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Total intravenous anaesthesia with gamma-hydroxybutyrate (GHB) and sufentanil in patients undergoing coronary artery bypass graft surgery: a comparison in patients with unimpaired and impaired left ventricular function.

The haemodynamic effects of anaesthesia with gamma-hydroxybutyrate (GHB)/sufentanil for elective coronary artery bypass grafting (CABG) were investigated and compared in patients with unimpaired left ventricular function (ejection fraction > or = 45%, left ventricular end diastolic pressure < or = 16 mmHg) and patients with impaired left ventricular function. In 38 consecutive patients scheduled for CABG (21 with unimpaired and 17 with impaired left ventricular function), anaesthesia was induced with etomidate, sufentanil and pancuronium. After tracheal intubation, the lungs were normoventilated (end tidal Pco2 4.9-5.6 kPa) with an oxygen-air mixture (Fio2 0.5). Total intravenous anaesthesia was maintained with GHB (20 mg kg-1 h-1 after a 'priming dose' of 40 mg kg-1) and sufentanil (2 micrograms kg-1 h-1). Haemodynamic measurements were made after induction of anaesthesia and at various times in the prebypass period. Patients in both groups showed similar haemodynamic trends. Mean arterial pressure showed a maximum reduction of 10%, whereas heart rate and right- and left-sided filling pressures remained unchanged within the groups after the induction of anaesthesia. Cardiac index remained unchanged in both groups, although values differed between the groups. A total of 14 out of 21 patients (67%) with unimpaired and 10 out of 17 patients (59%) with impaired ventricular function required supplementary administration of opioids to control temporary hypertension after sternotomy. No episodes of myocardial ischaemia were detected during the study period using ST segment analysis (leads II and V5). The results of this study suggest that GHB provides adequate haemodynamic conditions in the prebypass period and may be a suitable agent for TIVA also in patients with impaired left ventricular function undergoing CABG.

Aged↗

[Effect of acute hypoxia on blood viscosity, red blood cell deformability and the left ventricular function in rats].

Experiments were performed on SD rats anaesthetized with urethane and chloralose. The left ventricular function and the parameters of hemorrheology during acute hypoxia were investigated. It was found that during acute hypoxia of 15 min, arterial blood gas value PaO2 decreased markedly. The parameters of the left ventricular function such as +/- dP/dtmax, Peak, HR, Vce40, Vmp, Vmax, L0 (CFU), decreased markedly either. At the same time, hyperviscosity was induced and red blood cell filtration (IF) increased. All these parameters recovered to normal control level after reoxygenation of 15 min. By intravenous injection of propranolol (0.5 mg/kg) and then hypoxia, the left ventricular function were suppressed markedly; and so were to the elevation of blood viscosity and IF. Preinjection of regitine (3 mg/kg) prior hypoxia has the same effect on the blood viscosity and IF. Acute hypoxia induced hyperviscosity and elevation of IF could be suppressed by destruction of carotid sinus region with phenol, but the left ventricular function decreased markedly. These results suggest that acute hypoxia induces hyperviscosity and decreases of red blood cell deformability and left ventricular function, which is probably mediated via the sympathetic nervous system and carotid sinus region.

Animals↗

Key enzymes of myocardial energy metabolism in patients with valvular heart disease: relation to left ventricular function.

Endomyocardial biopsies were taken from the apex of the left ventricle in 15 patients operated on for aortic valve disease or ischaemic heart disease and from papillary muscles in six patients operated on for mitral valve disease. Activities of cardiac phosphofructokinase (PFK), total lactate dehydrogenase (LD), its isoenzyme LD1, aspartate aminotransferase (ASAT), total creatine kinase (CK), its isoenzyme MB, citrate synthase (CS) and myoglobin content (MYO) were related to the angiographically determined left ventricular function. Activities of total LD, PFK and PFK/CS ratio were lower in patients with decreased, than in those with normal, left ventricular function. Myoglobin content and activities of CS and ASAT were not related to left ventricular function. It is suggested that depressed left ventricular contractility is associated with a decreased glycolytic capacity while the oxidative capacity is mainly unaltered.

Aged↗

ALCAPA in an adult with preserved left ventricular function.

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is the most common congenital coronary artery defect. Left uncorrected, nearly 90% of patients will die within one year. Without surgical repair, surviving patients are subjected to risks of myocardial ischemia with global cardiomyopathy, chronic mitral regurgitation, and sudden death. We report a case of ALCAPA in a 23-year-old female with completely preserved left ventricular function. This article reviews the mechanism of this unusual presentation as well as the therapeutic options for adults presenting with ALCAPA.

Adult↗

Left ventricular function during and after right ventricular pacing.

OBJECTIVES: The aim of this research was to evaluate right ventricular pacing effects on left ventricular function. BACKGROUND: Right ventricular pacing alters the ventricular activation sequence and reduces left ventricular ejection fraction (EF). It is unclear whether the observed reduction in EF can be completely attributed to the alteration in activation sequence. METHODS: Twelve subjects (eight women), mean age 68 +/- 12 years, with transvenous dual-chamber pacemakers, normal left ventricular function, and intact atrioventricular (AV) conduction were studied with serial-gated blood pool studies. Left ventricular EF was measured at a fixed rate after at least 1 week of atrial pacing only (baseline), during short-term (2 h) and mid-term (1 week) AV sequential pacing with a short AV delay, and after short- and mid-term AV pacing. RESULTS: Baseline EF was 66.5 +/- 4.5%. Short-term AV pacing resulted in a decrease in EF to 60.3 +/- 5.2% (p < 0.0002). After one week of AV pacing, there was a further decline in EF to 52.9 +/- 8.3% (p < 0.0001). After cessation of mid-term pacing, EF was 57.3 +/- 5.9% (p < 0.0001 vs. baseline). A total of 2, 5, 8, and 24 h later, EF remained depressed (59% to 60%, p < 0.007). At 32 h, EF was 62.9 +/- 7.6% (p < 0.11 compared with baseline). CONCLUSIONS: The abnormal activation sequence resulting from right ventricular pacing accounts for only part of the reduction in EF as mid-term pacing is associated with a lower EF than short-term pacing, and EF remains depressed after cessation of AV pacing. Changes in ventricular function induced by right ventricular pacing may account for some of its associated adverse effects.

Aged↗

[Changes in left ventricular function during chemotherapy with doxorubicin].

The authors investigated by echocardiography changes of left ventricular function in 79 patients with non-Hodgkin lymphoma or Hodgkin's disease who were treated by chemotherapy containing doxorubicin. In 22% patients they diagnosed during treatment a significant gradual decline of the left ventricular ejection fraction (change > 10% or a drop of EF below 50%) after a cumulative dose of 185 +/- 52 mg/m2 doxorubicin (median 200 mg/m2). Changes of the ejection fraction were at the expense of an increasing endsystolic left ventricular volume. These changes correlated closely with the increase of endsystolic stress of the left ventricular wall (r = -0.87). After administration of a cumulative doxorubicin dose of 100 mg/m2 a significant deterioration of indicators of diastolic filling of the left ventricle occurred--of the isovolumic relaxation period (IRP) and deceleration time (DT). The contribution of these early changes of diastolic function of the left ventricle for assessment of the risk of development of systolic dysfunction is not unequivocal. Prolongation of IRP > 12% as compared with the baseline value and at the same time above 95 ms had a 50% sensitivity, 50% specificity, a 26% positive prediction value a 74% negative prediction value and 50% diagnostic accuracy, change of DT > 13%, and at the same time prolongation above 200 ms had a 47% sensitivity 55% specificity, a 22% positive prediction value, a 78% negative prediction value and a 53% diagnostic accuracy. The authors found a significant relationship between the assessed changes of left ventricular function and clinical and haemodynamic indicators. Only the patients' age correlated significantly with IRP and DT values. Changes of the left ventricular ejection fraction were not associated with clinical signs of cardiac failure, they did not call for cardiological intervention and did not affect the course of chemotherapy. Contrary to some statements in the literature, the authors did not consider the described functional changes as sufficient to justify interference with chemotherapy. On the other hand, their importance for the development of late sequelae of chemotherapy with anthracyclines in adult patients must be based on long-term prospective follow-up.

Adolescent↗

Significant effects of atrioventricular node ablation and pacemaker implantation on left ventricular function and long-term survival in patients with atrial fibrillation and left ventricular dysfunction.

Control of ventricular rate by atrioventricular node ablation and pacemaker implantation in patients with drug-refractory atrial fibrillation (AF) is associated with improved left ventricular (LV) function. The objective of this study was to determine the effect of atrioventricular node ablation on long-term survival in patients with AF and LV dysfunction. Survival was determined by the Kaplan-Meier method for 56 study patients with LV ejection fraction (EF) < or =40% who underwent atrioventricular node ablation and pacemaker implantation and 56 age- and gender-matched control patients with AF and LVEF >40%, and age- and gender-matched control subjects from Minnesota. Groups were compared using the log-rank test. In study patients (age 69 +/- 10 years; 45 men), LVEF was 26% +/- 8% and 34% +/- 13% (p <0.001) before and after ablation, respectively. During follow-up (40 +/- 23 months), 23 patients died. Observed survival was worse than that of normal subjects (p <0.001) and control patients (p = 0.005). After ablation, LVEF nearly normalized (> or =45%) in 16 study patients (29%), in whom observed survival was comparable to that of normal subjects (p = 0.37). Coronary artery disease, hyperlipidemia, chronic renal failure, previous myocardial infarction, and coronary artery operation were independent predictors for mortality. Near normalization of LVEF occurred in 29% of study patients, suggesting that AF-induced EF reduction is reversible in many patients. Normal survival in patients with reversible LV dysfunction highlights potential survival benefits of rate control. Poor survival in patients with persistent LV dysfunction confirms the importance of optimal medical therapy.

Aged↗

[Coronary artery bypass surgery in patients with poor left ventricular function].

As the indications for coronary artery bypass grafting (CABG) among patients with poor left ventricular function remain incompletely defined, We undertook the study to assess the results of CABG surgery for a group of such patients. We retrospectively reviewed the clinical features and outcome for 7 patients with poor left ventricular function defined as an ejection fraction below 0.3 who underwent CABG. The mean age of the patients was 63 years (range, 38 to 78 years), and 4 were 70 years of age or older. All patients had history of previous myocardial infarction, and all had left main trunk stenosis or left main equivalent stenosis. The patients underwent CABG with three to six distal anastomoses (mean, 4.3/patient), the internal thoracic artery could be used in all patients, for one or two distal anastomoses (mean, 1.6/patient). Combined coronary endarterectomy was performed in 2 patients. With the exception of one 78-year-old patient with renal failure who died during the early postoperative period, all patients showed marked postoperative improvement in cardiac function. Cardiac catheterization and exercise stress test studies revealed significant improvement in left ventricular function and exercise tolerance in these six patients. These results suggest that excellent results can be obtained with CABG surgery in patients with poor left ventricular function when the viability of the myocardium in the bypassed area has been confirmed.

Adult↗

Hemostatic function in young subjects with central obesity: relationship with left ventricular function.

This study was designed to evaluate coagulation and fibrinolysis activity and their relationship with left ventricular function in young obese subjects with central fat distribution. We assessed coagulation and fibrinolysis activity by evaluation of factor VII activity, fibrinogen and plasminogen, plasminogen activator inhibitor (PAI), and tissue plasminogen activator antigen basally (tPA1) and after venous occlusion (tPA2). These measures were evaluated in young (< 40 years) obese subjects with central fat distribution (n = 19) and in comparable lean subjects (n = 20). Blood glucose, triglycerides, total and high-density lipoprotein (HDL) cholesterol, apolipoprotein (apo) A1 and apo B, fasting immunoreactive insulin, and lipoprotein(a) levels were also measured by current methods. Left ventricular ejection fraction (LVEF) and peak filling rate (PFR) determined by radionuclide angiocardiography and left ventricular mass (LVM) and LVM indexed for body height (LVM/H) determined by echocardiographic study were calculated. Central obesity was evaluated by the waist to hip ratio (WHR) according to the criteria of the Italian Consensus Conference of Obesity. Factor VII (P < .001), fibrinogen (P < .001), plasminogen (P < .001), PAI activity (P < .001), tPA1 (P < .02), fasting blood glucose (P < .01), apo B (P < .02), and immunoreactive insulin (P < .01) were significantly higher in obese than in lean subjects. In contrast, HDL cholesterol (P < .01), tPA2 (P < .01), LVEF (P < .001), and PFR (P < .02) were significantly lower in obese than in lean subjects. In all subjects, WHR correlated directly with fibrinogen and inversely with tPA2; LVEF correlated inversely with tPA1, PAI, and fibrinogen; and PFR correlated inversely with factor VII activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Improved global and regional left ventricular function after angioplasty for chronic coronary occlusion.

Percutaneous transluminal coronary angioplasty can be performed safely and effectively in patients with chronic total coronary occlusion. To investigate the effect on left ventricular function, global and regional left ventricular ejection fraction were analyzed by contrast angiography in 49 patients before and 10 +/- 6 weeks after successful recanalization. Coronary angiography at follow-up showed reocclusion in 12 patients (24%). In 37 patients with patent arteries global ejection fraction increased from 55.8 +/- 7.1% at baseline to 62.5 +/- 11.3% at follow-up (P < 0.001), and regional wall motion assessed by the centerline method improved from -1.7 +/- 1.0 to -0.6 +/- 1.5 standard deviations/chord (P < 0.001). In contrast, in patients with reocclusion neither global ejection fraction nor regional wall motion were significantly different at follow-up compared with baseline. Changes in global or regional left ventricular function after coronary recanalization were unrelated to other parameters such as severity of angina, duration of occlusion, history of myocardial infarction, presence or absence of visible collaterals, or baseline left ventricular function. Thus in patients with primarily successful recanalization of chronically occluded coronary arteries persistent vessel patency is the major determinant of global and regional improvement of left ventricular function.

Adult↗

Blood pressure, insulin resistance and left ventricular function in alcoholics.

OBJECTIVE: To estimate the arterial blood pressure, left ventricular function and insulin secretion in alcoholics. DESIGN: We examined hospitalized patients between the second and seventh day of acute alcohol withdrawal and after a month of abstinence by 24 h ambulatory blood pressure monitoring, a standard oral glucose-tolerance test with determination of insulinaemia, two-dimensional and M-mode echocardiography and pulsed-wave Doppler statistical analysis was performed using Student's t test P < 0.05 was considered statistically significant PATIENTS: Fifty alcoholics aged 36.3 +/- 5.4 years with a history of alcohol abuse for a mean of 12 years. MAIN OUTCOME: We expected the cessation of drinking to exert an influence by lowering the blood pressure and left ventricular function with a concomitant lowering of the insulin resistance. RESULTS: During acute alcohol withdrawal the systolic (121.6 +/- 7.7 versus +115.8 +/- 8.7 mmHg) and diastolic blood pressures (74.5 +/- 6.3 versus 72.0 +/- 7.9 mmHg) were significantly higher. The nocturnal fall in blood pressure was smaller and the variability of the blood pressure was blunted. This period was characterized by hyperinsulinaemia detected by the glucose-tolerance test [In (SUMins) 8957 +/- 0.47 versus 8558 +/- 0.651] correlated to hyperdynamic circulation (cardiac index 3.38 +/- 0.86 versus 3.09 +/- 0.69 I/min per m2). The early: late atrial filling ratio had increased significantly after 1 month of abstinence (1.98 +/- 0.43 versus 2.08 +/- 0.50). CONCLUSIONS: One month of abstinence from drinking decreases the blood pressure and improves the diurnal profile of the blood pressure and the left ventricular diastolic function. Hyperinsulinaemia, which is observed during acute restriction of alcohol consumption, could be one of the causes responsible for hyperdynamic circulation.

Adult↗

Evaluation of left ventricular function using Tei index in patients with preinfarction angina.

OBJECTIVE: The study investigated whether preinfarction angina influences left ventricular functions assessed using Tei index, which is an independent predictor for left ventricular dysfunction in acute myocardial infarction. METHODS: We studied 96 patients with acute myocardial infarction with ST segment elevation (80 men, 16 women; mean age 57.5+/-9.9 years) who were assigned into 2 groups: with and without preinfarction angina. All patients were serially evaluated by 2-dimensional and Doppler echocardiography on the days 1, 6, and 30, and were followed up for 30 days for incidence of complications. RESULTS: We observed that Tei index was lower on the days 1, 6 and 30 (0.49+/-0.20 vs. 0.59+/-0.20, p=0.003, 0.46+/-0.20 vs. 0.56+/-0.20, p=0.001, 0.44+/-0.20 vs. 0.53+/-0.10, p=0.01) in patients with preinfarction angina as compared with those without angina. Tei index significantly decreased during follow-up (0.49+/-0.20, 0.46+/-0.20, 0.44+/-0.20; p=0.02) in patients with preinfarction angina, while it did not change significantly in patients without preinfarction angina (p=0.2). Echocardiographically significant improvements were observed in E deceleration time, isovolumic relaxation time and ejection time in all patients, whereas significant improvements in ejection fraction, wall motion score index and isovolumic contraction time were observed only in patients with preinfarction angina during follow-up. Mortality, Killip class >or=2, pericarditis, atrial fibrillation, and left ventricular thrombus were lower in patients with preinfarction angina. CONCLUSION: These data indicated that the patients with preinfarction angina had better preserved systolic left ventricular function and Tei index values. Also, it was observed that preinfarction angina may cause earlier and more prominent myocardial functional recovery and confer protection against complications on short-term after first acute myocardial infarction.

Angina, Unstable↗

[Effect of late revascularization of the responsible artery after infarction on left ventricular function and remodeling].

The effects of late angioplasty of the culprit artery after myocardial infarction on the decisive prognostic factors of left ventricular function and remodeling are not well known. When the culprit artery is narrowed but patent, angioplasty leads to improvement in segmental contractility and global left ventricular function: it does not seem to influence left ventricular end-diastolic volume. When the artery remains occluded, global and regional left ventricular function is also improved when the recanalised artery remains patent. Moreover, restoration of satisfactory artery patency prevents ventricular remodeling whereas in failed angioplasty or reocclusion, there is a progressive increase in left ventricular volume. However, these results observed in unselected patients could be improved: it would seem that the different beneficial effects only occur when there is residual myocardial viability; in the absence of signs of myocardial viability, the ventricular effects of limitations of angioplasty (incidence of restenosis or reocclusion in this specific context, lower primary success rate in complete arterial occlusion) explain the negativity of rare randomised studies comparing the outcome of left ventricular function depending on whether a conventional attitude or systematic revascularisation of the culprit artery is adopted.

Angioplasty, Balloon, Coronary↗

Determinants of the left ventricular function in patients with coronary heart disease: a multivariate approach.

251 patients with coronary heart disease (CHD) and a control group of 32 normal persons were examined with the purpose of establishing the determinants of the left ventricular function and comparing these determinants with the functional significance of coronary stenosis. The subjects were divided into four groups: I--controls; II--patients with normal left ventricular function (EF more than 60%); III--patients with impaired LV function (EF less than 60%) and Group IV--patients with left ventricular aneurysm. Nine parameters were obtained by multivariate discriminant analysis, which characterize and classify the left ventricular function: the ejection fraction (EF), angina pectoris, exercise ECG, left ventricular end-diastolic pressure, mean velocity of circumferential fibre shortening, left ventricular functional index, longitudinal shortening, LV systolic pressure/systolic volume ratio, and coronary index. On the basis of these parameters, all the normal persons, 88% of Group II, 92% of Group III and 72% of Group IV were classified correctly. The study proves that there is a good correlation between the EF and the haemodynamic and angiocardiographic parameters. The complex left ventricular function index facilitates the prognosis of surgical results. Abnormalities in left ventricular function cannot be reliably assessed by the coronary index values alone.

Adult↗

Echocardiographic assessment of left ventricular function during the injection of adriamycin.

Echocardiography was used to evaluate left ventricular function in 8 children treated with adriamycin for malignant disease. Preejection period (PEP), left ventricular ejection time (LVET) and percent change in left ventricular internal dimension with systole (delta LVID) were measured before, during and immediately after 22 injections of adriamycin as well as 14 injections of other cytotoxic drugs and physiologic saline. No immediate effects on left ventricular function could be discerned. When functional parameters were evaluated longitudinally in patients with relatively higher cumulative doses of adriamycin, percent change in left ventricular internal dimension with systole showed some tendency to decrease, while the other parameters remained essentially unchanged.

Adolescent↗

Effects of valve substitute on changes in left ventricular function and hypertrophy after aortic valve replacement.

BACKGROUND: Residual left ventricular hypertrophy adversely affects long-term outcome after aortic valve replacement. A stentless biological valve in the aortic position has been shown to offer a better hemodynamic profile than a stented one. However, it remains to be defined whether this difference is translated into inter-mediate-term effects on left ventricular structure and function. METHODS: One hundred thirty-seven patients receiving single aortic valve replacement (52 with concomitant coronary artery bypass graft) were enrolled in this study. Ninety-eight were men, and the mean age was 68 years (range, 55 to 90 years). Of the 137 patients, 39 had an aortic homograft, 72 a Toronto stentless porcine valve, and 26 had a stented porcine or bileaflet mechanical valve, with mean valve size of 25 +/- 2.5 mm (mean +/- standard deviation). Left ventricular muscle mass and function were assessed by M-mode echocardiography performed before and 0.5, 6, 12, 24, and 36 months after operation, and recorded on paper for off-line digitizing. Peak valve prosthesis pressure gradients were quantified by continuous wave Doppler. RESULTS: A total of 330 echocardiograms obtained during this study were adequate for computer digitizing. Clinical data, preoperative left ventricular function, and hypertrophy were similar between the three groups. Significant improvement in left ventricular function and major regression of left ventricular hypertrophy had occurred in the entire population by 6 months after operation. Multivariate analysis of variance showed that patients with previous aortic regurgitation had a larger left ventricular cavity size (p < 0.001) and greater mass index (p = 0.001) postoperatively than those with previous aortic stenosis. In addition, peak valvular gradient was lower (p < 0.001), mass index less (p < 0.001), and left ventricular function more normal both systolic, by a greater peak velocity of dimension shortening (p = 0.05) and wall thickening (p = 0.002), and diastolic, by a greater peak velocity of dimension lengthening (p = 0.046), with an aortic homograft or stentless porcine valve compared with a mechanical or stented biological valve. There was no significant difference in peak valve gradient, left ventricular mass index, or function between the aortic homograft and the stentless porcine valve. Age, sex, and concomitant coronary artery bypass graft, as well as aortic cross-clamp time, cardioplegia method, and valve size all proved to be insignificant determinants of postoperative left ventricular hypertrophy or function. CONCLUSIONS: In the first 2 years after implantation, the superior hemodynamic performance of aortic homograft and stentless porcine valve appears to result in more extensive regression of ventricular hypertrophy and greater improvement of left ventricular function than occurs with a mechanical or stented biological valve. These findings encourage the use of a stentless biological valve in older patients requiring aortic valve replacement, and a larger scale long-term randomized study of stentless versus stented biological valve or mechanical valve seems warranted.

Aged↗

MRI-derived ventricular volume curves for the assessment of left ventricular function.

To assess the utility of double oblique, ECG-gated 1H magnetic resonance (MR) derived volume curves for assessing LV function, cardiac short axis images were acquired with a fast field echo technique. We applied this methodology to assess left ventricular function in three groups: normals, patients with left ventricular hypertrophy, and dilated cardiomyopathy. Six slices with 16-20 phases per RR interval were analyzed, representing the initial 75-80% of the cardiac cycle. For each slice, the endocardial border of the left ventricular (LV) chamber was manually traced. Using Simpson's rule, the total LV volume at a given phase was determined considering the traced area, thickness and position in three-dimensional space of each of the six constituent slices. The calculated volumes were plotted against time and the stroke volume, ejection fraction and cardiac output were determined. The volume vs time plots for the systolic and diastolic portions of the curve were individually fit to third degree polynomials using a least squares approximation. From the fit curves, the following data were extracted: the mean slope (dV/dT) during filling and emptying, and the time to 1/4, 1/3 and 1/2 filling and emptying. These parameters are valuable indices of the functional status of the myocardium; thus, accurate and useful estimates of LV function can be obtained using MRI derived volume curves in normal and abnormal states.

Cardiac Volume↗

Safety of antitachycardia pacing in patients with implantable cardioverter defibrillators and severely depressed left ventricular function.

The purpose of this study was to investigate the efficacy and safety of antitachycardia pacing (ATP) in third-generation implantable cardioverter defibrillators (ICDs) for terminating spontaneously occurring ventricular tachycardias (VTs) in patients with severely depressed left ventricular (LV) function. Ninety-one patients with active ATP were followed for 16 +/- 13 months. During this period, 775 VT episodes occurring in 36 patients were treated by ATP. The patients were divided into two groups according to their LV ejection fraction (LVEF): group A with LVEF < or = 30% (n = 20), and group B with LVEF > 30% (n = 16). There were no differences between both groups in age, gender, underlying heart disease, indication for ICD therapy, or drug therapy. The VT rates were comparable (group A: 183 +/- 16 beats/min; group B: 180 +/- 21 beats/min; P = NS). Eighty-three percent of all episodes (n = 332) in group A and 93% of the VTs (n = 443) in group B were ATP terminated (P < 0.01). Ten percent of VTs in group A were accelerated by ATP into the ventricular fibrillation zone versus 2% in group B (P < 0.01). The individual termination rate and acceleration rate per patient were comparable in both groups. All VT episodes unresponsive to ATP were converted by backup shocks. The efficacy of first-shock therapy was similar in both groups (group A: 89%; group B: 97%; P = NS). The proportion of patients who needed at least one backup shock for unsuccessful ATP was comparable in both groups (group A: 65%; group B: 56%; P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Defibrillators, Implantable↗