The pericardial space: a new possible route for influencing cardiac activity

Recently, it has been shown that pericardial fluid accumulates several endogenous agents of cardiac origin and it has been considered to have a role in the regulation of cardiac function beside the lubrication of the heart surface.

Previous investigations demonstrated that certain agents applied intrapericardially (i.p.) may exert their cardiovascular effects, which offers a possibility for pharmaco-therapeutic interventions from the pericardial space. In experimental investigations a reliable access without thoracotomy to the normal pericardial space has been demonstrated.

In our investigations we have focused on pericardial effects and interactions of different endogenous regulatory agents applied intrapericardially into the in situ dog heart.

We found, that i.p. endothelin-1 (ET-1) induces myocardial ischaemia and activates the coronary metabolic autoregulatory process as it was reflected the significant elevation of pericardial purine metabolite levels (i), the i.p catecholamines (norepinephrine and dopamine) exert their caractheristic cardiac and circulatory effects and induce ADO and ET-1 release into the pericardial fluid (ii), the i.p. ET-1 effectively stimulates the myocardial release of adenosine, inosine and atrial natriuretic peptide into the pericardial fluid (iii); while the systemic plasma levels all of these agents remained unchanged.

In conclusion, the above regulatory agents can exert their effects from the pericardial space and their local interactions could be provoked and detected in the pericardium.

We think that the advantages of direct delivery of agents into the pericardial space would be that a maximal therapeutic effects may be achieved by local action while the side effects of systemic administration may be minimised and, due to the lower pericardial turnover of the agents their contact with myocardial tissue is longer and less amount of the agent maybe lost (vanish) in the systemic circulation.