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Biomedical subjects

F Eberhardt

Publications and source records attributed to F Eberhardt.

11 recordsLinked to original sources

Long term complications in single and dual chamber pacing are influenced by surgical experience and patient morbidity.

OBJECTIVE: To determine how short and long term complication rates after pacemaker implantation are influenced by patient morbidity, operator experience, and choice of pacing system. DESIGN: Retrospective analysis of 1884 patients who received VVI (n = 610), VDD (n = 371), or DDD devices (n = 903) between 1990 and 2001. Follow up period was 64 (34) months. The influence of age, sex, coronary artery disease, myocardial infarction, reduced left ventricular (LV) function, right ventricular (RV) dilatation, atrial fibrillation, device type, and operator experience on operation time and complication rate were analysed. RESULTS: Operation time was prolonged in patients with coronary artery disease, inferior myocardial infarction, reduced LV function, and RV dilatation. Implantation of DDD pacemakers prolonged operation time, particularly among operators with a low or medium level of experience. The overall complication rate was 4.5%. Sixty seven per cent of these complications occurred within the first three months. Complication rate was increased by age, reduced LV function, and RV dilatation. Implantation of DDD systems led to a higher complication rate (6.3%) than implantation of VVI (2.6%) or VDD pacemakers (3.2%). These differences were present only among operators with a low or medium level of experience. CONCLUSIONS: Operation time and complication rate increased with age, impaired LV function, and RV dilatation. Complication rates were higher with DDD than with VVI or VDD implantation and were excessive among inexperienced but not experienced operators.

Age Factors↗

Structural myocardial changes after coronary artery surgery.

BACKGROUND: Postoperative contractile dysfunction or 'myocardial stunning' has been described after coronary artery bypass grafting (CABG). In the present study we sought to determine if and to what extent clinical, structural and histochemical evidence of myocardial changes associated with stunning could be found in patients after CABG and cold crystalloid cardioplegia. MATERIALS AND METHODS: Left ventricular (LV) biopsies were obtained from CABG patients (n = 10) prior to and at the end of cardiopulmonary bypass (CPB). These biopsies were immunostained for the inducible heat-shock protein 70 (HSP-70i), intercellular adhesion molecule-1 (ICAM-1) and actin. ATP was measured by bioluminescence. RESULTS: Biopsies pre-CPB showed no evidence of myocardial damage as HSP-70i was absent and a regular actin cross-striation pattern and only constitutive ICAM-1-expression were present. After CPB we found significantly increased HSP-70i and ICAM-1 levels as well as a deranged actin cross-striation pattern with a widening of actin bands. ATP levels declined from 10 mmol L-1 pre-CPB to 4.9 mmol L-1 after CPB. Correspondingly, coronary sinus effluent showed a significant lactate production. Although, cardiac function determined by transoesophageal echocardiography did not deteriorate, significant inotropic support was necessary to maintain cardiac output. CONCLUSIONS: Our results present clinical and structural evidence of 'myocardial stunning' after CABG and cold crystalloid cardioplegia. Increased HSP-70i and ICAM-1 expression, as well as a deranged actin cross-striation pattern, might be structural markers to determine 'myocardial stunning' in clinical settings.

Actins↗

Myocardial beta-blockade as an alternative to cardioplegic arrest during coronary artery surgery.

The authors' recent experimental work has demonstrated that myocardial protection using continuous coronary perfusion with warm beta-blocker-enriched blood avoids myocardial ischaemia and minimizes myocardial oedema formation, thus completely preserving left ventricle function. The purpose of this clinical study was to compare this alternative technique in terms of structural and functional myocardial protection with the routinely used crystalloid Bretschneider cardioplegia. Sixty coronary artery surgery patients were randomized to receive either crystalloid cardioplegia or continuous coronary perfusion with warm blood enriched with the ultra-short acting beta-blocker esmolol. Cardiac function was evaluated using transoesophageal echocardiography (fractional area of contraction) and cardiac metabolism using arterial-coronary sinus lactate concentration difference (a - csD(LAC)). From left ventricular biopsies, the authors determined myocardial oedema, heat-shock-protein-70, intercellular-adhesion-molecule and actin pattern. Patients with crystalloid cardioplegia received 3.6 +/- 0.8 grafts during 64 +/- 20 min cross-clamp time (beta-blocker: 3.5 +/- 0.9 grafts during 68 +/- 22 min; NS). Following cross-clamp removal crystalloid cardioplegia hearts released significant lactate amounts (a- csD(LAC)) - 1.0 +/- 0.6 versus - 0.1 +/- 0.2 mmol/litre in beta-blocker hearts; P < 0.05). In crystalloid cardioplegia hearts, myocardial water content increased from 82.1 +/- 2.1% pre-cardiopulmonary bypass to 83.2 +/- 1.7% at the end of cardiopulmonary bypass (P < 0.05); in beta-blocker hearts myocardial water content remained unchanged (pre-cardiopulmonary bypass: 82.3 +/- 1.9%; end of cardiopulmonary bypass: 82.4 +/- 1.7%; NS). At the end of cardiopulmonary bypass, left ventricular biopsies of beta-blocker hearts showed less structural damage as determined by heat shock protein-70, intercellular adhesion molecule-I and deranged actin cross-striation pattern as compared with crystalloid cardioplegia hearts (P < 0.05). The post-cardiopulmonary bypass fractional area of contraction was similar in both groups (beta-blocker: 65 +/- 14%; crystalloid cardioplegia: 62 +/- 16%); however, beta-blocker patients required less inotropic stimulation (dopamine: beta-blocker: 2.9 +/- 2.5 versus crystalloid cardioplegia: 5.0 +/- 2.3 microg/kg per min; P < 0.05). The data suggest that continuous coronary perfusion with warm esmolol-enriched blood results in better myocardial protection compared with crystalloid cardioplegia. It is concluded that the concept of beta-blocker-induced cardiac surgical conditions may be a useful alternative for myocardial protection during coronary artery surgery.

Adrenergic beta-Antagonists↗