Atrial natriuretic peptide response to rapid atrial pacing in cardiac-denervated dogs

Insufficient secretion of atrial natriuretic peptide at acute phase of myocardial infarction

To investigate the secretion of the plasma levels of atrial natriuretic peptide (ANP) in patients with acute myocardial infarction (AMI), we evaluated the relationship between plasma levels of ANP and pulmonary capillary wedge pressure (PCWP) in 45 consecutive patients during the acute phase of AMI ( approximately 12 h after the attack) (group 1) and compared data with those obtained after 1 mo (group 2). In both groups 1 and 2, plasma ANP levels significantly correlated with PCWP. The slope of the linear regression line between the PCWP and ANP in group 1 was significantly lower, by about one-third, than that in group 2. In addition, we examined changes in ANP levels and left ventricular end-diastolic pressure (LVEDP) over 180 min after AMI induced by injection of microspheres into the left coronary arteries of three dogs. The LVEDP and ANP levels 30 min after AMI were significantly higher than those before; however, despite the persistent high LVEDP during the 180 min after AMI, ANP levels decreased gradually and significantly to 63% of the peak level at 150 min. These findings suggest that the secretion of ANP during the acute phase of myocardial infarction may be insufficient relative to the chronic phase.

Intractable chest pain in cardiomyopathy: treatment by a novel technique of cardiac cryodenervation with quantitative immunohistochemical assessment of success

A novel method of cardiac denervation by cryoablation has been developed experimentally. The technique uses liquid nitrogen delivered under pressure to ablate the principal sources of cardiac innervation--namely, the adventitia surrounding the aorta, pulmonary arteries, and veins. The technique has been verified experimentally both in vivo by physiological means and in vitro by quantitative immunohistochemistry and the measurement of myocardial noradrenaline concentrations. A 35 year old woman presented with intractable precordial pain, normal epicardial coronary arteries, and hypertrophic cardiomyopathy. Her symptoms were refractory to maximal medical treatment and she was thought to be unsuitable for either conventional myocardial revascularisation, autotransplantation, or allografting with the concomitant risk of transplant coronary artery disease. She therefore underwent cardiac denervation by the method developed in the laboratory. There was quantitative immunohistochemical evidence of extrinsic cardiac denervation associated with a considerable improvement in her symptoms. This improvement persisted during a follow up period of over 16 months.