Relationship Between Cardiac Output and Peripheral Resistance in Borderline Hypertension

Abstract

Eighty-eight observations on 77 patients with borderline hypertension and 82 single observations in healthy control subjects are reported. Hemodynamic effects of assumption of the sitting position, mild exercise, infusion of dextran, blockade with propranolol and with a combination of propranolol and atropine are evaluated. In the recumbent position, patients with borderline hypertension have increased cardiac output and "normal" peripheral resistance. Under all other experimental conditions, the peripheral resistance in patients with borderline hypertension was elevated. Increased resistance was accompanied by a decrease of the cardiac output. After administration of the atropine and propranolol combination, cardiac output in patients with borderline hypertension was significantly below the normal. Nevertheless, whether cardiac output was high or low and resistance normal or elevated, patients with borderline hypertension maintained mild elevations of the blood pressure. Consequently, borderline hypertension is not caused solely by elevations of cardiac output.

Hemodynamic effects of dietary sodium in man: a preliminary report.

“…The BP of the labile hypertensive subjects was significantly higher than that of the normal subjects at each level of sodium intake, demonstrating a disturbed relationship between cardiac index and total resistance. Similar observations have been reported by Julius and co-workers, 17 who carried out hemodynamic studies of subjects with labile hypertension at rest and in response to sitting, exercise, dextran infusion, and blockade of the sympathetic nervous system. In our studies, the disproportion between cardiac index and resistance could be brought out by sodium repletion.…”

Development of left ventricular hypertrophy in young spontaneously hypertensive rats after peripheral sympathectomy.

“…Because of increased sympathetic activity, vasoconstriction occurs which results in increased peripheral vascular resistance and elevated systemic pressure. Other genetically determined factors, such as increased reactivity of the arteriolar musculature 34 or increased levels of circulating catecholamines, 35 may also play a role. Because of high perpheral vascular resistance and continued hypertension, cardiac output is further diminished and left ventricular hypertrophy increases.…”

Low Plasma Volume in Normotensive Formerly Preeclamptic Women Predisposes to Hypertension

“…The resultant reduction in circulation time of the blood to pass the heart at each rotation will increase shear forces on the vascular endothelium, setting the stage for chronic hypertension. 7,14,23 Formerly preeclampsia women who developed hypertension gained more weight between the 2 visits and had higher fasting glucose levels at the second visit. This suggests a less healthy lifestyle in formerly preeclampsia women destined to develop hypertension.…”

“…This may vary from follow-up in primary care or in more specialized cardiovascular risk management collaborations of care takers including perinatology, cardiology, and vascular internal medicine specialists. 7 Structured follow-up more likely secures regular surveillance of CVD risk factors and hypertension, in particular, with treatment according to national guidelines for CVD prevention in these women. Ideally, this should be coupled with primary prevention strategies focusing at lifestyle modifications (physical exercise, healthy diet, weight loss, and smoking cessation) to optimize maternal cardiovascular health.…”

“…Low plasma volume (PV) is considered to reflect latent hypertension, 7 and normotensive formerly preeclampsia women with low PV (LPV) are prone to develop recurrent hypertensive disease in subsequent pregnancy. 8 Whether PV status also relates to chronic hypertension after a pregnancy complicated by preeclampsia has never been studied before.…”