Responses of internal mammary artery graft flow to nitroprusside: a duplex Doppler study in hypertensive hearts.

OBJECTIVE: To assess the response of internal mammary artery (IMA) flow of hypertensive hearts to nitroprusside infusion. METHODS: Fifteen patients were studied with a high-frequency duplex Doppler probe from the supraclavicolar approach. All the patients had undergone coronary artery bypass surgery with an IMA graft into the left anterior descending artery. The investigated patients were normotensives (controls, n = 5) and hypertensive with a normal (group 1, n = 5) or a hypertrophic (group 2, n = 5) left ventricle. Values of the left ventricular mass index were 102 +/- 11 g/m2 in controls, 115 +/- 18 g/m2 in group 1 and 153 +/- 8 g/m2 in group 2. The IMA flow volume was studied at baseline and continuously during nitroprusside infusion. The arterial blood pressure was measured each minute by a cuff sphygmomanometer. In each patient we considered the peak flow volume (percentage increment from baseline) and the flow volume at the end point (the lowest tolerated diastolic blood pressure). RESULTS: Nitroprusside infusion induced a comparable flow-volume increment in controls (38 +/- 27%) and in group 1 (24 +/- 11%). Conversely, the flow-volume increment was trivial in group 2 (6 +/- 6%). At the end point, the flow volume was similar to the baseline value in controls (with diastolic blood pressure 67 +/- 9 mmHg) and in group 1 (diastolic blood pressure 61 +/- 4 mmHg), whereas the flow volume declined significantly from baseline (by 23%) in group 2 at a perfusion pressure of 79 +/- 9 mmHg. CONCLUSION: Hypertensive patients with a normal left ventricular mass exhibit a coronary flow behaviour similar to that of normotensives in response to a nitroprusside infusion. Conversely, hypertrophic hypertensives show a blunted nitroprusside-induced coronary vasodilator response and are much more vulnerable to coronary flow reductions in the face of hypotension. This dynamic assessment of flow patterns can be obtained non-invasively by duplex Doppler monitoring of IMA graft flow.

[Echo-Doppler evaluation of hemodynamic response during exercise in patients with rate-responsive respiration-dependent pacemakers]. / Valutazione eco-Doppler di risposta emodinamica durante sforzo in pazienti portatori di pacemaker rate responsive dipendenti dal respiro.

The aim of this study was the 2D-echocardiographic and Doppler evaluation of the hemodynamic behaviour under stress in a group of 7 patients bearing Biotec BioRate RDP 3 and MB1 rate-responsive respiration-dependent pacemakers, programmed with the same heart rate/respiratory frequency correlation curve. The following parameters were monitored in basal conditions and during each level of the stress test at the horizontal cycloergometer: cardiac output (CO), cardiac index (CI), stroke volume (SV) and pacing rate (HR). All the 7 patients presented a progressive increase in CO and CI, but with a marked range of SV and HR increase. Two types of hemodynamic response under stress were consequently found: the first was characterized by a conspicuous increase in SV during the initial and middle levels of the stress, concomitant with scarce HR increase. The second, instead, was characterized by scarce or no SV increase during the same levels, concomitant with marked HR increase. At the highest stress levels, the CO increase was, in both types, almost exclusively due to HR increase. By analyzing the clinical features and the basal echocardiographic aspects of the patients studied, the first type was found to represent normal contractility features, while the second type was characterized by compromised contractility with reduced ejection fraction. It was thus demonstrated that there are 2 ways of increasing the CO under stress: by means of predominant increase of either the SV or the HR. This hemodynamic behaviour, very similar to the spontaneous behaviour of the heart, occurred in a group of constantly paced patients, thanks to the highly physiological guide parameter of their pacemakers: respiratory activity, which is bound to O2 consumption by a linear relationship.

Klinefelter's syndrome in nontwin brothers and maternal XX/XXX mosaicism.

A case of two nontwin brothers, 19 and 17 years old, who had both Klinefelter's syndrome with a chromosomal mosaicism 46 XY/47 XXY, is reported here. The analysis of their mother's karyotype revealed a 46 XX/47 XXX mosaicism. It is hypothesized that the presence of an extra X chromosome in all three subjects could depend on the transmission of two X chromosomes from the mother to the sons or, less likely, on an increased liability to nondisjunction of the X chromosomes during one of the early mitotic divisions in the zygotes.