RR interval variability in the evaluation of ventricular tachycardia and effects of implantable cardioverter defibrillator therapy

BACKGROUND

An implantable cardioverter defibrillator (ICD) is the most reliable therapeutic device for preventing sudden cardiac death in patients with sustained ventricular tachycardia (VT). Regarding its effectiveness, targeted VT is defined based on the tachyarrhythmia cycle length. However, variations in RR interval variability of VTs may occur. Few studies have reported on VT characteristics and effects of ICD therapy according to the RR interval variability. We aimed to identify the clinical characteristics of VTs and ICD therapy effects according to the RR interval variability.

METHODS

We analyzed 821 VT episodes in 69 patients with ICDs or cardiac resynchronization therapy defibrillators. VTs were classified as irregular when the difference between two successive beats was >20 ms in at least one of 10 RR intervals; otherwise, they were classified as regular. We evaluated successful termination using anti-tachycardia pacing (ATP)/shock therapy, spontaneous termination, and acceleration between regular and irregular VTs. The RR interval variability reproducibility rates were evaluated.

RESULTS

Regular VT was significantly more successfully terminated than irregular VT by ATP. No significant difference was found in shock therapy or VT acceleration between the regular and irregular VTs. Spontaneous termination occurred significantly more often in irregular than in regular VT cases. The reproducibility rates of RR interval variability in each episode and in all episodes were 89% and 73%, respectively.

CONCLUSIONS

ATP therapy showed greater effectiveness for regular than for irregular VT. Spontaneous termination was more common in irregular than in regular VT. RR interval variability of VTs seems to be reproducible.

Superior Rhythm Discrimination With the SmartShock Technology Algorithm - Results of the Implantable Defibrillator With Enhanced Features and Settings for Reduction of Inaccurate Detection (DEFENSE) Trial

BACKGROUND

Shocks delivered by implanted anti-tachyarrhythmia devices, even when appropriate, lower the quality of life and survival. The new SmartShock Technology^®(SST) discrimination algorithm was developed to prevent the delivery of inappropriate shock. This prospective, multicenter, observational study compared the rate of inaccurate detection of ventricular tachyarrhythmia using the SST vs. a conventional discrimination algorithm.Methods and Results:Recipients of implantable cardioverter defibrillators (ICD) or cardiac resynchronization therapy defibrillators (CRT-D) equipped with the SST algorithm were enrolled and followed up every 6 months. The tachycardia detection rate was set at ≥150 beats/min with the SST algorithm. The primary endpoint was the time to first inaccurate detection of ventricular tachycardia (VT) with conventional vs. the SST discrimination algorithm, up to 2 years of follow-up. Between March 2012 and September 2013, 185 patients (mean age, 64.0±14.9 years; men, 74%; secondary prevention indication, 49.5%) were enrolled at 14 Japanese medical centers. Inaccurate detection was observed in 32 patients (17.6%) with the conventional, vs. in 19 patients (10.4%) with the SST algorithm. SST significantly lowered the rate of inaccurate detection by dual chamber devices (HR, 0.50; 95% CI: 0.263-0.950; P=0.034).

CONCLUSIONS

Compared with previous algorithms, the SST discrimination algorithm significantly lowered the rate of inaccurate detection of VT in recipients of dual-chamber ICD or CRT-D.

Seizures and syncope due to complete atrioventricular block in a patient with acute myocarditis with a normal left ventricular systolic function

A 43-year-old man was admitted to our hospital presenting with seizures and syncope. He had a history of a cold with a fever of 39°C occurring three days earlier. Electrocardiography (ECG) showed complete atrioventricular block (AV block) with a maximum pause of 32 seconds, for which temporary pacing was performed. Echocardiography showed mild hypertrophy of the left ventricle (LV) with a normal ejection fraction of 61%. Coronary angiography showed normal coronary arteries. Then, an endomyocardial biopsy was performed, the results of which indicated a diagnosis of acute myocarditis. After admission, the complete atrioventricular block disappeared together with normalization of the LV wall thickness.

Insulin resistance and coronary risk factors in Japanese type 2 diabetic patients with definite coronary artery disease

Insulin resistance is known as an important risk factor for coronary artery disease (CAD). However, CAD-related mortality in Japanese type 2 diabetics is lower than in Caucasians. To investigate whether insulin resistance is related to CAD in Japanese type 2 diabetics, we measured insulin sensitivity and several coronary risk factors in Japanese patients with type 2 diabetes with and without CAD. Thirty-three patients with definite CAD and 33 age- and sex-matched patients without CAD (control) were studied. Insulin sensitivity was assessed by the K index of insulin tolerance test (KITT). Clinical characteristics, classical risk factors, lipoprotein (a), and insulin sensitivity were compared between the two groups. Patients with CAD had a significantly longer duration of diabetes (9.0 +/- 1.4 vs. 5.5 +/- 0.9 years, P < 0.05, respectively), were mostly hypertensive (69.7 vs. 39.4%, P < 0.05), and more likely to be treated with insulin (45.5 vs. 18.2%, P < 0.05) compared with the control. Concerning the metabolic parameters, patients with CAD had a significantly higher insulin resistance than control (2.40 +/- 0.15 vs. 3.23 +/- 0.17%/min, P < 0.01, respectively), higher triglyceride (1.39 +/- 0.10 vs. 1.05 +/- 0.05 mmol/l, P < 0.05), lower HDL cholesterol (1.05 +/- 0.05 vs. 1.28 +/- 0.06 mmol/l, P < 0.05), and higher lipoprotein (a) (27.5 +/- 4.3 vs. 17.4 +/- 2.0 mg/dl, P < 0.05). Multiple logistic regression analysis indicated that hypertension, insulin resistance, high lipoprotein (a) and triglyceride, and low HDL cholesterol were independently related to CAD. Our results suggest that insulin resistance per se is a significant risk factor for CAD in Japanese patients with type 2 diabetes.

A solid-state culture system using a cellulose carrier containing defined medium as a useful tool for investigating characteristics of koji culture

The purpose of this article is to establish a new solid-state culture system that uses a defined medium and allows control of the chemical factors in the medium in solid-state cultivation. To achieve this purpose, we produced a solid substrate, in which the defined medium was packed in a cellulose carrier with agar, and named it "cellulose agar cube (CA-cube)". In order to obtain growth conditions similar to koji culture, we then determined the moisture content of the CA-cube. Five runs of column reactor operations were carried out at various moisture contents of the CA-cube in the range of 50-90%. A very similar mycelial morphology to that of koji culture was observed on the surface of CA-cube with moisture content lower than 63%. The glucoamylase production and the production ratio of glucoamylase to alpha-amylase (G/A ratio) were both increased exponentially with decreasing moisture content and reached 237.5 units per g dry solid and 13.59, respectively, at the moisture content of 50%, which are almost comparable to those of koji culture. In addition, the glucoamylase "glaB", which is mainly produced in koji culture, was observed in the CA-cube culture with low moisture content. These results indicate that growth conditions similar to koji culture could be attained by the column reactor culture with the CA-cube.

Does the production of nitric oxide contribute to the early improvement after a single low-density lipoprotein apheresis in patients with peripheral arterial obstructive disease?

Low-density lipoprotein (LDL) adsorption using a dextran sulfate cellulose (DSC) column is commonly performed for extracorporeal removal of LDL in hypercholesterolemic patients with peripheral arterial obstructive disease. We investigated whether the use of heparin or nafamostat mesilate as anticoagulants in a single LDL apheresis produced different clinical effects, or brought about the production of bradykinin and endogenous nitric oxide (NO) in these patients. LDL apheresis was performed in ten patients with peripheral arterial obstructive disease. We measured plasma levels of bradykinin, NO and nitrosylhemoglobin as well as skin temperature. Plasma levels of bradykinin increased 12-fold during LDL apheresis with heparin, but did not increase during LDL apheresis with nafamostat mesilate. LDL adsorption resulted in an immediate rise in skin temperatures (1-2 degrees C) of the lower ischemic legs irrespective of the type of anticoagulant used, and this persisted after the end of LDL apheresis for up to 60 min. There was a progressive and significant increase in plasma NO after the commencement of single LDL apheresis in both groups (heparin group: 64.0 +/- 17.3 micromol/l at baseline, 73.3 +/- 15.2 micromol/l 60 min after apheresis, P<0.005; nafamostat mesilate group: 65.0 +/- 18.8 micromol/l at baseline, 75.5 +/- 17.5 micromol/l 60 min after apheresis, P<0.001). On the other hand, levels of nitrosylhemoglobin increased significantly after 1000 ml of plasma treatment but the level decreased thereafter, although it was significantly higher than baseline 60 min after LDL apheresis. Our results suggest that a single LDL apheresis enhanced peripheral microcirculation, probably as a result of increased production of NO, irrespective of changes in bradykinin release.

Argatroban increases nitric oxide levels in patients with peripheral arterial obstructive disease: placebo-controlled study

Intravenous argatroban infusion therapy is widely used for the restoration of peripheral microcirculation in patients with peripheral arterial obstructive disease (PAOD). We investigated the effect of argatroban infusion therapy on plasma levels of nitric oxide (NO) and nitrosylhemoglobin (HbNO) in patients with PAOD compared with a placebo-treated PAOD group. The chemiluminescence method was used to determine plasma NO and HbNO. Argatroban was administered as a continuous intravenous infusion for 60 minutes and repeated daily over a period of 2 weeks in 10 patients with PAOD. Treatment significantly improved the clinical signs and symptoms. Serial thermograms showed a 1-2 degrees C rise in the temperature of the affected legs in all patients immediately after intravenous argatroban infusion therapy. Enhancement of the peripheral circulation was maintained after the end of argatroban infusion for up to 90 minutes despite elimination of argatroban from the circulation. Furthermore, there was a progressive and significant increase in the mean concentration of plasma NO in PAOD patients after commencement of argatroban infusion (baseline, 58.0 +/- 13. 7;90 minutes after infusion, 65.7 +/- 13.4 microM; P < 0.01). HbNO significantly increased from a baseline value of 1063 +/- 126 to 1460 +/- 250 nM at 30 minutes after infusion (P < 0.01). However, the level of HbNo decreased thereafter, although it remained significantly elevated, even at 90 minutes after the end of argatroban infusion. Our results suggest that argatroban may lead to increased HbNO and plasma NO, and this may contribute to the improved microcirculation in PAOD patients.

Personality traits of Japanese patients in remission from an episode of primary unipolar depression

Personality traits were assessed by means of the Munich Personality Test (MPT) in 75 Japanese subjects, 27 patients in remission from an episode of moderate to severe primary unipolar depression, with melancholic features during one episode or more of the disorder, in 24 patients in remission from other non-organic mental disorders and in 24 healthy controls. Compared with healthy controls, unipolar depressives displayed decreased Frustration Tolerance and elevated Rigidity as well as a stronger Orientation towards Social Norms. No significant difference was found between patients in remission from either unipolar depression or other mental disorders. However, the increase in Rigidity in comparison with healthy subjects was significant in the depressives only whereas the other patients, in contrast to the depressives, had significantly lower scores in Extraversion than the healthy subjects. Our results in Japanese patients are similar to findings of previous German studies, including two high risk studies, in which the same assessment instrument was used. This suggests that, beyond cultural differences, Rigidity, possibly in combination with a strong Orientation towards Social Norms and a reduced Frustration Tolerance, is a stable vulnerability marker for at least the more severe forms of primary unipolar depression.

[Delusions and society in Japan and China from a transcultural-psychiatric viewpoint]

The relationship between contents of schizophrenic delusions and sociocultural background in the modern society of Japan and China were studied from transcultural psychiatric aspects. The data of this study were derived from the public mental hospitals in Tokyo and Shanghai in a similar size; of 186 cases (88 cases of male, 98 cases of female) of the first admission in Tokyo Metropolitan Matsuzawa Hospital during 1981-1983, 112 cases with delusions (53 cases of male, 59 cases of female) were selected, and of 200 cases (112 cases of male, 88 cases of female) of the first admission in Shanghai Psychiatric Hospital in 1983, 129 cases with delusions (70 cases of male, 59 cases of female) were chosen. The incidence of delusions of physical persecution and grandeur was relatively high in patients of both hospitals in Tokyo and Shanghai, while the incidence of delusions with hypochondria and guilt was low in both hospitals. Only the incidence of delusion of poisoning was significantly higher in Shanghai than in Tokyo (mean 2 = 12.97, p less than 0.001). After the World War II, the patriarchally oriented family system was abolished in Japan which caused shifting the system from a large family to a nuclear family. In China where the property (land) and daily life were closely connected the close human relationship among generations had important values in relation to the labor power within the frame of a large family. It is believed that occurrence of the delusion of poisoning might be a reflection of the disturbed human relationship within the family member in dining which should be helpful for making further understanding and reliance. It's occurrence conflict and struggle in the community of the outside of the family. At present there is a marked difference between Chinese and Japanese in their structure of consciousness. The former places high value and meaningfulness on the participation to the group and seeks protection and safety of individuals. The latter reveals a less strong tie with the traditional conformity and dependency to the mass due to the conformation of the nuclear family. It can not be ignored the possible effect of the close horizontal interaction and cautious human relationships among neighbours with fear of rumor and watching in the Chinese community on the occurrence of the delusion of persecution. After the World War II, abolishment of the principle of vertical control system and introduction of multiple value system together with loss of authority had taken place in Japan.(ABSTRACT TRUNCATED AT 400 WORDS)