Noninvasive evaluation of arterial abnormalities in young patients with neurofibromatosis type 1

Neurofibromatosis regroups at least two different autosomal dominant genetic disorders: neurofibromatosis type 1 (NF1) and neurofibromatosis type 2 (NF2). Vascular disease is an underestimated complication of NF1. Few studies are available on this, all based on case reports. Neurofibromin, NF1 protein product, has also been detected in aortic smooth muscle. The purpose of this study was to evaluate the physical properties of the vessels, by measuring the carotid-femoral pulse wave velocity (PWV). This parameter was assessed by the Complior, a new noninvasive, validated device, used to screen a large population. The authors studied 64 neurofibromatosis patients (34 boys and 30 girls) with a mean age of 12 years (range 5-25 years). To investigate the presence of vascular lesions, aortic stiffness was evaluated by carotid-femoral PWV by using an automatic processor (Complior). They compared data from the PWV with a control group (30 healthy children, 17 boys and 13 girls, mean age 11 years, range 5-23 years). The calculated mean PWV in the control group was 6.5 +/- 1.15 m/s. The mean PWV of the 64 young patients with NF1 was 6.3 +/- 1.02 m/s. There was no difference between the two groups (p=0.39). Nevertheless, analysis of the linear regression has shown a linear relationship between systolic blood pressure (SBP) and PWV in the control group, while in NF1 patients this relationship is not present. The authors suggest that the coexistence of different factors, such as intimal proliferation, thinning media, fragmentation of the elastic tissue, irregularity, stenosis and tortuosity of the vessels, dysplasia of the small vessels, that counterbalance PWV, normalize the mean value. They emphasize the importance of a careful vascular evaluation, using noninvasive method, such as Complior. This device is well accepted by NF1 patients.

Efficacy of carvedilol on complex ventricular arrhythmias in dilated cardiomyopathy: double-blind, randomized, placebo-controlled study

AIMS

The aim of the present study was to investigate whether the addition of carvedilol to conventional therapy in dilated cardiomyopathy patients is associated with further benefits in the treatment of complex non-sustained ventricular arrhythmias (Lown class III, IV or V).

METHODS AND RESULTS

We recruited 168 patients with ischaemic or idiopathic dilated cardiomyopathy, with complex ventricular arrhythmias. Patients able to tolerate low doses of carvedilol were randomized to treatment with carvedilol or placebo for 6 months. Carvedilol treatment improved ventricular function and reduced the incidence of arrhythmic episodes. Notably, by the end of the first month of treatment, the antiarrhythmic efficacy of the drug was significantly greater in patients with ischaemic than in those with idiopathic dilated cardiomyopathy, an effect that could probably be attributed to the anti-ischaemic properties of carvedilol. After 3 months, at a time when ejection fraction was significantly improved in all treated patients, the antiarrhythmic efficacy of carvedilol was similar in the two study groups.

CONCLUSIONS

Carvedilol antiarrhythmic efficacy was paralleled by the improvement in ejection fraction, independent of the aetiology of heart failure. The possibility of adding to an already 'optimized' conventional therapy a drug able to reduce the incidence of complex non-sustained ventricular arrhythmias is a therapeutic option that should be considered in the treatment of these patients.

Clinical significance of cytomegalovirus-specific T helper responses and cytokine production in lung transplant recipients

Cytomegalovirus (CMV) disease continues to be a major problem for lung transplant recipients. In CMV-seropositive individuals, we detected two types of CMV-specific responses: a self-restricted response stimulated by soluble CMV antigen (sCMV-Ag) and a non-self-restricted response induced by CMV-infected cells (cCMV-Ag). Lung transplant recipients who develop the CMV-specific self-restricted T helper response have a low risk of recurrent CMV disease. In contrast, during CMV disease, lung transplant recipients exhibit only the non-self-restricted T helper responses. We characterized the T cell activation and the kinetics of cytokine production of sorted CD4+ and CD8+ T cells from PBLs of CMV seropositive donors. The two types of CMV antigens induced cytokine production in both T cell subsets. We also performed competitive RT-PCR for Granzyme B (GB) in BAL cells of lung transplant recipients prior to, during and following CMV disease. CMV disease was associated with increase in GB gene expression when was accompanied by acute cellular rejection while it remained low in patients with CMV disease that did not have a complicated course. In summary, CMV-activated T cells within the allograft may produce inflammatory cytokines and effector molecules that may promote allograft rejection.

Exercise capacity in young patients after total repair of Tetralogy of Fallot

Tetralogy of Fallot is the most common form of cyanotic congenital heart disease. Measurement of physical activity is usually performed as a routine part of the patient's cardiac evaluation. The aim of this study was to examine the exercise performance of young patients operated on for tetralogy of Fallot, assessing the possible influence of known negative prognostic factors related to the surgical repair. The study group comprised 41 consecutive patients (29 male and 12 female, ages 11.2 +/- 3.9 years, range 6-16 years) operated on for tetralogy of Fallot. Patients in the study group were divided in subgroups in relation to the age of surgical intervention (before or after 2 years of life), the surgical approach (combined transatrial/transpulmonary approach or right ventriculotomy), and the presence of aortopulmonary shunts prior to performing total correction. Their data were compared with those of 33 aged-matched asymptomatic control subjects (19 male and 14 female, ages 11.9 +/- 1.3 years, range 11-16 years). Blood pressure and heart rate measured at rest were similar between control and Fallot groups. A normal increase in systolic blood pressure was observed in response to exercise intensity for all subgroups. No significant difference between control and Fallot groups was found under conditions of mild or moderate exercise or for diastolic blood pressure at rest and in response to exercise. Lower maximal heart rate and systolic blood pressure values were recorded in all patients when compared with the control subjects. Significant differences in peak workload were detected between control and Fallot groups and between the control and each subgroup; however, no difference was found between subgroups. In conclusion, despite their very satisfactory clinical status, all patients showed a reduced peak workload, irrespective of the surgical approach, age at surgery, and aortopulmonary shunts prior to performing total correction.

Ventricular tachyarrhythmias following coronary surgery: predisposing factors

The perioperative factors potentially associated with post-coronary artery bypass grafting (CABG) ventricular tachyarrhythmias (VT) onset have not been deeply investigated. Monomorphic or polymorphic ventricular tachycardia and ventricular fibrillation represent the most dreadful arrhythmic events that can complicate the postoperative course of CABG. As a consequence, the aim of our paper was to identify which perioperative variables might predict post-CABG VT occurrence. One hundred and fifty-two consecutive patients who underwent CABG surgery at our Institution were included in the study. Post-CABG VT occurred in 13 out of 152 patients (8.5%, six cases of monomorphic ventricular tachycardia and seven cases of ventricular fibrillation). At univariate analysis, VT patients were significantly younger (54.8+/-6.6 vs. 60.1+/-8.8, P=0.038), exhibited a more severe coronary artery disease (CAD) (number of diseased vessels 2.92+/-0.3 vs. 2.45+/-0.7, P=0.023, and percentage of patients with three-vessel CAD 91.7% vs. 57.3%, P=0.043) and received a greater number of CABGs than those remaining in sinus rhythm (SR) (percentage of patients receiving three or more CABGs 76. 9% vs. 38.8%, P1000 76.9% vs. 38%, Pnormal range 72.7% vs. 30.7%, P=0.014), electrolyte derangement (84.6% vs. 45.6%, P=0.017) and a severe haemodynamic impairment (need for IABP 23% vs. 2.9%, P1000, postoperative electrolyte imbalance, the need for three or more CABGs and of IABP all were independent correlates for VT. In conclusion, post-CABG VT seem to be related to the preexistence of a severe underlying coronary artery disease along with perioperative triggering factors such as acute ischemia, electrolytic disorders and a sudden haemodynamic impairment.

Perioperative correlates of malignant ventricular tachyarrhythmias complicating coronary surgery

Sustained ventricular tachyarrhythmias (VT), such as monomorphic or polymorphic ventricular tachycardia, and ventricular fibrillation, represent the most serious arrhythmic events that can complicate the postoperative course of coronary artery bypass grafting (CABG). The perioperative factors potentially associated with post-CABG sustained VT onset have not been thoroughly investigated. As a consequence, the aim of our study was to identify which perioperative variables might predict post-CABG VT occurrence. One hundred and fifty-two consecutive patients who underwent CABG surgery at our Institute were included in the study. Post-CABG VT occurred in 13 out of 152 patients (8.5%, six cases of monomorphic ventricular tachycardia and seven cases of ventricular fibrillation). Univariate analysis revealed that VT patients were significantly younger (54.8 +/- 6.6 vs 60.1 +/- 8.8, P = 0.038), exhibited more severe coronary artery disease (CAD) (no. of diseased vessels, 2.92 +/- 0.3 vs 2.45 +/- 0.7, P = 0.023; and percentage of patients with three-vessel CAD, 91.7 vs 57.3%, P = 0.043), and received a greater number of CABGs than those remaining in sinus rhythm (SR) (percentage of patients receiving three or more CABGs, 76.9 vs 38.8%, P = 0.018) Moreover, VT patients more frequently developed intra- or postoperative myocardial infarction (total CK > 1,000, 76.9 vs 38%, P = 0.016; and MB-CK > normal range, 72.7 vs 30.7%, P = 0.014), electrolyte derangement (84.6 vs 45.6%, P = 0.017), and a severe hemodynamic impairment (need for intra-aortic balloon pump (IABP), 23 vs 2.9%, P = 0.009). On multivariate analysis, total CK > 1,000, postoperative electrolyte imbalance, the need for three or more CABGs, and for IABP all were independent correlates for VT. In conclusion, post-CABG VT seem to be related to the preexistence of a severe underlying coronary artery disease along with perioperative triggering factors, such as acute ischemia, electrolytic disorders, and sudden hemodynamic impairment.

Arrhythmogenic substrate in young patients with repaired tetralogy of Fallot: role of an abnormal ventricular repolarization

Ventricular repolarization analysis has been shown to be effective in the identification of electrical myocardial instability leading to ventricular arrhythmias. The aim of the present study was to examine ventricular repolarization time indexes, in terms of both absolute measures and dispersion across the myocardium, in young patients with repaired tetralogy of Fallot (41 pts; 28M/13F, age 11.7+/-3.6 years), assessing, furthermore, the possible influence of known negative prognostic factors relative to the surgical operation and residual haemodynamic abnormalities. The data of the study group were compared with those of 33 aged-matched asymptomatic control subjects (22M/11F, age 11.7+/-2.3 years). Ventricular depolarisation, as expressed by QRS duration, resulted significantly longer in total Fallot group than in the Control group (P<0.0001). Particularly, patients operated through a right ventricular approach showed higher values of QRS interval (P<0.0001) than those operated through a combined transatrial-transpulmonary approach. All the patients operated on for tetralogy of Fallot exhibit, with respect to control subjects, an inhomogeneous prolongation of ventricular repolarization across the myocardium, as showed by the significant increase in the absolute indexes of ventricular repolarization, JTc (P<0.001), QT (P<0.0001) and QTc (P<0.0001) with a concomitant prolongation of the indexes of dispersion of ventricular recovery time, QTcD (P<0.0001), JTcD (P<0.0001), 'adjusted' QTcD (P<0.001) and Tp-Te interval (P<0.0001). A temporal and regional variation in the ventricular repolarization across the myocardium in patients with repaired tetralogy of Fallot, could create the pathophysiological substrate for an increased cardiac electrical instability. The presence of negative prognostic factors, relative to the surgical intervention or residual haemodynamic abnormalities, even if not influencing the arrhythmic substrate, invariably present, could determine 'trigger' conditions essential for the development of ventricular arrhythmias.

[Angiotensin-II receptor inhibitors in hemodialysed uremia patients with arterial hypertension: candesartan cilexitil versus losartan]

BACKGROUND

The aim of this study was to evaluate, in patients with chronic renal failure in hemodialysis and arterial hypertension, the effectiveness of a new angiotensin II receptor antagonist, the candesartan cilexitil, comparing it with losartan, the first of this new class of drugs.

METHODS

We have selected 128 patients with chronic renal failure (92 males and 36 females, mean age 56 +/- 6 years) and arterial hypertension, subjected to hemodialysis 3 times a week, with hemodialytic seniority of 90 +/- 10 months. The inclusion criteria in the study were given from the presence, after 15 days of pharmacological wash-out, of values of diastolic blood pressure (DBP) > or = 95 mmHg and systolic blood pressure (SBP) > or = 150 mmHg, despite a hemodialysis correctly performed. Patients were divided into two groups whether they received single blind randomized candesartan cilexitil 16 mg or losartan 50 mg at hour 8.00 for a period of 8 weeks at the end of which, after a period of pharmacological wash-out of 15 days, the drugs were administered to inverted groups for other 8 weeks. After 4 and 8 weeks of treatment an evaluation of the anti-hypertensive effectiveness by means of medical complete visit and measurement of blood pressure were made. The statistical analysis was made by means of Student's t test for paired data.

RESULTS

All the patients concluded the study. After 4 weeks of treatment SBP and DBP were reduced in the group with candesartan cilexitil with regard to baseline values (SBP 151.8 +/- 6.3 vs 159.8 +/- 5.1 mmHg, p < 0.05; DBP 93.6 +/- 4.5 vs 98.1 +/- 3.7 mmHg, p < 0.05). In the losartan group (SBP 151.8 +/- 6.3 vs 158.7 +/- 5.5 mmHg, p < 0.05; DBP 93.6 +/- 4.5 vs 97.5 +/- 3.8 mmHg, p < 0.05) no significant reduction in blood pressure values was observed compared with baseline values (SBP 158.7 +/- 5.5 vs 159.8 +/- 5.1 mmHg, NS; DBP 97.5 +/- 3.8 vs 98.1 +/- 3.7 mmHg, NS). After 8 weeks of treatment in the candesartan cilexitil group (SBP 128.3 +/- 5.9 vs 159.8 +/- 5.1 mmHg, p < 0.05; DBP 81.5 +/- 4.1 vs 98.1 +/- 3.7 mmHg, p < 0.05) and in the losartan group (SBP 151.7 +/- 5.1 vs 159.8 +/- 5.1 mmHg, p < 0.05; DBP 92.7 +/- 3.9 vs 98.1 +/- 3.7 mmHg, p < 0.05) blood pressure values were reduced in the same manner as at baseline. By comparing the two drugs, candesartan cilexitil proved to have a better antihypertensive effectiveness (SBP 128.3 +/- 5.9 vs 151.7 +/- 5.1 mmHg, p < 0.05; DBP 81.5 +/- 4.1 vs 92.7 +/- 3.9 mmHg, p < 0.05).

CONCLUSIONS

Our experience suggests that angiotensin II receptor antagonists may be a therapeutic remarkable option in patients with chronic renal failure in hemodialysis and arterial hypertension; the antihypertensive effect seems to be class-specific. Nevertheless, at least for our data, a better and more rapid antihypertensive results was obtained with candesartan cilexitil.

Comparison of losartan and hydrochlorothiazide on cognitive function and quality of life in hypertensive patients

We examined long-term changes in cognitive function and quality of life (QL) in hypertensive patients by comparing the antihypertensive effect of hydrochlorothiazide (HCTZ) and losartan. We studied 69 patients (age range, 30 to 73 years) with mild-to-moderate hypertension. All patients, in a double-blind study, were randomly allocated to either treatment with 50 mg losartan once daily or 25 mg HCTZ once daily. The sample in each treatment group was divided by age (younger than 60 years or 60 years or older). At baseline and after 26 months, a QL questionnaire appropriate for the hypertensive patients was given. Cognitive function was evaluated, at baseline and after 26 months, by psychometric tests consisting of items from the Mini-Mental State Examination (MMSE) and the Sandoz Clinical Assessment Geriatric (SCAG). A score of less than 24 on the MMSE and more than 40 on the SCAG was predictive of cognitive impairment. The losartan group had a significant improvement in SCAG (P<.001) and MMSE (P<.001). No significant changes were observed in the HCTZ group (SCAG, P = .1; MMSE, P = .2). Sixty-five percent of the elderly had a MMSE score less than 24 and 70% had a SCAG score greater than 40, v. 35% and 48%, respectively, in younger patients. The health state index of QL improved significantly in both groups (losartan group, P<.01; HCTZ group, P<.02); the improvement in QL scores in patients using HCTZ was significant only in subjects aged 60 years and older (P<.04). These results suggest that losartan can have a positive effect not only on blood pressure but also on impaired cognitive function, reversing even minimal cognitive deficits induced by hypertension. The elderly patients in our sample had worse scores and cognitive performance was lower than in younger patients, even if in the losartan group the score improvement was the same at all ages. The same could not be said for HCTZ.

[Idiopathic left fascicular ventricular tachycardia: the evidence for a "bystander" bundle of His participation]

Idiopathic left ventricular tachycardia is a rare arrhythmia whose electrophysiological basis is not yet well-defined. We report a case of idiopathic left ventricular tachycardia caused by a reentrant circuit limited exclusively to the two fascicles of the left bundle branch.

[Efficacy of diltiazem in uremic hemodialyzed patients with isolated diastolic dysfunction and dialysis hypotensive crisis]

The aim of our study was to assess the effects of diltiazem on diastolic function, left ventricular mass and intradialytic hypotension, in uremic patients on maintenance hemodialysis. Forty-eight uremic patients on maintenance hemodialysis (mean age 46 +/- 5 years) with diastolic heart failure and normal systolic function (ejection fraction > 40%), although hemodialysis had been correctly performed, were included in the study. All patients had left ventricular hypertrophy. Diltiazem was given at the dosage of 60 mg, twice a day, for 3 months. At the end of this period, significant improvement of Doppler echocardiographic filling pattern and clinical symptomatology were observed, but left ventricular mass index was unchanged. Episodes of intradialytic hypotension were significantly reduced. We conclude that diltiazem improves symptoms and left ventricular diastolic filling in uremic patients with diastolic heart failure, without modifying left ventricular mass index; impaired diastolic function has an important role in recurrent dialysis hypotension.

The significance of bronchus-associated lymphoid tissue in human lung transplantation: is there an association with acute and chronic rejection?

BACKGROUND

In animal models of acute rejection in lung allografts, bronchus-associated lymphoid tissue (BALT) plays a major role in the induction and persistence of the alloreactive response. We undertook a study of the clinical and histologic associations with BALT identified on transbronchial biopsy in human lung allograft recipients.

METHODS

Transbronchial biopsies of patients receiving single lung, double lung, and combined heart-lung transplantation from 1984 to 1997 at the University of Pittsburgh Medical Center were reviewed. Seventy-seven patients had transbronchial biopsies demonstrating BALT. We examined all pathologic reports and slides, and graded rejection utilizing the Revised Working Formulation for the Classification of Pulmonary Allograft Rejection. Twenty-nine of 77 patients were selected at random to evaluate the distribution of BALT lymphocyte subsets immunohistochemically.

RESULTS

There was no relationship between native disease or the transplant procedure and the identification of BALT. BALT was found from 9 days to 2431 days after transplant (average: 440 days; median: 157 days) in association with clinically insignificant acute cellular rejection (A0, A1) in 75% of cases. Bronchiolitis obliterans developed in 29% of patients with a BALT-positive biopsy, a percentage not different from that of our overall lung transplant population. Immunohistochemical examination of BALT showed helper T cells predominated over cytotoxic T cells in zones surrounding B cell-rich follicular center cells.

CONCLUSIONS

The association of BALT with high-grade acute cellular rejection and with the development of bronchiolitis obliterans could not be confirmed in human lung allografts. BALT most often accompanied A0 or A1 rejection. This raises the possibility that the presence of BALT on transbronchial biopsy may be part of the evolution of immunologic tolerance in human pulmonary allografts.

Unopposed neutrophil elastase in bronchoalveolar lavage from transplant recipients with cystic fibrosis

Large numbers of neutrophils with unopposed neutrophil elastase (NE) proteolytic activity are found in lower respiratory tract secretions from most patients with advanced cystic fibrosis (CF). To determine whether antielastase defenses may be overwhelmed in epithelial lining fluid after lung transplantation, we measured NE activity (cleavage of the specific substrate, MeO-Suc-Ala-Ala-Pro-Val-pNA) in bronchoalveolar lavage fluids (BALF) obtained for surveillance or diagnostic purposes at various intervals (1 mo to 7 yr after transplantation) from 52 recipients who had undergone double or bilateral lung transplantation for end-stage CF. Unopposed NE activity was found in BALF from 14 recipients, most of whom also had >= 10(5) colony forming units (cfu) of Pseudomonas aeruginosa in BALF. Ten of the 14 recipients with unopposed NE in bronchoalveolar lavage (BAL) had developed obliterative bronchiolitis (OB), but only 8 of the 38 subjects without unopposed NE activity had OB (p = 0. 002; Fisher exact test). We conclude that antiprotease defenses in lower respiratory tract secretions of CF patients receiving lung allografts are sufficient in the majority of patients to prevent unopposed NE activity. However, the presence of unopposed NE activity in BAL from lung allografts of patients with CF is associated with progressive, irreversible OB and graft failure.

Repolarization abnormalities in patients with idiopathic ventricular tachycardias

STUDY POPULATION

Twenty patients without laboratory evidence of cardiac disease who underwent electrophysiological study because of recurrent ventricular tachyarrhythmias.

PATIENTS AND METHODS

The study population was divided into two groups: group A (20 patients [six males and 14 females] mean age 42.2 +/- 13 years), with idiopathic ventricular tachycardia (VT), and group B (30 controls [10 males and 20 females] mean age 43.6 +/- 16 years). Noninvasive multiparametric analysis of the ventricular repolarization phase was performed on the standard 12-lead electrocardiogram by using a digitizer connected with a computerized system. The intervals JT, heart rate-corrected JT (JTc), JT apex (JTa), heart rate-corrected JTa (JTac), T apex T end (TaTe) and heart rate-corrected TaTe (TaTec) were measured and considered to be representative of the whole depolarization process. QT dispersions (QTeD) and QTc dispersions (QTecD) were calculated to assess the degree of spatial inhomogeneity of action potential duration.

RESULTS

Patients in group A had higher JT (272 +/- 36 ms versus 265 +/- 25 ms, P = 0.01), JTc (336 +/- 28 ms versus 318 +/- 18 ms, P = 0.01), JTa (210 +/- 28 ms versus 185 +/- 28 ms, P = 0.001) and JTac (240 +/- 20 ms versus 215 +/- 13 ms, P < 0.001) values than those of patients in group B, despite shorter TaTe (71 +/- 10 ms versus 90 +/- 18 ms, P < 0.001) and TaTec (88 +/- 12 ms versus 110 +/- 12 ms, P < 0.001). Moreover, QTeD and QTecD were significantly longer in group A than in group B (55 +/- 18 ms versus 42 +/- 19 ms [P = 0.01] and 80 +/- 18 ms versus 55 +/- 28 ms [P = 0.001], respectively).

CONCLUSIONS

Patients with idiopathic VT exhibit inhomogeneous prolongation of ventricular repolarization, due to a considerable increase in the initial part in association with a shorter terminal phase, as well as a greater dispersion of ventricular repolarization.

Clinical significance of CMV-specific T helper responses in lung transplant recipients

BACKGROUND

Cytomegalovirus (CMV) disease continues to be a major problem for lung transplant patients who generate an inefficient immune response to control this viral infection. Both T helper and cytotoxic T cells are thought to play an important role in prevention and control of CMV disease. We investigated the clinical significance of CMV-specific memory responses in lung transplant recipients.

METHOD

Peripheral blood samples (140) were collected from 99 lung transplant recipients. Patients were grouped according to their pre-transplant CMV serological status as recipient/donor (R-/D+, 25 patients), 28 R+/D+ patients, 35 R+/D- patients and 11 R-/D- patients. Memory responses to CMV whole antigen, 5 CMV proteins, and tetanus toxoid (TT) were measured in a 6-day proliferative assay. Results were expressed as the stimulation index (SI = experimental cpm/background cpm), and were considered positive if the SI was >3 and the cpm values were over 1,000.

RESULTS

The frequency of positive CMV memory responses was similar in three groups: 64% for R-/D+, 63% for R+/D+ and 56% for R+/D- except for R-/D- (21%). The memory response to TT was similar for all four groups (70% of samples were positive). The level of responsiveness to individual CMV proteins was much higher in R+/D+ group (65%) than the other two groups (35% for R+/D-, and 31% for R-/D+). We determined the temporal relationship between the presence of CMV-specific memory responses and the diagnosis of CMV disease. In the R-/D+ group, 16 of 17 patients who had CMV disease eventually developed CMV-specific memory. In those patients (n = 3) who failed to develop CMV-specific T helper response for a prolonged time, all had recurrent CMV disease. In the R+/D+ group, 4 of 8 patients with CMV disease exhibited CMV-specific memory responses. Three of 4 patients in whom we observed a persistent absence of CMV-specific memory had multiple episodes of CMV pneumonitis. In the R+/D- group, only one of 4 patients with CMV disease had suppressed CMV-specific memory response after first episode of CMV pneumonitis and had recurrent disease.

CONCLUSION

In lung transplant recipients, the loss or persistent lack of CMV-specific memory following infection was associated with chronic CMV disease. These data suggest that monitoring T helper memory responses following primary CMV infection or after augmented immunosuppression for treatment of rejection may identify those patients at risk for morbidity associated with recurrent CMV disease.

[Incremental doses of diltiazem in patients with coronary artery disease in end-stage renal failure maintained on hemodialysis: which is the optimal dose?]

End-stage renal disease patients on maintenance hemodialysis suffering from coronary artery disease probably receive too low doses of calcium-antagonists, because the attempt to avoid adverse effects prevails the well-documented antianginal activity of the drug. The aim of our study was to assess the safety and efficacy of incremental doses of diltiazem in treating angina pectoris in hemodialyzed patients with coronary artery disease, to identify the optimal dose. Ninety-four chronic hemodialyzed patients (59 males and 35 females; mean age 55.2 +/- 3.3 years; on periodic dialysis for 80.3 +/- 25.6 months) with coronary artery disease and more than 5 min of transient myocardial ischemia during 48 hours of Holter monitoring were included in the study. A double-blind, randomized, placebo-controlled trial design was used. Incremental doses of diltiazem (from 120 to 240 mg/day) were administered in 4 months. At doses of 120 and 180 mg/day it was observed a statistically significant reduction in the number and duration of total and symptomatic ischemic episodes in 48 hours, compared with baseline (p < 0.001). Instead, the number and the duration of silent ischemic episodes did not significantly change (NS). The efficacy on silent myocardial ischemia was obtained only with the dosage of 240 mg/day (p < 0.001). If this dosage was obtained with a sustained-release formulation (120 mg twice a day), the efficacy was similar to the administration of 4 tablets/day of 60 mg, but the tolerability was better, especially during dialysis. The circadian variations of transient ischemic episodes showed two peaks in the 24 hours, one from 6.00 to 9.00 a.m. and another from 4.00 to 8.00 p.m., just during the dialysis. Both peaks were reduced only with 240 mg/day. In conclusion, this study demonstrates that sustained-release diltiazem (120 mg twice a day) is greatly useful in patients with coronary artery disease on maintenance dialysis because it reduces the frequency of silent ischemic episodes, has a good tolerability, and modifies the circadian pattern of ischemic episodes, reducing both peaks during the day.

Atrial fibrillation: what are the effects of drug therapy on the effectiveness and complications of electrical cardioversion?

Atrial fibrillation is the most common cardiac rhythm disorder associated with hospitalization. Two therapeutic options have been available: antiarrhythmic drug therapy, and external or internal electrical cardioversion. Electrical cardioversion of atrial fibrillation remains one of the most widely used and effective treatments for the restoration of normal sinus rhythm. However, many patients continue to receive an antiarrhythmic drug before and after cardioversion in an attempt either to cardiovert the arrhythmia chemically or to maintain sinus rhythm after successful cardioversion. Because some pharmacological agents can affect the cardioversion procedure for atrial fibrillation or flutter, and because many patients with such arrhythmias may require electrical cardioversion when they are taking antiarrhythmic drugs, the question of a possible effect of drug therapy on the efficacy and safety of electrical cardioversion of atrial fibrillation arises. Early reports of direct current cardioversion provoking potentially lethal ventricular arrhythmias raised suspicions of an arrhythmogenic role for digoxin antiarrhythmic therapy, and it is customary to withhold these drugs for 24 to 48 h before cardioversion is attempted. However, this complication is likely to arise only in patients who are close to, or actually manifesting, signs of drug toxicity. On the other hand, treatment with therapeutic concentrations of antiarrhythmic drugs before cardioversion may in some cases be associated with a significant reduction in the number of shocks and decreased energy required to restore sinus rhythm, a lower incidence of postshock arrhythmias and a reduced risk of early recurrence of atrial fibrillation.

Compared effects of sotalol, flecainide and propafenone on ventricular repolarization in patients free of underlying structural heart disease

Antiarrhythmic drugs are known to affect the depolarization and repolarization time in a different fashion. The aim of the present study was to compare the effects of Sotalol, Flecainide and Propafenone on some common (QT, QTc, JT, JTc) or uncommon (QTc dispersion, T-peak to T-end interval) electrocardiographic parameters in order to evaluate the effects of these antiarrhythmic drugs on ventricular repolarization time both in terms of absolute values and of dispersion across the myocardium. The analysis of these antiarrhythmic drug effects was performed on the standard 12-lead electrocardiograms of 31 patients (17F and 14M, age 38.1+/-17 years, range 11-67 years) in the free-drug state and at the steady state after oral treatment with Sotalol (160 mg daily), Flecainide (200 mg daily) and Propafenone (450 mg daily). These drugs were prescribed, separately, to all the 31 patients, free of underlying structural heart disease, for the treatment of their atrio-ventricular nodal re-entry tachycardia. Data of the present study show that Sotalol, over the range prescribed, significantly prolongs ventricular repolarization index QT (P=0.001), JT (P=0.0001) and JTc (P=0.0001) values in an homogeneous fashion, as shown by the significant decrease in QTcD (P=0.019) and Tp-Te (P=0.01). On the contrary, Flecainide treatment was associated with an increase in QTcD (P=0.029), Tp-Te (0.0001), QT (P=0.001), QTc (P=0.0001) and QRS (P=0.0001), with no significant changes in JT and JTc. Propafenone, over the range prescribed, did not affect repolarization time, resulting only in a prolongation of depolarization time as expressed by the increase of QRS (P=0.0001).

Impact of heart rate and atrioventricular delay on left ventricular diastolic filling in patients with dual-chamber pacing for sick sinus syndrome or atrioventricular block

We examined the effect of left ventricular filling on different combinations of programmable heart rate and atrioventricular delay in patients with dual-chamber pacemakers. Pacing mode with heart rates of 60 beats/min and 156 ms of atrioventricular delay induced a diastolic pattern that resembles more than others the one observed in healthy subjects in sinus rhythm.

Effects of losartan on hypertension and left ventricular mass: a long-term study

This study evaluated the anti-hypertensive efficacy, tolerability and effects on left ventricular mass of losartan, a selective angiotensin II receptor antagonist, after 22 months in patients with essential hypertension. The study included 77 hypertensive patients who were randomised at baseline to 22 months double-blind once-daily treatment with losartan 50 mg (L group n = 44 patients, mean age 54+/-9 years) or hydrochlorothiazide 25 mg (HCTZ group, n = 33 patients, mean age 56+/-7 years). Routine haematology, blood chemistry, standard electrocardiography, echocardiography and ambulatory non-invasive 24-h blood pressure (BP) monitoring were performed at baseline and after 10 and 22 months. The results showed good tolerability and a significant mean systolic and diastolic BP reduction in all groups (L group: 22 mm Hg and 11 mm Hg; HCTZ group: 11 mm Hg and 7 mm Hg, respectively for systolic and diastolic mean BP). Moreover, a remarkable reduction in left ventricular mass index was reached after 10 and 22 months only in the L group (L group: delta = -11 g/m2, P<0.02; HCTZ group: delta = -5 g/m2, P= 0.38). In conclusion, losartan was well tolerated and produced a significant reduction in BP and left ventricular mass in hypertensive patients

[New experimental evidence of complex dynamics of heart beat. II. Correlation dimension, Lyapunov's exponents]

In this paper we applied mathematical techniques of non-linear dynamics, to an ECG signal. The first step is to compute the shift-delay time, via average displacement of the digital ECG. Phase space is constructed at a prescribed shift-delay and correlation dimension and dominant Lyapounov exponent versus the embedding dimension are monitored. This technique was applied to 5 healthy volunteers and 4 patients with VVI pacemaker.

[Syndrome X and microvascular angina]

The term X syndrome is used to indicate a group of patients who present anginous symptoms and ischemic-type electrocardiographic alterations which appear during exercise tolerance tests, dipiridamol tests or Holter's dynamic monitoring where coronary ultrasonography reveals no evident coronary lesions, vasospastic angina, arterial hypertension and/or diabetes mellitus, block of the left branch when resting or exercising, cardiomyopathy or valvulopathy. The highest incidence is in females with a mean age of around 50. A reduced reserve of coronary flow, highlighted both in response to vasodilatators or rapid stimulation and by positron emission tomography (PET), underlies this syndrome. It is thought to be caused by a dysfunction of the coronary microcirculation which consists in a deficit of the endothelium-dependent vasodilatory mechanisms, probably also owing to the accumulation of vasoconstrictive type substances, like endothelin-1. In addition to a dysfunction of the coronary microcirculation, one widely backed hypothesis concerns the existence of an altered perception of painful symptoms in patients with X syndrome: the anomalous constriction of prearteries might cause an increased release of adenosine, able to provoke angina despite the scarce signs of myocardial ischemia in terms of the metabolic or functional profile. From a therapeutic point of view, treatment of these patients is often ineffective: treatment should be based on the use of nitrates, calcium-antagonists or beta-blockers, if necessary moving on to other forms of therapy (aceinhibitors, xanthine methylate, estrogens, alphablockers, imipramine); the simultaneous use of tranquillizers may be useful in view of the anxious personality often characteristic of these patients.

[Complex ventricular arrhythmias and carvedilol: efficacy in hemodialyzed uremic patients]

Carvedilol has been shown to be effective in systemic hypertension and coronary artery disease in patients with end-stage renal disease, on maintenance hemodialysis. The aim of our study was to assess the effects of carvedilol on ventricular arrhythmias in these patients. Ninety-eight uremic patients maintained on hemodialysis, with complex ventricular arrhythmias (class III, IV and V of Lown's classification), not only during dialysis, were included in the study. They were divided into two groups, with mild-to-moderate hypertension or coronary artery disease. The efficacy and safety of carvedilol (50 mg/day) was compared to placebo in a 6-week randomized, double-blind study. Carvedilol significantly reduced, in both hypertensive and ischemic patients, total ventricular premature contractions (82.7 +/- 11.3 vs 358.1 +/- 73.9, p < 0.001; 88.3 +/- 24.4 vs 369.9 +/- 77.8, p < 0.001), repetitive ventricular premature contractions (1.3 +/- 1.3 vs 6.3 +/- 3.5, p < 0.001; 1.2 +/- 0.7 vs 6.9 +/- 2.6, p < 0.001) and episodes of ventricular tachycardia (1.1 +/- 1.2 vs 11.8 +/- 7.5, p < 0.001; 1.4 +/- 1.2 vs 14.0 +/- 8.3, p < 0.001). In placebo-treated patients, instead, these parameters were not significantly changed (329.1 +/- 76.5 vs 361.7 +/- 71.7, NS, and 324.6 +/- 79.7 vs 359.3 +/- 58.1, NS; 6.2 +/- 3.7 vs 7.3 +/- 3.7, NS, and 4.9 +/- 2.2 vs 6.1 +/- 3.2, NS; 9.8 +/- 6.3 vs 13.3 +/- 8.0, NS, and 9.0 +/- 6.2 vs 12.4 +/- 7.8, NS). Carvedilol confirmed a significant effect on myocardial ischemia and systemic hypertension. No significant side effects were reported. Ventricular arrhythmias are frequent in patients with end-stage renal disease maintained on hemodialysis. They are often due to an underlying cardiac disease, namely systemic hypertension with left ventricular hypertrophy and coronary artery disease. The results of our study show that the antiarrhythmic effect of carvedilol is linked, at least partly, to an improvement of the underlying cardiac disease. Uremic patients have a chronic increase in adrenergic tone, with a direct correlation between norepinephrine plasmatic concentration and frequence of premature ventricular contractions. Beta-blockers are very important in these patients because of their modulation on the adrenergic system. They also reduce potassium flow, from extracellular to intracellular fluid. Therefore carvedilol can affect the sudden hypokalemia occurring in the first phase of hemodialysis treatment, that may be an important cause of intradialytic arrhythmias.