Supraventricular arrhythmia before and after surgical closure of atrial septal defects: spectrum, prognosis and management.

UNLABELLED: Supraventricular arrhythmias are often observed in patients before and after atrial septal defect repair. Although several papers report different incidences of sustained supraventricular arrhythmias, postoperative 'incisional' macroreentrant tachycardias have not been systematically investigated. METHODS: We reviewed 136 consecutive patients (79 female, 57 male, mean age 36.8+/-17.8 years) who underwent atrial septal defect repair at our institutions between January 1990 and January 1999. Coexisting valve disease requiring surgical intervention was noted in 13 patients (9.5%). The mean follow-up period was 78.8+/-30.1 months. RESULTS: Sustained supraventricular arrhythmias occurred in 12 patients (8.8%) before surgery (atrial fibrillation in 11 patients). Using multivariate analysis the occurrence of arrhythmia significantly correlated with the presence of coexisting heart disease (P< 0.001) and age at surgery (P=0.011) After surgery sustained supraventricular arrhythmias were recorded in 16 patients (11.7%). Eleven of them had atrial fibrillation, permanent in 8 cases, 4 'incisional' macroreentrant atrial tachycardia and 1 atrioventricular re-entry tachycardia. There was a significant correlation between pre and postoperative arrhythmia (P< 0.001). Two of the 4 patients with macroreentrant atrial tachycardia underwent successful radiofrequency catheter ablation, whereas the arrhythmia was controlled medically in the remaining 2 patients. CONCLUSIONS: Atrial fibrillation remains the most frequent form of arrhythmia before and after surgical closure of atrial septal defects in adulthood, and relates to age at the time of repair and coexisting heart disease. Incisional macroreentrant atrial tachycardia is an identifiable, albeit less common, form of tachycardia, which can be treated by transcatheter ablation.

Pathology of the Pericarbon bovine pericardial xenograft implanted in humans.

BACKGROUND AND AIMS OF THE STUDY: Pericarbon is a new-generation bovine pericardial bioprosthesis designed to withstand mechanical wear. Following optimal in vitro testing and animal experiments, clinical trials were initiated in many European centers and explants sent to our department for pathological evaluation. This included gross, radiographic, histologic and ultrastructural investigations. METHODS: Between 1986 and 1996, 24 bioprostheses (eight aortic, 11 mitral, two mitro-aortic, one tricuspid) were collected from 22 patients (10 males and 12 females; mean age 57.0 +/- 18.9 years) either at autopsy (nine) or reoperation (15). RESULTS: Ten bioprostheses explanted < 2 months after surgery were either normal or failed because of surgical problems or non-structural causes. Among the other 14 bioprostheses (mean placement 41.9 +/- 23.6 months; range: 7 to 90 months), structural deterioration occurred in seven and was due to dystrophic calcification with stenosis in five (three aortic, two mitral), mixed lesion in one (mitral), and incompetence in one by calcium-related commissural tear (mitral). At the ultrastructural level, calcification was detected either on cell debris or upon collagen fibers. No bioprosthesis failed because of fibrous tissue overgrowth. Of the remaining seven bioprostheses, vegetative endocarditis occurred in two, thrombosis in one, and aseptic paravalvular leak in one; whereas three showed no signs of dysfunction. CONCLUSIONS: This pathologic experience with the Pericarbon valve showed calcification to be the main cause of late structural failure, causing mainly cusp stiffness and bioprosthesis stenosis. Tissue rupture or abrupt dysfunction never occurred. Thus, prevention of mineralization remains the main challenge.

[Caffeine and children]. / Kofein i deti.

Beverages containing caffeine are consumed by most people in most countries most days. Consumption is mostly in beverages such as coffee, tea and some soft drinks, and smaller amounts from other foods such as chocolate. Children also consume caffeine, though in smaller amounts even relative to their smaller size. Many questions have been asked about possible health effects of caffeine and have been answered by scientific research. Studies on pregnant women consuming caffeine show no effects on the fetus, infants, or on development followed up to school age. There have been many studies on children of school age. For example, it has been shown that a single dose of 3 mg/kg is without appreciable effect on a variety of behavioral and physiological functions, and even 10 mg/kg, had only minimal effects, within the normal range of differences between the children without caffeine. While newborn infants metabolize caffeine slowly, children from less than 1 year to adolescence metabolize caffeine about twice as fast as non-smoking adults. The numerous studies showing safety of caffeine in adults, combined with the direct studies in children showing they are similar and not more susceptible to caffeine than adults, gives assurance that lifelong consumption of caffeine in foods and beverages, starting in childhood, is without deleterious effects on health.

Hemodynamic evaluation of 23 mm Pericarbon and 23 mm Hancock II bioprostheses in the aortic position at mid-term follow up.

BACKGROUND AND AIMS OF THE STUDY: Pericardial xenografts were introduced for clinical use following evidence of their good hemodynamic characteristics in laboratory tests; however, their efficiency in comparison with porcine valves has not been fully assessed. Pericarbon, a new type of pericardial bioprosthesis, has been recently developed in order to provide better hemodynamic performances and longer durability than such bioprostheses currently in use. METHODS: Fifteen patients operated on for aortic valve replacement with a 23 mm Pericarbon and a sex- and age-matched group operated on with a 23 mm Hancock II bioprosthesis were submitted to echocardiographic and Doppler examinations in order to compare the hemodynamic performance of the two devices. RESULTS: Peak transvalvular gradients for Pericarbon and Hancock II bioprostheses (38.9 +/- 13.0 vs. 33.9 +/- 13.0 mmHg; p = 0.294) and mean transvalvular gradients (24.7 +/- 7.6 vs. 20.8 +/- 9.9 mmHg, p = 0.24) showed no significant difference. However, the indexed effective prosthetic dynamic area was significantly larger for the Hancock II device (0.73 +/- 0.14 vs. 0.62 +/- 0.13 cm2; p < 0.05). CONCLUSIONS: When installed as 23 mm pericardial bioprostheses, the Pericarbon device appears not to demonstrate superior hemodynamic performance to that of the Hancock II; however, additional studies are needed to provide a definitive conclusion.

Low-profile porcine bioprosthesis (Liotta): pathologic findings and mode of failure in the long-term.

BACKGROUND AND AIMS OF THE STUDY: The Liotta low profile porcine bioprosthesis (LBP) was designed in order to minimize complications due to excessive protrusion of the stent prongs in the left ventricle. MATERIALS AND METHODS: From April 1984 to November 1993, 25 LBP surgical explants were available for pathology study, which included gross and X-ray evaluations. Reoperation was performed after a mean period of 95 +/- 25 months (range 46 to 143 months), in five males and 20 females (mean age at implantation 51.1 +/- 11.4 years). RESULTS: The cause of failure was stenosis due to cusp stiffness caused by dystrophic calcification in one and incompetence in 24 LBPs. In only one case was incompetence ascribable to endocarditis; in the remaining 23 the mechanism of regurgitation was due to commissural tearing (21 LBPs), commissural dehiscence (one LBP) and both tears and dehiscence (one LBP). Overall, 28 commissural tears were observed: 20 involved the right coronary cusp, eight the left coronary cusp, and none the non-coronary cusp. The anterior commissure was most frequently involved by tears (n = 17) followed by the right posterior (n = 9) and the left posterior (n = 2). Tears were calcium-related in all but two cases. Calcific deposits were observed in each explant, involving a total of 62 commissural attachments, 17 cusp bodies and five right muscular shelves. CONCLUSION: In conclusion, valve regurgitation is the usual mode of LBP failure in the mitral position; commissural tearing of the right coronary cusp was the most common cause of valve regurgitation, and occurred even in the presence of pin-point calcification. These pathologic findings seem to confirm that low profile design, which implies bulging of the right coronary cusp, entails the risk of increased stress at the commissures, accelerated calcification and tearing.

Usefulness of transthoracic and transoesophageal echocardiography in recognition and management of cardiovascular injuries after blunt chest trauma.

OBJECTIVE: To assess the diagnostic potential of transthoracic and transoesophageal echocardiography for the detection of traumatic cardiovascular injuries in patients suffering from severe blunt chest trauma. DESIGN: Prospective study over a three year period. SETTING: A regional cardiothoracic centre. PATIENTS: 134 consecutive patients (94 M/40 F; mean age 38 (SD 14) years) suffering from severe blunt chest trauma (injury severity score 33.5 (18.2)). Most patients (89%) were victims of motor vehicle accidents. EVALUATION: All patients underwent transthoracic and transoesophageal echocardiography within 8 h of admission. Aortography was performed in the first 20 patients and in a further five equivocal cases. RESULTS: Transthoracic echocardiography provided suboptimal images in 83 patients, detecting three aortic ruptures, 28 pericardial effusions (one cardiac tamponade), 35 left pleural effusions, and 15 myocardial contusions. Transoesophageal echocardiography was feasible in 131 patients and detected 14 aortic ruptures (13 at the isthmus), 40 pericardial effusions, 51 left pleural effusions, 34 periaortic haematomas, 45 myocardial contusions, right atrial laceration in one patient with cardiac tamponade, one tricuspid valve rupture, and one severe mitral regurgitation caused by annular disruption. For the detection of aortic rupture transoesophageal echocardiography showed 93% sensitivity, 98% specificity, and 98% accuracy. Time to surgery was significantly shorter (30 (12) v 71 (21) min; P < 0.05) for patients operated on only on the basis of transoesophageal echocardiographic findings. CONCLUSIONS: Transthoracic echocardiography has low diagnostic yield in severe blunt chest trauma, while transoesophageal echocardiography provides accurate diagnosis in a short time at the bedside, is inexpensive, minimally invasive, and does not interfere with other diagnostic or therapeutic procedures.

Detection of acute thrombosis of mitral tilting disk prosthesis by transesophageal echocardiography.

Acute thrombosis is a very severe complication in the replacement of mechanical prostheses and most often fatal if immediate treatment is not implemented. We describe a case in which an acute thrombosis of a mitral tilting disk prosthesis was adequately diagnosed by transesophageal echocardiography and immediate surgical replacement of the dysfunctioning device was possible without catheterizing the patient.

Comparative diagnostic value of transesophageal echocardiography and retrograde aortography in the evaluation of thoracic aortic dissection.

The aim of this study was to assess the comparative diagnostic value of transesophageal echocardiography (TEE) and retrograde aortography for morphologic evaluation and anatomic mapping of aortic dissection. Seventy patients (aged 18 to 79 years) were prospectively evaluated with both techniques for suspected aortic dissection. In 64 patients, findings on aortography and TEE could be validated against intraoperative (n = 53) and postmortem (n = 11) findings. Examination time was significantly shorter for TEE (9 +/- 6 vs 48 +/- 25 minutes; p < 0.001). For the detection of aortic dissection, aortography showed lower sensitivity (87.5% vs 97.5%) and negative predictive value (85.3% vs 96.7%; both trends did not reach statistical significance) due mostly to the inability to identify noncommunicating dissection (dissection without intimal tears). For the epiphenomena of aortic dissection, aortography was significantly more accurate (97.2% vs 78%; p < 0.05) in assessing the site of entry, and TEE was more accurate in identifying thrombus formation (90% vs 65%; p < 0.05). There was no significant difference between aortography and TEE with regard to assessing secondary tears, aortic regurgitation, coronary dissection, and extension of the dissection. Thus, both TEE and aortography offer detailed anatomic mapping for guided surgical interventions. In elective patients, integration of both techniques seems the best approach; in unstable patients, TEE may be preferential because it is less invasive, requires no contrast injection, and provides accurate diagnosis in a short time at the bedside.

The pericardium reinforced suture annuloplasty: another tool available for mitral annulus repair?

From May 1985 to May 1992, 169 patients underwent surgery for mitral valve repair. In 87% of these patients, the valve reconstruction involved the mitral annulus. At the beginning, in an effort to preserve systolic movement of the annulus and avoid the implant of prosthetic materials inside the heart, we mainly used simple suture annuloplasty in 66 patients. When we reoperated upon three patients only a few months after reconstruction of the mitral valve for a dehiscence of the suture annuloplasty, we decided to perform ring annuloplasty with the Carpentier ring in 23 patients. Though we have not seen any problems with the Carpentier ring in our series, we performed a suture annuloplasty reinforced with a strip of autologous pericardium to eliminate all prosthetic material. Since introducing this technique in 1989, we have used this annuloplasty in 58 patients. We have not observed any dehiscence of the suture or other complications related to this procedure. Three patients with a pericardial annuloplasty underwent reoperation for other reasons; the autologous pericardium was perfectly attached to the annulus, covered by a smooth layer of fibrous tissue without calcification. After this encouraging initial experience, we believe that long-term follow-up is necessary to confirm that autologous pericardium is an effective method of mitral annulus repair.

The Meadox-Gabbay pericardial xenograft: failure of the unicusp principle.

Durability of a new bioprosthesis, the Meadox-Gabbay unileaflet pericardial xenograft, was evaluated by reviewing a series of 12 patients who received this device in the mitral position from 1983 to 1985. Bioprosthetic failure necessitated reoperation in 5 patients 21, 22, 53, 66, and 81 months after placement. Three patients died of cardiac failure after 31, 52, and 70 months; no postmortem examinations were done. In 2 of the 3 patients, an echocardiographic study had shown signs of valvular dysfunction. Pathological examination of five available explants revealed the presence of redundancy and stretching of the single pericardial leaflet in all of them; in one, this lesion alone caused severe prosthetic incompetence. Other pathological findings included cusp and commissural calcification and commissural tears with or without calcification. Histologic examination and electron microscopy showed intrinsic calcification involving both collagen bundles and cellular debris and various degrees of collagen disruption. In this limited series of patients, the Meadox-Gabbay pericardial xenograft demonstrated various modes of failure that markedly impair its durability and render it unsuitable as a cardiac valve substitute.

Durability of glutaraldehyde-fixed pericardial valve prostheses: clinical and animal experimental studies.

Bovine pericardium has been widely employed as a xenograft tissue for the manufacture of bioprosthetic valve substitutes. Early three-leaflet valve models showed poor tissue preservation and shortcomings in valve design, which accounted for tissue wear and prosthesis failure due to cuspal tear. Reducing the number of cusps in the unicusp pericardial valve has proved unsuccessful due to stretching of the single pericardial leaflet with consequent valvular incompetence. The new generation of pericardial xenografts present basic changes in valve design and optimal tissue preservation after industrial processing, with no evidence of leaflet tear at medium term follow up. However, clinical experience is limited and, similarly to porcine xenografts, dystrophic calcification still appears to be a major problem.

Surgical treatment of left-ventricular outflow-tract obstruction guided by intraoperative transesophageal echocardiography.

Transesophageal echocardiography may provide additional morphologic information in many cases of cardiovascular disease when compared with the traditional transthoracic approach. In our department 3 male patients underwent surgical treatment with preoperative diagnosis of left-ventricular outflow-tract obstruction. We describe the intraoperative transesophageal echocardiographic findings and in which way they guided the surgical strategy.