New real-time interactive cardiac magnetic resonance imaging system complements echocardiography

OBJECTIVES: We conducted an initial clinical trial of a newly developed cardiac magnetic resonance imaging (CMRI) system. We evaluated left ventricular (LV) function in 85 patients to compare the clinical utility of the CMRI system with echocardiography, the current noninvasive gold standard. BACKGROUND: Conventional CMRI systems require cardiac-gating and respiratory compensation to synthesize a single image from data acquired over multiple cardiac cycles. In contrast, the new CMRI system allows continuous real-time dynamic acquisition and display of any scan plane at 16 images/s without the need for cardiac gating or breath-holding. METHODS: A conventional 1.5T Signa MRI Scanner (GE, Milwaukee, Wisconsin) was modified by the addition of an interactive workstation and a bus adapter. The new CMRI system underwent clinical trial by testing its ability to evaluate global and regional LV function. The first group (A) consisted of 31 patients with acceptable echocardiography image quality. The second group (B) consisted of 31 patients with suboptimal echocardiography image quality. The third group (C) consisted of 29 patients with severe lung disease or congenital cardiac malformation who frequently have suboptimal echo study. Two independent observers scored wall motion and image quality using the standard 16-segment model and rank-order analysis. RESULTS: CMRI evaluation was complete in less than 15 min. In group A, no significant difference was found between ECHO and CMRI studies (p = NS). In group B, adequate visualization of wall segments was obtained 38% of the time using ECHO and 97% of the time using CMRI (p < 0.0001). When grouped into coronary segments, adequate visualization of at least one segment occurred in 18 of 30 patients (60%) with ECHO and in all 30 patients (100%) with CMRI (p < 0.0001). In group C, adequate visualization of the wall segments was obtained in 58% (CI 0.53-0.62) of the time using echocardiography and 99.7% (CI 0.99-1.0) of the time using CMRI (p < 0.0001). CONCLUSIONS: The new CMRI system provides clinically reliable evaluation of LV function and complements suboptimal echocardiography. In comparison with the conventional CMRI, the new CMRI system significantly reduces scan time, patient discomfort and associated cost.     

Exercise echocardiography or exercise SPECT imaging? A meta-analysis of diagnostic test performance

CONTEXT: Cardiac imaging has advanced rapidly, providing clinicians with several choices for evaluating patients with suspected coronary artery disease, but few studies compare modalities directly. OBJECTIVES: To review the contemporary literature and to compare the diagnostic performance of exercise echocardiography (ECHO) and exercise single-photon emission computed tomography (SPECT) imaging in the diagnosis of coronary artery disease. DATA SOURCES: Studies published between January 1990 and October 1997 identified from MEDLINE search; bibliographies of reviews and original articles; and suggestions from experts in each area. STUDY SELECTION: Articles were included if they discussed exercise ECHO and/or exercise SPECT imaging with thallous chloride TI 201 (thallium) or technetium Tc 99m sestamibi for detection and/or evaluation of coronary artery disease, if data on coronary angiography were presented as the reference test, and if the absolute numbers of true-positive, false-negative, true-negative, and false-positive observations were available or derivable from the data presented. Studies performed exclusively in patients after myocardial infarction, after percutaneous transluminal coronary angioplasty, after coronary artery bypass grafting, or with recent unstable coronary syndromes were excluded. DATA EXTRACTION: Clinical variables, technical factors, and test performance were independently extracted by 2 reviewers on a standardized spreadsheet. Discrepancies were resolved by consensus. RESULTS: Forty-four articles met inclusion criteria. In pooled data weighted by the sample size of each study, exercise ECHO had a sensitivity of 85% (95% confidence interval [CI], 83%-87%) with a specificity of 77% (95% CI, 74%-80%). Exercise SPECT yielded a similar sensitivity of 87% (95% CI, 86%-88%) but a lower specificity of 64% (95% CI, 60%-68%). In a summary receiver operating characteristic model comparing exercise ECHO performance to exercise SPECT, exercise ECHO was associated with significantly better discriminatory power (parameter estimate, 1.18; 95% CI, 0.71-1.65), when adjusted for age, publication year, and a setting including known coronary artery disease for SPECT studies. In models comparing the discriminatory abilities of exercise ECHO and exercise SPECT vs exercise testing without imaging, both ECHO and SPECT performed significantly better than exercise testing. The incremental improvement in performance was greater for ECHO (3.43; 95% CI, 2.74-4.11) than for SPECT (1.49; 95% CI, 0.91-2.08). CONCLUSIONS: Exercise ECHO and exercise SPECT have similar sensitivities for the detection of coronary artery disease, but exercise ECHO has better specificity and, therefore, higher overall discriminatory capabilities as used in contemporary practice.     

Long-term MR follow-up of cerebral lesions in neuro-Beh?et's disease

To study the long-term evolution of cerebral lesions in neuro-Beh?et's disease, MRI was carried out on 12 patients, with follow-up from 1.5 to 6 years (mean 3.5 years). On the first MRI, 66 lesions in all were found; each patient had 1-10 lesions (mean 5.5). There were 30 (46%) lesions in the brain stem, 18 (27%) in the basal ganglia region and 18 (27%) in the periventricular white matter. Of these 22 (33%) were small, 31 (47%) medium-size and 13 (20%) large lesions. On the last MRI, 60 lesions were found: each patient had 1-10 lesions (mean 5). At this time 31 lesions (52%) were in the brain stem, 13 (22%) in the basal ganglia region and 16 (26%) in the periventricular white matter. There were 41 (68%) small, 13 (22%) medium-size and 6 (10%) large lesions. About 40% of the lesions disappeared, 35% reduced in size and 25% remained unchanged. No lesion had enlarged. Of the 60 final lesions 20 (34%) were not observed on the first study. Small new lesions were found in 5 of 12 patients (42%), and were asymptomatic. Medium-size or large new lesions were found in 2 patients (17%) who had stopped steroid treatment and had a neurological relapse. Enlargement of the ventricular system or worsening of initial cerebral atrophy was observed in 9 of 12 patients. Appearance of small lesions and worsening of cerebral atrophy on long-term follow-up suggest the possibility of subclinical progression of cerebral vasculitis and should be considered in the prognosis of neuro-Beh?et's disease.     

Valve operations through a minimally invasive approach

BACKGROUND: We analyzed in-hospital results of 87 patients undergoing minimally invasive valvular operations (right parasternal incision through third and fourth cartilages). METHODS: Age was 21 to 84 years (mean, 56.2 +/- 16); 45 patients (51.7%) were female. Five (5.7%) had a previous valvular operation and 8 (9.2%) had severe left ventricular dysfunction. Valve diseases were as follows: aortic in 35 patients (40.2%), mitral in 44 (50.5%), double in 5 (5.7%), tricuspid regurgitation in 2 (2.2%), and mitral periprosthetic leak in 1 (1.1%). RESULTS: Nineteen mitral repairs (21.9%), 22 replacements (25.3%), 1 leak closure (1.1%), 1 tricuspid repair (1.1%), and 1 replacement (1.1%) were performed. Thirty-one patients (35.7%) underwent aortic replacement, 2 (2.3%) aortic decalcification, 1 (1.1%) subaortic membrane resection, 4 (4.6%) a double-valve procedure, and 5 (5.7%) a single-valve operation combined with myocardial revascularization. In-hospital mortality was 5.7% (5 patients). Univariate analysis was significant for previous operation, New York Heart Association class IV and severe ventricular dysfunction. Multivariate analysis was significant for previous operation and severe ventricular dysfunction. Atrial fibrillation (12.6%) was the most frequent complication. Postoperative stay was 6.5 +/- 6 days. CONCLUSIONS: The minimally invasive approach is a useful technique in valvular surgery. Patients with a previous valvular operation, severe ventricular dysfunction, and New York Heart Association class IV dyspnea have higher in-hospital mortality.     

Study of the viscosity of excited membranes using combined dispersion spectroscopy

Tuberous sclerosis (TSC) is an autosomal dominant disorder characterized by seizures, mental retardation, and hamartomatous lesions. Although hamartomas can occur in almost any organ, they are most common in the brain, kidney, heart, and skin. Allelic loss or loss of heterozygosity (LOH) in TSC lesions has previously been reported on chromosomes 16p13 and 9q34, the locations of the TSC2 and TSC1 genes, respectively, suggesting that the TSC genes act as tumor-suppressor genes. In our study, 87 lesions from 47 TSC patients were analyzed for LOH in the TSC1 and TSC2 chromosomal regions. Three findings resulted from this analysis. First, we confirmed that the TSC1 critical region is distal to D9S149. Second, we found LOH more frequently on chromosome 16p13 than on 9q34. Of the 28 patients with angiomyolipomas or rhabdomyomas, 16p13 LOH was detected in lesions from 12 (57%) of 21 informative patients, while 9q34 LOH was detected in lesions from only 1 patient (4%). This could indicate that TSC2 tumors are more likely than TSC1 tumors to require surgical resection or that TSC2 is more common than TSC1 in our patient population. It is also possible that small regions of 9q34 LOH were missed. Lastly, LOH was found in 56% of renal angiomyolipomas and cardiac rhabdomyormas but in only 4% of TSC brain lesions. This suggests that brain lesions can result from different pathogenic mechanisms than kidney and heart lesions.     

Utility of psychophysiological measurement in the diagnosis of posttraumatic stress disorder: results from a Department of Veterans Affairs Cooperative Study

OBJECTIVE: Predicting postrepair right ventricular/left ventricular pressure ratio has prognostic relevance for patients undergoing total repair of pulmonary atresia, ventricular septal defect, and major aortopulmonary collateral arteries. To this purpose, we currently rely on 2 novel parameters: (1) preoperative total neopulmonary arterial index and (2) mean pulmonary artery pressure changes during an intraoperative flow study. METHODS: Since January 1994, 15 consecutive patients (aged 64 +/- 54 months) with pulmonary atresia, ventricular septal defect, and major aortopulmonary collaterals were managed according to total neopulmonary arterial index. Seven patients with hypoplastic pulmonary arteries and a total neopulmonary arterial index less than 150 mm(2)/m(2) underwent palliative right ventricular outflow tract reconstruction followed by secondary 1-stage unifocalization and ventricular septal defect closure. The other 8 patients with a preoperative index of more than 150 mm(2)/m(2) underwent primary single-stage unifocalization and repair. The ventricular septal defect was closed in all cases (reopened in 1). In 9, such decision was based on an intraoperative flow study. RESULTS: Patients treated by right ventricular outflow tract reconstruction had a significant increase of pulmonary artery index (P=.006) within 22 +/- 6 months. Repair was successful in 14 cases (postrepair right ventricular/left ventricular pressure ratio = 0.47 +/- 0.1). One hospital death occurred as a result of pulmonary vascular obstructive disease, despite a reassuring intraoperative flow study. Accuracy of this test in predicting the postrepair mean pulmonary artery pressure was 89% (95% CI: 51%-99%). At follow-up (18 +/- 12 months), all patients are free of symptoms, requiring no medications. CONCLUSIONS: The integrated approach to total repair of pulmonary atresia, ventricular septal defect, and major aortopulmonary collaterals by preoperative calculation of total neopulmonary arterial index, right ventricular outflow tract reconstruction (when required), and intraoperative flow study may lead to optimal intermediate results.     

Isolated limb reperfusion with tumor necrosis factor and melphalan in patients with extremity melanoma after failure of isolated limb perfusion with chemotherapeutics

BACKGROUND: This retrospective study evaluated the benefit of using tumor necrosis factor (TNF) and melphalan administered via an isolated limb perfusion (ILP) in a series of patients with metastatic melanoma who failed initial ILP with chemotherapeutics. METHODS: Seventeen patients with extremity melanoma who underwent prior ILP with conventional chemotherapeutics (10 with melphalan; 4 with platinum; 2 with platinum, dacarbazine, thiotepa, actinomycin D, and nitrogen mustard; and 1 with thiotepa, actinomycin D, and nitrogen mustard) and had local recurrences were treated with a 90-minute isolated hyperthermic limb reperfusion with melphalan (10 mg/L limb volume) plus TNF (2-6 mg). Five prior ILPs were adjuvant and 12 were therapeutic. RESULTS: Reperfusion was associated with an overall 94% response rate and a 65% complete response (CR) rate. Of the patients who failed an initial ILP with melphalan alone the overall response rate was 90% after the reperfusion with TNF and melphalan. In patients who failed an initial ILP with agents other than melphalan the CR rate was 100% after ILP with TNF and melphalan. TNF/melphalan isolated limb reperfusion was found to be more effective in terms of CR after initial ILP regimens that did not utilize melphalan (100% CR after nonmelphalan ILP vs. 50% CR after melphalan ILP [P = 0.04]). Regional toxicity was comprised of mild skin blistering and peeling in 47% of patients. One patient developed Grade 3 (based on National Cancer Institute Common Toxicity Criteria) skin necrosis, and one developed Grade 5 muscle and nerve toxicity, requiring an amputation. CONCLUSIONS: Isolated limb reperfusion with TNF and melphalan can be performed safely with response rates similar to those of other trials of single perfusions. Repeat ILP using TNF and melphalan in patients with melanoma who have failed prior ILP with chemotherapeutics is justified. The utility of TNF (vs. melphalan alone) will be defined in ongoing Phase III trials.     

Mortality and platelet depletion occur independently of fibrinogen consumption in murine models of tumour necrosis factor-mediated systemic inflammatory responses

The link between left ventricular dysfunction and arrhythmogenesis is commonly known. However, so far, only the systolic left ventricular dysfunction has been evaluated. Because of the controversial results of those studies, we decided to assess if is there a link between late potentials (LP) and left ventricular diastolic dysfunction. Our material consisted of 56 patients: 11 women and 45 men, mean age was 61.12 +/- 10.07 years. Signal averaged ECG and ECHO were performed in each patient, 2-3 months after myocardial infarction. For high pass filter of 40 Hz, LP were defined as 2 or 3 abnormal SAECG variables (the averaged QRS > 114 ms, the low amplitude signal duration LAS > 38 ms and root mean square voltage of the terminal 40 ms RMS40 < 20 microV). During ECHO study, we assessed E and A waves E/A ratio, left ventricular end-diastolic volume (LVEDV), ejection fraction (EF), acceleration (AT) and deceleration times (DT). The patients were divided into 2 groups: group I-30 patients LP positive and group II-26 patients LP negative. There were no significant differences between the groups in terms of age, EF, and heart rate. We presented significant differences between group I and II in terms of E wave velocity (0.75 +/- 0.19 vs 0.64 +/- 0.19 p < 0.03) E/A ratio (2.13 +/- 1.56 vs 1.0 +/- 0.5 p < 0.05) respectively. We did not confirm significant differences as regards A wave velocity, AT, isovolumetric time (IVRT) and LVEDV between both tested groups. In group I we revealed a significant correlation between E wave (r = 0.45), E/A ratio (r = 0.62), AT (r = -0.42) E/A ratio (r = 0.56), DT (r = 0.55) and QRS, as well as DT and LPD (r = 0.40) and between IVRT and RMS40 (r = -0.43). The results of our study suggest that in patients after myocardial infarction: 1/incidence of LP depends on the degree of left ventricular filling pattern like in impaired relaxion, quite well correlated with filtered QRS time 3/in LP positive patients there was predominance of restrictive left ventricular filling pattern, quite well correlation with RMS40 amplitude.     

Focus on bovine products

Echocardiographic (ECHO) findings in 211 consecutive examinations performed at Eldoret Medical Services from August 1992 to May 1994 were analysed. Most patients were referred by physicians from Eldoret and from the surrounding hospitals for assessment of heart failure or a heart murmur. Thirty three echocardiograms were judged as being normal and 177 abnormal. Of the abnormal ECHOs, congenital heart disease accounted for 38.4% while rheumatic heart disease accounted for 40.7%: Of the 68 patients with congenital defects, 21 (30.1%) had ventricular septal defects; 19 (27.9%) persistent ductus arteriosus; five (7.5%) mitral valve; four (5.9%) tetralogy of Fallot; and three (4.4%) atrial septal defects. In addition, there were two (3.0%) patients each with complete atrio-ventricular septal defects, tricuspid atresia, complete transposition of the great arteries, truncus arteriosus, single ventricle and bicuspid aortic valve. Of the 67 patients with uncomplicated rheumatic heart disease, mitral valve involvement alone was seen in 39 (58.2%), mitral and aortic in 26 (38.8%) and aortic valve alone in two (3.0%). Rheumatic heart disease was complicated by bacterial endocarditis in five patients. Nine patients had pericardial effusion. The possible role of colour-flow ECHO as a feasible, non-invasive and, in the long term, cost-effective means of allowing for early detection and timely institution of secondary prophylaxis while rheumatic heart disease is still asymptomatic is highlighted.     

Effects of norepinephrine on right ventricular function in septic shock patients

OBJECTIVE: To study the effects of norepinephrine on right ventricular function in patients with hyperdynamic septic shock. DESIGN: Prospective, open study. SETTING: A 15 bed ICU in a university hospital. PATIENTS: 9 patients with hyperdynamic septic shock (SBP < 90 mmHg, Cl > or = 4 l.min-1.m-2, SVRI < or = 850 dynes.s.cm-5m-2 and oliguria). INTERVENTIONS: Plasma volume expansion was used to correct a suspected volume deficit and then, norepinephrine infusion was started and titrated to restore systemic blood pressure to the normal range (mean infusion rate: 1.1 +/- 0.2 mcg.kg-1.min-1). Norepinephrine was the only vasoactive agent used in these patients. MEASUREMENTS AND RESULTS: A modified Swan-Ganz catheter mounted with a fast response thermistor was inserted in each patient, allowing repeated measurements of RVEDVI and RVEF. At time of inclusion to the study, all but one patient had elevated MPAP (23 +/- 4 mmHg) and RVEF < or = 50%, and all patients had RVEDVI > or = 90 ml.m-2. During norepinephrine infusion, MAP increased from 51 +/- 9 to 89 +/- 10 mmHg (p < 0.0001), PVRI increased from 204 +/- 35 to 286 +/- 63 dynes.s.cm-5.m-2 (p < 0.05), and despite this increase in right ventricular afterload, no detrimental effect in RVEF (36 +/- 11 to 36 +/- 10%) or in RVEDVI (116 +/- 30 to 127 +/- 40 ml.m-2) was observed. A Frank-Starling relationship for the right ventricle was constructed by plotting an index of ventricular performance (RVSWI) against an index of ventricular preload (RVEDVI). A significant upward shift to the right of the relationship was observed during norepinephrine infusion. CONCLUSION: It was concluded that norepinephrine exerted a favourable effect on right ventricular function.     

Polyclonal/monoclonal ratio in kidney and bone marrow transplanted patients treated with cyclosporine

OBJECTIVE: To examine the hypothesis that suppression of frequent premature ventricular contractions may be associated with improvement in left ventricular function in patients with presumed idiopathic dilated cardiomyopathy. DESIGN: We conducted a retrospective case study and statistical analysis of the effect of cardiac medical therapy on outcome. MATERIAL AND METHODS: The study population consisted of 14 patients with more than 20,000 premature ventricular contractions in 24 hours recorded by Holter monitoring and associated left ventricular dysfunction (ejection fraction, 40% or less). Clinical characteristics, number of premature ventricular contractions per hour on 24-hour ambulatory Holter monitoring, and ejection fraction based on transthoracic echocardiography were compared before and after cardiac therapeutic intervention. RESULTS: Of the 14 patients, 10 had presumed idiopathic dilated cardiomyopathy, and 4 had ischemic heart disease. Of the overall study group, seven had received additional cardiac medical therapy after the index evaluation, including four patients who had amiodarone therapy. A significant reduction (75% or more from baseline) in premature ventricular contractions after medical therapeutic intervention was observed in five patients at the first follow-up examination. The mean interval to the first follow-up examination was 6 +/- 3 months. Of the five patients, four had significant improvement in clinical functional status and the ejection fraction. The mean ejection fraction of these five patients increased from 27 +/- 10% at baseline to 49 +/- 17% after medical therapy (P = 0.04). CONCLUSION: The suppression of frequent premature ventricular contractions may be associated with improvement of left ventricular function in patients with presumed idiopathic dilated cardiomyopathy.     

Subependymal astrocytic hamartomas in the Eker rat model of tuberous sclerosis

Tuberous sclerosis (TSC) is an autosomal dominant syndrome that is linked to two genetic loci: TSC1 (9q34) and TSC2 (16p13). Brain manifestations such as cortical tubers and subependymal hamartoma/giant cell astrocytomas are major causes of TSC-related morbidity. In this study, we describe the central nervous system involvement in a unique rodent model of tuberous sclerosis. The Eker rat carries a spontaneous germline mutation of the TSC2 gene and is predisposed to multiple neoplasia. In a series of 45 adult Eker carriers (TSC2 +/-), three types of focal intracranial lesions were found, of which the subependymal and subcortical hamartomas were most prevalent (65%). There exist remarkable phenotypic similarities between the Eker rat and human subependymal lesions. Our study indicates that the predominant cellular phenotype of the subependymal hamartomas is astroglial and suggests that the neuronal contribution within these lesions is, in part, the result of pre-existing myelinated axons. The hamartomas did not show evidence of loss of the wild-type TSC2 allele; it remains to be determined whether TSC2 inactivation is necessary for their pathogenesis. This genetically-defined rodent model may be useful in elucidating the molecular and developmental basis of the subependymal giant cell astrocytoma in humans.     

Left ventricular lesions in arrhythmogenic right ventricular dysplasia and 12-lead electrocardiographic findings

Left ventricular lesions in arrhythmogenic right ventricular dysplasia have not been well described, and the relationship between the left ventricular lesions and the 12-lead electrocardiographic findings has not been analyzed. This study examined whether the presence of left ventricular lesions and the extent of right ventricular lesions due to arrhythmogenic right ventricular dysplasia are predictable by 12-lead electrocardiographic findings. The 12-lead electrocardiograms during sinus rhythm and left and right ventriculography were studied in 29 patients (27 males and 2 females, mean age 42.6 +/- 15.5 years) diagnosed by the current criteria for this disease. After evaluation, patients were divided into two groups: those with normal left ventricles (normal group) and those with left ventricular wall motion abnormalities (abnormal group). Seventeen of the 29 patients (59%) were classified into the abnormal group. Left ventricular wall motion abnormalities were located in the posterolateral (4 patients), apical (1), and posterolateral and apical regions (12). QS patterns of abnormal Q waves in lead I, aVL or V5, V6 rS patterns (R/S ratio < 1) in leads I and V6, and/or R or Rs patterns (R/S ratio > 1) in lead V1 were observed in all patients in the abnormal group, but in none in the normal group. There was a positive correlation between the right ventricular end-diastolic volume index and the number of precordial negative T waves (r = 0.746, p < 0.0001), and the time from onset of the QRS to the terminal portion of the epsilon wave in lead V1 (r = 0.627, p < 0.001). The correlation coefficients showed no significant differences between the groups. A left ventricular lesion associated with arrhythmogenic right ventricular dysplasia was not unusual (59%), and our study suggests that the posterolateral and apical regions are the most frequent sites. The presence of these lesions were predictable by the QRS abnormalities. Moreover, regardless of the presence of such a lesion, the extent of the right ventricular lesion is also predictable by the 12-lead electrocardiographic findings.     

The expression of HLA, Epstein-Barr virus nuclear antigen and the infiltration of T lymphocyte subsets in nasopharyngeal biopsy tissues

In this study, 79 patients with locally advanced head and neck cancer were treated with induction chemotherapy. Cisplatin, 25 mg/m2, and 5-fluorouracil (5-FU), 1000 mg/m2, were employed, both of them in 24-hour continuous infusion over 96 hours, four cycles. The patients later underwent surgery and/or radiation therapy. The response to chemotherapy was 49%: of the complete responses (CR), 56% were histological; 29% were partial responses (PR). With the administration of the fourth cycle, CR increased from 30% to 49%. Once the complete treatment had been finished, 75% of CR and 5% PR were achieved. With a maximum follow-up period of 44 months, overall survival stands at 50%.     

Impact of size mismatch and left ventricular function on performance of the St. Jude disc valve after aortic valve replacement

BACKGROUND: The hemodynamic function of the St. Jude valve may change relative to changes in left ventricular function after aortic valve replacement for aortic stenosis. From theoretical reasons one may hypothesize that prosthetic valve hemodynamic function is related to left ventricular failure and mismatch between valve size and patient/ventricular chamber size. METHODS: Forty patients aged 24 to 82 years who survived aortic valve replacement for aortic stenosis with a standard St. Jude disc valve (mean size, 23.5 mm; range, 19 to 29 mm) were followed up prospectively with Doppler echocardiography and radionuclide left ventriculography preoperatively and 9 days, 3 months, and 18 months after the operation with assessment of intravascular hemolysis at 18 months. Follow-up to a maximum of 7.4 years (mean, 6.3 years) was 100% complete. RESULTS: Left ventricular muscle mass index decreased from 198 +/- 62 g.m-2 preoperatively to 153 +/- 53 g.m-2 at 18 months (p < 0.001), paralleled by a significant increase in left ventricular ejection fraction, peak ejection rate, and peak filling rate; only 18% of the patients had normal left ventricular muscle mass index and only 32% normal ventricular function (normal left ventricular ejection fraction, peak ejection rate, peak filling rate, early filling fraction, and late filling fraction during atrial contraction) at 18 months. Prosthetic valve peak Doppler gradient dropped from 20 +/- 6 mm Hg at 9 days to 17 +/- 5 mm Hg at 18 months (p < 0.05). Reduction of left ventricular muscle mass index was unrelated to peak gradient and size of the valve. Peak gradient at 18 months rose with valve orifice diameter of 17 mm or less (by 6 mm Hg), orifice diameter/body surface area of 9 mm.m-2 or less (by 5 mm Hg), left ventricular enddiastolic dimension (by 23 mm Hg per 10 mm increase), and impaired ventricular function (by 3 mm Hg). All but 2 patients (5%) had intravascular hemolysis; none had anemia. Two patients with moderate paravalvular leak had the highest serum lactic dehydrogenase levels; 4 patients with trivial leak had higher serum lactic dehydrogenase levels than those without leak. Serum lactic dehydrogenase levels rose with moderate paravalvular leak, impaired ventricular function, and valve orifice diameter. Six patients with trivial or moderate paravalvular leak had a cumulative 7-year freedom from bleeding and thromboembolism of 44% +/- 22% compared with 87% +/- 5% for those without leak (p < 0.05). CONCLUSIONS: The peak gradient of the St. Jude aortic valve dropped marginally over the first 18 postoperative months in association with incomplete left ventricular hypertrophy regression and marginal improvement of ventricular function. Mismatch between valve size and ventricular cavity size or patient size and impaired function of a dilated ventricle significantly compromised the performance of the St. Jude valve. Probably explained by platelet destruction or activation, paravalvular leak was related to bleeding and thromboembolic complications.     

Ventricular tachycardia during follow-up in patients resuscitated from ventricular fibrillation: experience from stored electrograms of implantable cardioverter-defibrillators

OBJECTIVE: The purpose of this study was to use the electrogram storage capabilities of the implantable cardioverter-defibrillator (ICD) to categorize any arrhythmic event during follow-up in a group of patients who had survived an episode of ventricular fibrillation (VF) and to possibly identify clinical predictors of future arrhythmic events. BACKGROUND: Little is known about the electrophysiologic characteristics of ventricular arrhythmias recurring during follow-up in survivors of VF as the sole documented arrhythmia at the time of resuscitation. METHODS: Forty patients (58+/-10 years; 73% men; left ventricular ejection fraction 42+/-18%; 70% with coronary artery disease) who had survived an episode of VF and subsequently received an ICD capable of intracardiac electrogram recording and storage were followed for 23+/-11 months. In all patients, the arrhythmogenic substrate was investigated by means of programmed electrical stimulation (PES). RESULTS: Among the 40 patients, 41 episodes of ventricular arrhythmias were documented in 13 patients (33%): 36 episodes of ventricular tachycardias (VT) were recorded in 11 patients (28%) and 5 episodes of VF were recorded in the remaining 2 patients (5%). Age, gender, cardiac disease and left ventricular ejection fraction failed to distinguish between patients with clinical recurrences and patients without. The sensitivity, specificity and positive accuracy of PES were 29%, 63% and 46%, respectively, for prediction of ventricular arrhythmia recurrence; 45%, 70% and 36%, respectively, for prediction of VT; and 50%, 98% and 50%, respectively, for prediction of VF during follow-up. CONCLUSIONS: In survivors of VF receiving ICD therapy, VT is the most common ventricular arrhythmia recorded on device-incorporated electrograms during follow-up. This finding, associated with the relatively well-preserved ventricular function, may account for the ability of these patients to survive at time of the index arrhythmia; the use of antitachycardia pacing as a modality to treat arrhythmia recurrences may contribute to reduce the incidence of shock during follow-up in these patients.     

Heart rate variability index in congestive heart failure: relation to clinical variables and prognosis

AIM: To evaluate the clinical and prognostic value of the heart rate variability index in patients with congestive heart failure. METHODS: Sixty-four patients with chronic congestive heart failure and sinus rhythm underwent clinical assessment, 24-h ambulatory electrocardiography and echocardiography. Patients were followed for 6 to 30 months. Cardiac death or heart transplantation constituted the primary end-point of the study. RESULTS: The heart rate variability index was related to left ventricular ejection fraction (r=0.29, P=0.02) and New York Heart Association class (P=0.01). Patients with a restrictive left ventricular filling pattern had a lower heart rate variability index compared to patients with a non-restrictive pattern (26+/-11 vs 33+/-9 units, P=0.01). Patients who died (n=11) or underwent heart transplantation (n=4) had a lower heart rate variability index compared to survivors (21+/-10 vs 33+/-9 units, P<0.0001). In multivariate survival analysis, a reduced heart rate variability index was related to survival independent of parameters of left ventricular function. CONCLUSION: The heart rate variability index provides independent information on clinical status and prognosis in patients with chronic congestive heart failure.     

Partial left ventriculectomy with mitral valve preservation in the treatment of patients with dilated cardiomyopathy

OBJECTIVE: This study reports initial results of partial left ventriculectomy performed with preservation of the mitral valve in the treatment of 27 patients with idiopathic dilated cardiomyopathy. METHODS: Patients were in New York Heart Association class III or IV. Partial ventriculectomy was performed as an isolated procedure in four patients and associated with mitral annuloplasty in 23 patients. There were four hospital deaths (14.8%) and the remaining patients were followed for 11.2 +/- 6 months. RESULTS: Decrease of left ventricular diastolic diameter (81.8 +/- 8.7 to 68.5 +/- 7.6 mm, p < 0.001) and improvement of left ventricular wall shortening (12% +/- 3.1% to 18.1% +/- 3.9%, p < 0.001) were demonstrated by echocardiography after the operation. Left ventricular radioisotopic angiography showed reduction of diastolic volume (495 +/- 124 ml to 352 +/- 108 ml, p < 0.001) and increase of ejection fraction (17.7% +/- 4.6% to 23.7% +/- 8.8%, p < 0.001). Right-sided heart catheterization demonstrated improvement of stroke index (24.3 +/- 7.7 ml/m2 to 28.3 +/- 7.6 ml/m2, p < 0.01) and decrease of pulmonary wedge pressure (23.2 +/- 8.8 mm Hg to 17 +/- 7 mm Hg, p < 0.01). Similar results were documented at 6 and 12 months of follow-up. Functional class improved from 3.6 +/- 0.5 to 1.4 +/- 0.6 (p < 0.001). However, seven patients died at midterm follow-up because of heart failure progression or arrhythmia-related events, and survival rate was 59.2% +/- 9.4% from 6 to 24 months of follow-up. CONCLUSIONS: Partial left ventriculectomy performed with preservation of the mitral valve improves left ventricular function and congestive heart failure in patients with dilated cardiomyopathy. Nevertheless, the high incidences of heart failure progression and arrhythmia-related deaths observed after this procedure preclude its wide clinical application.     

Three-year outcome after balloon aortic valvuloplasty. Insights into prognosis of valvular aortic stenosis

BACKGROUND: To identify predictors of long-term outcome after balloon aortic valvuloplasty, we analyzed data on 674 adults (mean age, 78 +/- 9 years; 56% were women) undergoing this procedure at 24 clinical centers who had a mean initial increase in aortic valve area of 0.3 cm2. METHODS AND RESULTS: Baseline data included clinical, echocardiographic, and catheterization variables. Follow-up data included mortality, cause of death, rehospitalization, 6-month echocardiography, and functional status. Kaplan-Meier curves and log-rank tests were used to evaluate survival in subgroups. Multivariate Cox regression models were used to identify independent predictors of survival. Overall survival was 55% at 1 year, 35% at 2 years, and 23% at 3 years, with the majority of deaths (70%) classified as cardiac by an independent review committee. Rehospitalization was common (64%), although 61% of survivors at 2 years reported improved symptoms. Echocardiography at 6 months (n = 115) showed restenosis from the postprocedural valve area of 0.78 +/- 0.31 cm2 to 0.65 +/- 0.25 cm2 (P < .0001). With stepwise multivariate analysis, sequentially adding clinical, echocardiographic, and catheterization variables, the overall model identified independent predictors of survival as baseline functional status, baseline cardiac output, renal function, cachexia, female gender, left ventricular systolic function, and mitral regurgitation. Baseline and postprocedural variables were examined to identify which subgroup of patients has the best outcome after aortic valvuloplasty. A "lower-risk" subgroup (28% of the study population), defined by normal left ventricular systolic function and mild clinical functional limitation, had a 3-year survival of 36% compared with 17% in the remainder of the study group. CONCLUSIONS: Long-term survival after balloon aortic valvuloplasty is poor with 1- and 3-year survival rates of 55% and 23%, respectively. Although survivors report fewer symptoms, early restenosis and recurrent hospitalization are common.     

The role of subunit composition on prepulse facilitation of the cardiac L-type calcium channel

The prevalence of neurocysticercosis has been well documented in rural communities in Latin America using the enzyme-linked inmmunoelectrotransfer blot (EITB) assay. We studied the prevalence of neurocysticercosis in an urban, upper-middle class population in Cuenca, Ecuador. Family members of 34 index cases with parenchymal neurocysticercosis on a computed tomography (CT) scan and family members of 14 patients who had normal CT scans after a trauma or migraine were enrolled in the study. Serum was obtained from 226 individuals, 173 (72%) from the case families and 67 (28%) from the control families. Twelve percent of the case family members and 4% of the control family members were seropositive by the EITB assay. This was a statistically significant difference (P < 0.05) when age and education were held constant by logistic regression. Seropositivity was not related to age. No neurologic symptom proved predictive of serostatus and the only demographic variable that correlated with seropositivity was increased crowding. Positive serology in index cases did correlate with CT findings as follows: 86% of patients with active lesions, 67% with transitional lesions, and only 41% of patients with inactive lesions were positive by the EITB assay. Eighteen percent of family members with a positive EITB test result had parenchymal lesions on a subsequent CT scan. This study demonstrates a high rate of seropositivity of cysticercosis among urban, middle to upper-middle class individuals in a region endemic for Taenia solium. Household contacts of patients with neurocysticercosis had a three-fold higher risk of positive serology for cysticercosis, in comparison with controls.