Baroreflex Sensitivity as a Cardiac and Arrhythmia Mortality Risk Stratifier

The last two decades have provided clear evidence for the tight and casual relation existing between arrhythmic mortality and the autonomic nervous system, particularly with imbalances characterized by decreases in vagal and/or increases in sympathetic activity. A series of compelling experimental results has represented the driving force for the clinical evaluation of the potential prognostic value of baroreflex sensitivity (BBS), a measure that can provide information on the capability to augment vagal activity. This article reviews the methodology more commonly used to quantify the clinical evaluation of this parameter, and then focuses on the key clinical studies highlighting those performed in postmyocardial infarction patients. Among them the most informative is ATRAMI, a multicenter prospective study involving almost 1300 patients. The main conclusion is that both heart rate variability and BRS are strong and independent risk factors for post-infarction mortality, thus demonstrating the clinical usefulness of autonomic markers.     

Acute and chronic effects of nicardipine on rest and exercise haemodynamics in post-myocardial infarction patients with latent cardiac failure

The acute and chronic haemodynamic effects of nicardipine werestudied, at rest and during exercise, in 10 post-myocardialinfarction patients with latent cardiac failure and no signsof residual my ocardial ischaemia. Intravenous administrationof nicardipine (5 mg over 10 min) was associated with a significantincrease in cardiac index and significant reductions in meanpulmonary artery pressure, mean pulmonary wedge pressure, totalpulmonary resistance and systemic vascular resistance underconditions of rest and peak exercise. After 3 weeks of oraltreatment (20 mg three times daily) cardiac index did not change,but the improvements in mean pulmonary artery pressure, meanpulmonary wedge pressure and total pulmonary resistance weresustained at rest and during exercise, at the same workloadattained prior to medication. Chronic treatment with nicardi–pinesignificantly increased exercise tolerance, while mean pulmonaryartery pressure, mean pulmonary wedge pressure and total pulmonaryresistance were maintained below the control values. It is concludedthat nicardipine improves both rest and exercise cardiac performancein post–myocardial infarction patients with latent cardiacfailure, thus avoiding the risk of pulmonary congestion.     

Baroreflex Sensitivity

Baroreflex Sensitivity. Baroreflex sensitivity (BRS) has rapidly gained considerable attention as a result of multiple experimental and clinical reports on its prognostic value after a myocardial infarction. This article reviews the several aspects related to the use and significance of BRS. The methodology of baroreflex testing in man is described. The complex pathophysiology underlying BRS and the hypotheses proposed to explain its frequent reduction after a myocardial infarction are discussed. The section on experimental data also provides a rationale to understand the relation between increased vagal activity and reduced propensity for ventricular fibrillation. The article focuses largely on the clinical studies relating BRS and risk of cardiac mortality and also discusses the several attempts to modify this marker of reflex vagal activation.     

Pleomorphic lipoma of the dermis

A case of pleomorphic lipoma is described. The neoplastic tissue developed exclusively within the dermis and characteristically involved the fibrous root sheaths of hair follicles, where several layers of lamellar collagen encircled the follicles and entrapped atypical spindle and multinucleated cells. A possible origin of this tumour in the adventitial dermis is postulated.     

Variable threshold of exertional ischaemia in patients with positive exercise test at low workload

In order to determine individual variability of ischaemic thresholdon different days, 18 patients with exertional ischaemia atlow workload were studied. All patients performed two exercise tests during different daysin the morning and three on the same day at 9 am, 2 pm and 5pm. The test performed in the morning on different days resultedin a significant difference in the mean values of rate pressureproduct at the ischaemic threshold as a consequence of individualvariability observed in 10 patients. In 8 of these patientsthe differences were greater than 4000 mmHg beats min^–1.Two patients showed respectively, 1 and 5 negative exercisetests despite the greater values of rate pressure product reached.Only 3 patients showed circadian variation of the ischaemicthreshold; in these 3 patients variations of rate pressure productat the ischaemic threshold were also observed between differentdays. These data indicate that in patients with exertional ischaemiaat low workload the rate pressure product at the ischaemic thresholdshows considerable variability between tests performed on differentdays.