg in the supine position and 62/34 mmHg in the upright position) with syncope or presyncope. Oral midodorine and fludrocortisone therapies failed to prevent his symptoms. After administration of subcutaneous erythropoietin, his blood pressure drop in the upright position was decreased and symptoms disappeared unassociated with improvement of anemia. Although previous reports have shown that the mechanism by which erythropoietin improves orthostatic hypotension is related to improvement in anemia, other mechanisms may also play a role.

Aged↗
PubMed2003

Sustained polymorphic ventricular tachycardia unassociated with QT prolongation or bradycardia in the Kearns-Sayre syndrome.

Cardiac dysfunction, including congestive heart failure and impulse conduction abnormalities, have been implicated in the sudden death of patients suffering from the Kearns-Sayre syndrome. This report describes a 29-year-old woman who suffered syncopal episodes due to sustained polymorphic VT. Sustained polymorphic VT was not associated with prolongation of the QT interval or bradycardia on the ECG. The implantation of a cardioverter defibrillator should be considered in this syndrome.

Adult↗
PubMed2003

Microdislodgment: a likely mechanism of pacing failure with high impedence small area electrodes.

High impedance tined steroid-eluting leads, Medtronic CapSure Z family, incorporating a small surface (1.2 mm2) electrode made of porous platinum material are designed to reduce battery current drain. However, in some prior studies, an increased incidence of microdislodgment with this lead was reported thought to be due to the reduced electrode surface area. This article reports the experience that ventricular pacing failure due to microdislodgment occurred after CapSure Z lead implantation and the previous literature is reviewed. (

Aged↗
PubMed2003

Effects of orthostatic self-training on head-up tilt testing for the prevention of tilt-induced neurocardiogenic syncope: comparison of pharmacological therapy.

Although a wide variety of medical treatments for neurocardiogenic syncope have been proposed, therapy has largely been emperic based on the mechanisms commonly believed to lead to neurocardiogenic fainting. To determine the utility and efficacy of drug therapy and an orthostatic self-training program in the prevention of tilt-induced neurocardiogenic syncope, we investigated 43 consecutive patients who had shown syncope and were induced by head-up tilt test reproducibly, with either traditional medical treatments or orthostatic self-training at home. The initial 19 of 43 patients were treated with either oral propranolol or disopyramide therapies. The remaining 24 patients were treated with an orthostatic self-training program alone. Effects of these therapies on head-up tilt test were reevaluated in all patients. Propranolol prevented syncope in only six (32%) and disopyramide in five (26%) of the 19 patients. There was no significant difference in the effectiveness between them. Syncope was prevented in nine (47%) patients with either propanolol or disopyramide therapy alone, while in the remaining 10 patients it was not. On the other hand, orthostatic self-training program prevented syncope in 22 (92%) of 24 patients. We concluded that orthostatic self-training program is far more effective than traditional drug therapies. Orthostatic self-training is an effective, safe and well accepted therapy in the prevention of tilt-induced neurocardiogenic syncope.

Adult↗
PubMed2003

Efficacy of orthostatic self-training in medically refractory neurocardiogenic syncope.

BACKGROUND: Orthostatic self-training is effective in the prevention of neurocardiogenic syncope, though the success of this method in drug refractory patients has not been reported. STUDY OBJECTIVE AND METHODS: This study examined the effectiveness of orthostatic self-training in 15 patients with head-up tilt testing (HUT)-inducible neurocardiogenic syncope, who were intolerant of, or refractory to standard drug therapy. They were enrolled in a home orthostatic self-training program for up to 30 min/session, twice daily. Head-up tilt testing was repeated within 4 weeks after onset of the training program, using the same protocol as at baseline. Orthostatic self-training was continued once daily, for up to 30 min, for a mean follow-up period of 11 months, in the drug-free state. RESULTS: Syncope was not reinducible by follow-up HUT, and spontaneous syncope occurred in no patient during the follow-up period. CONCLUSIONS: Home orthostatic self-training, up to 30 min once daily following an initial twice daily program, was highly effective in the suppression of recurrent neurocardiogenic syncope in patients intolerant of, or refractory to standard drug therapy.

Adult↗
PubMed2003

What is the optimal increase in resting heart rate with low dose isoproterenol infusion for tilt-induced vasovagal response?

Isoproterenol is widely used as a provocative medium for vasovagal responses during tilt testing. Dose of isoproterenol infusion is generally titrated empirically by increase in resting heart rate before tilt up. To determine the optimal increase in resting heart rate with isoproterenol for tilt-induced vasovagal responses, we studied 97 consecutive patients with unexplained syncope. After the end of a negative baseline tilt (80 degrees for 30 min), the isoproterenol tilt was performed using one of two protocols: two-stage isoproterenol-tilt protocol, with doses of 0.01 and 0.02 microg/kg per min for 10 min each, or one-stage isoproterenol-tilt protocol, with a dose of 1 or 2 microg/min for 10 min. The resting heart rate increase was defined as a percentage increase in the resting heart rate after isoproterenol infusion, compared to the baseline heart rate before the tilt test. In 117 tilt procedures, 28 (93%) of the 30 positive responses occurred with a resting heart rate increase of > or = 21%. With the resting heart rate increase of 60 and 100%, 18 (60%) and 27 (90%) positive responses were observed, respectively. In conclusion, the minimum resting heart rate increase of > or = 21% was required to provoke a vasovagal response during subsequent isoproterenol-tilt (80 degrees for 10 min). Preferably, heart rate should be increased to 60-100% by isoproterenol titration before tilting.

Adult↗