Spurious redetection of sinus rhythm by an implantable cardioverter defibrillator during spontaneous ventricular fibrillation

Implantable cardioverter defibrillator undersensing leading to delayed or aborted therapy delivery has been reported with induced arrhythmias and following failed defibrillator shocks. We describe a case in which spurious redetection of sinus rhythm during a spontaneous episode of ventricular fibrillation resulted in aborted device therapy.

Significant differences in charge times among currently available implantable cardioverter defibrillators

Capacitor charging accounts for most of the delay between arrhythmia detection and therapy delivery in ICDs. Long capacitor charge times may increase the risk of syncope in patients with poorly tolerated arrhythmias. To determine if there are clinically important differences in charge time among currently available devices, we analyzed charge times at various delivered energy levels in three manufacturers' devices: Medtronic, CPI, and Ventritex. Charge times were measured for shocks delivered for spontaneous or induced arrhythmias occurring from time of implant to 4 months after implant. A total of 343 shocks were assessed in 63 patients with ICDs: 16 Medtronic (MicroJewel II, model 7223Cx), 14 CPI (Mini II, model 1762), and 33 Ventritex (Cadet and Contour, models V-115 and V-145). The curves of the relationship between charge time and delivered energy for the three types of devices were significantly different, with Medtronic charge times shorter than CPI or Ventritex (P < 0.0001), and CPI charge times shorter than Ventritex (P = 0.002). The difference in mean charge times between the Ventritex and Medtronic devices ranged from 1.7 seconds at a delivered energy of 10 +/- 2.5 J to 8.0 seconds at a delivered energy of 30 +/- 2.5 J. Thus, clinically important differences in charge time exist among the three types of defibrillators studied. These results should be considered in selecting an ICD for patients with poorly tolerated arrhythmias.

Comparison of oversensing during bradycardia pacing in two types of implantable cardioverter-defibrillator systems

BACKGROUND

During bradycardia pacing in Ventritex Cadence (Models V-100 and V-110) implantable cardioverter-defibrillators, amplifier gain is maximal and oversensing and false tachyarrhythmia detection have been reported. Newer Ventritex devices (Cadet, Model V-115 and Contour, Model V-145) have a modified automatic gain control that may minimize oversensing.

METHODS AND RESULTS

We prospectively studied 50 patients (22 with Cadence, 28 with Cadet or Contour). Electrograms were evaluated for oversensing during bradycardia pacing. The bradycardia pacing refractory period required to prevent oversensing of T waves of paced beats and the time and number of beats required to achieve minimum gain after cessation of pacing were assessed. The bradycardia pacing refractory period could be left at its default setting of 350 ms in only 15 (30%) of 50 patients. The mean bradycardia pacing refractory period required to avoid oversensing of paced T waves was 386+/-32 ms. During pacing, oversensing of nonpaced T waves was seen in 12 (24%) devices, with similar incidence in Cadence devices (18%) and Cadet and Contour devices (29%, p = not significant). The time and number of beats to achieve minimum gain after pacing were longer in Cadence devices (19.0+/-4.5 vs 4.6+/-1.2 sec; 21.3+/-3.3 vs 5.0+/-0.4 beats, both p < 0.001).

CONCLUSIONS

The incidence of oversensing at maximum gain is similar in both types of devices, but more rapid changes in autogain levels in the newer devices may reduce the likelihood of false tachyarrhythmia detection.

Apoptotic activity of REAPER is distinct from signaling by the tumor necrosis factor receptor 1 death domain

REAPER (RPR) is a 65-amino acid protein that is critical activator of programmed cell death in Drosophila. On the basis of sequence alignment data, it was recently proposed that RPR might represent an ancestral molecule from which the death domain in a number of proteins may have evolved. We tested this idea by examining the activity of mutations in RPR that parallel inactivation mutations of the tumor necrosis factor receptor 1 death domain. The RPR mutants retained potent apoptotic function, suggesting that cell death activity mediated by RPR is distinct from signaling by the tumor necrosis factor receptor 1 death domain.

[Quantification of tricuspid insufficiency--comparison of Doppler echocardiography and radionuclide ventriculography]

In 40 patients (pts) (ages 34-83 years) the severity of tricuspid regurgitation (TR) was graded by pulsed Doppler echocardiographic determination of regurgitant jet extension. Mild TR was assessed in seven pts (group I), mode-rate TR in 20 pts (group II), and severe TR in 13 pts (group III). The enddiastolic diameter of the left ventricle as measured by M-mode-echocardiography was 55 +/- 16 mm in group I, 48 +/- 6 mm in group II, and 50 +/- 10 mm in group III. The regurgitant index (RI), i.e., the ratio of left-to-right-ventricular stroke counts (normal range 0.89-1.97) and the time-activity curve over the liver area were measured by equilibrium radionuclide ventriculography (RNV). The RI differed significantly between group I (1.6 +/- 0.5), II (1.0 +/- 0.3), and III (0.8 +/- 0.3) (p less than 0.01). An RI-value below 0.89 as an index of right-ventricular volume overload was found in 14% (group I), 45%, (group II) and 77% (group III). The time-activity curve over the liver area, as graded by count variation in phase with the right atrium from 1 (no count variation) to 4 (typical count variation) showed all grades in groups I and II, but only grade 2 to 4 in group III. The RI resp. the time-activity curve over the liver is a sensitive parameter for the detection of moderate to severe TR. If TR is ascertained, severe regurgitation can be differentiated from mild regurgitation by RNV-derived RI as an index of right-ventricular volume overload.

Daydreaming, absorption and hypnotizability

The revised form of the Absorption Scale extracted from Tellegen's Multidimensional Personality Questionnaire (Tellegen, 1981; Tellegen & Atkinson, 1974) and the Short Imaginal Processes Inventory (Huba, Aneshensel, & Singer, 1981), a self-report questionnaire concerned with daydreaming activity, were administered to 2 samples of Ss (N = 479, N = 476), who also received the Harvard Group Scale of Hypnotic Susceptibility, Form A (Shor & E. Orne, 1962). In both samples, hypnotizability was significantly correlated with absorption (average r = .24) and with a subscale measuring positive-constructive daydreaming (average r = .13). Absorption and positive-constructive daydreaming were also highly correlated (average r = .57). Of the subscales of the positive-constructive daydreaming scale, only those relating to positive reactions to daydreaming, and problem solving in daydreaming, consistently correlated with hypnotizability. Daydreaming and absorption each share some features in common with hypnosis, but they appear to have more in common with each other.

[Rational procedures in the differential diagnosis of jaundice]

In jaundice after exclusions of prehepatic and functional hepatogenic hyperbilirubinaemias the sonography should pre-eminently be used as a riskless, economical and qualified investigation method, taking into consideration clinical and laboratory-chemical data. If sonographically the findings of an intrahepatic cholostatis are shown, in therapeutic relevance the histological clarification must follow. Only in unequivocal focal changes of the liver (perhaps thin needle puncture) further investigations are unnecessary. If there are findings of an extrahepatic cholostasis, in a not unequivocal sonographic result or before a surgical intervention further aimed investigations, such as ERCP, PTC and CT, are necessary for the exact clarification of the cause of the obstruction of the bile ducts.

Levamisole therapy in chronic hepatitis--results of a multicentric double blind trial

The effectiveness of levamisole in the immunmodulatory treatment of chronic hepatitis was assessed in a multicentric double blind trial. Twenty patients received in the first week 50 mg, in the second 100 mg and thereafter 150 mg, levamisole on two days every week for 6 months, 20 others received a placebo. Five patients dropped out (non-compliance 1, pregnancy 1, adverse effects 3). The diagnoses were confirmed by clinical, biochemical immunological and histological data. After 6 months 26 subjects allowed us to take a control liver biopsy. The results showed that the rate of improved, unchanged and impaired cases was not significantly different in the levamisole and placebo groups. No correlation was found between etiology, activity or histological type of chronic hepatitis, skin test reactivity (DNCB, PPD, Streptokinase) and therapeutic effect, respectively. Clinical improvement was not associated with the elimination of HBs antigen. In general levamisole was well tolerated, but we saw one case of severe agranulocytosis.

[Cellular immunoreaction in alcohol-induced liver damage]

Of 231 patients with alcohol-induced liver diseases of different degrees of severity 170 patients had a pathological result of the migration inhibition test, when autologous homogenate of the liver was used as antigen. Of them in 25 cases a stimulation, in the other patients an inhibition of the migration of leucocytes was present. With increasing degree of severity of the liver lesion the number of cases with migration inhibition increased. These findings refer to a cellular immune reactivity in alcohol induced liver diseases.

[Hepatic coma--causes, recognition, treatment]

The name of the disease coma hepaticum is a collective notion for etiologically, pathologo-anatomically and biochemically different kinds of a failure of the function of the liver. A demarcation of different forms of the liver coma is necessary above all for prognostic and therapeutic reasons: hepatic disintegration coma, coma in hepatic failure, mixed coma, false hepatic coma, ferment block coma. Despite certain progress the therapeutic possibilities in hepatic coma cannot satisfy in recent years. Also the use of different, partly very expensive methods of the so-called liver substitute (exchange function and plasmapheresis, heterologous and homologous extracorporal liver perfusion, parasymbiotic crossed circulation, haemoperfusion with encapsulated activated charcoal, liver transplantation) up to now did not lead to a decisive improvement of the nearly infaust prognosis of the hepatic disintegration coma. Therefore preventing measures and careful control of endangered patients deserve particular attention.

[Discriminatory function of serum proteins in liver and biliary tract diseases]

In 104 patients with acute virus hepatitis, chronic hepatitides, cirrhoses, fatty livers and biliary diseases with partial and complete obstructive jaundice, respectively, IgG, IgA, IgD, beta1A- and beta1E-globulin, cholinesterase, total protein, and albumin, in 45 of these patients additionally prealbumin, retinol binding protein, thymol turbidity test were determined as well as an electrophoretic separation of the serum was performed. 11 persons with healthy liver served as control group. According to the results of univariate and multivariate variance analyses with following test of redundance (test for indispensability) and analysis of discriminance with calculations of reclassification IgD, beta1E-globulin and retinol binding protein were identified as not evident or redundant. Electrophoresis and thymol turbidity test give sufficient basis informations and can further be recommended for orienting examinations. Immune globulinogrammes from IgB, IgA and IgM are suitable as so-called mesenchyma tests particularly for controls of the course. Prealbumin and cholinesterase prove to be the most sensitive parameter of synthesis, whereas albumin and beta1A-globulin possess a high prognostic evidence.

[Use of the leukocyte migration test in the clinical diagnosis of liver diseases]

A simple performance of the leucocyte migration test is described and its use in the clinical laboratory diagnostics is recommended. The reduction of the methodical expenditure is prerequisite of a broad use and obtaining of experiences in large groups. The possible loss of specifity can be compensated by critical inclusion into the general picture. The test can help in the decision, whether the indication of an immunosuppressive therapy is necessary.