The changes of hemodynamics during bathing in patients with heart diseases were studied by invasive methods using a Swan-Ganz catheter and UCG. As a population, we have used 37 peatients with heart disease, ages 20 to 76 (average age 52.9). There were 26 cases of myocardial infarction, 5 cases of valvular disease, 5 cases of cardiomyo pathy, and 1 case of VSD. Bathing was done with tap water in a Hubbard tank, for 10 minutes at 40°C and for 5 minutes at 43°C in a supine position. Arterial pressure, heart rate, pulmonary arterial pressure, pulmonary wedge pressure, right atrial pressure, cardiac output, stroke volume and stroke work index were increased during bathing and decreased after bathing. Systemic vascular resistance and pulmonary arteriolar resistance were decreased during bathing. Their changes were marked with a bath of 40 to 43°C. These findings suggest that preload may be increased during bathing, and preload and afterload reduced after bathing. Hydrostatic pressure, autonomic nervous reflexes or endocrine system were thought of as possible reasons for the increase in pulmonary arterial pressure. Because pulmonary arterial pressure, pulmonary wedge pressure and right atrial pressure increased during bathing even though systemic vascular resistance and pulmonary arteriolar resistance decreased, increase in venous return was thought of as the biggest possibility. And because the patients with low cardiac function could not control the extent of increase in venous return, pulmonary arterial pressure increased markedly in patients with low cardiac function. The patients with myocardial infarction were classifed into a group showing elevation of pulmonary arterial pressure (PAP) and a group showing no elevation of PAP. The group showing elevation of PAP, compared with that without PAP elevation, included many cases of severe myocardial infarction deter-mined by Forrester's classification, Killip's classification and Peel's prognostic index at admission to hospital. Among these patients showing PAP elevation, there were more cases having low physical work capacity and low ejection fraction at discharge from hospital than among the patients without PAP elevation.

Little is known about how isosorbide dinitrate (ISDN) contribute to bathing effects on patients with myocardial infarction. A study using an invasive method was made on 29 patients with myocardial infarction to clarify the hemodynamic changes occurring during bathing with and without sublingual ISDN, and to evaluate the overall effects of the ISDN. In bathing after discontinuing dosing of vasodilators (PRE-ISDN), patients were divided into the following two groups depending on the difference between the peak pulmonary capillary wedge pressure (PCWP) during bathing and PCWP before bathing: Increased PCWP group [(Group A): Δ PCWP≥10mmHg] and Unincreased PCWP group [(Group B): Δ PCWP <10mmHg].
Bathing was taken for 5 minutes at 42°C in a Hubbard tank, hemodynamics were observed during bathing and for 10 minutes after bathing, and after 30 minutes of sublingual administration of 5mg ISDN, bathing was taken in a similar manner. Group A patients showed a greater increase in heart rate, blood pressure, pulmonary arterial pressure (PAP), and right artial pressure than of Group B patients during bathing before being dosed with ISDN, and it seemed to be a considerable load on the heart. Although the remarkable increase of PAP and PCWP observed during the early stage of bathing before dosing with ISDN significantly decreased after sublingual dosing of ISDN (POST-ISDN) among Group A patients, these effects were not found in Group B patients. Group A showed more frequent reinfarction from a clinical viewpoint and triple vessel disease upon coronary arteriography, a lower ejection fraction upon left ventriculography, a higher left ventricular end-diastolic pressure, and lower left ventricular performance in most cases as compared to Group B. Although ISDN was found to be effective for severe cases in which the marked pre-load was observed by bathing, no beneficial effect on mild cases with well-maintained left ventricular performance was obtained.