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Biomedical subjects

L E Grigg

Publications and source records attributed to L E Grigg.

31 records · Page 2Linked to original sources
PubMed1995

Insertion of the pulmonary autograft as an inclusion cylinder--modifications to existing techniques.

Ten pulmonary autograft procedures have been performed (mean age 27, range 19-40 years) all using root replacement techniques. In six operations the inclusion cylinder method was performed, as first preference. Because of root asymmetry associated with the congenitally deformed aortic valves, modifications to the standard procedure were necessary in four out of the six patients. In one, the aortic annular dimension was reduced by a Dacron collar inserted around the proximal autograft suture line. In another the sinotubular dimension was trimmed by wedge excision of part of the non-coronary sinus and ascending aortic tailoring. In the remaining two patients, pericardial patch enlargement of the lower ascending aorta was employed to increase the sino-tubular diameter. In the remaining four patients, full free-standing root replacement was performed as second best option because of inexperience (early in the series), or coronary artery anomalies, and more severe degrees of root symmetry (later in the series). All 10 patients are alive and have been recently reviewed with Doppler echocardiography (mean follow up 14 months, range 4-29 months). Mean aortic gradient was 5 mmHg, aortic regurgitation minimal (trivial seven, mild three), good pulmonary homograft function and normalization of left ventricular function were documented. In summary, we aim to perform the inclusion cylinder technique in most cases, and it is presumed that this may result in better long term aortic valve competence.

Adult↗
PubMed1992

Transesophageal Doppler echocardiography in obstructive hypertrophic cardiomyopathy: clarification of pathophysiology and importance in intraoperative decision making.

To better understand the pathophysiology of obstruction of left ventricular outflow in hypertrophic cardiomyopathy and to determine the value of intraoperative transesophageal Doppler echocardiography in decision making, 32 consecutive patients undergoing ventriculomyectomy were assessed. The mean preoperative left ventricular outflow gradient was 83 +/- 39 mm Hg and the mean basal septal width was 24 +/- 6 mm. Compared with transesophageal findings in 10 normal control subjects, the mitral leaflets were longer and the coaptation point was abnormal in the patients with obstructive hypertrophic cardiomyopathy (anterior and posterior leaflet lengths in the patients were 31 +/- 4 vs. 22 +/- 3 mm in the control group [p less than 0.00001] and 20 +/- 2 vs. 15 +/- 3 mm in the control group [p less than 0.00001]). The coaptation point in the patient group was in the body of the leaflets at a mean of 9 +/- 2 mm from the anterior leaflet tip, whereas it was at or within 3 mm of the leaflet tip in the normal group. During early systole, the distal third to half of the anterior mitral leaflet angled sharply anteriorly and superiorly (systolic anterior motion), resulting in leaflet-septal contact and incomplete mitral leaflet coaptation in mid-systole. This caused the formation of a funnel, composed of the distal parts of both leaflets, that allowed a jet of posteriorly directed mitral regurgitation to occur in mid- and late systole. The sequence of events in systole was eject/obstruct/leak. Transesophageal echocardiography was also helpful in planning the extent of the resection, assessing the immediate result and excluding important complications. In successful cases, the post-myectomy study showed 1) a dramatic thinning of the septum, with widening of the left ventricular outflow tract to a width similar to that in the normal subjects, 2) resolution of systolic anterior motion and the left ventricular outflow tract color mosaic, and marked reduction or abolition of mitral regurgitation despite persistence of abnormal mitral leaflet length and an abnormal mitral leaflet coaptation point. The routine use of transesophageal echocardiography in patients undergoing surgical myectomy for the treatment of obstructive hypertrophic cardiomyopathy is recommended.

Adult↗
PubMed1990

Comparison of transthoracic and transesophageal assessment of prosthetic valve dysfunction.

Transesophageal echocardiography has added another dimension to the assessment of prosthetic valve dysfunction with high-resolution images that allow for more detailed structural evaluation of tissue and mechanical valves. This study is a retrospective analysis of 140 prosthetic valves (90 tissue, 50 mechanical) in the mitral (89), aortic (45), and tricuspid (6) position in 116 patients studied by transthoracic and transesophageal echocardiography techniques. Transesophageal echocardiography was consistently better than the transthoracic technique in the evaluation of structural abnormalities of tissue valves in the mitral and aortic positions with respect to leaflet thickening, prolapse, flail, and vegetations. With transesophageal echocardiography, five tissue mitral valves had flail leaflets that were not identified by the transthoracic technique. Transesophageal echocardiography was better than transthoracic in the detection, quantification, and localization of prosthetic mitral regurgitation. Physiological mitral regurgitation was detected in 31 valves by transesophageal echocardiography compared to seven by transthoracic technique. By transesophageal echocardiography, mitral regurgitation was paravalvular in 24% compared with 4% by transthoracic technique. Left atrial spontaneous contrast was seen in 42% of the patients with a mitral prosthesis detected only by transesophageal echocardiography. Six patients had left atrial or left atrial appendage thrombus and in five patients they were detected only by transesophageal echocardiography. We conclude that transesophageal echocardiography should be a complimentary test to transthoracic studies in patients with suspected prosthetic valve dysfunction or for the follow-up of older tissue valves.

Adult↗
PubMed1989

Determinants of restenosis and lack of effect of dietary supplementation with eicosapentaenoic acid on the incidence of coronary artery restenosis after angioplasty.

The effect of an eicosapentaenoic acid-rich encapsulated preparation of fish oil on the incidence of early restenosis after coronary angioplasty was assessed by a randomized double-blind placebo-controlled study. A total of 108 patients received either 10 capsules of fish oil (1.8 g eicosapentaenoic acid, 1.2 g docosahexaenoic acid) or 10 control capsules (50% olive oil, 50% corn oil), commencing the day before angioplasty and continuing for 4 months after angioplasty, in addition to treatment with aspirin and verapamil. In 101 (94%) of the 108 patients, follow-up angiographic or postmortem result was evaluated at a mean (+/- SD) of 100 (+/- 22) days. Angiographic restenosis was observed in 34% of patients (29% of lesions) in the fish oil-treated group and 33% of patients (31% of lesions) in the control group (no significant difference). The overall incidence of angiographic restenosis was significantly higher in patients with 1) recurrent angina pectoris, 2) a positive exercise test at follow-up after angioplasty, 3) residual stenosis greater than 30% immediately after angioplasty, and 4) dilation of the left anterior descending or right coronary artery. Biochemical investigations showed a greater decrease in the serum triglyceride levels in the fish oil-treated group versus the control group (p less than 0.05) but no differences between the two groups in cholesterol levels or platelet counts over the 4 month period. In conclusion, in this study, the administration of fish oil at a dose of 10 capsules/day did not reduce the incidence of early restenosis after coronary angioplasty.

Adult↗
PubMed1988

Short- and long-term results of transvenous catheter ablation of the atrioventricular conduction system.

Twenty-two patients with refractory supraventricular arrhythmias were treated by catheter-delivered high-energy shocks to the atrioventricular conduction system. All patients had a minimum follow-up period of six months (mean +/- SD, 15 +/- 9 months), at which time 21 of the 22 patients were free of symptoms and required no antiarrhythmic therapy. Permanent pacemakers were implanted in all patients. These results show that transvenous ablation or modification of atrioventricular conduction is a safe and effective technique to treat a wide range of supraventricular arrhythmias, and obviates the need for open-heart surgery for the interruption of atrioventricular nodal conduction.

Adolescent↗
PubMed1988

Assessment of aortocoronary bypass graft patency by intra-arterial digital subtraction angiography compared to selective graft angiography.

The value of digital subtraction angiography (DSA), in assessing aortocoronary bypass graft patency, was evaluated by studying 22 consecutive patients with 54 aortocoronary saphenous vein bypass grafts, who had postoperative angina pectoris. Each patient underwent selective graft angiography and non-gated DSA. The DSA consisted of a run of 15 to 20 frames, taken at 2.3 frames per second during injection of diluted contrast in the ascending aorta, performed after a test exposure was made. Thirty-two of the 54 grafts (59%) were patent. Thirty of the 32 grafts were seen to be patent by both selective graft angiography and DSA. In addition, a further two grafts were found to be patent on DSA, but were not able to be selectively catheterised and were not seen on the conventional aortogram. Selective graft angiography revealed four tight proximal graft stenoses, of which one only was seen on DSA; and poor distal run-off in five grafts, two of which showed up as late filling grafts on DSA. In summary, the accuracy of intra-arterial DSA in assessment of bypass graft patency was excellent. All grafts seen to be patent on selective graft angiography were also seen by DSA alone and in addition two grafts which could not be selectively catheterised were found to be patent. However, in patients with postoperative chest pain, selective graft angiography is probably required as non-gated intra-arterial DSA does not provide sufficient information to assess graft stenoses, distal flow and the native coronary vessels.

Adult↗
PubMed1988

Long-term clinical and angiographic results following percutaneous transluminal coronary angioplasty.

The long-term results of percutaneous transluminal coronary angioplasty were evaluated in our first 42 patients, who had initial successful angioplasty and no restenosis on angiogram performed four months after angioplasty. Evaluation included repeat follow-up angiogram performed approximately two years after angioplasty in 22 of the 42 patients. All 42 patients had single vessel disease with severe angina pectoris refractory to medical treatment before angioplasty; at a mean follow-up of 28 months after angioplasty, 37 (88%) were asymptomatic. No patient died or underwent coronary artery bypass graft surgery during the follow-up period, although three patients (7%) suffered a myocardial infarction due to occlusion of a nondilated artery. In the 22 cases studied at a mean of 28 months after angioplasty, angiogram showed that successful coronary artery dilatation remained in all cases, with no deterioration of a dilated lesion between the four and 28 month angiograms. Progression of atherosclerosis, however, did occur in five of the 22 patients (23%), with development of either stenosis or occlusion of a non-dilated vessel. This study suggests that the development of restonsis between four and 28 months after percutaneous transluminal coronary angioplasty is unlikely. The results suggest an excellent long-term prognosis after angioplasty, in patients who have no evidence of restenosis at four months after an initially successful dilatation.

Adult↗
PubMed1987

Benign congenital intracardiac thyroid and polycystic tumor causing right ventricular outflow tract obstruction and conduction disturbance.

A patient with a rare intracardiac tumor arising from the right side of the interventricular septum who developed conduction disturbances and symptoms of right ventricular outflow tract obstruction is reported. The patient was successfully treated with insertion of a permanent pacemaker and surgical removal of the tumor after two-dimensional echocardiography diagnosed the intracardiac mass. Pathologic examination confirmed the benign nature of the tumor and showed the unusual features of both ectopic thyroid and benign congenital polycystic tumor.

Choristoma↗
PubMed1985

Ventricular tachycardia and sudden death in myotonic dystrophy: clinical, electrophysiologic and pathologic features.

A 37 year old man who presented with a cardiomyopathy, conduction defects and atrial and ventricular arrhythmias was found to have the neuromuscular manifestations of myotonic dystrophy. Despite implantation of a permanent cardiac pacemaker, antiarrhythmic drug therapy and antiarrhythmic surgery, sudden death occurred. The results of electrophysiologic studies, coronary arteriography and pathologic findings are described. This case confirms previous observations that ventricular arrhythmias, in addition to atrial arrhythmias and conduction disturbances, are cardiac manifestations of myotonic dystrophy and can lead to sudden death.

Adult↗
PubMed1985

Arrhythmogenic right ventricular dysplasia. Clinical, electrophysiological, and pathological features.

Arrhythmogenic right ventricular dysplasia (ARVD) describes the syndrome of recurrent ventricular tachycardia of right ventricular origin and cardiomyopathic changes of the right ventricle. We report the clinical, electrophysiologic, and angiographic characteristics of four patients who presented with ventricular tachycardia of left bundle branch block configuration, and in whom the right ventricular origin of tachycardia was confirmed by endocardial mapping, and a diagnosis of ARVD was substantiated by histological examination. ARVD should be suspected in all patients with ventricular tachycardia of left bundle branch block configuration, especially in young adults with an otherwise normal heart. Once suspected, diagnosis can often be established by non-invasive investigation. Surgical treatment may be difficult because of the diffuse nature of right ventricular involvement.

Adolescent↗
PubMedDate not supplied

Transvenous ventricular pacing options in Ebstein's anomaly.

Transvenous pacing in patients with Ebstein's anomaly is challenging due to anatomical abnormalities of the tricuspid valve and right heart chambers. This paper describes the various transvenous ventricular lead placement options for permanent pacing in patients with Ebstein's anomaly. In Ebstein's anomaly, stable long-term ventricular pacing can be achieved by positioning the lead either in the atrialised right ventricle, true right ventricle or the cardiac venous system. The pitfalls and advantages of pacing from these sites with the electrocardiographic and chest X-ray appearances are described.

Cardiac Pacing, Artificial↗