Rat model of attention-deficit hyperactivity disorder exhibits delayed recovery from acute incisional pain due to impaired descending noradrenergic inhibition

Chronic pain and attention-deficit hyperactivity disorder (ADHD) frequently coexist. However, the common pathology is still unclear. Attenuated noradrenergic endogenous analgesia can produce acute pain chronification, and dysfunction of noradrenergic systems in the nervous system is relevant to ADHD symptoms. Noxious stimuli-induced analgesia (NSIA) is measured to estimate noradrenergic endogenous analgesia in spontaneously hypertensive rats (SHR) as an ADHD model and control. Recovery of pain-related behaviors after paw incision was assessed. Contributions of noradrenergic systems were examined by in vivo microdialysis and immunohistochemistry. The SHR showed attenuated NSIA and needed a more extended period for recovery from acute pain. These results suggest ADHD patients exhibit acute pain chronification due to pre-existing attenuated noradrenergic endogenous analgesia. Immunohistochemistry suggests abnormal noradrenaline turnover and downregulation of the target receptor (alpha2a adrenoceptor). Standard ADHD treatment with atomoxetine restored NSIA and shortened the duration of hypersensitivity after the surgery in the SHR. NSIA protocol activated the locus coeruleus, the origin of spinal noradrenaline, of both strains, but only the control exhibited an increase in spinal noradrenaline. This result suggests dysfunction in the noradrenaline-releasing process and can be recognized as a novel mechanism of attenuation of noradrenergic endogenous analgesia.

Randomized active-controlled study of a single preoperative administration of duloxetine to treat postoperative pain and numbness after posterior lumbar interbody fusion surgery

BACKGROUND

This prospective, randomized, double-blinded, active controlled trial assessed whether a single preoperative administration of 40 mg of duloxetine could decrease postoperative pain and numbness after posterior lumbar interbody fusion surgery (PLIF).

METHODS

Patients with an American Society of Anesthesiologists physical status I or II undergoing PLIF were included. At 2 hours before inducing anesthesia, patients were administered 40 mg duloxetine or 4 mg diazepam (control drug). Postoperative pain and other symptoms were evaluated on the basis of a visual analog scale, amount of fentanyl used, fentanyl dose request times, rate of use of adjunctive analgesics (diclofenac sodium or pentazocine), and lower limb numbness score (0-3) during the first 2 postoperative days.

RESULTS

Forty-six patients were randomly assigned to the duloxetine and diazepam groups (n = 23 each); 6 were lost to follow-up, and analysis was performed on data from 22 patients in the duloxetine group and 18 in the diazepam group. No significant differences were detected in the patient background, postoperative visual analog scale score at rest in the lumbar region and lower limbs, fentanyl use, rate of analgesic adjuvant use, or incidence of side effects. The numbness score in the lower limbs, however, was significantly lower in the duloxetine group.

CONCLUSION

A single preoperative 40-mg dose of duloxetine did not improve postoperative pain after PLIF, but did improve lower limb numbness. Duloxetine may suppress neuropathic pain-like symptoms after PLIF surgery.

Spinal γ-Aminobutyric Acid Interneuron Plasticity Is Involved in the Reduced Analgesic Effects of Morphine on Neuropathic Pain

Systemic administration of morphine increases serotonin (5-HT) in the spinal dorsal horn (SDH), which attenuates the analgesic effects of morphine on neuropathic pain through spinal 5-HT3 receptors. We hypothesized that dysfunction of the descending serotonergic system, including the periaqueductal gray (PAG), contributes to attenuate the efficacy of morphine on neuropathic pain through spinal 5-HT3 receptors and GABA neurons. Morphine (100 ng) injected into the PAG produced analgesic effects in normal rats, but not in spinal nerve ligation (SNL) rats. In vivo microdialysis showed that PAG morphine increased the SDH 5-HT concentration in both groups. Intrathecal injection of the 5-HT3 receptor antagonist ondansetron and the GABA_A receptor antagonist bicuculline attenuated the analgesic effects of PAG morphine in normal rats, but increased the effects in SNL rats. The increased analgesic effect of PAG morphine induced by bicuculline was reversed by pretreatment with the tropomyosin receptor kinase B (TrkB) antagonist K252a. Activation of spinal 5-HT3 receptors by 2-methyl-5-HT increased the GABA concentration in both groups. Morphine activates GABAergic interneurons in the SDH by activating descending serotonergic neurons. Functional changes in GABA_A receptors from inhibitory to facilitatory through the activation of TrkB receptors may contribute to the attenuated efficacy of morphine against neuropathic pain. PERSPECTIVE: Although morphine provides strong analgesia against acute pain, it has limited efficacy against neuropathic pain. This article demonstrates that functional changes in GABA_A receptors in the spinal dorsal horn after nerve injury might strongly contribute to the attenuation of opioid-induced analgesia for neuropathic pain.

Repeated Administration of Amitriptyline in Neuropathic Pain: Modulation of the Noradrenergic Descending Inhibitory System

BACKGROUND

The tricyclic antidepressant amitriptyline, the serotonin and noradrenaline reuptake inhibitor duloxetine, and gabapentinoids are first-line drugs for treatment of neuropathic pain. The analgesic effect of these drugs relates to brainstem-spinal descending noradrenergic systems. However, amitriptyline utilizes a variety of mechanisms for analgesia in neuropathic pain, and it is unclear which mechanism is most important. In the present study, we investigated the role of descending noradrenergic systems in the analgesic effect of these drugs for treatment of neuropathic pain. We also examined whether amitriptyline modifies the descending noradrenergic systems.

METHODS

Seven days after L5 spinal nerve ligation (SNL), rats received N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4, 50 mg/kg) to degenerate noradrenergic fibers. The rats then received 5 daily intraperitoneal injections of amitriptyline (10 mg/kg), duloxetine (10 mg/kg), pregabalin (10 mg/kg), or gabapentin (50 mg/kg) from 21 days after SNL surgery. Paw withdrawal thresholds were determined to assess the effect of the drugs on hyperalgesia after SNL. To determine whether 5 daily injections of amitriptyline activated noradrenergic neurons in the locus coeruleus (LC) and spinal cord with or without DSP-4 treatment, we performed immunohistochemistry using antibodies for c-Fos and dopamine beta-hydroxylase (DβH).

RESULTS

Five daily injections of amitriptyline, duloxetine, pregabalin, and gabapentin exerted antihyperalgesic effects in SNL rats (P < .001; estimated treatment effect of amitriptyline [99% confidence interval]: 59.9 [35.1-84.7] g). The antihyperalgesic effects of duloxetine, pregabalin, and gabapentin were reversed by pretreatment with DSP-4 (P < .001, respectively). However, antihyperalgesia was still observed after treatment of amitriptyline in SNL rats with DSP-4 pretreatment (P < .001, 59.7 [30.0-89.3] g), and this analgesic effect was not reversed by the α2-adrenoceptor antagonist idazoxan (30 μg). Additionally, 5 daily injections of amitriptyline increased the ratio of c-Fos-immunoreactive (IR) cells in noradrenergic LC neurons in SNL rats with or without DSP-4 pretreatment (P < .001, respectively). Five daily injections of amitriptyline increased DβH-IR in the LC and the spinal dorsal horn of SNL rats (P < .001, respectively). With DSP-4 pretreatment, DβH-IR was dramatically decreased with or without 5 daily injections of amitriptyline (P < .001).

CONCLUSIONS

Five daily injections of amitriptyline produced antihyperalgesic effects against neuropathic pain despite suppression of noradrenergic descending inhibitory systems. Amitriptyline activated LC neurons and increased noradrenergic fibers density in SNL rats. These results suggest that amitriptyline could still produce analgesia under pathological dysfunction of the descending noradrenergic system. Amitriptyline may enhance the analgesic effect of drugs for neuropathic pain that require normal descending noradrenergic inhibition to produce analgesia, such as serotonin and noradrenaline reuptake inhibitors and gabapentinoids.

Loss of Secreted Frizzled-Related Protein-1 expression is associated with poor prognosis in intrahepatic cholangiocarcinoma

AIMS

Secreted Frizzled-Related Protein-1 (SFRP1) is a well-known negative regulator of the wingless type (Wnt)-β-catenin pathway and its inactivation plays an important role in the development and progression of many cancers. In this study, we aimed to determine the clinical significance of SFRP1 expression in intrahepatic cholangiocarcinoma (IHCC) and to define the relationship to Wnt-β-catenin pathway.

METHODS

Fifty IHCC patients who had liver resection were enrolled in this study. SFRP1 protein expression was examined by immunohistochemistry in tumor tissues. The patients were divided into two groups: SFRP1 positive (n = 30) and negative (n = 20). Clinicopathological characteristics were analyzed.

RESULTS

SFRP1 significantly correlated with curability (Cur A, B vs. C, p = 0.029); and recurrent pattern (intrahepatic vs. extrahepatic, p = 0.010). The negative SFRP1 group had significantly poorer prognosis, and 5-year survival rates were 8.1% of the negative SFRP1 group and 44.6% of the positive SFRP1 group, respectively. Moreover, the disease-free survival rate in the negative SFRP1 group was significantly poorer (p < 0.001). Multivariate analysis revealed that loss of SFRP1served as an independent prognostic factor in IHCC for both overall (HR, 2.923; 95% CI, 1.30-6.56; p = 0.009) and disease-free (HR, 2.631; 95% CI, 1.31-5.27; p = 0.006) survival. In addition, SFRP1 expression negatively correlated to β-catenin expression (p = 0.005).

CONCLUSIONS

Those results suggested that the loss of SFRP1 could be a poor prognostic factor for IHCC, through the Wnt-β-catenin pathway.

[Anesthetic Management of a Patient with Double Outlet Right Ventricle and Situs Inversus for Dilatation and Curettage of the Uterus]

A 30-year-old woman with a double outlet right ven- tricle and situs inversus was scheduled for dilatation and curettage of the uterus. We selected intravenous anesthesia which allowed spontaneous respiration, because of the short operation time and the low invasive surgery. We administered dexmedetomidine hydrochloride 1.1 μg · kg⁻¹ · hr⁻¹ and fentanyl (total amount 150 μg, three doses of 50 μg each) during operation. We accomplished anesthesia without appar- ent hemodynamic change or respiratory depression. We should select anesthetic method and anesthetic cautiously, considering patient's state.

[Effect of fibrinogen concentrate on coagulopathy patient with left ventricular assist system in surgical repair of thoracic abdominal aortic aneurysm (TAAA): a case report]

We describe a case in which fibrinogen concentrate was useful to improve anticoagulation after aortic graft replacement. A 44-year-old man with left ventricular assist system (LVAS) underwent thoracic abdominal aortic aneurysm (TAAA) graft replacement. LVAS requires anticoagulant therapy for thromboprophylaxis. Therefore, we supposed that it would be difficult to stop bleeding in TAAA graft replacement surgery. For this reason, we planned to administer fibrinogen concentrate during the surgery. When the patient was weaned from cardiopulmonary bypass, blood fibrinogen value decreased to 58.0 mg x dl(-1). At this time, we administered fibrinogen concentrate 6 g with other blood preparations. After the administration of fibrinogen concentrate, calculated blood fibrinogen level increased immediately to 120.0 mg x dl(-1). Three hours after administration of fibrinogen concentrate, TAAA graft replacement operation was finished. Ten days after the surgery, he was discharged from the ICU. Fibrinogen concentrate might be useful in difficult hemostasis reducing consumption of blood preparations.

Long-term effects of LDL apheresis on carotid arterial atherosclerosis in familial hypercholesterolaemic patients

OBJECTIVES

To assess the long-term effect of LDL apheresis on carotid arterial atherosclerosis in severe familial hypercholesterolaemic (FH) patients.

DESIGN

Changes in existing plaque, new plaque formation and annual progression rate of carotid early plaque were evaluated by B-mode ultrasonography.

SUBJECTS

LDL apheresis group: two homozygous FH and nine heterozygous FH patients received a combination of LDL apheresis and cholesterol-lowering drug therapy for a mean of 7.8 years.

CONTROL GROUP

10 heterozygous FH patients were maintained by medication only for a mean of 5.5 years.

RESULTS

As a result of LDL apheresis treatment, LDL cholesterol levels reduced from 16.0+/-3.60 to 6.43+/-0.07 mmol L(-1) in homozygous FH patients and from 11.5+/-2.46 to 4.32+/-1.2 mmol L(-1) in heterozygous FH patients. During the long-term treatment period, the existing plaque tended to progress and new plaque formation in carotid arteries was also observed in both groups. The annual progression rate of mean maximum intima-media thickness in the common carotid artery was a mean of -0.0023+/-0.0246 mm year(-1) in heterozygous FH patients in the LDL apheresis group, suggesting regression. This was significantly lower when compared with the control group, which had a mean of 0.0251+/-0.0265 mm year(-1) CONCLUSION: The results suggest that the long-term treatment with combined LDL apheresis and drugs may delay the progression of the atherosclerotic process and prompt the stabilization of atheromatous plaque in severe FH patients.

Structure of the rat methionine adenosyltransferase 2A gene and its promoter

In this study, to understand the regulation of methionine adenosyltransferase (MAT) gene expression, we isolated the rat MAT2A gene encoding MAT alpha2, the catalytic subunit of non-hepatic-type enzyme MAT II and characterized its structural organization and 5'-flanking region. The gene spans approximately 7 kbp and consists of nine exons interrupted by eight introns. The transcription initiation site, as demonstrated by primer extension analysis, is located 123 bp upstream of the translation start codon. Comparison of the structural organization of the rat MAT2A gene to that of the mouse MAT1A gene encoding MAT alpha1, the subunit of liver-type enzymes MAT I and III, shows that the exon structure of two genes is very similar and the insertion sites of all corresponding introns are identical. A canonical TATA box and a GC box, the potential Sp1-binding site, are found 32 bp and 70 bp upstream of the transcription initiation site, respectively. The 5'-flanking region also contains potential recognition sites for various transcription factors including AP-1, AP-2 and NF-IL6 (C/EBPbeta), and a large G+C-rich domain with the characteristics of a CpG island. The 5'-flanking sequence of the rat MAT2A gene has no significant similarity with those of the MAT1A genes. Transient transfection experiments using a luciferase reporter gene showed that the first 820-bp sequence of the 5'-flanking region directed high levels of luciferase activity in cultured rat kidney fibroblast (NRK-49F) and hepatocellular carcinoma (FAA-HTC1) cells, but not in primary rat hepatocytes. Deletion analysis suggested that the first 343 bp of the 5'-flanking region contained cell-type-specific promoter elements of this gene.

Hyperinsulinemia in patients with spastic angina pectoris

We evaluated the association between coronary spasm and hyperinsulinemia (high immunoreactive insulin, IRI) in patients with angina pectoris. The study cohort comprised 30 patients with spastic angina pectoris, 30 patients with angina pectoris showing fixed-obstructive coronary sclerosis and 30 control subjects who were matched for body mass index, age and sex. A 75-gram oral glucose test was performed, and blood sugar and IRI were serially measured concomitant with serum total cholesterol, triglyceride and HDL cholesterol. The IRI level at 60 min, the peak IRI during the test, sigma IRI and sigma IRI/sigma blood sugar were significantly higher in the patients than in the controls. Total cholesterol and LDL cholesterol levels were significantly increased in patients showing fixed-obstructive coronary sclerosis compared to controls.

Effects of an angiotensin II antagonist on reperfusion arrhythmias in dogs

Losartan, an angiotensin II receptor antagonist with no bradykinin potentiating property, provides the opportunity to study the consequences of blocking angiotensin II. The objective of this study was to evaluate the antiarrhythmic responses of reperfusion arrhythmia to losartan in dogs. The effects of losartan on ventricular tachyarrhythmias induced during occlusion and reperfusion of the left anterior descending coronary artery were investigated in 30 dogs. The animals were randomized to receive either losartan (n = 15) or saline (n = 15). The VF inducing threshold was measured before occlusion and after reperfusion. Losartan (50 micrograms/kg per min) or saline was intravenously administered 5 minutes before occlusion and continued throughout the entire study period. The incidence of ventricular tachyarrhythmias during reperfusion was lower in the losartan group than in the control group (4/15 vs 6/15). There was no significant change in VF inducing threshold between the period before occlusion and during reperfusion in the losartan group [10.9 +/- 5.7 vs 11.1 +/- 5.7 mA, P = NS), whereas there was a significant decrease in the control group (15.5 +/- 4.4 vs 7.7 +/- 3.9 mA, P < 0.01). Blockade of the angiotensin II receptor has beneficial effects on reperfusion arrhythmias.

Evaluation of abnormal signal-averaged electrocardiograms in young athletes

Our objectives in this study were to determine the incidence of abnormal signal-averaged ECG (SAECG) and its relation to the extent and type of exercise in young healthy athletes, and to evaluate the association, if any, between the development of abnormal SAECGs and vigorous exercise. The presence of abnormal SAECG was evaluated in 796 athletes (mean age 19 years), and its relation to findings on 12-lead electrocardiogram, echocardiogram, and the presence arrhythmias was studied using Holter monitoring. An SAECG was considered abnormal when any one of the three following criteria was met: filtered QRS duration of more than 114 msec, root-mean-square voltage in the terminal 40 msec of less than 20 muV, or a voltage of less than 40 muV for more than 38 msec. Abnormal SAECGs were present in 68 (8.5%) of the athletes and were associated with a smaller left ventricular mass. Athletes who performed anaerobic exercise tended to exhibit a high incidence of abnormal SAECGs, which was associated with a smaller left ventricular mass. No serious ventricular arrhythmias were observed on 24 h Holter monitoring or during the follow-up period of 20 +/- months. There were no sudden cardiac deaths. Continuous anaerobic exercise may induce abnormal SAECGs through the development of delayed myocardial conduction or electrical inhomogeneity in cardiac tissue. Te presence of an abnormal SAECG was unrelated to the development of arrhythmias in young athletes.

[Signal-averaged electrocardiograms in young athletes--sudden death during exercise]

Our objective was to evaluate the incidence of abnormal SAECG in young athletes, and to evaluate the relationship between abnormal SAECG and electrocardiographic and echocardiographic parameters. The presence of an abnormal SAECG was evaluated in 796 athletes (mean age 19 years), and its relation to findings on 12-lead electro-cardiograms, echocardiograms, and arrhythmias was studied, as recorded by the Holter monitor. An abnormal SAECG was defined as two of the three following criteria: filtered QRS duration > or = 114 msec, root mean squared voltage in the terminal 40 msec < or = 20 microV, or duration < 40 microV > or = 38 msec. Abnormal SAECGs were present in 68 (8.5%) of the athletes and were associated with a smaller left ventricular mass. Athletes who performed anaerobic exercise tended to exhibit a high incidence of abnormal SAECG, which was associated with smaller left ventricular mass. No serious ventricular arrhythmias were observed on Holter monitoring for 24h and during a follow-up period of 20 +/- 10 months in 796 subjects. Continuous anaerobic exercise may induce abnormal SAECG due to the development of delayed myocardial conduction or to electrical inhomogeneity in the cardiac tissue. The presence of an abnormal SAECG was unrelated to the development of arrhythmias in young athletes.

Wavelength index: a predictor of the response to disopyramide in paroxysmal lone atrial fibrillation

We investigated whether the new parameter wavelength index could predict the response to chronic disopyramide therapy in patients with paroxysmal atrial fibrillation (AF). Twenty-seven patients with AF underwent electrophysiologic studies and the wavelength index was determined before and after intravenous administration of disopyramide. Then all patients were treated with oral disopyramide for 6 months. In 17 patients, AF was eliminated (group A), while it persisted in another 10 patients (group B). The ratio of the wavelength index before and after intravenous disopyramide was higher in group A than in group B. Thus, the wavelength index proved useful for predicting the response of AF to disopyramide.

[Early diagnosis and management of acute pulmonary embolism: clinical evaluation those of 225 cases]

To contribute for making early diagnosis and treatment of acute pulmonary embolism (APE), we investigated on clinical pictures of 225 patients with APE. Common underlying factors were heart disease, prolonged bed rest, post-surgical state, thrombophlebitis, malignant tumor and post-catheterization state in this order. Dyspnea, chest pain, tachycardia and shock were frequently seen as initial symptoms and signs. Blood screening showed leukocytosis, hypoxemia, hypocapnia and elevated serum LDH. Electrocardiographic findings highly demonstrated were ST.T abnormalities, such as T inversion with ST elevation in V1-3, ST depression in V4-6 and sinus tachycardia. Chest X-rays showed diminished pulmonary vascular marking and pulmonary artery dilation. Right ventricular dilatation were frequently seen on 2-dimensional echocardiograms. Pulmonary artery pressure were elevated up to 49/20 (30) mmHg. Twenty-five percent of the patients died, and the recurrence was seen in 4%. Thus, as soon as APE is suspected by above clinical findings, definitive diagnosis should be obtained by the lung perfusion scan and pulmonary arteriography, then oxygen and thrombolytic agents should be given immediately to prevent the fatal outcome.

Pathological extent of interventricular septal infarction in patients with acute anteroseptal myocardial infarction with and without right bundle branch block

The purpose of the present study is to elucidate the difference in extent of myocardial infarction (MI) between those cases with and those without right bundle branch block (RBBB) occurring during the course of acute MI. We examined postmortem hearts from 20 patients with acute anteroseptal MI; 10 with (group A) and 10 without RBBB (group B). The extent of MI was studied pathologically in the interventricular septum (IVS) and reconstructed. The longitudinal extent of MI did not distinctly differ between groups A and B. In 5 hearts of group B, the anterior limit of the MI extended as high, or as close to the cardiac base, as in group A hearts. Transmural MI was relatively common and seen more frequently in group A than in group B. However, the MI did not always extend evenly to the left and right ventricular sides in the IVS. Left-sided predominance in extent of the MI was more frequently observed in group B than in group A. Right-sided predominance in the extent of septal MI was relatively rare and was seen in 5 cases at the portion where the right bundle branch came down. Four of these were group A patients. Thus, involvement of the right bundle branch might partly depend on the unevenness of the mural extent of the MI as well as the height of extension of the MI in the IVS.

Use of monophasic action potentials to evaluate postpacing T wave changes

We examined the relationship between postpacing T wave changes and monophasic action potentials recorded from the ventricle in dogs. MAPs were recorded from the right and left ventricle before and after cessation of pacing. The duration of the MAP was calculated as the time in milliseconds from the upstroke to 90% repolarization (MAPD90). T waves in limb leads were flat or had a biphasic pattern, eventually becoming negative after pacing. The Q-T interval of the escape beat after pacing was prolonged compared with the control. After right ventricular pacing, the average duration of MAPD90 in the right ventricle, but not in the left ventricle, was prolonged. (right MAPD: control 275 +/- 10 ms; after pacing: 311 +/- 17 ms, p < 0.05; left MAPD: control: 266 +/- 23 ms, after pacing: 284 +/- 26 ms, NS). After left ventricular pacing, the average duration of MAPD90 in the left ventricle, but not in the right ventricle, was prolonged (right MAPD: control: 247 +/- 75 ms, after pacing: 287 +/- 39 ms, NS; left MAPD: control: 257 +/- 23 ms, after pacing: 303 +/- 25 ms, p < 0.05). Furthermore, the average duration of MAPD90 at the pacing site became progressively prolonged over time. These results suggest that myocardial cells retain the memory of abnormal repolarization associated with pacing.

A fast Fourier transform analysis of coronary reperfusion-induced ventricular fibrillation and the modification by dibutyryl cyclic AMP in a cat model

To investigate the effect of dibutyryl cyclic AMP (dbcAMP) on ventricular fibrillation after coronary reperfusion, the proximal portion of the anterior descending branch of left coronary artery was reperfused 20 min after ligation in 24 cats. McFee X Y Z electrocardiograms were recorded and ventricular fibrillation was analyzed using a fast Fourier transform analysis (FFT). Ventricular fibrillation occurred in 20 of 24 cases. Sixty seconds after the occurrence of ventricular fibrillation, an intracardiac infusion of dbcAMP was administered. Nine of the 20 were defibrillated and converted to sinus rhythm or junctional rhythm after the administration of dbcAMP. The amplitude and frequency of the main power spectrum of the ventricular fibrillation waves were analyzed by FFT before and after the infusion of saline or dbcAMP. In the saline group there was no significant change in FFT. However, in the dbcAMP group, the amplitude increased significantly from 0.036 +/- 0.015 (MV--2) to 0.054 +/- 0.013 (MV--2) (p < 0.01) and the frequency decreased significantly from 4.22 +/- 1.37 (Hz) to 1.33 +/- 0.91 (Hz) (p < 0.01). Those results indicate that dbcAMP increased the amplitude and decreased the frequency of the main power spectrum of ventricular fibrillation analyzed by FFT. These distinctive changes in FFT analysis were associated with defibrillation in 9 of 20 cases.

Transesophageal low-energy synchronous cardioversion of atrial flutter/fibrillation in the dog

The purpose of this study was to determine the feasibility and efficacy of terminating atrial flutter/fibrillation using low-energy synchronous shocks delivered through a transesophageal catheter in dogs with talc-induced pericarditis. Atrial flutter/fibrillation was induced by employing the pulse train method. The minimum effective cardioversion energy level was compared for three different methods--method A, delivery between a distal esophageal electrode and a proximal esophageal electrode; method B, delivery of shocks through a distal esophageal electrode and a plate placed on the chest; method C, transthoracic cardioversion. The minimum effective cardioversion energy level did not differ significantly between methods A and B (1.30 +/- 0.46 joules versus 1.29 +/- 0.35 joules). Transesophageal cardioversion decreased the defibrillation threshold three- to fourfold from that of conventional transthoracic cardioversion. There were no complications of heart block, ventricular fibrillation, or any pathologic evidence of esophageal injury. Thus transesophageal low-energy synchronous cardioversion is considered a feasible and effective method for the treatment of atrial flutter/fibrillation.

Lymphocytic active myocarditis characterized by numerous clusters of lymphocytes: a chronic variant of myocarditis?

We report three patients with a particular form of myocarditis characterized by numerous clusters of lymphocytes. Their common clinical manifestation was progressive and fatal heart failure with a 3- to 6-year duration. Atrioventricular and intraventricular conduction disturbances were observed in two patients. At necropsy, the hearts weighed 480, 530, and 430 gm, respectively, and showed marked dilatation of the bilateral ventricles and atria, with frequent mural thrombi. Histologic examination revealed numerous lymphocytic clusters and scattered foci of acute myocardial cell damage on a background of extensive fibrosis. We propose the term "chronic active myocarditis" to denote clinicopathologic characteristics of the present cases.

Effects of transcatheter cardioversion on chronic lone atrial fibrillation

The effectiveness and safety of internal transcatheter cardioversion on chronic lone atrial fibrillation were examined in ten patients resistant to external electrical (400 joules) and pharmacological cardioversion. Transcatheter cardioversion was performed by pulling back the atrioventricular junction catheter just inferior to the site of the His-bundle recording and delivering the shock between a proximal electrode (cathode) and backplate (anode). Transcatheter cardioversion restored sinus rhythm in all of the ten patients. The only complication observed was transient atrioventricular block after the shock and this was treated by temporary pacing. However, atrial fibrillation recurred in five patients at 30, 27, 52, 1, and 6 days, respectively. A second attempt at transcatheter cardioversion was performed in those patients an was successful in three patients. During a follow-up period ranging from 12 to 22 months, eight patients continued in sinus rhythm. Thus, transcatheter cardioversion is considered effective and safe in selected patients with chronic lone atrial fibrillation in whom external cardioversion was unsuccessful.

Alcohol intake and nonfatal acute myocardial infarction in Japan

The relation between alcohol and nonfatal acute myocardial infarction (AMI) was examined in a case-control study of 89 male patients and 271 control subjects in Fukuoka, Japan. Patients admitted for the first AMI at 2 hospitals in Fukuoka City were aged 40 to 69 years, and control subjects were recruited based on the telephone directory of the city. Information on alcohol drinking and potential coronary risk factors was obtained by using a self-administered questionnaire, and past drinkers were separated from lifelong abstainers in the analysis. After adjustment for age, occupation, cigarette smoking, strenuous exercise, body mass index, hypertension, diabetes mellitus and parental heart disease, the risk of AMI was progressively less with increasing levels of alcohol consumption. With those who never drank as a referent, adjusted odds ratios for current drinkers consuming less than 30, 30 to 59, and greater than or equal to 60 ml/day of alcohol were 1.11 (95% confidence interval 0.51 to 2.42), 0.31 (0.11 to 0.83), and 0.13 (0.05 to 0.36), respectively. These findings add to the body of data showing that alcohol drinkers are less likely to have AMI.

Electrophysiological properties in chronic lone atrial fibrillation

BACKGROUND

Although the electrophysiological mechanisms underlying self-sustaining atrial fibrillation (AF) are unclear, recent studies suggest that one requirement for reentry, slow conduction, is frequently present in patients with AF. However, these observations limited to paroxysmal AF may not necessarily apply to chronic AF. Therefore, electrophysiological properties of the atrium and sinus nodal function in chronic lone AF were evaluated.

METHODS AND RESULTS

Electrophysiological studies were performed after electrocardioversion in 12 patients with chronic lone AF. Atrial enlargement was absent in the patients with AF. Twelve patients without atrial arrhythmias served as the control group. The patients with AF had a higher incidence of sinus nodal dysfunction, a shorter atrial effective refractory period (215 +/- 19 msec versus 238 +/- 23 msec, p less than 0.02), and a longer P wave duration than control patients (115 +/- 16 msec versus 86 +/- 16 msec, p less than 0.01). The conduction delay zone was significantly greater in patients with AF (60 +/- 12 msec) than that in the control patients (8 +/- 13 msec, p less than 0.01), and the maximal conduction delay was also greater in the study patients than those in the control group, both to the His bundle region (31 +/- 12 msec versus 10 +/- 15 msec, p less than 0.01) and to the coronary sinus (41 +/- 15 msec versus 15 +/- 11 msec, p less than 0.01). The fragmented atrial activity zone was wider in the study group (23 +/- 25 msec) than in control subjects (1.7 +/- 4 msec, p less than 0.02). Repetitive atrial firing was observed in four patients with AF but it was not seen in the control group.

CONCLUSIONS

These electrophysiological features, which are manifestations of the abnormal atrial electrophysiology, would favor production of atrial reentry in chronic lone AF.

Effects of atrioventricular block on ventricular fibrillation threshold in dog

The effects of complete atrioventricular block (CAVB) on ventricular vulnerability were studied 1 week after a transcatheter electrical ablation of the AV junction in 18 closed-chest dogs. All dogs exhibited CAVB and a stable ventricular escape rhythm with a mean cycle length of 1795 +/- 600 ms. Although QT interval during CAVB was significantly prolonged compared with that during the sinus rhythm, QTc interval was significantly shortened. The ventricular fibrillation threshold was significantly elevated after creation of the block (from 9.35 +/- 2.28 to 12.3 +/- 3.69 mA, p less than 0.01). Thus, CAVB which is not associated with QTc prolongation would be even less likely to play an important role in producing ventricular fibrillation presumably including torsades de pointes or polymorphous ventricular tachycardia.

A quantitative histopathological study of right bundle branch block complicating acute anteroseptal myocardial infarction

The aim of the present study was to evaluate whether necrosis of the right bundle branch is responsible for development of right bundle branch block in acute myocardial infarction. Twenty patients with acute anteroseptal myocardial infarction were studied--10 with right bundle branch block (group A) and 10 without (group B)--to evaluate by serial sectioning the pathological extent of myocardial infarction surrounding the right bundle branch and also that of right bundle branch necrosis. Myocardial infarction reached the right bundle branch more than 8 mm above the moderator band in all of group A, whereas myocardial infarction reached the right bundle branch less than 3 mm above the moderator band in only three patients in group B. Nine hearts in group A showed significant necrosis of the right bundle branch. In group B and in one case with transient right bundle branch block no necrosis was found. The occurrence of right bundle branch block was almost entirely explained by necrosis of the right bundle branch, but transient right bundle branch block did develop without necrosis of the right bundle branch.

Antiarrhythmic and proarrhythmic properties of diazepam demonstrated by electrophysiological study in humans

We evaluated the electrophysiological parameters before and after the intravenous infusion of diazepam (0.2 mg/kg) in 20 cardiac patients to investigate the drug's antiarrhythmic effect. Diazepam did not significantly change the arterial pressure. After the intravenous infusion of diazepam, the sinus cycle length significantly shortened from 847 +/- 132 to 747 +/- 155 ms (p less than 0.01). No significant change in the maximal sinus node recovery time was noted. The AH interval at the atrial pacing length of 600 ms shortened significantly from 140 +/- 40 to 127 +/- 39 ms (p less than 0.05). However, there was no significant change after the administration of diazepam in the longest atrial pacing rate associated with Wenckebach conduction in the atrioventricular (AV) node, effective and functional refractory periods of the AV node, HV interval, and QRS width during ventricular pacing at the cycle length of 600 ms. The atrial and ventricular effective refractory periods remained unchanged after the administration of diazepam. Six of the eight patients who showed dual AV nodal refractory period curves in the control study did not demonstrate them after diazepam administration by increasing the atrial or AV node effective refractory period. Thus, diazepam showed significant electrophysiological effects of the heart including shortening of the sinus cycle length, improvement in AV node conduction, and no significant effect on the His-Purkinje or intraventricular conduction and refractoriness of the atrium, AV node and ventricle. On the other hand, diazepam may influence the inducibility of supraventricular reentrant tachycardia incorporating the AV node.

Normalization of reverse redistribution of thallium-201 with procainamide pretreatment in Wolff-Parkinson-White syndrome

Stress thallium-201 myocardial perfusion imaging was performed in a patient with Wolff-Parkinson-White syndrome. Reverse redistribution phenomenon was observed in the absence of coronary artery disease. This seems to be the first report of normalization of this phenomenon in association with reversion of accessory pathway to normal atrioventricular conduction after pretreatment with procainamide.

Effects of dibutyryl cyclic AMP on ventricular vulnerability during atrioventricular block in dog

The effects of dibutyryl cyclic AMP (DBcAMP) on ventricular vulnerability during complete atrioventricular block (CAVB) were studied one week after transarterial electrical ablation of the AV junction in 18 closed-chest dogs. All dogs exhibited CAVB and a stable ventricular escape rhythm with a mean cycle length of 1812 +/- 638 ms. After the administration of DBcAMP at a rate of 0.1 mg/kg/min for 30 min, the ventricular cycle length was significantly shortened, and the QTc interval was slightly prolonged, although the QT interval did not change. The ventricular fibrillation threshold after the administration of DBcAMP was significantly increased (from 12.2 +/- 3 84 to 18.4 +/- 5.08 mA, p less than 0.01). Thus, it was demonstrated that DBcAMP exhibited suppressive effects on the ventricular vulnerability in the experimentally induced CAVB.

[A rare adult case of double-outlet right ventricle without pulmonary stenosis: an autopsy case]

Double outlet right ventricle (DORV) is a rare cardiac malformation especially in adulthood. We report a woman with DORV who survived to the age of 33 years. She had not been seriously limited, before she visited our hospital for cardiac evaluation at the age of 25 years. She was cyanotic, and had clubbing of fingers and toes and facial edema. Holosystolic murmur and diastolic regurgitant murmur were audible along the left sternal border. Chest X-ray showed cardiomegaly and enlarged pulmonary trunks. Electrocardiography showed right axis deviation and biventricular hypertrophy. Laboratory examination revealed polycythemia (Hb: 22.4 g/dl), increased levels of hepatic enzymes due to congestive liver and marked hypoxemia (Pao2: 40 mmHg), Diagnosis of DORV was made with cardioangiography. Surgical repair was not indicated. Thereafter, she experienced recurrent heart failure which progressed gradually. She died probably of ventricular arrhythmia at the age of 33 years. At autopsy, the heart showed dilatation of the right atrium and ventricle, and hypertrophy of the bilateral ventricles. Both the pulmonary artery without stenosis and the aorta originated completely from the right ventricle, which were almost normally positioned with bilateral conus. Large ventricule septal defect was found at the subaortic portion. Patent ductus arteriosus and preductal aortic coarctation co-existed. To our knowledge, few cases with DORV who survived over 30 years have been reported, and they all manifested pulmonary stenosis. The present case is a very rare DORV that survived over 30 years without the complication of pulmonary stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Automatic junctional tachycardia in an adult

We report an adult patient with junctional ectopic tachycardia, a condition which was initially described in infants, frequently in association with congenital defects. The patient had a rapid, irregular paroxysmal junctional tachycardia with a rate ranging from 160 to 220 beats/min, distinguishing it from the more common nonparoxysmal junctional tachycardia in which a slower heart rate is seen. The electrophysiological study performed during an episode of tachycardia demonstrated periods of atrioventricular dissociation and narrow QRS complexes as well as a junctional ectopic rhythm, which was suggested by a His deflection preceding each ventricular depolarization with a normal HV interval. Both the response to exercise and the results of atrial and ventricular stimulation suggested enhanced automaticity of a high junctional focus. Therapy combining procainamide, verapamil, and digitalis proved to be effective. Thus, junctional ectopic tachycardia can also occur in adults, probably due to enhancement of automaticity.

Right bundle branch block. Echocardiographic study with special reference to the site of block within the right bundle

One hundred and fifty-seven patients with complete right bundle branch block (CRBBB) were studied with echocardiography (UCG). In 87 of them, both ECG and UCG of good quality were obtained and analyzed to differentiate the site of the block within the right bundle. Their mean age was 53.2 +/- 17.6 (SD) years, and they consisted of 62 males (50.2 +/- 16.8 years) and 25 females (60.8 +/- 17.3 years), suggesting that males were more susceptible to CRBBB than females, with a male to female ratio of 2.48 among our study group. In a normal control group, the time interval from the initial deflection of the QRS complex of the ECG to mitral valve closure (QMC) was 52.3 +/- 11.6 msec, to tricuspid valve closure (QTC) 87.7 +/- 11.5 msec, to the point of full opening of the pulmonary valve (QPO) 124.5 +/- 13.7 msec, from mitral to tricuspid valve closure (MCTC) 35.5 +/- 11.2 msec, and from tricuspid valve closure to the maximum opening of the pulmonary valve (TCPO) 38.0 +/- 13.8 msec, and in patients with CRBBB, QMC 58.7 +/- 13.2 msec, QTC 95.4 +/- 24.2 msec, QPO 169.1 +/- 24.6 msec, MCTC 36.7 +/- 18.2 msec, and TCPO 73.7 +/- 23.7 msec. Although prolonged QMC and QTC are characteristic features in CRBBB as a whole, CRBBB was divided into 4 groups in this study depending on the difference in MCTC and TCPO: Proximal block with prolonged MCTC, peripheral block with prolonged TCPO, diffuse block with both MCTC and TCPO prolonged, and non-specific block without prolongation of either of the two. The incidences were 11.5% (10 patients) for proximal block, 64.4% (56 patients) for peripheral block, 16.1% (14 patients) for diffuse block, and 8.0% (7 patients) for non-specific block. Thus, conduction disturbance in the peripheral portion of the right bundle branch was observed in 80.5% of our cases, suggesting that peripheral block is much more common than proximal block in adults.

[A case of myxedema with diffuse myocardial fibrosis proven by endomyocardial biopsy]

We report a middle-aged woman with myxedema heart who presented both clinical features resembling dilated cardiomyopathy and the diffuse myocardial fibrosis proven by endomyocardial biopsy. Thirty years previously, when she was 36 years old, partial thyroidectomy had been performed after a diagnosis of hyperthyroidism was made. Four years later, she experienced dry skin and peripheral edema, and hypothyroidism was diagnosed. Several months after, replacement therapy for hypothyroidism improved her symptoms. However, the therapy was discontinued because of her ignorance of the disease. Twenty six years later (64 years old), she felt exertional dyspnea, and was admitted to Fukuoka University Hospital for evaluation of her cardiac state. Thyroid function test revealed primary hypothyroidism with low T3, low T4 and high TSH levels. Cardiothoracic ratio on chest X-ray film was 69%. Electrocardiogram showed low voltage in the limb leads and intraventricular conduction disturbance. Echocardiogram demonstrated marked dilatation and severely reduced wall motion of the left ventricle and pericardial effusion. Left ventriculogram showed diffuse hypokinesis with 27% of the ejection fraction. No significant stenosis was observed on coronary arteriogram. Seventeen-month replacement therapy did not improve these cardiac findings significantly. Transvenous right ventricular endomyocardial biopsy demonstrated diffuse myocardial fibrosis without inflammatory infiltrate, which was interpreted as a sequel of interstitial lesions of the myxedema heart such as edema or mucoid infiltration. This pathological finding suggests that long-standing untreated hypothyroidism can cause irreversible myocardial damage.

Low energy synchronous transcatheter cardioversion of atrial flutter/fibrillation in the dog

The feasibility and effectiveness of low energy synchronous transcatheter cardioversion of atrial flutter and fibrillation were examined in dogs with talc-induced pericarditis. A conventional electrode catheter was positioned transvenously in the right atrial appendage. Atrial flutter/fibrillation was induced by using the train pulse method, and the tachyarrhythmia-inducing threshold was determined. The minimal effective cardioversion energy levels were compared in three different cardioversion methods: method A = delivery of shock between the proximal electrode (cathode) and the backplate (anode), method B = delivery between the proximal electrode (cathode) and the distal electrode (anode) and method C = conventional external cardioversion. In both methods A and B, all 149 cardioversion attempts were successful with shocks of less than or equal to 5 J. Shocks of less than or equal to 1 J resulted in successful cardioversion in 57 (70%) of 81 attempts, 50 (74%) of 68 attempts and 5 (12%) of 41 attempts with methods A, B and C, respectively. The mean minimal effective cardioversion energy levels were not significantly different between methods A and B (0.62 +/- 0.67 versus 0.58 +/- 0.71 J). Transcatheter cardioversion decreased the defibrillation threshold 3- to 75-fold (mean 6- to 7-fold) from that of transthoracic cardioversion. The defibrillation threshold was not influenced by the inducibility of atrial flutter/fibrillation. There were no complications of heart block, ventricular fibrillation or pathologic evidence of severe shock-induced atrial injury. Thus, low energy synchronous transcatheter cardioversion of atrial flutter/fibrillation is considered feasible and effective. This technique may also be useful in managing the atrial flutter/fibrillation that can occur during electrophysiologic studies.

A transarterial approach of electrical ablation of atrioventricular junction in a dog model: comparison of the effects between high and low energy shocks

To analyze the effectiveness of a transarterial catheter technique for electrical ablation of the atrioventricular junction, 30 mongrel dogs were studied by means of synchronized electrical shock between the catheter adjacent to the noncoronary cusp and a metal plate behind the dog's back using a standard cardioversion unit. These dogs were classified into two groups according to the energy delivered. The high energy group received more than 100 joules (group A) and the low energy group received from 20 to 60 joules (group B). Complete atrioventricular block was induced by a single shock in all dogs. In group A, ventricular premature beats appeared in all dogs; ventricular fibrillation and ventricular tachycardia appeared immediately in half (6/12) after electrical ablation. No ventricular dysrhythmias occurred in group B. Temporary right ventricular pacing was also performed in 10 out of 12 dogs in group A after electrical ablation. In contrast only one dog required pacing in group B. The cycle length of the subsidiary pacemaker rhythm was essentially identical in both groups. The QRS duration of the subsidiary pacemaker rhythm in group A was significantly longer in group B (P less than 0.01). The extent of myocardial damage induced by electrical ablation in group B was more localized than those in group A. However, the histological lesion representing the granulation tissue with necrosis and slight chronic inflammatory cell infiltration, was identical between both groups A and B. It was concluded that this technique of low energy electrical ablation of the atrioventricular junction adjacent to the noncoronary cusp via a transarterial approach was useful in producing an experimental model of chronic complete AV block.

Plasma fibrinogen levels as an independent indicator of severity of coronary atherosclerosis

The relationship between plasma fibrinogen levels and the severity of coronary atherosclerosis was examined in 229 patients, aged 25-82 years (162 men and 67 women), undergoing coronary angiography. Severity of coronary atherosclerosis was assessed in terms of the number of vessels with a 75% or greater stenosis and Gensini's severity score. Fibrinogen levels increased progressively with the severity of coronary atherosclerosis, determined by both the number of involved vessels and Gensini's severity score in men, and the relationships were statistically significant. Similar patterns were noted among women, but the trends were not statistically significant. The association was evident even after adjustment for age, hypertension, total cholesterol, cigarette smoking, alcohol intake, high density lipoprotein cholesterol and body mass index. These results provide evidence that in the Japanese also plasma fibrinogen levels can serve as an independent indicator of the progression of coronary atherosclerosis.

A case of cross stimulation

Cross stimulation in a dual chamber pacing system, in which the atrial stimulus intermittently captured the right ventricle, occurred immediately after pacemaker implantation in a 71-year-old man. It was prevented temporarily by reducing the pacing rate so that P wave synchronous ventricular (VDD) pacing resulted and by reducing the output of the atrial circuit from 5 to 4 volts. Cross stimulation disappeared spontaneously 14 days after surgery.

Effect of nifedipine, dilazep, dinitrates and propranolol on blood lactate accumulation during intensive graded exercise testing in healthy young subjects

The aim of the present study was to elucidate the effects of 4 different cardiovascular drugs on blood lactate levels during an intensive graded exercise test in 17 healthy male subjects. In acute studies, isosorbide dinitrate and nifedipine were used. In chronic studies, propranolol dihydrochloride and dilazep dihydrochloride were used. Oxygen uptake (VO2), heart rate, blood pressure and blood lactate were measured at rest and during the final minute of each exercise session. Hemodynamic measurements during submaximum exercise were influenced by all drugs except isosorbide dinitrate. VO2 during submaximum and maximum exercises remained unchanged by all drug treatments. Blood lactate levels at rest and during submaximum and maximum exercise also did not change significantly. Work load corresponding to blood lactate concentration of 4 mM (W4 mM) and the 1st and 2nd break points of lactic acid (WBPLA1 and WBPLA2) were almost the same in all treatments. It is concluded that the 3 criteria of blood lactate obtained during the graded exercise test are not affected by these drugs in healthy males.

Acute pulmonary thromboembolism treated successfully by balloon angioplasty--a case report

Acute pulmonary thromboembolism frequently occurs in patients on protracted bed rest and by itself can cause acute right ventricular failure. The authors report findings in a patient with this disorder treated successfully by balloon angioplasty.

"Torsades de pointes" and atrioventricular block

In order to elucidate the trigger factor of the production of torsades de pointes (TdP), electrophysiological study was conducted in 15 patients with atrioventricular (AV) block; 6 with TdP (TdP group) and 9 without TdP (control group). In the TdP group, all had an episode of syncope and frequent ventricular premature beats (VPBs) on routine ECG, while four (44%) had syncope and three (33%) had VPBs in the control group. Aging, QRS width, ventricular cycle length, QT interval, and block site from His bundle electrogram were similar in both groups, however the QTc interval was significantly (p less than 0.01) longer in the TdP group than in the control group (580 +/- 112 vs. 459 +/- 37, respectively). Furthermore, four patients (67%) in the TdP group showed advanced AV block in which a slow ventricular rate and an irregular rhythm were characteristic, whereas only one control (11%) showed advanced AV block and all other control patients (89%) had complete AV block. These data indicate that patients with advanced atrioventricular block associated with prolonged QTc interval and frequent ventricular premature beats might induce torsades de pointes.

Arterial changes after percutaneous transluminal coronary angioplasty: results at autopsy

Light and electron microscopic examinations were performed on 20 coronary artery sites from nine patients who had undergone percutaneous transluminal coronary angioplasty. Twelve successfully dilated sites without prior thrombosis showed evidence of a tear in the luminal surface (with or without fracture of an atheroma) even at 140 days after angioplasty. The tear split through a relatively undistensible intima in 9 (75%) of the 12 sites. Two successfully dilated sites with prior thrombosis showed an intraintimal tear with a widely lacerated fibrous cap and thin mural thrombus. After dilation, the occluded prior nonthrombosed site showed marked protrusion of a separated plaque. An occluded prior thrombosed site after dilation revealed intraintimal canal-like hematoma. Four sites that occluded after balloon passage revealed a dissecting hematoma in three and plaque disruption in the other.

Echocardiographic and electrocardiographic measures in obese children after an exercise program

The influence of an exercise training on anthropometric changes and cardiac dimensions was studied in 18 obese children (age 10 to 11 years). Eighteen obese children participated in a jogging program, 5 days/week, for 1 or 2 years and 15 normal weight children (age 10 to 11 years) in the control group participating in their regular physical education class. Anthropometric measurements, echocardiograms and electrocardiograms were obtained before and after the exercise programs. The weight, degree of obesity and resting heart rate had decreased after 1 year of the exercise training. Left ventricular end-diastolic dimension increased after 1 year of the exercise training. Left ventricular wall thickness did not change. The total voltage in SV1 + RV5 decreased after 3 months of the exercise training but returned to pre-training voltage after 1 year of training. There was no change after 2 years of training. In conclusion, 1 year of exercise in obese children decreased resting heart rate and increased left ventricular end-diastolic dimension and left ventricular mass.