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Biomedical subjects

R Sutton

Publications and source records attributed to R Sutton.

At least 163 records · Page 9Linked to original sources
PubMed1979

Electrophysiological and haemodynamic basis for application of new pacemaker technology in sick sinus syndrome and atrioventricular block.

A fundamental description of pacemaker systems which are commercially available or in clinical validation is given as a background for their application in a series of 62 consecutive patients presenting over a period of 1 year for permanent cardiac pacing. The patients (23 (37%) sick sinus syndrome, 38 (61%) atrioventricular block, and 1 ventricular tachycardia) were studied electrophysiologically and haemodynamically to allow the appropriate application of a pacemaker system. In sick sinus syndrome, 8 patients had permanent atrial pacing, 14 ventricular pacing, and 1 atrioventricular sequential pacing; in atrioventricular block, 8 patients had atrial synchronous ventricular inhibited pacing and the remaining 30 had ventricular pacing. A high incidence of atrial fibrillation, 9 patients, and abnormal sinus node function, 15 patients, precluded wider use of atrial synchrony. The results show benefit in acute haemodynamic studies of using systems including atrial sensing and/or pacing, and with greater availability of atrioventricular sequential and still more advanced pacemakers with dual sensing as well as dual pacing the majority of patients may be offered this benefit.

Aged↗
PubMed1977

Noninvasive assessment of left ventricular function in chronic heart disease.

Externally recorded STI were compared with invasively determined EF in 10 normal subjects and 86 patients with various forms of chronic heart disease. From phono-, apex-, and electrocardiograms and carotid pulse tracings, recorded without rigidly controlled conditions (postabsorptive state, fixed time of day, exclusion of atrial fibrillation, and discontinuation of cardiac drugs), PEP, electromechanical interval, isovolumic contraction period, and LVET were measured and deltaPEP (deviation from predicted normal) and PEP/LVET were drived. EF was determined with biplane angiocardiographic methods. Patients were divided into groups based on pathophysiology and state of clinical compensation. The ability of STI to discriminate abnormal from normal function, as compared with EF, varied with each noninvasive parameter and with each physiologic group. On a group basis, the discriminatory ability of PEP was better than that of other noninvasive parameters studied, but did not always parallel that of EF. PEP also tended to correlate better with EF than the other noninvasive measurements. On an individual patient basis, however, the ability of even PEP to predict EF was poor. It is concluded that the usefulness of assessing left ventricle function in chronic heart disease by STI is limited.

Adolescent↗
PubMed1977

Mitral regurgitation in coronary heart disease.

Mitral reguritation is a relatively common finding in coronary heart disease. In this series of 127 patients, selected with a view to coronary or left ventricular surgery on the basis of severity of symptoms, the incidence was 39 (31%). Mitral regurgitation is significantly more common in patients with a history or electrocardiographic evidence of previous myocardial infarction. Clinically it may present as a pan- or late systolic or even a mid-systolic, ejection type murmur at the apex or at the left sternal edge; but in 39 per cent of the patients with angiographic mitral regurgitation no murmur was present. Angiographically important mitral regurgitation (grades 2-4/4) was usually associated with a systolic murmur; this finding was independent of ejection fractions. Left ventricular enlargement clinically or radiographically is likely to accompany mitral regurgitation but left atrial enlargement (electrocardiographically or on chest x-ray) is a more reliable pointer to mitral regurgitation and pulmonary venous hypertension is even more strongly suggestive of its presence. The electrocardiographic signs of papillary muscle infarction were rare in this series (15%) and were not related to angiographic mitral regurgitation. There was no difference in the incidence of mitral regurgitation in association with anterior or inferior myocardial infarction or in distribution of coronary artery disease. There is, however, a higher incidence of mitral regurgitation in more severe coronary arterial disease (P less than 0-05). The incidence of mitral regurgitation is significantly higher with reduction in left ventricular ejection fraction (P less than 0-001), with rise in the left ventricular end-diastolic pressure (P less than 0-02), and with abnormal contraction patterns, but the severity of mitral regurgitation is not significantly related to these findings.

Adult↗
PubMed1977

Long-term prognosis after acute anterior infarction with atrioventricular block.

The purpose of this study was to evaluate the need for permanent pacing in patients who have survived the effects of anterior myocardial infarction with complete heart block and have returned to sinus rhythm but who are left with impairment of intraventricular conduction. We have reviewed 52 patients with complete heart block complicating recent anterior myocardial infarction. Temporary pacing was instituted in all patients. There were 25 hospital survivors who were followed for an average of 49 months. Long-term pacing was established in 4 patients. Of the 21 patients in sinus rhythm, 14 had partial bilateral bundle-branch block with either right bundle-branch block and left anterior hemiblock or right bundle-branch block and left posterior hemiblock; at the end of the follow-up period, 10 of these 14 were alive and well. Furthermore, permanent pacing failed to prevent sudden death in 2 patients. At the present time, therefore, we conclude that long-term pacing is not justified in patients, otherwise asymptomatic, with partial bilateral bundle-branch block persisting after transient complete heart block in anterior myocardial infarction.

Adult↗
PubMed1977

[Systolic time intervals and abnormal left ventricular contraction in coronary heart disease (author's transl)].

UNLABELLED: Systolic time intervals (STI) were determined in relation to haemodynamic and angiographic data in 72 patients (pts.) with chronic cornary heart disease (CHD). Routine right-and left-heart catheterization was performed with a view to coronary surgery and/or left ventricular (LV) aneurysmectomy. LV and pulmonary pressure were measured before LV and coronary angiography. Non-invasive investigation (not simultaneously done with catheterization) included the registration of phono-and apexcardiogram and the carotid pulse. The following time intervals were averaged over a period of 5 beats: electromechanical systole (QA2), left ventricular ejection time (LVET), pre-ejection period (PEP), electro-mechanical interval (EMI), isovolumetric contraction and relaxation period (IVCT and IVRP), and the ratio PEP/LVET. LV angiography showed normal con-raction in 24 pts., localized dyskinesis in 25 pts., aneurysm in 12 and generalized dyskinesis in another 11 pts. (groups 1-4). RESULTS: in pts. with chronic CHD, PEP and IVCT are prortionally prolonged (r=0.816***). QA2 and (even more) LVET are shortened. The correlation of LVET and QA2 with heart rate remains significant (p less than 0.005). Prolongation of PEP and IVCT and shortening of LVET and AQ2 increase with the extent of LV contraction abnormality. The degree of STI abnormality correlates with an increase in pulmonary pressure. Shortening of LVET does not correlate with lengthening of PEP. PEP/LVET ratio increases significantly with LV dyskinesis: being 0.394+/-0.085 in pts. with normal contraction, 0.448+/-0.076 with normal contraction, 0.448+/-0.076 with localized dyskinesis, 0.541+/-0.167 with generalized dyskinesis and 0.565+/-0.093 with LV aneurysm. -IVRP is prolonged (to 0.131+/-0.019 sec) without significant differences between the four groups. Non-invasive findings in chronic CHD roughly classify pts. into groups with definite LV contraction abnormality. However, clear estimation of the actual pressure in the (diastolic) LV and in the pulmonary circulation from non-invasive data is of course not possible.

Adult↗
PubMed1976

Left ventricular function after aortic valve replacement.

Changes in haemodynamics and in systolic time intervals, early after valve replacement, were studied in a group of 15 patients. Though all the haemodynamic measurements were within normal limits at 44 hours after operation, there was a persistent change in systolic time intervals (shortening of left ventricular ejection time and electromechanical systole, and prolongation of pre-ejection period and increase in the ratio PEP/LVET). The effect of periods of myocardial ischaemia during cardiopulmonary bypass on myocardial function is suggested as the explanation for the changes observed.

Adult↗
PubMed1976

Hemodynamic effects of verapamil and practolol in man.

The hemodynamic effects of verapamil and practolol were investigated in a group of 10 selected patients (7 with coronary artery disease) undergoing cardiac catherization. The drugs were given i.v. in a dose of 0.1 mg/kg, alone or in combination, before and after controling the heart rate by atrial pacing. Measured hemodynamic parameters included aortic and left ventricular pressure and its first derivative, cardiac output, and echocardiographically derived left ventricular dimensions. Each drug given individually caused minor hemodynamic changes, but the combination of practolol and verapamil when the heart rate was fixed by atrial pacing invaribly caused a reduction in LV dp/dt max which was independent of preload and afterload. It is concluded that both drugs have a mildly negative inotropic effect when administered at this dose intravenously to patients with normal or mildly impaired left ventricular function. The myocardial depression was more apparent when practolol preceded verpamil. Caution must be exercised when using these drugs in combination in patients with impaired myocardial function.

Adult↗