ABSTRACT
PURPOSE: To evaluate the diagnostic value of a combined method, i.e. ergometer cycling with continuous bilateral transcranial Doppler monitoring (TCD) to detect cerebral hemodynamic abnormalities in recently diagnosed hypertensive patients. METHODS: 30 neurologically symptom-free, nontreated patients with essential hypertension and 30 age- and sex-matched controls were studied. Carotid ultrasound, resting ECG and blood parameters were investigated. Cycling ergometry was performed according to the WHO protocol. Blood pressure, heart rate, end-tidal CO2 (etCO2) and bilateral middle cerebral artery (MCA) blood flow velocity (MV) were monitored. RESULTS: At rest, MV in the MCA did not differ significantly between controls and hypertensive subjects. MV continuously increased in controls until the end of loading whereas a plateau was reached at 4 min in hypertensive subjects. During 6 min of cycling, the time course of absolute values of MV in the MCA and that of the changes in the ratio of mean velocity/end-tidal CO2 (DeltaMV/DeltaetCO2) differed significantly between hypertensive subjects and controls (p = 0.03 and p = 0.02, respectively). CONCLUSION: Ergometer cycling combined with TCD revealed altered vasoreactivity, therefore this may be a sensitive method for the detection of early hemodynamic impairment in nontreated hypertensive subjects.
Subject(s)
Exercise , Hypertension/diagnostic imaging , Hypertension/physiopathology , Ultrasonography, Doppler, Transcranial , Adult , Blood Flow Velocity , Carbon Dioxide , Cerebral Arteries/physiopathology , Cerebrovascular Circulation , Exercise Test , Female , Heart Rate , Hemodynamics , Humans , Hypertension/diagnosis , Male , Middle Aged , Reference Values , Respiration , Sensitivity and Specificity , Tidal VolumeABSTRACT
Role of beta-blockers in the treatment of chronic heart failure has been changed over a 25-year period from contraindication to an established indication. To date, controlled clinical trials performed in more than 13,000 patients with chronic heart failure have consistently shown that the long term administration of beta-blockers is associated with significant improvement in left ventricular function, clinical symptoms, and survival. This favorable clinical trial experiences support a recommendation that beta-blockers should be used in all heart failure patients with stable symptoms due to left ventricular systolic dysfunction unless contraindicated. Ongoing beta-blocker studies address further new topics, such as treatment of elderly patients and direct comparison of different agents. Although, the use of beta-blockers for heart failure tends to increase, implementation of the experiences from the clinical trials to the everyday practice still remains a challenge.
Subject(s)
Adrenergic beta-Antagonists/therapeutic use , Heart Failure/drug therapy , Adrenergic beta-Antagonists/administration & dosage , Adrenergic beta-Antagonists/adverse effects , Adrenergic beta-Antagonists/economics , Bisoprolol/therapeutic use , Carbazoles/therapeutic use , Carvedilol , Chronic Disease , Controlled Clinical Trials as Topic , Disease Progression , Drug Administration Schedule , Heart Failure/economics , Heart Failure/mortality , Heart Failure/physiopathology , Humans , Metoprolol/therapeutic use , Myocardial Contraction/drug effects , Patient Selection , Propanolamines/therapeutic use , Survival Rate , Ventricular Dysfunction, Left/drug therapy , Ventricular Function, Left/drug effectsABSTRACT
PURPOSE: We studied the usefulness of transcranial Doppler sonography for assessing changes in vasoreactivity in patients with hypertension and the hemodynamic consequences of hypertension. METHODS: The study group comprised 25 patients with chronic severe hypertension and 25 age- and sex-matched healthy subjects. Cerebrovascular reserve capacity was assessed by transcranial Doppler recording of the blood flow velocity in both middle cerebral arteries before and 5, 10, 15, and 20 minutes after intravenous injection of 1 g of acetazolamide (Diamox). Blood pressure, blood gases, and other blood parameters were also measured before and after acetazolamide injection. The sizes of the left atrium, left ventricle, and aortic root were measured by echocardiography and correlated with the vasoreactivity after acetazolamide injection. RESULTS: After acetazolamide injection, no significant changes in blood pressure were observed in either group. The mean blood flow velocity in the middle cerebral arteries of hypertensive patients (60.8 +/- 2.6 cm/sec) was not significantly different from that of controls (58.8 +/- 1.9 cm/sec) before acetazolamide injection. Ten minutes after acetazolamide injection, the percentage change in blood flow velocity was significantly lower in the hypertensive group (36.2 +/- 4.5%) than in the controls (52.6 +/- 3.7%). A significant negative correlation (p < 0.05) between decreased vasoreactivity and increased size of the left atrium and aortic root was observed. CONCLUSIONS: Vasoreactivity decreases in hypertensive patients without neurologic deficits or computed tomography abnormalities. Enlargement of the left atrium correlates well with the severity of the impairment in vasoreactivity. Transcranial Doppler sonography can be a sensitive tool in the investigation of vascular impairment caused by hypertension and in the follow-up of hypertensive patients.