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Biomedical subjects

C A Morley

Publications and source records attributed to C A Morley.

13 recordsLinked to original sources
PubMed1991

Torsades de pointes ventricular tachycardia and terodiline.

We report five patients (four women, one man; mean age 74 years, range 55-87) taking terodiline who had torsades de pointes ventricular tachycardia associated with prolongation of the QT interval. The QT interval was normal before the introduction of terodiline in three patients and returned to normal after terodiline withdrawal in four. Atrioventricular conduction disturbance or bradycardia were evident in all patients. Terodiline should be prescribed with caution to elderly patients.

Aged↗
PubMed1989

Cardiovascular reflex responses in patients with unexplained syncope.

1. This study was undertaken to determine whether, in a group of patients complaining of recurrent syncopal attacks but with no apparent cause, there was evidence of abnormal cardiovascular reflex control. 2. The steady-state responses of blood pressure, heart rate and cardiac output to head-up tilting were determined in 67 patients using entirely 'non-invasive' methods. In some patients we also studied the immediate response of pulse interval to carotid baroreceptor stimulation by neck suction. 3. Two of the patients developed vasovagal attacks during the 20 min test period of head-up tilting. Eighteen others showed postural hypotension, defined as a fall in blood pressure to outside the limits of two SDS from the mean values of age-related control subjects. 4. Patients who showed postural hypotension had a mean fall in cardiac output significantly larger than that in age-related control subjects. Responses in the nonhypotensive patients did not differ significantly from controls. 5. Stimulation of carotid baroreceptors resulted in significantly smaller responses of pulse interval in the patients defined as having postural hypotension compared with the non-hypotensive patients and with the age-related control subjects. 6. In some of the patients who did not show postural hypotension during the standard test, the duration of tilt was prolonged for up to 1 h. Five out of 26 patients developed vasovagal attacks. All the vasovagal patients showed an initial tachycardia and the response of pulse interval to neck suction was significantly larger than in the controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1986

Oral xamoterol in patients with sinoatrial disease.

Twelve patients with sinoatrial disease were assessed while on oral xamoterol (200 mg twice daily) and placebo by a double blind randomised, crossover trial that lasted four weeks. Nine of the patients had been referred for permanent pacing. Xamoterol produced favourable changes in the number of pauses and the mean heart rate in six patients. Another patient deteriorated on xamoterol. Six patients were started on long term xamoterol. Xamoterol produces short term electrocardiographic improvement in some, but not all, patients with symptomatic sinoatrial disease.

Adrenergic beta-Agonists↗
PubMed1984

A scientific evaluation of the carotid sinus syndrome.

Assessment of the carotid sinus baroreceptor control of pulse interval has been made, by means of neck suction, in 10 patients with a clinical diagnosis of the carotid sinus syndrome (CSS). Results have been compared with 16 age-matched control patients. The mean gain in the CSS patients was 11.64 +/- 2.51 ms . mmHg-1, whereas the mean gain in the control patients was 3.61 +/- 0.68 ms . mmHg-1 (p less than 0.02). There was a significant correlation (p less than 0.01) between the degree of cardiac slowing, following carotid sinus massage, and the gain, following neck suction, in the CSS patients. Abnormality of the carotid sinus baroreceptor control of heart rate is confirmed in these patients and neck suction is an useful method of investigation of this syndrome.

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PubMed1984

Baroreflex sensitivity measured by the phenylephrine pressor test in patients with carotid sinus and sick sinus syndromes.

Baroreflex sensitivity was measured by the heart rate response to the transient rise in blood pressure induced by phenylephrine, in 11 patients with carotid sinus syndrome, 6 patients with sick sinus syndrome and nine age and blood pressure matched controls. Patients with carotid sinus syndrome were divided into those with a hypersensitive carotid sinus reflex manifest as sinus arrest (n = 9) and those with a reflex manifest as atrioventricular block (n = 2). The mean gain of the baroreflex sensitivity was significantly increased (p less than 0.001) in patients with carotid syndrome manifest as sinus arrest (12.7 +/- 5.1 ms . mmg-1) compared to that in patients with sick sinus syndrome (3.8 +/- 2.6 ms . mmHg-1) and controls (4.2 +/- 2.1 ms . mmHg-1). Patients with carotid sinus syndrome manifest as atrioventricular block did not have increased baroreflex sensitivity measured by their sinus node response (2.1 +/- 0.5 ms . mmHg-1). There was significant correlation (p less than 0.001) between the corrected carotid sinus inhibitory response to carotid sinus massage and the measurement of baroreflex sensitivity in the carotid sinus syndrome patients. Patients with carotid sinus syndrome manifest as reflex sinus arrest have an increased gain in baroreflex sensitivity for their age, which is not seen in patients with symptomatic sinoatrial disease. This study provides further evidence of a different mechanism of bradycardiac symptoms in patients with carotid sinus and sick sinus syndromes.

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PubMed1983

A comparison of once daily atenolol and metoprolol SA in mild to moderate hypertension.

Atenolol 100 mg once daily and metoprolol SA 200 mg once daily were compared in 20 patients with mild to moderate hypertension, in a randomised, double-blind cross-over trial. Blood pressure and heart rate were compared at rest and during maximal exercise on a bicycle ergometer at 2 and 24 h post-dose. Blood pressure control was similar with both drugs, except at 2 h when systolic blood pressure was significantly lower with atenolol. Blood pressure and heart rate were less well controlled at 24 h than at 2 h with both drugs, but the majority of patients were still considered adequately controlled at 24 h. Atenolol and metoprolol SA can be considered equally effective in the treatment of mild to moderate hypertension and can be recommended as a once daily regime.

Adult↗
PubMed1983

The role of rate hysteresis pacing in the hypersensitive carotid sinus syndrome.

The ability of rate hysteresis programming with the escape interval longer than the automatic interval to reduce the hypotensive response to carotid sinus massage at the onset of ventricular pacing was studied in six patients paced for carotid sinus syndrome. Rate hysteresis significantly reduced this hypotensive response and abolished spontaneous symptoms in two patients and symptoms reproduced by carotid sinus massage in four patients.

Adult↗
PubMed1983

Randomised controlled trial of physiological and ventricular pacing.

Thirteen patients have completed a randomised double blind cross over study to compare the effects of chronic ventricular and atrial synchronous pacing on exercise capacity and symptoms. Maximal symptom limited exercise was significantly increased after one month of atrial synchronous pacing compared with ventricular pacing. Symptomatic assessment (by diary card and monthly symptom scores) of "shortness of breath", "palpitation", and "general well-being" was significantly improved during the physiological pacing mode. Atrial synchronous pacing has been shown to be superior to ventricular pacing.

Adult↗
PubMed1982

Carotid sinus syncope treated by pacing. Analysis of persistent symptoms and role of atrioventricular sequential pacing.

Seventy patients have been paced for carotid sinus syndrome over four years. Twelve patients had persistent symptoms despite adequate ventricular pacing. Patients with persistent symptoms were found to have a significant vasodepressor response, a significant hypotensive response to ventricular pacing (pacemaker effect), and a severe hypotensive response to carotid sinus massage with introduction of ventricular pacing, which reproduced symptoms in all patients. A group of 14 asymptomatic paced carotid sinus patients was found to have a significantly lower vasodepressor response, pacemaker effect, and combined vasodepressor response plus pacemaker effect than the group with persistent symptoms. Atrioventricular sequential pacing was shown to eliminate the hypotensive effect of ventricular pacing and is considered to be the treatment of choice for patients with carotid sinus syndrome who have both cardioinhibitory and significant vasodepressor responses.

Aged↗