Subpectoral implantation of cardioverter-defibrillator combined with a nonepicardial lead system: preliminary experience with a novel approach.
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Aged↗
Biomedical subjects
D Mehta
Publications and source records attributed to D Mehta.
Circumferential wiring for fractures (Le Fort types) of the maxilla.
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Bone Wires↗
Device use patterns and clinical outcome of implantable cardioverter defibrillator patients with moderate and severe impairment of left ventricular function.
The beneficial effects of implanted cardioverter defibrillator (ICD) therapy in patients with malignant ventricular tachyarrhythmias and variable degrees of left ventricular (LV) dysfunction are debated. ICD use and patient survival were examined in 128 patients with malignant ventricular arrhythmias and moderate or severe LV dysfunction. Group I included 64 patients with moderate LV dysfunction (LV ejection fraction of > 30%) and group II, 64 patients with severe LV dysfunction (LV ejection fraction of < or = 30%). Follow-up period ranged from 1 to 78 months. The two groups were similar in age, incidence of coronary artery disease and presenting arrhythmia. The mean LV ejection fraction in group I was 44% +/- 8% and group II was 22% +/- 5% (P < 0.0001). At 4 years of follow-up, 66% of patients from group I and 62% from group II (P = NS) had ICD activation for presumed ventricular tachyarrhythmia. Survival was calculated using actuarial analysis. Arrhythmic or sudden death mortality at 4 years of follow-up was 4% in group I and 7% in group II (P = NS). Cardiac mortality was for group I, 7% (P < 0.05), 12% (P < 0.01), 15% (P < 0.01), and 15% (P < 0.01) for follow-up years 1, 2, 3, and 4, respectively. For group II, cardiac mortality was 27%, 36%, 41%, and 41% for follow-up years for 1, 2, 3, and 4, respectively. The majority of cardiac deaths in both groups was observed in the first 2 years of follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)
Actuarial Analysis↗
Total pectoral implantation: a new technique for implantation of transvenous defibrillator lead systems and implantable cardioverter defibrillator.
We describe a new approach to total pectoral implantation of cardioverter defibrillators with an endocardial defibrillation lead system. Endocardial lead configuration used was an FDA approved right atrial-superior vena cava defibrillation spring electrode, right ventricular bipolar sensing electrode, and a pectoral patch. Endocardial leads were implanted via a cephalic or an axillary venesection. Pectoral patch was placed in a submuscular position. In case of failure to obtain satisfactory thresholds, a small intercostal thoracotomy was performed via the same skin incision and patch placed over the epicardium instead of submuscular position and used with the right atrial spring electrode. The device was implanted in the pectoral region, submuscularly, over the patch. Sixteen consecutive patients underwent this approach. With a submuscular patch, adequate defibrillation thresholds (< or = 15 joules [J]) were obtained in 14 (87.5%) patients. In the other two, defibrillation thresholds of < or = 15 J were obtained with a epicardial patch. Pectoral implantation of the device was feasible in all 16 patients and none needed repositioning. Average postimplant hospital stay was 5 days. During follow-up period (average 5 months), none of the patients reported any major local symptoms and no problems have been encountered in device interrogation. Thus, total pectoral implantation of the cardioverter defibrillator including the patch, leads, and the device is feasible. Furthermore, in case of failure to obtain adequate defibrillation thresholds with submuscular patch, an epicardial patch can easily be implanted and allows 100% successful defibrillation at energy levels of < or = 15 J with right atrial patch configuration.
Adult↗
Probable de novo 17q duplication (q11.2-->q21.1): a newly recognised chromosomal syndrome in a child with Klinefelter's syndrome.
A child is described with a previously unreported probable trisomy for a segment of the long arm of chromosome 17 responsible for some distinct clinical features. These include craniofacial and skin abnormalities, failure to thrive, partial malrotation of the gut, malabsorption, gastro-oesophageal reflux, neurodevelopmental delay, autonomic disturbance, and cardiac and CNS abnormalities. The coexistence of Klinefelter's syndrome (47,XXY) is of minor significance in relation to this child's phenotype.
Abnormalities, Multiple↗
The reduced canine pancreas to study the effects of intra-operative radiotherapy.
A canine model is described to study the tolerance of the pancreas to intra-operative radiotherapy (IORT). The canine pancreas is a horseshoe-shaped organ. To create a homogeneous delivery of IORT to the whole pancreas surgical manipulation is necessary which may induce pancreatitis. A resection of the left and right lobes of the pancreas facilitates the delivery of IORT, reduces the risk of pancreatitis and will demonstrate, eventually, minimal functional changes in the exocrine and endocrine pancreas at an earlier stage. Sixteen beagles were used. Investigations before and after the reduction procedure were intravenous glucose tolerance tests, serum insulin levels, faecal fat excretion, blood chemistry tests and body weight. Eight weeks after the pancreas reduction 15 dogs underwent an IORT procedure in which 25, 30 or 35 Gy IORT was delivered to the pancreatic remnant. We conclude that the pancreas reduction technique used to study the effects of IORT to the canine pancreas is feasible without mortality or morbidity. Endocrine and exocrine pancreatic function remained normal with a minimal follow-up of 3 months.
Animals↗
Metoclopramide decreases thiopental hypnotic requirements.
We compared the effect of metoclopramide (MCA) with droperidol (DPD) on thiopental hypnotic requirements in 96 unpremedicated female patients. The study was randomized, double-blind, and placebo-controlled. The response to the verbal command was used as an end-point of anesthesia. Two methods of determination of thiopental hypnotic requirements were used: titration (infusion of thiopental at a rate of 0.5 mg.kg-1 x min-1) until the end-point was reached and construction of the dose-response curve based on bolus injections of predetermined doses of thiopental (with the use of probit analysis). The ED50 value of thiopental determined by probit analysis was reduced after the 0.2 mg/kg MCA administration by 44% (P < 0.0001). The thiopental hypnotic requirements obtained with the titration method were as follows: 5.3 +/- 0.3 mg/kg in control, 4.5 +/- 0.2 mg/kg (delta 14%, P < 0.03) with 0.1 mg/kg MCA, 3.2 +/- 0.2 mg/kg (delta 39%, P < 0.0001) with 0.2 mg/kg MCA, and 2.9 +/- 0.2 mg/kg (delta 45%, P < 0.0001) with 0.4 mg/kg MCA. DPD decreased thiopental hypnotic requirements almost to the same degree as MCA, with the ceiling effect observed at doses of 0.01 and 0.02 mg/kg (delta 44%, P < 0.0001). The results indicate that MCA causes a profound decrease in thiopental hypnotic requirements. The similarity between the thiopental sparing effects of MCA and DPD suggests that the blockade of D2 receptors is the main mechanism underlying this effect.
Adolescent↗
Serum lipase levels in nonpancreatic abdominal pain versus acute pancreatitis.
OBJECTIVE: 1) To determine whether serum lipase is elevated in patients with nonpancreatic abdominal pain, and 2) to compare the levels of serum lipase and serum amylase found in patients with nonpancreatic abdominal pain with those found in acute pancreatitis in order to differentiate between the two groups. METHODS: Serum lipase and amylase levels were estimated in 95 patients with nonpancreatic abdominal pain (group A). These levels were then compared with those found in 75 patients with acute pancreatitis (group P). RESULTS: Serum amylase in group A ranged from 11 to 416 U/L [mean 58 +/- 46 (SD)]. Three patients (3.3%) had raised amylase levels. The maximum elevation noted in this group was 416 U/L. Serum amylase in group P ranged from 124 to 13,000 U/L (mean 1620 +/- 1976). Twenty of the 75 patients (27%) in group P had levels that overlapped those found in group A. The serum lipase in group A ranged from 3 to 680 U/L (mean 111 +/- 101). Ten of the 93 patients (11%) had elevated lipase levels. The maximum elevation noted was roughly 3 times normal (680 U/L). Serum lipase in group P ranged from 711 to 31,153 (mean 6705 +/- 7022). None of the patients in group P had levels that overlapped those found in group A. The sensitivity of a serum lipase level > 3 normal in detecting acute pancreatitis was 100% and the specificity was 99%. The corresponding figures for serum amylase were 72% and 99%, respectively. CONCLUSION: A serum lipase level > 3 normal has a better diagnostic accuracy than serum amylase in differentiating nonpancreatic abdominal pain from acute pancreatitis.
Abdominal Pain↗
Prospective comparison of biphasic and monophasic shocks for implantable cardioverter-defibrillators using endocardial leads.
Bidirectional shocks using 2 current pathways have been used in endocardial lead systems for implantable cardioverter-defibrillators, but the optimal shock waveform for endocardial defibrillation is unknown. The clinical efficacy and electrical characteristics of bidirectional monophasic and biphasic shocks for endocardial cardioversion-defibrillation of fast monomorphic or polymorphic ventricular tachycardia (VT), or ventricular fibrillation (VF) were evaluated. Thirty-three patients (mean age 60 +/- 12 years, and mean left ventricular ejection fraction 34 +/- 13%) were studied. Defibrillation catheter electrodes were located in the right ventricular apex and superior vena cava/right atrial junction. A triple-electrode configuration including the 2 catheter electrodes and a left thoracic patch was used to deliver bidirectional shocks from the right ventricular cathode to an atrial anode (pathway 1) and the thoracic patch (pathway 2). The shock waveforms examined were sequential and simultaneous monophasic, and simultaneous biphasic. The efficacy of 580 V (20 J) shocks for fast monomorphic VT were comparable for the 3 waveforms (73% for sequential monophasic, 73% for simultaneous monophasic, and 100% for simultaneous biphasic). However, for polymorphic VT and VF, 580 V sequential monophasic shocks had a significantly lower efficacy (25%) than did simultaneous monophasic (75%; p = 0.01) or biphasic (89%; p less than 0.001) shocks. Single-shock defibrillation thresholds with simultaneous biphasic shocks were significantly lower (9 +/- 5 J) than were those with simultaneous monophasic shocks (15 +/- 4 J; p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)
Electric Countershock↗
Survival of implantable cardioverter-defibrillator recipients: role of left ventricular function and its relationship to device use.
The quantitative benefit of ICD therapy in patients with malignant ventricular tachyarrhythmia with different degrees of left ventricular dysfunction is unclear. We evaluated patterns of ICD use and survival in 112 patients with moderate to severe left ventricular dysfunction. Group 1 included 57 patients with moderate left ventricular dysfunction (defined as left ventricular ejection fraction greater than 30%) and group 2 comprised 55 patients with severe left ventricular dysfunction (defined as ejection fraction equal to or less than 30%). The follow-up period ranged from 1 to 78 months. Age, incidence of coronary artery disease, and presenting arrhythmia in the two groups were similar. The mean left ventricular ejection fraction in group 1 was 44.6 +/- 8.2% and in group 2 was 21.6 +/- 6% (p < 0.0001). At 3 years of follow-up 65% of the patients in group 1 and 71% in group 2 (p = NS) had ICD activation for presumed ventricular tachycardia. Survival was calculated by means of actuarial analysis. Arrhythmia or sudden death mortality at 4 years of follow-up was 5% in group 1 and 9% in group 2 (NS). Cardiac mortality was higher in patients with severe left ventricular dysfunction reaching levels of statistical significance at 2 years of follow-up. At 2 years of follow-up it was 12% in group 1 and 40% in group 2 (p = 0.05), and at 4 years of follow-up it was 15% in group 1 and 43% in group 2 (p < 0.01). In both groups there was no difference in cardiac mortality in patients who did and did not have appropriate ICD shocks.(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
Twiddler's syndrome with the implantable cardioverter-defibrillator.
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Electric Countershock↗
Comparison of clinical benefits and outcome in patients with programmable and nonprogrammable implantable cardioverter defibrillators.
Technological advances in implantable cardioverter defibrillators (ICDs) have provided a variety of programmable parameters and antitachycardia therapies whose utility and impact on clinical outcome is presently unknown. ICDs have capabilities for cardioversion defibrillation alone (first generation ICDs), or in conjunction with demand ventricular pacing (second generation ICDs), or with demand pacing and antitachycardia pacing (third generation ICDs). We examined the pattern of antitachycardia therapy use and long-term survival in 110 patients with sustained ventricular tachycardia (VT) or ventricular fibrillation (VF). Group I included 62 patients with nonprogrammable first generation ICDs that delivered committed shock therapy after ventricular tachyarrhythmia detection based on electrogram rate and/or morphology was satisfied. Group II included 48 patients with multiprogrammable ICDs (including second and third generation ICDs) that had programmable tachyarrhythmia detection based on rate and tachycardia confirmation prior to delivery of electrical treatment with either programmable shocks and/or, as in the third generation ICDs, antitachycardia pacing. Incidence and patterns of antitachycardia therapy use and long-term survival were compared in the two groups. The incidence of appropriate shocks in patients who completed 1 year of follow-up was significantly greater in group I (30 of 43 patients = 70% vs 11 of 26 patients = 42%; P less than 0.05). In the total follow-up period, a significantly larger proportion of group I patients as compared to group II patients used the shock therapies (46 of 62 patients = 74% vs 25 of 48 patients = 52%; P less than 0.01), with the majority doing so within the first year of implantation (96% and 92%, respectively). Although the frequency of antitachycardia therapy activation was similar, the number of shocks delivered per patient was lower in group II, particularly in the initial 3 months of follow-up (P = 0.06). No clinical variable aided in identifying users from nonusers of antitachycardia therapy. Arrhythmic mortality was virtually eliminated in both groups. Two-year actuarial cardiac survival in the two groups was similar (group I = 78% vs group II = 84%; P greater than 0.2). Survival from cardiac mortality in users and nonusers of antitachycardia therapies was also similar in both groups (P greater than 0.2) and in the total patient group (P greater than 0.2). We conclude that programmable ICDs continue to confer advantages in prevention of sudden death that were observed with nonprogrammable ICDs and can be expected to improve patient tolerance and physician acceptance of device therapy for VT/VF.
Adult↗
Streptococcus associated toxic shock.
In the past few years, there appears to have been a change in the spectrum of disease caused by group A beta-haemolytic streptococcus (GABHS), and a toxic shock-like syndrome caused by this organism has recently been described in adults. We report four children with an acute illness characterised by rapid progression of shock, erythematous rash, multisystem organ involvement, electrolyte derangements, and desquamation who fulfil the previously established diagnostic criteria for toxic shock syndrome. Three of the children had extensive cutaneous and soft tissue infection and the fourth had peritonitis. All four developed bacteraemia. Treatment included aggressive cardiovascular resuscitation and antibiotic therapy. Although no patient died, they suffered multiple and severe complications requiring prolonged treatment and hospitalisation. Streptococcal toxic shock syndrome is a separate and clearly defined entity occurring in previously healthy children.
Cardiopulmonary Resuscitation↗
Efficacy of flecainide, sotalol, and verapamil in the treatment of right ventricular tachycardia in patients without overt cardiac abnormality.
OBJECTIVE: A comparison of the efficacy of verapamil, sotalol, and flecainide to suppress right ventricular tachycardia (VT) in patients with a clinically normal heart. DESIGN: Patients underwent treatment serially with verapamil (360 mg daily), sotalol (240 or 320 mg daily), and flecainide (200 or 300 mg daily), (the larger dose was for patients heavier than 80 kg) to suppress tachycardia. Each drug was given orally for five half lives before testing. PATIENTS: 23 patients with right VT associated with a clinically normal heart were studied. OUTCOME MEASURES: The effects of drug treatment were examined by the number of ventricular events on 24 hour Holter monitoring, and the ability of tachycardia to be induced by treadmill exercise testing (Bruce protocol) and programmed ventricular stimulation (Wellens protocol), compared with drug free baseline tests. SETTING: Patients were studied in a tertiary referral centre. RESULTS: All three drugs suppressed ventricular salvos (> 3, < 5 consecutive ventricular premature contractions) (p < 0.01) and VT (p < 0.05) on Holter monitoring and did not differ statistically in effect. Exercise induced VT was also suppressed by all three drugs (p < 0.01), and of these sotalol was the most effective although this was not statistically significant (14/23 inducible when drug free, 4/23 on flecainide, 2/23 on sotalol, 5/23 on verapamil). Sustained and non-sustained VT induced by programmed stimulation was also suppressed by the three drugs (p < 0.01) and again sotalol was the best of these though the differences did not achieve statistical significance (17/23 inducible when drug free, 4/17 on flecainide, 2/17 on sotalol, and 6/17 on verapamil). Proarrhythmic effects of drugs were found in a few patients. There was no difference in the efficacy of the drugs in patients with histological abnormalities of the myocardium when compared with those of normal histology. CONCLUSIONS: Ventricular tachycardia associated with a clinically normal heart can be suppressed by flecainide, sotalol, or verapamil. In individual patients sotalol was the most frequently effective drug (effective in > 89% of patients) and is a suitable choice for first line treatment.
Adult↗
Experience with a third-generation implantable cardioverter-defibrillator.
A Medtronic 7216A pacemaker cardioverter-defibrillator was implanted in 16 patients (mean age 56 years) with sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) and organic heart disease with a mean left ventricular ejection fraction of 33%. Endocardial and epicardial defibrillation shock efficacy was evaluated before or at implant using 1 to 3 shock patterns, i.e., monophasic single, sequential or simultaneous shocks with dual and triple electrode configurations. Endocardial leads used a common right ventricular cathode and dual anodes, whereas epicardial leads used 2 or 3 helical coil patches. VT termination was evaluated using pacing or shock therapy, or both, whereas only shocks were used in VF. Programmable bradycardia pacing, individual zones for VT and VF detection and individualized pacing and shock therapy for VT and VF were used. Monophasic shocks had epicardial defibrillation thresholds ranging from 3 to 18 (mean 10) J and were comparable for sequential and simultaneous shocks (p greater than 0.2). VT detection rates ranged from 340 to 470 ms and VF detection rates from 270 to 330 ms. VT or VF induction, or both, was performed noninvasively in 13 patients after implant and was reproducibly terminated by rapid pacing alone (5 patients), low-energy shocks (2 patients), high-energy shocks (3 patients) and combined therapy (3 patients). Intermediate or high-energy shocks terminated all induced VF episodes. During follow-up (2 to 12 months), there have been 2 noncardiac deaths. Electrical therapy was delivered in 7 patients, for VT (3 patients), VT and VF (3 patients) and indeterminate tachyarrhythmia (1 patient). All VT/VF episodes were successfully terminated, with 78 of 96 (81%) spontaneous VT episodes terminated by pacing. Follow-up reprogramming was required in 5 patients. It is concluded that successful application of individualized electrical therapy prescriptions in patients with VT/VF is feasible. Pacing therapies, which are effective for induced VT, can be reliably used for effective long-term spontaneous VT termination in conjunction with shock therapy and can permit reduced patient exposure to shock therapy. Thus, a programmable hybrid pacemaker cardioverter-defibrillator system provides nonthoracotomy implantation, effective VT/VF termination, demand ventricular pacing and noninvasive modes for arrhythmia induction, event monitoring and clinical trouble-shooting.
Adult↗
Effect of automobile exhaust on the distribution of trace elements and its modulation following Fe, Cu, and Zn supplementation.
The effect of automobile exhaust on the distribution of trace elements with special reference to Pb and its modulation following Cu, Zn, and Fe supplementation, in mouse organs, has been studied using Energy Dispersive X-ray Fluorescence technique. Seven elements, namely K, Fe, Cu, Zn, Br, Rb, and Pb, were detected in all the organs. The maximum concentration of Pb was found in lungs followed by that in liver and kidney. The effect of automobile exhaust was found to be significant on the concentrations of Fe and Pb; their concentrations were found to increase in all the organs. However, the concentrations of Cu and Zn were found to be decreased significantly in the liver. In the animals given Fe, Cu, or Zn supplementation along with motor exhaust, the percentage change in the concentration of Pb in lungs was decreased, and that of Fe was increased significantly. In kidney, no significant change was observed for the animals given Cu and Zn, whereas for animals given Fe, the level of Pb decreased significantly. In liver, the reduction in the level of Zn in the exhaust-exposed animals was made up and the level of Pb was reduced following Zn supplementation. These results clearly indicate that Fe and Zn play an important role in Pb metabolism and tend to lower the absorption of Pb. The effect of Fe is more pronounced than that of Zn, whereas the effect of Cu seems to be insignificant.
Administration, Inhalation↗
Signal averaging of the electrocardiogram in the remote differential diagnosis of broad complex tachycardias.
The diagnosis of the origin of a broad complex tachycardia may be difficult, especially in the absence of a 12-lead electrocardiogram of the tachycardia. This study investigates the value of signal averaging in the differential diagnosis of broad complex tachycardia. Signal averaging during sinus rhythm was performed in 102 consecutive patients who presented with broad complex tachycardia (QRS width greater than 110 ms), in whom a definitive electrophysiological diagnosis was made. The presence of late potentials was determined on the basis of two definitions, the second including total QRS duration. The patients studied included 75 with ventricular tachycardia; 33 of these patients had suffered previous myocardial infarction, five had dilated cardiomyopathy, and 37 had a 'normal' heart. Of the 27 patients with supraventricular tachycardia, 22 had an atrioventricular accessory pathway (seven with a delta wave in sinus rhythm), three had atrioventricular nodal tachycardia and two had atrial tachycardia. The sensitivity of late potentials for the diagnosis of ventricular tachycardia was low utilizing both definitions (28% and 45%) although specificity was high (96% and 95%). The sensitivity for the diagnosis of ventricular tachycardia was higher for patients with ischaemic heart disease (43% and 70%) but very low for patients with ventricular tachycardia and a normal heart (16% and 22%). In conclusion, signal averaging in the remote diagnosis of broad complex tachycardia is specific but not sensitive for ventricular tachycardia, which limits its usefulness in selecting patients for electrophysiological study.
Coronary Disease↗
Density-dependent regulation of epidermal growth factor receptor expression.
Previous studies have demonstrated that binding of peptide growth factors such as epidermal growth factor (EGF) decreases as cell density increases. We now report that binding of EGF to MDA 468 breast carcinoma cells is reduced as cells increase in density with time in culture. Cells at low density bound more EGF per cell than cells at higher density. The reduction of EGF binding was due to a reduction in receptor number. Metabolic labeling of MDA 468 cells with [35S]-methionine followed by immunoprecipitation of the EGF receptor (EGFR) indicated that the amount of total receptor protein was decreased. Using RNA blot hybridization, we found that high-density cells contained decreased amounts of EGFR transcripts. Northern analysis revealed that both the 10- and 5.6-kilobase mRNA transcripts encoding the EGFR were decreased. These data suggest that increasing cell density with time in culture results in modulation of EGFR content, with changes at the level of both protein and mRNA expression.
Blotting, Northern↗