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Biomedical subjects

G Breithardt

Publications and source records attributed to G Breithardt.

At least 325 records · Page 18Linked to original sources
PubMed1993

[Therapy of ventricular tachyarrhythmia with implantable cardioverters/defibrillators--mortality and complications using epicardial electrodes].

Technical improvements of third generation implantable cardioverter defibrillators (ICD) like antitachycardia pacing modalities lead to an extended use of ICDs, not only in patients with aborted sudden cardiac death, but also in patients with hemodynamically tolerable ventricular tachycardia. In addition, anticipated results of current prospective studies might indicate the prophylactic use of ICDs in patients with high risk for sudden cardiac death, but without documented ventricular tachyarrhythmias. This report reviews mortality and complications associated with the ICDs with epicardial defibrillation leads. Mortality is separated in cardiac death, sudden cardiac, arrhythmogenic "not so sudden" cardiac death, and overall mortality. Pulmonary complications and infections are related to the underlying disease and the surgical procedure. Device- and lead-related complications, high defibrillation thresholds, pacemaker interactions, inappropriate shocks, arrhythmic effects, syncope, and psychosocial problems are reported, respectively.

Adolescent↗
PubMed1993

[Diagnostic value of intravascular ultrasound diagnosis in peripheral arteriosclerotic blood vessel changes].

Intravascular ultrasound is an adjunct for the diagnosis of atherosclerotic peripheral vessels. In this in-vitro study, 69 segments of human peripheral arteries were fixed in formalin, examined with intravascular ultrasound and pathomorphologically evaluated. Sensitivity, specificity, both positive and negative predictive value and accuracy of intravascular ultrasound for the detection of irregular lumen contours, intraarterial structures and intimal thickening were determined for each of four quadrants. Sonographic features (echogeneity, homogeneity, shadowing of echoes) were compared to the architecture of lesions. Intravascular ultrasound detected regular (normal) lumen contours with high specificity (96.5%), a sensitivity of 65.0%, and an accuracy of 88.4%; intraluminal structures were detected with a sensitivity of 88.6%, a specificity of 97.8%, and an accuracy of 96.4%. Most atherosclerotic lesions could be localized with a sensitivity of 86.1%, a specificity of 99.1%, and an accuracy of 86.9%. Slight intimal thickening was detectable with a sensitivity of 85.9%, a specificity of 87.8%, and an accuracy of 86.2%. Comparison of sonographic features and the pathomorphological architecture of atherosclerotic lesions revealed that fibrous, atheromatous, and complex lesions without calcification did not show shadowing of echoes. The majority of fibrous or atheromatous lesions presented with homogeneous echoes; these lesions showed hypo-, hyper- and normodense echoes. The homogeneity of echoes did not help to identify the different components of combined atherosclerotic lesions. Thus, intravascular ultrasound is able to detect irregular lumen contours, intraluminal structures, and intimal thickening, but further sonographic criteria are needed to identify the architectural structure of combined lesions.

Aorta, Abdominal↗
PubMed1993

[Detection of pacemaker electrode infection using intravascular ultrasound].

The case of a 60-year-old man who developed fever 14 months after last implantation of a DDD pacemaker system is reported. Though staphylococcus epidermidis could be identified in several blood cultures, transthoracic and transesophageal echocardiograms and scintigraphy with antibodies to human leucocytes could not identify any focus of infection. The percutaneous intravascular and intracavitary ultrasound examination clearly demonstrated a vegetation within the subclavian vein, being attached to the ventricular lead; within that segment of the vein the atrial lead showed a small hyperdense structure. Further vegetations along the leads within the right atrium and ventricle could be ruled out. Subsequent removal of the pacemaker system caused resolution of the signs of inflammation.

Anti-Bacterial Agents↗
PubMed1993

201Tl reinjection predicts improvement of left ventricular function following revascularization.

The aim of this study was to evaluate the correlation between improved Tl uptake in reinjection imaging with improvements in regional wall motion and global ejection fraction following PTCA or aorto-coronary bypass surgery. 19 patients with CHD were investigated and divided into two groups according to their thallium uptake in the reinjection studies. Group I showed additional uptake on reinjection imaging compared to the redistribution image, whereas group II showed no additional uptake. Both groups had a similar number and distribution of affected vessels and location of the leading stenosis. Stress, redistribution and reinjection images were obtained prior to revascularization and evaluated semiquantitatively from a bulls eye scheme. There was a postoperative increase in regional wall motion in group 1 from 5.3 to 8.8% whereas group II did not show a relevant change (6.3 vs 6.0%). The ejection fraction increased II from 55.0 to 66.7% in group I and dit not increase in group II (59.8 vs 58.7%). The overall predictive value of the reinjection image for improvement in wall motion (> 10%) was 91% and for the redistribution image 58%. Increased uptake in reinjection imaging predicts improved ventricular function following revascularization and indeed indicates viable myocardium with reversible functional impairment.

Aged↗
PubMed1993

[Cardiopulmonary effects of CPPV (continuous positive pressure ventilation) and IRV (inverse ratio ventilation) in experimental myocardial ischemia].

Continuous positive pressure ventilation (CPPV) is an established therapy for treatment of acute respiratory failure (ARF). However, cardiac performance may be severely disturbed due to elevated intrathoracic pressure, inducing a decrease in cardiac output (CO) and oxygen delivery (DO2). Alternatively, mechanical ventilation with prolonged inspiratory to expiratory duration ratio (inversed ratio ventilation IRV) has been successfully used in ARF. No data are available about IRV in acute haemodynamic oedema. Thus, the cardiopulmonary effects of CPPV (positive end-expiratory pressure [PEEP] = 10 cm H2O) and IRV (inspiration to expiration duration ratio [I:E] = 3.0) were studied in nine dogs (body weight 29.9 +/- 4.3 kg) before and after induction of myocardial ischaemia. METHODS. Continuous intravenous anaesthesia and muscle paralysis were provided by 1.2 mg.kg-1 x h-1 piritramide and 0.08 mg.kg-1 x h-1 pancuronium, and the animals were ventilated with intermittent positive pressure ventilation (IPPV) as reference method. Cardiocirculatory performance was determined by means of heart rate (HR), mean arterial pressure (MAP), mean pulmonary arterial pressure (MPAP), central venous pressure (CVP), pulmonary artery occlusion pressure (PAOP) and left ventricular end-diastolic pressure (LVEDP). Cardiac output (CO) was determined by thermodilution method. Systemic vascular resistance (SVR) was calculated. Pulmonary function was assessed by arterial and mixed venous blood gas tension for oxygen (PaO2, PvO2) and carbon dioxide (PaCO2). Functional residual lung capacity (FRC) was measured by means of the foreign gas wash-in method using helium as inert gas, and determination of extravascular lung water (EVLW) using the thermal-dye indicator technique. CPPV and IRV were studied in random sequence in the control phase and 60 min after induction of acute left ventricular ischaemia, which was achieved by occlusion of the ramus interventricularis anterior. RESULTS. During the control phase CPPV induced an increase in MPAP (P < 0.05), CVP (P < 0.05) and PAOP (P < 0.05). HR and MAP remained unchanged, whereas CO decreased by 16% (P < 0.05). FRC was elevated by 25 ml.kg-1 (P < 0.01), but not EVLW (9.1 +/- 3.5 ml.kg-1). There was no improvement in oxygenation; instead, oxygen delivery (DO2) decreased (P < 0.05). During inversed ratio ventilation MPAP, CVP, PAOP increased, but less than during CPPV. FRC was elevated mu 7.0 ml.kg-1 (P < 0.05), which was significantly less than during CPPV (P < 0.05). EVLW revealed no differences. During IPPV in the ischaemia phase cardiopulmonary performance deteriorated significantly. CO decreased by 19% (P < 0.05), whereas HR, MPAP, CVP and PAOP increased (P < 0.05). PaO2 was lower (P < 0.05) and alveolo-arterial PO2 gradient (PAaO2) increased (P < 0.05). All animals revealed moderate pulmonary oedema (EVLW = 15.1 +/- 8.4 ml.kg-1) (P < 0.01) and a lower FRC. Mechanical ventilation with PEEP significantly improved oxygenation and FRC; however, DO2 was slightly lower than during IPPV (not significant). IRV elevated PaO2, FRC and DO2, since CO was not depressed when compared with IPPV. CONCLUSIONS. CPPV and IRV may induce a recruitment of collapsed or hypoventilated lung areas, which is more pronounced during CPPV. During both modes of ventilation, oxygenation was improved without apparent changes in EVLW. Haemodynamic performance was more impaired during CPPV, and no improvement of left ventricular function secondary to an elevated intrathoracic pressure was observed. Occlusion of the RIVA coronary artery typically induces an infarction of 35% of left ventricular muscle mass; however, non-ischaemic myocardium reveals an unchanged or increased contractility. Thus, a reduction of left ventricular preload secondary to CPPV mainly contributes to haemodynamic depression, which is less pronounced during IRV due to a lower peak inspiratory airway pressure and mean airway pressure. IRV may be useful for mechanical ventCntCo

Animals↗
PubMed1993

[Anisotropic impulse conduction characteristics in chronic myocardial infarct. The importance for initiation and perpetuation of ventricular tachycardia].

The underlying mechanism of most ventricular tachycardias in the setting of chronic myocardial infarction is reentrant excitation. At that time, the active membrane properties like upstroke velocity and amplitude of action potentials of muscle fibers surviving in the border zone of the infarction have returned nearly completely to normal. Anisotropic conduction characteristics, however, importantly contribute to the electrophysiologic properties of the epicardial and/or endocardial border zones in chronic myocardial infarction. In normal myocardial tissue with tight coupling between muscle fibers, conduction velocity is slower for impulses propagating transverse to fiber orientation compared to longitudinal to fiber orientation due to a higher effective axial resistivity ("uniform" anisotropy). With infarct healing, connective tissue invading into the epicardial border zone separates surviving muscle fiber bundles and thereby decreases cell-to-cell coupling ("non-uniform" anisotropy). In this setting, excitation waves propagate transverse to fiber orientation in an irregular sequence and conduction velocity in this direction is significantly reduced without occurrence of acute ischemia. Block of conduction waves propagating longitudinally to fiber orientation may lead to activation of the area distal to the block with long delay by very slow transverse wavefronts. This long delay allows fibers proximal to the line of block to regenerate excitability, and reentrant excitation may be initiated. The common pathway of figure-eight tachycardias preferentially orientates longitudinally to fiber orientation. Very slow conduction transverse to fiber orientation at the pivoting points of reentrant circuits may lead to the occurrence of excitable gaps.

Animals↗
PubMed1993

[Diagnostic and therapeutic problems in idiopathic prolonged QT syndrome. A case report].

The case of a 36-year-old woman with suspected idiopathic long QT syndrome is reported. Diagnosis was made late after syncopal attacks and several episodes of resuscitation had occurred. Although therapy with a beta-blocking agent was initiated and a cardioverter/defibrillator was implanted, the patient died, due to a hydrocephalus internus resulting in cerebral damage. Diagnostic and therapeutic problems in idiopathic long QT syndrome are discussed.

Adult↗
PubMed1992

Doppler echocardiographic assessment of the pressure gradient during bicycle ergometry in hypertrophic cardiomyopathy.

To assess the behavior of the subvalvular pressure gradient under physical exercise, 13 patients with obstructive hypertrophic cardiomyopathy were examined during upright bicycle ergometry by means of Doppler echocardiography. Additionally, right-sided cardiac catheterization was performed within 7 days. In 10 patients adequate Doppler tracings could be obtained during exercise. The Doppler-derived systolic pressure gradient increased from 75 +/- 24 to 140 +/- 42 mm Hg (p less than 0.0005). This was associated with an increase in the duration of the systolic mitral-septal contact from 59 +/- 21 to 136 +/- 28 ms (p less than 0.0005). Correlation between the pressure gradient and the duration of mitral-septal contact at rest and during exercise was good (r = 0.86), whereas correlation between the resting and exercise pressure gradient (r = 0.34) did not reach statistical significance. The increase in stroke volume during exercise, from 90 +/- 18 to 95 +/- 24 ml, was significant (p less than 0.05) but minimal. Therefore, only a moderate increase in systolic flow, from 205 +/- 54 to 268 +/- 78 ml/s (p less than 0.0005), was observed. Outflow tract resistance, defined as the ratio of the pressure gradient to systolic flow, increased from 0.38 +/- 0.11 to 0.57 +/- 0.24 mm Hg.s/ml (p less than 0.01). Thus, in a selected group of patients with hypertrophic cardiomyopathy a substantial increase in the maximal pressure gradient during upright bicycle ergometry was demonstrated in most patients. Exercise Doppler echocardiography may be valuable to assess the hemodynamic significance of obstruction in individual patients in a physiologic setting and has a potential to monitor the effect of therapeutic interventions.

Adult↗
PubMed1992

Thallium-201 single photon emission tomography of myocardium: additional information in reinjection studies is dependent on collateral circulation.

A second thallium-201 injection under resting conditions is able to improve the differentiation between myocardial scar and ischaemia when compared with simple redistribution imaging. The aim of this study was to evaluate the dependence of this improvement on the degree of stenosis and the presence of collaterals. Single photon emission tomography (SPET) studies under exercise, redistribution and reinjection conditions were performed on 84 patients with 181 stenotic vessels (70 left anterior descending, 47 left circumflex, 64 right coronary artery) and compared with angiography. An improvement of the 201Tl uptake in the reinjection image was observed in 53% of the myocardial areas served by a coronary artery with a stenosis of over 90%. This is compared with 13% of the areas served by a vessel with a stenosis between 50% and 90%. 90% of the collateralized areas showed a fill-in effect, but only 7 of the 118 without angiographically visible collateralization (6%). The dependence of the fill-in effect, collateralization and stenosis was highly significant (chi 2 test, p less than 0.0001). In our patient group, there was much greater benefit from the reinjection study in vessels with a greater than 90% narrowing. The fill-in effect was closely correlated to the presence of collaterals. In these cases, the fill-in may be an indication for hibernating myocardium.

Collateral Circulation↗
PubMed1992

Factors which provoke post-infarction depression: results from the post-infarction late potential study (PILP).

Symptoms of depression in the majority of patients immediately following acute myocardial infarctions (AMI) resolve rapidly; they are an adjustment reaction. However, in a group of 552 male patients there were 80 (14.5%) patients with persistent major depressive symptoms during a finite period after AMI. Infarction size was assessed by maximum creatine kinase levels, the QRS-complex and the occurrence of late potentials. These measures did not correlate with the degree of depressed moods in these groups. An arrhythmic event in the early hospitalization phase, a recurrent infarction, dyspnoea, and persistent angina pectoris before the AMI were significantly related to more profound degrees of depression. Patients who reported serious life-events in the last 2 yr before AMI, or who suffered from exhaustion and fatigue in the prehospital phase were subject to significantly higher levels of depression. A prodromal phase prior to hospitalization free of bodily symptoms and the use of denial were related to low levels of depression. The logistic regression model incorporating all univariate significant variables revealed that symptoms of exhaustion and fatigue prior to AMI had the strongest independent correlation with post AMI depression.

Activities of Daily Living↗
PubMed1992

Characteristics of local electrogram predicting successful transcatheter radiofrequency ablation of left-sided accessory pathways.

OBJECTIVES: The purpose of this study was to analyze and compare the local electrograms recorded at successful and unsuccessful sites of ablation to identify the criteria that may predict successful sites and minimize unnecessary radiofrequency delivery. BACKGROUND: Transcatheter ablation of accessory pathways using radiofrequency energy requires extremely precise localization of an accessory pathway. METHODS: Local electrograms from 50 consecutive patients with left-sided accessory pathways who underwent transcatheter radiofrequency ablation were analyzed. During catheter ablation, localization of accessory pathways was performed in 39 pathways during pre-excited sinus rhythm and in 14 pathways during orthodromic tachycardia. A total of 429 local electrograms at target sites obtained before delivery of radiofrequency current was analyzed. A prospective study was performed in another 20 patients using the criteria derived from the retrospective study. RESULTS: Accessory pathway conduction block was achieved in 36 (92%) of 39 pathways in which mapping was performed during pre-excited sinus rhythm and in 9 (64%) of 14 pathways in which mapping was performed during orthodromic tachycardia (p less than 0.05). When mapping was performed during pre-excited sinus rhythm, a combination of four variables (that is, an accessory pathway potential, stability of local electrograms, atrial activation greater than 1 mV and ventricular activation preceding the onset of the delta wave) showed a 62% probability of success. In contrast, excluding these variables resulted in a 95% probability of failure (noneffective or transiently effective). The prospective study shows that the use of these criteria can significantly reduce the number of current applications. When mapping was performed during orthodromic tachycardia, recording the earliest atrial activation was the most powerful predictor of success. A stable local electrogram with a small notch on the ventricular potential, presumed to be an accessory pathway potential, may add predictive value. CONCLUSIONS: Transcatheter radiofrequency ablation is highly effective in the treatment of patients with left-sided accessory pathways. Specific characteristics of local electrograms can be important predictors of success or failure. Mapping during pre-excited rhythm renders ablation more effective than does mapping during orthodromic tachycardia.

Adolescent↗
PubMed1992

Prediction of the site and severity of obstruction in hypertrophic cardiomyopathy by color flow mapping and continuous wave Doppler echocardiography.

OBJECTIVE: We investigated whether the site and severity of an obstruction in hypertrophic cardiomyopathy can be accurately predicted by the combined use of color-coded and continuous wave Doppler echocardiography. BACKGROUND: Predicting the site of obstruction by end-systolic cavity shape is not reliable. Therefore, hemodynamic localization of the obstruction is required before surgery is performed. Such localization should be possible with color flow imaging, which provides two-dimensional velocity mapping reflecting the distribution of pressures within the left ventricle. Discrepancies in assessment of the pressure gradient by Doppler echocardiography and cardiac catheterization (which are usually not performed simultaneously) may be due to spontaneous variation of the dynamic obstruction in addition to technical factors related to both methods. METHODS: Twenty consecutive patients with hypertrophic cardiomyopathy were examined 1 day before transseptal left heart catheterization. The obstruction site was defined by color flow mapping. The pressure gradient was determined by continuous wave Doppler echocardiography. Measurements were also performed simultaneously in 10 patients during cardiac catheterization. RESULTS: Midventricular obstruction was correctly identified in 4 patients and subvalvular obstruction in 15 patients. One patient had no obstruction at rest. Invasively and noninvasively determined pressure gradients correlated well (r = 0.89, SEE = 16.3 mm Hg). Multiple single-beat analysis in 10 patients, also simultaneously examined with Doppler echocardiography and catheterization, yielded an excellent correlation (r = 0.97, SEE = 13.1 mm Hg). Comparing the simultaneous (r = 0.96, SEE = 12.5 mm Hg) and nonsimultaneous (r = 0.81, SEE = 23.8 mm Hg) recordings in these patients, we found that the spontaneous variation of the dynamic obstruction mainly accounted for discrepancies (p less than 0.05). CONCLUSION: The combined use of color-coded and continuous wave Doppler echocardiography provides the relevant hemodynamic information required for decision-making in patients with hypertrophic cardiomyopathy who are considered for transaortic myectomy.

Adult↗
PubMed1992

Technique of aortic valve replacement with the Edwards stentless aortic bioprosthesis 2500.

Aortic valve replacement with a stentless device ought to result in superior hemodynamic function, because obstructing stents and sewing rims are eliminated. From 15 June 1991 to 15 October 1991, 15 patients underwent aortic valve replacement with the newly designed Edwards stentless aortic bioprosthesis 2500. Patients' ages ranged from 51 to 70 years (mean 61 years). Preoperatively 4 patients presented with aortic regurgitation, 7 with aortic stenosis and 4 with combined lesions; 7 patients were male and 8 female. No additional cardiac or noncardiac diseases were encountered. The operations were performed under normothermic extracorporeal cardiopulmonary bypass and cold cardioplegic cardiac arrest. The implanted valves ranged from 21 mm to 27 mm in diameter. Ten patients received a subcoronary implantation with the lower row of stitches made up of interrupted sutures and the upper row of a continuous suture. In 5 patients the so-called miniroot technique was used, also with lower interrupted sutures and running upper sutures, after adaptation of coronary ostia to the performed openings in the graft. Aortic cross-clamp time ranged between 73 min and 94 min (mean 82 min). There was no operative mortality or morbidity. Postoperative echocardiography showed no signs of aortic valve regurgation in any patient and continuous wave-Doppler measurements showed that resting pressure gradients across the aortic valve were absent or low. Our preliminary experiences with a stentless aortic xenograft valve show that in presence of an increased cross-clamp time an improved hemodynamic function will be obtained. Further studies will be needed, however, to establish the long-term behavior of this device.

Aortic Valve Insufficiency↗
PubMed1992

Subthreshold electrical stimulation for termination and prevention of reentrant tachycardias.

Subthreshold electrical stimulation (STS) was used to terminate and prevent reentrant supraventricular and ventricular (VT) tachycardia. Of 12 patients with SVT, 8 had atrioventricular nodal (AVN) reentry, and 4 had orthodromic tachycardias. Trains of STS applied close to the AVN area terminated the tachycardias in five of the eight patients with AVN re-entry and two of the patients with orthodromic tachycardia. In 13 patients with recurrent sustained hemodynamically stable VT (mean cycle length 370 +/- 40 ms), trains of STS were delivered at the site of early activity during the tachycardia. Number of train cycles ranged between 3 to 8 pulses and their cycle lengths ranged between 20 and 70 ms. In 7 of the 13 patients VTs were effectively terminated by STS application close to the site of early activity and in the remaining 6 patients it did not. In nine patients the effect of STS applied at the site of early activity on VT induction from the right ventricular apex was examined. In four of the nine patients STS prevented VT induction and in the remaining five patients it did not. These observations suggest that STS applied in proximity to the area critical for initiation and maintenance of reentry can terminate or prevent induction of the tachycardia.

Adult↗
PubMed1992

Nd:YAG laser-photocoagulation: acute electrophysiological, hemodynamic, and morphological effects in large irradiated areas.

Laser-photocoagulation (LPC) of arrhythmogenic myocardium has been reported to successfully ablate ventricular tachycardia. The purpose of this study was to investigate the acute hemodynamic and electrophysiological effect of continuous laser energy (Nd:YAG, 1060 nm) applied via a 0.4-mm quartz fiberoptic on the epicardial surface of the heart in nine dogs. A total of 51 +/- 2.3 pulses was delivered in each animal to induce homogeneous tissue necrosis. Applied energy was 12.3 +/- 2.7 J/mm2, irradiated surface measured 12.6 +/- 3.0 cm2, lesion depth was 6.3 +/- 1.2 mm (range: 5.0-8.1 mm), lesion volume was 8.1 +/- 2.8 cm3 (6.8% of left ventricular [LV] mass). After LPC, epicardial stimulation threshold significantly rose from 1.0 +/- 0.3 to 10.2 +/- 4.9 mA in the border zone to nontreated tissue and from 0.9 +/- 0.4 to 32 +/- 15.7 mA in the center of the lesions. Loss of epicardial activation in the irradiated areas could be demonstrated by epicardial mapping. Ventricular extrasystoles during LPC were seen in all dogs, ventricular tachycardia in seven, and ventricular fibrillation in two dogs. After LPC, cardiac output and LV dP/dtmax significantly decreased by 14.2% and 11.2%. LPC induced predictable homogeneous tissue edema, eosinophilic staining, contraction band necrosis, and sharp demarcated hemorrhagic border zones with a sharp electrical border zone to nontreated tissue and loss of epicardial activation. During LPC, various arrhythmogenic effects could be observed. However, no persistent arrhythmic activity developed after LPC. The results confirm the feasibility of epicardial LPC of the myocardium. Although not rested in this study, LPC of arrhythmogenic tissue may also be feasible as a treatment modality of ventricular tachycardia.

Animals↗
PubMed1992

Radiofrequency ablation of accessory pathways: characteristics of transiently and permanently effective pulses.

The purpose of this study was to characterize and compare the radiofrequency current applications that produced permanent or transient accessory pathway conduction block. One hundred fifty-two radiofrequency energy applications that induced permanent (permanently effective pulses, n = 48) or transient (transiently effective pulses, n = 104) accessory pathway block in 57 patients with 60 accessory pathways were analyzed. The time from the onset of current application to disappearance of preexcitation or termination of supraventricular tachycardia by permanently effective pulses was 1-15 seconds (mean 3.6 +/- 3.8 sec) compared to 2-29 seconds (mean 11.5 +/- 7.5 sec) by transiently effective pulses (P less than 0.01). After transiently effective pulses that induced block in accessory pathway, conduction resumed within 5 minutes while induced block by permanently effective pulses persisted in 44 of 48 patients (92%) during follow-up of 11 +/- 12 months. The accessory pathway conduction returned in the remaining four patients after ablation 2 weeks to 7 months. After transiently effective pulses, 41 impulses were delivered to the same site using a higher power output (n = 32) and/or longer energy delivery duration (n = 20) without new mapping of accessory pathway location. Thirty-six of these impulses again resulted in transient accessory pathway block, four had no effect, only one impulse induced a permanent block in the accessory pathway. Pulses with higher power outputs tended to induce transient effects more frequently than pulses with lower energy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Implantation of a cardioverter/defibrillator in the subpectoral region combined with a nonthoracotomy lead system.

An implantable cardioverter defibrillator was placed into a subpectoral pocket via the incision for cephalic venotomy during implantation of a nonthoracotomy lead system. The approach obviated another incision and subcutaneous tunneling of the leads. There were no perioperative complications and after 6 months of follow-up, the patient continues to tolerate the device satisfactorily.

Electric Countershock↗