Transesophageal echocardiography during cardioversion of atrial fibrillation.
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Anticoagulants↗
Biomedical subjects
H Omran
Publications and source records attributed to H Omran.
Prevalence of left atrial chamber and appendage thrombi in patients with atrial flutter and its clinical significance.
OBJECTIVES: The study was done to assess the prevalence of left atrial (LA) chamber and appendage thrombi in patients with atrial flutter (AFl) scheduled for electrophysiologic study (EPS), to evaluate the prevalence of thromboembolic complications after transesophageal echocardiographic (TEE)-guided restoration of sinus rhythm and to evaluate clinical risk factors for a thrombogenic milieu. BACKGROUND: Recent studies showed controversial results on the prevalence of atrial thrombi and the risk of thromboembolism after restoring sinus rhythm in patients with AFl. METHODS: Between 1995 and 1999, patients with AFl who were scheduled for EPS were included in the study. After transesophageal assessment of the left atrial appendage and exclusion of thrombi, an effective anticoagulation was initiated and patients underwent EPS within 24 h. RESULTS: We performed 202 EPSs (radiofrequency catheter ablation, n = 122; overdrive stimulation, n = 64; electrical cardioversion, n = 16) in 139 consecutive patients with AFl. Fifteen patients with a thrombogenic milieu were identified. All of them had paroxysmal atrial fibrillation (AF). Transesophageal echocardiography revealed LA thrombi in two cases (1%). After EPS no thromboembolic complications were observed. Diabetes mellitus, arterial hypertension and a decreased left ventricular ejection fraction were found to be independent risk factors associated with a thrombogenic milieu. CONCLUSIONS: The findings of a low prevalence of LA appendage thrombi (1%) in patients with AFl and a close correlation between a history of previous embolism and paroxysmal AF support the current guidelines that patients with pure AFl do not require anticoagulation therapy, whereas patients with AFl and paroxysmal AF should receive anticoagulation therapy. In addition, the presence of clinical risk factors should alert the physician to an increased likelihood for a thrombogenic milieu.
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Mutation of BSND causes Bartter syndrome with sensorineural deafness and kidney failure.
Antenatal Bartter syndrome (aBS) comprises a heterogeneous group of autosomal recessive salt-losing nephropathies. Identification of three genes that code for renal transporters and channels as responsible for aBS has resulted in new insights into renal salt handling, diuretic action and blood-pressure regulation. A gene locus of a fourth variant of aBS called BSND, which in contrast to the other forms is associated with sensorineural deafness (SND) and renal failure, has been mapped to chromosome 1p. We report here the identification by positional cloning, in a region not covered by the human genome sequencing projects, of a new gene, BSND, as the cause of BSND. We examined ten families with BSND and detected seven different mutations in BSND that probably result in loss of function. In accordance with the phenotype, BSND is expressed in the thin limb and the thick ascending limb of the loop of Henle in the kidney and in the dark cells of the inner ear. The gene encodes a hitherto unknown protein with two putative transmembrane alpha-helices and thus might function as a regulator for ion-transport proteins involved in aBS, or else as a new transporter or channel itself.
Animals↗
Establishing an algorithm for molecular genetic diagnostics in 127 families with juvenile nephronophthisis.
BACKGROUND: Juvenile nephronophthisis (NPH1), an autosomal recessive cystic disease of the kidney, represents the most common genetic cause of end-stage renal disease in the first two decades of life. On the basis of identification of the gene (NPHP1) defective in NPH1 and the presence of homozygous deletions of NPHP1 in the majority of NPH1 patients, molecular genetic diagnosis for NPH1 is now possible. Molecular genetic testing offers the only method for definite diagnosis of NPH1 and avoids invasive diagnostic measures like renal biopsy. METHODS: We examined 127 families (204 patients) with the presumed diagnosis of NPH using molecular genetic diagnostic techniques. In 68 families, renal biopsy was performed and was consistent with NPH, and in 61 families, there was more than one affected child ("multiplex families"). RESULTS: In 74 families (115 patients), there was proof of the diagnosis of NPH1 by detection of a homozygous deletion of the NPHP1 gene, and in 5 families a heterozygous deletion in combination with a point mutation in NPHP1 was demonstrated. Furthermore, for 16 families, NPH1 was excluded with high likelihood by linkage analysis, and for 20 families by detection of heterozygosity for two newly identified polymorphic markers within the deletion region. In 5 of the remaining 12 families, which were noninformative for these markers, fluorescence in situ hybridization did not detect any further heterozygous deletions. CONCLUSIONS: The diagnosis of NPH1 was proven by molecular genetic techniques in 62% of families with one or more children with the presumed diagnosis of NPH. We present evidence that there is a fourth locus for NPH, since only 6 of the 26 multiplex families in whom the diagnosis of NPH1 was excluded were compatible with linkage to other loci for NPH. On the basis of the presented data, we propose an algorithm for molecular genetic diagnostics in NPH.
Adaptor Proteins, Signal Transducing↗
Blood flow assessment by ultrasound-induced destruction of echocontrast agents using harmonic power Doppler imaging: which parameters determine contrast replenishment curves?
OBJECTIVE: To evaluate the feasibility of flow determinations by contrast replenishment using harmonic power Doppler imaging (H-PDI). BACKGROUND: The application of indicator dilution principles on contrast echocardiography is limited by numerous methodical problems. Recently, a new method was introduced that relies on ultrasound-mediated microbubble destruction and evaluation of the contrast replenishment. METHODS: Definity, a perfluorocarbon-derived contrast agent under development, was continuously infused into a steady flow phantom and H-PDI registrations were performed within a silicone tube (d = 8 mm). Replenishment interval between destruction and imaging frame was varied from 0.04-2 seconds. Nonlinear curve fitting was performed using an exponential mathematical model. RESULTS: Strong linear correlation between contrast dose and maximum signal intensity as well as between flow and the slope variable beta of the replenishment curve was found for all settings (r > 0.96). Maximum signal intensity and contrast replenishment rate were found to be a function of emission power and were significantly influenced by depth and focus position. CONCLUSION: The feasibility of flow assessment using replenishment curves obtained by H-PDI was demonstrated. However, in experimental conditions, flow analysis was severely influenced by ultrasound system settings and imaging conditions such as emission power, sound field geometry, and investigation depth. For a clinical use of this promising approach, algorithms that take specific system settings and imaging conditions into account have to be found. Imaging modalities that enable a most homogeneous scan field are best suited for the assessment of contrast replenishment.
Contrast Media↗
Evidence for further genetic heterogeneity in nephronophthisis.
BACKGROUND: A new type of nephronophthisis (NPH) has been recently identified in a large Venezuelan kindred: adolescent nephronophthisis (NPH3) causes end-stage renal disease (ESRD) at a median age of 19 years. The responsible gene (NPHP3) maps to 3q21-q22. NPH3 shares with juvenile nephronophthisis (NPH1) the same disease manifestations such as polyuria, polydipsia, and secondary enuresis. Histopathological findings consist of tubular basement membrane changes, cysts at the corticomedullary junction, and a chronic sclerosing tubulointerstitial nephropathy. The only difference is a younger age at ESRD in NPH1 (median age of 13 years) when compared with NPH3. METHODS: In order to evaluate whether there might be a fourth locus of isolated nephronophthisis, we studied eight NPH families without extrarenal disease manifestations and without linkage to the NPH1 locus (NPHP1) on chromosome 2q12-q13. ESRD was reached at ages ranging from 7 to 33 years. Individuals were haplotyped with microsatellites covering the genetic locus of NPHP3. Infantile NPH (NPH2) was excluded in all families by the clinical history and histological findings. RESULTS: In four of the examined families haplotype analysis was compatible with linkage to the NPHP3 locus. In one of these families identity by descent was observed. In contrast, in another four families linkage was excluded for NPHP3. CONCLUSION: Four NPH-families were neither linked to NPHP1 nor to NPHP3, indicating further genetic heterogeneity within the group of nephronophthisis. The finding of further genetic heterogeneity in NPH has important implications for genetic counselling.
Adaptor Proteins, Signal Transducing↗
Serum levels and cardiovascular effects of tricyclic antidepressants and selective serotonin reuptake inhibitors in depressed patients.
Tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs) are used to treat depression. Whereas cardiovascular effects have occasionally been reported during controlled studies with SSRIs, TCA treatment poses a well-known problem in this respect. To investigate the putative correlation between antidepressant dose or serum levels and adverse effects, the authors devised a naturalistic study to evaluate the tricyclic antidepressants' and SSRIs' effect on the cardiovascular system. The authors also compared antidepressant serum levels to adverse effects. Inpatients treated with TCAs or SSRIs were included; an electrocardiogram (ECG) and a Schellong test were carried out on the day patients entered the hospital and during steady-state treatment with antidepressant drugs when blood was drawn for therapeutic drug monitoring. The patient population consisted of 114 acutely depressed patients; 81 patients were treated with TCAs and 33 with SSRIs. The TCAs comprised amitriptyline (n = 43), clomipramine (n = 11), doxepin (n = 19) and imipramine (n = 8); the SSRIs comprised fluvoxamine (n = 14) and paroxetine (n = 19). In TCA-treated patients, the authors observed the same type of abnormalities in conduction and orthostatic hypotension as had been observed earlier. The authors also observed cases of first-degree atrioventricular block, prolonged QTc interval, and orthostatic hypotension in SSRI-treated patients. Thus SSRIs also appear to affect the cardiovascular system, which might pose a problem for patients with preexisting conduction disease. The authors observed a strong correlation between the decrease in systolic pressure and antidepressant serum concentration (except for clomipramine and paroxetine), suggesting that antidepressant serum level is a better correlate than dose.
Adolescent↗
Continuous-infusion contrast-enhanced US: in vitro studies of infusion techniques with different contrast agents.
PURPOSE: To evaluate the infusion properties of three ultrasonographic (US) contrast agents and to compare different infusion techniques for achieving constant signals during harmonic power Doppler US. MATERIALS AND METHODS: In vitro studies were performed in a flow phantom. SH U 508A, NC100100, or FS069 was continuously infused at clinically usable doses and infusion rates. To assess agent-specific physical properties, these agents were administered by using a vertically fixed infusion pump and varying infusion start times. The contrast agents were administered by also using a horizontally oriented infusion pump that was either fixed or continuously rotated to homogenize the agent in the syringe. RESULTS: With SH U 508A and NC100100, constant signals were achieved, regardless of the infusion modality used. Compared with conventional infusion, the continuous homogenization of SH U 508A, although not necessary for signal constancy, increased the agent's usefulness (P <.05). With FS069, only continuous homogenization yielded constant signals (P <.001). CONCLUSION: Continuous infusion of SH U 508A or NC100100 provided constant harmonic power Doppler US signals, regardless of the infusion modality used. Because of the special physical properties of FS069, only homogenization produced constant harmonic power Doppler US signals during continuous infusion of this agent.
Contrast Media↗
[Transthoracic echocardiography in endocarditis: a comparison of conventional and harmonic echocardiography].
BACKGROUND AND OBJECTIVE: Compared with conventional echocardiography (CEC) harmonic imaging (HEC) provides better resolution of the endocardial line and valvular apparatus. This prospective study was undertaken to compare the value of harmonic and conventional transthoracic echocardiography in endocarditis and compare them with standard transoesophageal echocardiography (TOE) and operative findings. PATIENTS AND METHOD: Conventional and harmonic echocardiographic imaging was compared in 30 patients (aged 58 +/- 17 years; 19 males and 11 females) with endocarditis clinically judged to require surgical intervention. The results of both methods were then compared with those of standard TOE and the intraoperative findings. RESULTS: Intraoperatively 15 floating structures, 9 abscesses and 5 perforations were demonstrated. Transoesophageal echocardiography was better than the standard method in diagnosing floating structures and detecting abscesses (15 vs. 10 vegetations, p < 0.05; 7 vs. 5 abscesses, p = 0.05). TOE was better than either method in the diagnosis of abscess. CONCLUSION: Harmonic transthoracic echocardiography is better than the conventional mode in diagnosing complications of endocarditis.
Abscess↗
Clinical experience with implantable atrial and combined atrioventricular defibrillators.
UNLABELLED: The high prevalence of atrial fibrillation (AF) and its clinical complications, the poor efficacy of medical therapy for preventing recurrences, and dissatisfaction with alternative modes of therapy stimulated interest in implantable atrial and combined atrioventricular defibrillators. In a multicenter study, the safety and efficacy of a stand alone implantable atrial defibrillator, the Metrix system, were evaluated. The device was implanted in 51 patients with highly symptomatic episodes of AF refractory to pharmacological treatment. During a follow-up of 9 months, 96% of 227 spontaneous AF episodes were successfully converted to sinus rhythm in 41 patients. In 62 episodes (27%), several shocks and/or additional drug treatment were required to maintain stable sinus rhythm because of early recurrences of AF. A total of 3719 shocks were delivered and no induction of ventricular proarrhythmia or inaccurately synchronized shocks occurred. The AF detection algorithm exhibited a 100% specificity for the recognition of sinus rhythm and a 92.3% sensitivity for the detection of AF. The combined atrioventricular defibrillator, Jewel AF 7250, was evaluated in a multicenter, randomized, cross-over trial. The primary study objectives included: overall safety as determined by complications-free survival at 6 months, efficacy of tiered atrial pacing and defibrillation therapies for termination of spontaneous atrial tachycardias (AT) and AF, and relative sensitivity of a new dual-chamber detection algorithm. The device was implanted in 211 patients with either a history of ventricular tachyarrhythmias (VT/VF) alone or with a history of both AT/AF and VT/VF. During a mean follow-up of 4.5 months, it has been shown that the Jewel AF is safe and effective in treating atrial and ventricular tachyarrhythmias. Pace termination of 85% of AT episodes were achieved with painless delivery of antitachycardia pacing; additional 35% of AT episodes were terminated by high frequency burst pacing. CONCLUSIONS: The stand alone implantable atrial defibrillator may be safe and clinically useful in selected patients for the treatment of highly symptomatic, drug resistant recurrences of AF. The combined atrioventricular defibrillator may be particularly indicated in patients presenting with both a history of atrial and ventricular tachyarrhythmias.
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Incidence of left atrial thrombi in patients in sinus rhythm and with a recent neurologic deficit.
OBJECTIVES: We sought to determine the incidence of left atrial (LA) thrombi in patients in sinus rhythm (SR) and with a recent neurologic deficit and to analyze the relation between LA thrombi and LA chamber and appendage function in patients in SR. METHODS: A prospective study was conducted in 869 consecutive patients. The study group consisted of 583 patients in SR (67%). The remaining 286 patients had atrial fibrillation (AF) and served as controls (33%). RESULTS: The incidence of LA thrombi was significantly higher in patients with AF (n = 39 [14%]) compared with patients in SR (n = 6 [1%]; P <.001). Three of 6 patients with thrombi in SR had mitral stenosis, 1 patient had aortic stenosis, 1 patient had coronary artery disease, and another patient had a cardiomyopathy. Of the patients with detected thrombi, those in SR did not receive anticoagulation, whereas those with AF did in 18 cases. Patients with thrombi in SR and with AF did not significantly differ in LA diameter (5.1 +/- 0.8 cm vs 4.8 +/- 0.7 cm; 95% confidence interval [CI], -0.78 to 0.45), left ventricular ejection fraction (46% +/- 13% vs 42% +/- 15%; 95% CI, -18.7 to 7.4), LA appendage area (5.8 +/- 2.7 cm(2) vs 6.7 +/- 3.2 cm(2); 95% CI, -1.9 to 3.6), peak emptying velocity of the LA appendage (0.19 +/- 0.08 m/s vs 0.17 +/- 0.07 m/s; 95% CI, -0.08 to 0.04), or LA spontaneous echo contrast (3. 5 +/- 0.6 vs 3.9 +/- 0.5; 95% CI, -0.06 to 0.45). CONCLUSIONS: LA appendage thrombi are an infrequent cause of thromboembolism in patients in SR and are associated either with mitral valve disease or LA chamber and appendage dysfunction. Routine transesophageal echocardiography for the exclusion of LA thrombi is not recommended in patients in SR without underlying heart disease and normal LA function as assessed by transthoracic echocardiography.
Aortic Valve Stenosis↗
Survival and dominant transmission of "lethal" platyspondylic dwarfism of the "West coast" types.
Torrance, San Diego, and Luton types ("West coast" types) of neonatal platyspondylic short-limbed dwarfism are suspected to be caused by dominant mutations that are obligatorily lethal. We report on an affected mother, who passed the disease to her daughter, confirming dominant disease transmission. Survival of the mother indicates a wider phenotypic spectrum.
Dwarfism↗
Identification of a new gene locus for adolescent nephronophthisis, on chromosome 3q22 in a large Venezuelan pedigree.
Nephronophthisis, an autosomal-recessive cystic kidney disease, is the most frequent monogenic cause for renal failure in childhood. Infantile and juvenile forms of nephronophthisis are known to originate from separate gene loci. We describe here a new disease form, adolescent nephronophthisis, that is clearly distinct by clinical and genetic findings. In a large, 340-member consanguineous Venezuelan kindred, clinical symptoms and renal pathology were evaluated. Onset of terminal renal failure was compared with that in a historical sample of juvenile nephronophthisis. Onset of terminal renal failure in adolescent nephronophthisis occurred significantly later (median age 19 years, quartile borders 16.0 and 25.0 years) than in juvenile nephronophthisis (median age 13.1 years, quartile borders 11.3 and 17.3 years; Wilcoxon test P=.0069). A total-genome scan of linkage analysis was conducted and evaluated by LOD score and total-genome haplotype analyses. A gene locus for adolescent nephronophthisis was localized to a region of homozygosity by descent, on chromosome 3q22, within a critical genetic interval of 2. 4 cM between flanking markers D3S1292 and D3S1238. The maximum LOD score for D3S1273 was 5.90 (maximum recombination fraction.035). This locus is different than that identified for juvenile nephronophthisis. These findings will have implications for diagnosis and genetic counseling in hereditary chronic renal failure and provide the basis for identification of the responsible gene.
Adolescent↗
Homozygosity mapping of a gene locus for primary ciliary dyskinesia on chromosome 5p and identification of the heavy dynein chain DNAH5 as a candidate gene.
Reduced mucociliary clearance in primary ciliary dyskinesia (PCD) causes recurrent infections of the upper and lower respiratory tract. The disease is usually inherited as an autosomal recessive trait. To identify a gene locus for PCD, we studied a large consanguineous family of Arabic origin. Direct examination of the respiratory cilia revealed ciliary akinesia. Electron microscopic examination of cilia showed absence of the outer dynein arms. Two of four affected individuals exhibited a situs inversus, typical for Kartagener syndrome, due to randomization of the left/right body axis. A total genome scan with 340 highly polymorphic microsatellites was performed. We localized a new gene locus for PCD to a region of homozygosity by descent on chromosome 5p15-p14 with a parametric multipoint logarithm of odds ratio (LOD) score of Zmax = 3.51 flanked by markers D5S2095 and D5S502 within an interval of 20 centimorgans sex-averaged genetic distance. Applying a polymerase chain reaction-based approach, we identified a 1.5-kb partial complementary DNA of DNAH5 encoding a Chlamydomonas-related axonemal heavy dynein chain within the critical disease interval of this new PCD locus. On the basis of the Chlamydomonas model for PCD, this gene represents an excellent candidate for PCD.
Amino Acid Sequence↗
Right atrial appendage thrombosis in atrial fibrillation: its frequency and its clinical predictors.
This study assesses the incidence of right atrial (RA) chamber and appendage thrombosis in patients with atrial fibrillation (AF) in relation to RA appendage morphology and function. Transthoracic and multiplane transesophageal echocardiography were performed in 102 patients with AF to assess the incidence of RA and left atrial (LA) thrombi and spontaneous echo contrast. Both right and left ventricular sizes, atrial chamber and appendage sizes and function were measured. Twenty-two patients in sinus rhythm served as the control group (SR). Complete visualization of the RA appendage was feasible in 90 patients with AF. Patients with AF had lower tricuspid annular excursion (p = 0.008) and larger RA chamber area (p = 0.0001) than patients in SR. In addition, RA appendage areas were larger (p <0.05) and RA ejection fraction and peak emptying velocities (both p <0.0001) were lower in patients with AF patients than in those in SR. Equivalent differences were found for the LA appendage. Six thrombi were found in the RA appendage and 11 thrombi in the LA appendage in AF patients. Spontaneous echo contrast was found in 57% and 66% in the right atrium and in the left atrium, respectively. AF patients with RA appendage thrombi had a larger RA area (p = 0.0001), and lower RA appendage ejection fraction and emptying velocities (both p = 0.0001) than patients without thrombi. Spontaneous echo contrast was detected in all patients with thrombi. Spontaneous echo contrast was the only independent predictor of RA (p = 0.03) and LA appendage thrombosis (p = 0.036). In conclusion, multiplane transesophageal echocardiography allows the assessment of RA appendage morphology and function. RA spontaneous echo contrast is the only independent predictor of RA appendage thrombosis.
Adult↗
Hemodynamic and cardiorespiratory function following internal atrial defibrillation for chronic atrial fibrillation.
Internal atrial defibrillation (IAD) is able to restore sinus rhythm in patients with chronic atrial fibrillation (AF) and failed external electrical and/or pharmacologic cardioversion. To assess whether cardiorespiratory and hemodynamic function improve after IAD, 35 patients were prospectively investigated during constant workload exercise by spiroergometry and Doppler echocardiography before IAD, and 1 day and 1 month after IAD. Oxygen uptake kinetics, ventilation, left atrial mechanical function, and pulmonary artery pressure were determined simultaneously at rest and during steady state. During the serial follow-up, 20 patients maintained sinus rhythm. The time interval for achieving the steady state (146 +/- 53 vs 132 +/- 42 seconds; p = 0.5) and the oxygen deficit (645 +/- 190 vs 670 +/- 174 ml; p = 0.7) were not different before and 1 day after IAD, but decreased significantly after 1 month (98 +/- 16 seconds, p = 0.01 and 487 +/- 72 ml, p = 0.02). Exercise pulmonary artery systolic pressures were 38 +/- 13 mm Hg before IAD, increased significantly to 46 +/- 11 mm Hg on day 1 (p = 0.03), and decreased below baseline values at 1 month to 31 +/- 12 mm Hg (p = 0.07). Peak A-wave velocities increased from 0.51 +/- 0.1 m/s after 1 day to 0.67 +/- 0.2 m/s after 1 month (p = 0.03). Restoration of sinus rhythm in patients with AF resistant to external electrical and/or pharmacologic cardioversion improves hemodynamic and cardiorespiratory function at daily activity exercise levels.
Atrial Fibrillation↗
Transverse conduction capabilities of the crista terminalis in patients with atrial flutter and atrial fibrillation.
OBJECTIVES: In this study, the transverse conduction capabilities of the crista terminalis (CT) were determined during pacing in sinus rhythm in patients with atrial flutter and atrial fibrillation. BACKGROUND: It has been demonstrated that the CT is a barrier to transverse conduction during typical atrial flutter. Mapping studies in animal models provide evidence that this is functional. The influence of transverse conduction capabilities of the CT on the development of atrial flutter remains unclear. METHODS: The CT was identified by intracardiac echocardiography. The atrial activation at the CT was determined during programmed stimulation with one extrastimulus at five pacing sites anteriorly to the CT in 10 patients with atrial flutter and 10 patients with atrial fibrillation before and after intravenous administration of 2 mg/kg disopyramide. Subsequently, atrial arrhythmias were reinduced. RESULTS: At baseline, pacing with longer coupling intervals resulted in a transverse pulse propagation across the CT. During shorter coupling intervals, split electrograms and a marked alteration of the activation sequence of its second component were found, indicating a functional conduction block. In patients with atrial flutter, the longest coupling interval that resulted in a complete transverse conduction block at the CT was significantly longer than that in patients with atrial fibrillation (285 +/- 49 ms vs. 221 +/- 28 ms; p < 0.05). After disopyramide administration, a transverse conduction block occurred at longer coupling intervals as compared with baseline (287 +/- 68 ms vs. 250 +/- 52 ms; p < 0.05). Subsequently, a sustained atrial arrhythmia was inducible in 15 of 20 patients. This was atrial flutter in three patients with previously documented atrial fibrillation and in eight patients with history of atrial flutter. Mapping revealed a conduction block at the CT in all of these patients. CONCLUSIONS: It was found that the CT provides transverse conduction capabilities and that the conduction block during atrial flutter is functional. Limited transverse conduction capabilities of the CT seem to contribute to the development of atrial flutter.
Aged↗