Effects of thoracic epidural anaesthesia on central haemodynamics compared to cardiac beta adrenoceptor blockade in conscious rats with acute myocardial infarction

Abstract

The study aimed to compare the effects of thoracic epidural anaesthesia (TEA) with those of the beta-adrenoceptor blocker, metoprolol, on central haemodynamics in conscious rats with acute myocardial infarction. During methohexital anaesthesia, appropriate vascular catheters were inserted, a thoracic epidural catheter was implanted and the left coronary artery was ligated. A recovery period of 1-2 h elapsed after termination of surgery and anaesthesia. Experiments were performed on four separate groups of animals (A-D). In Group A (n = 10) mean arterial pressure (MAP), heart rate (HR), and cardiac output (CO) were measured, and stroke volume (SV) and systemic vascular resistance (SVR) were calculated before and 10-15 min after the induction of TEA (bupivacaine 5 mg.ml-1). In Group B (n = 6) left ventricular end-diastolic pressure (LVEDP) and maximal dP/dt were recorded as in Group A. In Group C (n = 10) central haemodynamics were measured 10 min after i.v. metoprolol (0.5 mg.kg-1) and again 10-15 min after the addition of TEA. In Group D (n = 6) LVEDP and max dP/dt were measured as in Group C. The reduction in CO, SV, HR and max dP/dt was of the same magnitude with TEA and metoprolol. TEA lowered MAP by 17%, while metoprolol did not change MAP. Metoprolol caused an increase in LVEDP from 20.8 +/- 1.8 to 27.5 +/- 2.7 mmHg (2.8 +/- 0.2 to 3.7 +/- 0.4 kPa) (P less than 0.01), while TEA induced a decrease in LVEDP from 24.2 +/- 1.4 to 17.8 +/- 1.6 mmHg (3.2 +/- 0.2 to 2.4 +/- 0.2 kPa) (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of thoracic epidural blockade on mortality of patients with idiopathic dilated cardiomyopathy and heart failure

“…Experimental and clinical data reported improvement in left ventricular function in coronary artery disease, unstable angina pectoris, and myocardial infarction with TEB [4][5][6][7][8][9]. Hypothetically, the blockade of hyper-activated sympathetic nerves by TEB could be helpful in patients with IDCM and heart failure (HF).…”

“…The introduction of dedicated guidewires and the development of new techniques have improved the success rate in the crossing of CTO lesion while the widespread use of drug-eluting stent (DES) has reduced the occurrence of restenosis and the need for target lesion revascularization [3]. Of note, two recent meta-analysis showed that first-generation DES use was associated with a lower rate of major adverse cardiovascular events (MACEs), as compared to bare-metal stent (BMS), both at mid-and long-term follow-up [4,5]. However, some concerns about long-term complications of DES implantation [late restenosis and stent thrombosis (ST)] are emerging [6,7].…”

Sympatho-modulatory therapies in perioperative medicine

“…A comparison between thoracic epidural anaesthesia and b-AA on haemodynamic parameters in conscious rats with acute myocardial infarction revealed the following intriguing ®ndings. 10 While thoracic epidural anaesthesia decreased left ventricular end-diastolic pressure and systemic vascular resistance remained unaffected, metoprolol in contrast increased both parameters. Heart rate and cardiac output were similarly decreased in both treatment regimens.…”

Perioperative Strategien zur Regulierung des Sympathikotonus

“…Es gibt nur spärliche klinische und experimentelle Daten über Wirksamkeit und eventuell unerwünschte Effekte von kombinierten antiadrenergen Therapiekonzepten. Ein tierexperimenteller Vergleich zwischen thorakaler Epiduralanästhesie und β-AA bezüg-lich der Auswirkung auf hämodynamische Parameter bei wachen Ratten mit akutem Myokardinfarkt ergab folgende interessanten Resultate [9]: Während eine thorakale Epiduralanästhesien den linksventrikulären enddiastolischen Druck erniedrigte und der systemische Widerstand unverändert blieb, erhöhte Metoprolol dagegen beide Parameter. Herzfrequenz und Herzminutenvolumen ("cardiac output") wurden bei beiden Behandlungsgruppen gleichermaßen vermindert.…”