N. De Luca

Failure of atrial natriuretic factor to increase with saline load in patients with dilated cardiomyopathy and mild heart failure.

To investigate whether the response of atrial natriuretic factor (ANF) to volume expansion is impaired in the early stages of dilated cardiomyopathy, the effects of saline load (SL; 0.25 ml/kg.min for 120 min) were assessed in 12 patients with dilated cardiomyopathy and asymptomatic to mildly symptomatic heart failure (HF) and in nine normal subjects (N). SL increased plasma ANF levels in N (from 14.3 +/- 2 to 19.5 +/- 3 and 26 +/- 4 pg/ml, at 60 and 120 min, respectively, P less than 0.001), but not in HF (from 42.9 +/- 9 to 45.9 +/- 9 and 43.9 +/- 8 pg/ml). Left ventricular end-diastolic volume (LVEDV) and stroke volume were increased (P less than 0.001) by SL in N but not in HF. Urinary sodium excretion (UNaV) increased in N more than in HF during SL, whereas forearm vascular resistance (FVR) did not change in N and increased in HF (P less than 0.001). In five HF patients SL was performed during ANF infusion (50 ng/kg, 5 ng/kg.min) that increased ANF levels from 37.1 +/- 10 to 146 +/- 22 pg/ml. In this group, SL raised both LVEDV (P less than 0.01) and ANF (P less than 0.05), whereas FVR did not rise. In addition, the UNaV increase and renin and aldosterone suppressions by SL were more marked than those observed in HF under control conditions. Thus, in patients with dilated cardiomyopathy and mild cardiac dysfunction, plasma ANF levels are not increased by volume expansion as observed in N. The lack of ANF response is related to the impaired cardiac adaptations. The absence of an adequate increase of ANF levels may contribute to the abnormal responses of HF patients to saline load.

Participation of endogenous catecholamines in the regulation of left ventricular mass in progeny of hypertensive parents.

To investigate whether adrenergic activity is a determinant of left ventricular hypertrophy in human hypertension, in each of 10 normotensive subjects with two hypertensive parents we have examined the relationship between changes in echocardiographic parameters of left ventricular anatomy and those in circulating catecholamine levels induced by three, 3 week periods of different sodium and potassium intakes. A high sodium-normal potassium regimen induced a significant reduction in upright plasma norepinephrine (from 599 +/- 89 to 379 +/- 45 pg/ml, p less than .01) and in posterior wall (PWT) and interventricular septal (IVST) thickness, as well as in the left ventricular mass index (LVMi). Changes in upright plasma norepinephrine concentrations correlated with those in IVST (r = .822, p less than .01) and in LVMi (r = .833, p less than .01). A low sodium-normal potassium diet resulted in increases in supine and upright plasma norepinephrine levels (from 356 +/- 44 to 488 +/- 89 pg/ml, p less than .001; and from 565 +/- 42 to 744 +/- 33 pg/ml, p less than .01) as well as increases in IVST and LVMi (from 97 +/- 7 to 107 +/- 7 g/m2, p less than .001). The changes in norepinephrine levels in supine and upright subjects correlated with changes in IVST (r = .836, p less than .01 and r = .796, p less than .01) and in LVMi (r = .931, p less than .001 and r = .947, p less than .001). No significant change in plasma catecholamine concentrations or in PWT, IVST, or LVMi was detected after a low sodium-high potassium regimen.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular geometry in obesity: Is it what we expect?

Obesity is characterized by the disproportionate growth of the components of body size, including adipose tissue and lean body mass. Left ventricular (LV) hypertrophy often develops, due to the coexistence of hemodynamic (cardiac workload) and non-hemodynamic components (including body composition and activity of visceral fat). While the hypertrophy of cardiomyocytes is produced by the hemodynamic load, through sarcomeric replication, there is a parallel growth of non-muscular myocardial components, including interstitial fat infiltration and accumulation of triglycerides in the contractile elements, which are thought to influence LV geometric pattern. Thus, pure intervention on hemodynamic load is unlikely to result in effective reduction of LV hypertrophy in obese. We review pathophysiology and prevalence of LV hypertrophy in obesity, with specific attention to LV geometric abnormalities and relations with body size.

Converting enzyme inhibition prevents the effects of atrial natriuretic factor on baroreflex responses in humans.

The aim of this study was to assess the influence of atrial natriuretic factor (ANF) on arterial baroreflex chronotropic responses and to investigate whether this effect of ANF is affected by angiotensin converting enzyme inhibition (CEI). For this purpose, in 13 normal volunteers, the reflex chronotropic responses to arterial baroreceptor stimulation (phenylephrine, 25-100 micrograms i.v.) or deactivation (nitroglycerin, 25-100 micrograms i.v.) were evaluated in control conditions and during the steady-state phase of a sustained infusion of ANF (50 ng/kg/min) or placebo, before and during prolonged treatment with the converting enzyme inhibitor enalapril (20 mg p.o. for 5 days). ANF infusion, which raised plasma ANF levels from 48 +/- 19 to 1,765 +/- 203 pg/ml, was associated with a slight decrease in systemic blood pressure and no change in heart rate. In addition, it caused a significant increase of the regression slope obtained with phenylephrine (from 11.3 +/- 2 to 18.5 +/- 2 msec/mm Hg) and a significant reduction of slope of the nitroglycerin-produced regression line (from 9.3 +/- 1 to 5.6 +/- 0.6 msec/mm Hg). After sustained CEI, which raised plasma renin activity from 1.4 +/- 0.4 to 19.9 +/- 5 ng/ml/hr, ANF infusion induced an increase in plasma ANF levels and a reduction in blood pressure comparable to those observed in control conditions. During CEI, however, ANF infusion had no significant effect on the chronotropic baroreflex responses produced by phenylephrine or nitroglycerin. Chronotropic and pressor responses to cold exposure were unchanged after CEI and during ANF.(ABSTRACT TRUNCATED AT 250 WORDS)

Blunted sympathetic response to cardiopulmonary receptor unloading in hypertensive patients with left ventricular hypertrophy. A possible compensatory role of atrial natriuretic factor.

To investigate whether or not hypertension with left ventricular hypertrophy (LVH) modifies the mechanisms underlying the vascular adjustments to orthostatic stress, we evaluated the hemodynamic and hormonal effects of graded lower-body negative pressure (LBNP) (-10 and -40 mm Hg) before and after sympathetic blockade in 10 hypertensive patients with LVH and in five age- and sex-matched normotensive subjects. In control conditions, LBNP elicited comparable vasoconstrictor responses in the forearm in the two groups. In normotensive subjects, graded increases in plasma norepinephrine and plasma renin activity (PRA) and reductions in plasma immunoreactive atrial natriuretic factor (irANF) were recorded. In hypertensive patients, a significant increase in plasma norepinephrine and plasma renin activity was obtained only with the higher level of LBNP, whereas irANF plasma levels decreased progressively. In both groups, sympathetic blockade abolished the increase in plasma renin activity and did not modify the changes in plasma irANF induced by both levels of LBNP in control conditions. The vascular response to -10 mm Hg LBNP remained unchanged after sympathetic blockade in both groups. However, after sympathetic blockade, the vasoconstrictor response to -40 mm Hg LBNP in normal subjects was no longer different from that elicited by -10 mm Hg LBNP, whereas in hypertensive patients the vasoconstrictor response was still significantly higher than that induced by -10 mm Hg LBNP. Direct correlations between the percent changes in forearm vascular resistance and those in plasma norepinephrine and plasma renin activity were found only in normal subjects in control conditions but were not observed after sympathetic blockade. On the contrary, the inverse correlation between changes in irANF plasma levels and in forearm vascular resistance found in control conditions in both groups was still observed after sympathetic blockade. In a separate group of hypertensive patients with left ventricular hypertrophy, exogenous infusion of ANF induced an increase in venous irANF plasma levels of the same magnitude of the decrease evoked by LBNP and significantly reduced forearm vascular resistance. These data show that in hypertensive patients with left ventricular hypertrophy, sympathetic activation does not contribute to the vascular response to cardiopulmonary receptor unloading (-10 mm Hg LBNP). They also suggest that in these patients inhibition of ANF secretion may play a role in the response to a low level of LBNP so that the peripheral vasoconstriction induced by cardiopulmonary receptor unloading is comparable to that observed in normal subjects despite the lack of appropriate sympathetic reflex vasoconstriction.

Indapamide reduces hypertensive left ventricular hypertrophy : an international multicenter study

The effect of 6 months of treatment with indapamide (IND, 2.5 mg/day) on regression of left ventricular hypertrophy (LVH), an independent predictor of poor prognosis in hypertension, was compared by echocardiography to that of nifedipine (NFD, 40 mg/day), enalapril (ENL, 20 mg/day), atenolol (ATL, 100 mg/day), and hydrochlorothiazide (HCTZ, 25 mg/day) in four parallel double-blind studies in 151 hypertensive patients with a diastolic blood pressure between 95 and 120 mm Hg and a raised left ventricular mass index (LVMI) (mg/m2) (Devereux). Patients were randomized to IND or comparator following a 2-week washout (1 month in the IND vs. ATL study). Respective baseline and 6-month LVM1 values (mg/m2) were: IND (n = 20) vs. HCTZ (n = 20): 151.4 ± 6.3 and 125.70 ± 4.6 (p > 0.001) vs. 141.3 ± 6.6 and 135.6 ± 8.3 (p = N.S.); IND (n = 22) vs NFD (n = 19): 144.1 ± 5.3 and 125.1 ± 4.3 (p > 0.001) vs. 170.4 ± 6.6 and 148.2 ± 6.2 (p > 0.001); IND (n = 9) vs. ENL (n = 9): 155.1 ± 6.3 and 143.4 ± 5.2 (p > 0.001) vs. 142.0 ± 6.7 and 130.0 ± 5.9 (p > 0.001); IND (n = 17) vs. ATL (n = 12): 146.2 ± 5.1 and 130.8 ± 6.5 (p > 0.001) vs. 156.7 ± 8.4 and 142.9 ± 10.3 (p > 0.01). All drugs significantly reduced diastolic blood pressure, and all except HCTZ induced a significant and similar reduction in left ventricular mass.

Atrial natriuretic factor potentiates forearm reflex vasoconstriction induced by cardiopulmonary receptor deactivation in man.

Previous evidence suggests that atrial natriuretic factor (ANF) interferes with the autonomic control of circulation. In the present study we investigated whether ANF modulates forearm vasoconstriction reflexly induced by cardiopulmonary receptor unloading in man. For this purpose, the hemodynamic response to -20 mm Hg lower body negative pressure (LBNP) was assessed under control conditions and during the constant infusion of alpha-human ANF (0.5 micrograms/kg bolus followed by 0.05 micrograms/kg/min) in seven normal subjects. ANF infusion resulted in a slight reduction in blood pressure and right atrial pressure, did not modify heart rate or forearm vascular resistance, but significantly potentiated the reflex increase in forearm vascular resistance during LBNP (+25 +/- 9% under control conditions vs +40 +/- 12% during ANF, p less than .05). In an attempt to clarify the mechanisms underlying the enhanced reflex vasoconstriction during infusion of ANF, in five additional subjects we demonstrated that there was a comparable vascular reflex response to LBNP under control conditions and during nitroglycerin infusion at a dose that induced a reduction in atrial pressure comparable to that observed during ANF. Finally, in seven additional subjects we found that ANF infusion did not alter the reflex hemodynamic responses elicited by carotid baroreceptor unloading induced by a +60 mm Hg increase in external neck pressure. We conclude that during the infusion of a pharmacologic dose of ANF the reflex forearm vasoconstriction in response to selective cardiopulmonary receptor unloading is potentiated. This effect does not seem to be related to the hemodynamic actions of the peptide or to interference with the sympathetic control of peripheral circulation.

Impaired responsiveness of the ventricular sensory receptor in hypertensive patients with left ventricular hypertrophy.

We studied the control of forearm vascular resistance (FVR) by cardiopulmonary receptors in seven patients with hypertension and left ventricular hypertrophy (LVH) and in seven normotensive control subjects. Increasing levels of lower body negative pressure (LBNP) (-10 and -40 mm Hg) induced a progressive decrease in central venous pressure (CVP) and an increase in FVR. The changes in these two variables were correlated both in normal subjects and patients with hypertension (slope for normal subjects = -29.9, for patients with hypertension = -40.3, NS). After propranolol, there was a significant reduction in the increase in FVR induced by -40 mm Hg LBNP in normal subjects (+107 +/- 5 vs +129 +/- 15 mm Hg/ml/sec, p less than .05) but not in patients with hypertension. Consequently, the slope of the delta CVP/delta FVR regression was reduced in normal subjects (-20.6, p less than .01) but not in patients with hypertension. In another seven normal subjects and seven patients with hypertension and LVH we assessed the effects of -10 and -40 mm Hg LBNP on left ventricular filling pressure (LVFP). LBNP induced similar changes in CVP, LVFP, and total peripheral resistance both in normal subjects and in patients with hypertension. Propranolol failed to modify the effects of LBNP on CVP and LVFP in both groups and reduced the response of total peripheral resistance to -40 mm Hg LBNP only in normal subjects. Propranolol did not reduce the response of FVR to the cold pressor test and sustained handgrip or the arterial baroreflex response to the injection of phenylephrine and increased neck tissue pressure. Thus, hypertension-induced LVH seems to be associated with a selective impairment of the left ventricular sensory receptors.

Echocardiography in clinical practice: the burden of arterial hypertension. A multicenter Italian survey

Little information is available about the burden of hypertension on echo-lab activity in current practice. The aim of the present nation-wide survey in outpatient echo-labs was to investigate the prevalence rates of (1) echo examinations performed for the evaluation of hypertensive cardiac damage; (2) reports providing quantitative data on left ventricular (LV) structure and geometry; (3) LV hypertrophy (LVH) in hypertensives referred to echo labs. The study was carried out in 14 outpatient echo-labs across Italy. Prescriptions written by general practitioners were used to identify the indications for the examinations. Estimates of LVH were derived from original echo reports or were calculated from LV primary measures, when available, with Devereuxs formula in a post-analysis. Echo examination was performed in 2449 subjects (1245 men and 1204 women); hypertension was the indication for echo in 745 (30.4%) cases. In this subgroup, LV mass (LVM), LVM indexed to body surface area, LVM indexed to height2.7 and relative wall thickness ratio were reported in 58, 59, 54 and 52%, respectively. LVH was present in 53% of untreated hypertensives and, among treated patients, in 45 and 65% of those with and without blood pressure control, respectively. Our findings show that (1) hypertension accounts for approximately one-third of echo examinations performed in clinical practice; (2) a large fraction of echo reports do not provide quantitative data on LVM and LV geometry, (3) LVH is highly prevalent in hypertensives referred to echo labs for assessment of cardiac damage.

Primary prevention with statins and incident diabetes in hypertensive patients at high cardiovascular risk

BACKGROUND AND AIMS The ESC/ESH guidelines for arterial hypertension recommend using statins for patients with high cardiovascular (CV) risk for both secondary and primary prevention. A recent meta-analysis, combining previous studies on statins, concluded that they are associated with a 9% increased risk of incident type 2 diabetes mellitus (DM). There is no information on whether statins increase incidence of DM in primary prevention. METHOD AND RESULTS We evaluated risk of incident DM in relation to statin prescription in 4750 hypertensive, non-diabetic outpatients (age 58.57 ± 9.0 yrs, 42.3% women), from the CampaniaSalute Network, without chronic kidney disease more than grade 3, free of prevalent CV disease and with at least 12 months of follow-up. DM was defined according to ADA criteria. At the end of follow-up period (55.78 ± 42.5 months), 676 patients (14%) were on statins. These patients were older (62.54 ± 7.3 vs 57.91 ± 9.1 yrs; p < 0.0001), more often female (49% vs 41.2%; p = 0.0001), with higher initial total cholesterol (217.93 ± 44.3 vs 205.29 ± 36.6 mg/dl), non-HDL cholesterol (167.16 ± 44.5 vs 155.18 ± 36.7 mg/dl) and triglycerides (150.69 ± 85.2 vs 130.98 ± 72.0 mg/dl; all p < 0.0001) than patients no taking statins, without other differences in clinical and laboratory characteristics. At the end of follow-up, prevalence of DM was 18.1% among patients on statins and 7.2% among those without lipid-lowering therapy (p < 0.0001). However, incident DM was 10.2% in patients on statins and 8.7% in those free of statin therapy (NS). CONCLUSION In real-life outpatient environment, statin prescription for primary prevention is not associated with increased risk of incident DM.