SUMMARY Utilizing a Doppler ultrasonic flownteter catheter, right carotid artery blood velocity was measured during 91 coughing episodes in 16 patients. Such coughing reduced carotid blood velocity by 40 ± 22% (control = 34 ± 8 cm per second, cough = 20 ± 9 cm per second, p < 0.001). There was an insignificant low degree of correlation between the level of simultaneously recorded mean right pressure and the percent decline of peak carotid blood velocity, suggesting that impaired venous return was not the only factor responsible for the observed changes. It is concluded that (1) coughing diminishes phasic carotid blood velocity and (2) reduced cerebral perfusion may play a role in the pathogenesis of cough syncope.COUGH SYNCOPE is a well-recognized clinical entity which has intrigued clinicians for approximately 100 years. Previous studies have documented the influence of tussive episodes on intrathoracic, cardiovascular or cerebrospinal fluid pressures 1 " 4 and changes in fluoroscopic images of the right atrium, vena cava and pulmonary vein. 5 In addition, EEG monitoring has been performed during the act of coughing. 3 We report here the influence of cough on phasic carotid arterial blood velocity. MethodsSixteen patients comprised the study group; there were 12 men and four women whose ages ranged from 23 to 58 with a mean of 44 years. Eight subjects had normal cardiovascular function and seven had coronary artery disease. One patient had mitral stenosis. No subject had symptoms suggestive of cough syncope. All diagnoses were established on the basis of right and left heart catheterization, indicator dilution curves and selective coronary cineangiography. Normal subjects were studied because of the presence of chest pain or systolic murmurs originally thought to represent heart disease. Patients were studied in a supine position in the postabsorptive state.Phasic instantaneous right carotid artery blood velocity was measured with a Doppler ultrasonic flowmeter catheter as previously described.6 ' 7 Under local anesthesia (1% lidocaine), the crystal-tipped catheter was introduced into a brachial arterial incision and advanced to the origin of the right carotid artery. In addition, a standard fluid-filled catheter connected to a Statham P23Db strain gauge was advanced from a medial antecubital vein to the right heart for the purpose of obtaining right atrial pressures. All subjects were instructed to cough in varying degrees while phasic carotid artery blood velocity, mean right atrial pressure and lead II of the ECG were recorded. Catheter tip position and stability were monitored by means of constant fluoroscopic image intensification. In six subjects, phasic aortic blood velocity also was recorded during cough.The Doppler catheter utilized in this study measured the velocity of blood cells flowing past its tip and reflected volumetric flow only as a function of stable arterial lumen diameter. ResultsNinety-one coughing episodes in the study group reduced peak carotid artery blood velocity by an average of 40 ...

The efficacy and safety of isradipine (PN 200-110), a new dihydropyridine calcium antagonist, was evaluated in 87 hypertensive patients in a placebo-controlled, double-blind, randomized multicenter trial. After a 3-week single-blind washout phase, isradipine (or matching placebo) was administered for 4 weeks, beginning at 2.5 mg b.i.d. with increments of 2.5 mg b.i.d. at weekly intervals if supine diastolic blood pressure remained greater than or equal to 90 mm Hg. At the end of 1 week average supine blood pressure in the isradipine group (n = 45) fell from a baseline of 156 +/- 13/104 +/- 4 mm Hg to 146 +/- 14/97 +/- 7 mm Hg. By week 4 blood pressure was reduced by 19/14 mm Hg compared with 4/5 mm Hg in the placebo group (P less than 0.001 between groups). Supine and standing pulse rates were slightly increased initially with isradipine therapy but returned to baseline with increasing isradipine doses. Blood pressure responses at week 4 were good or excellent (supine diastolic less than or equal to 90 mm Hg or greater than or equal to 10 mm Hg decrease from baseline) in 87% of isradipine-treated patients and in 26% of placebo-treated patients. Headache, edema, abdominal discomfort, and constipation occurred slightly more frequently in isradipine-treated patients than in placebo-treated control subjects. The results indicate that isradipine, administered as monotherapy in doses of 2.5 to 10 mg b.i.d., is safe and effective in patients with mild to moderate essential hypertension.