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H P Hamer

Publications and source records attributed to H P Hamer.

9 recordsLinked to original sources
PubMed1995

Additional value of biplane transesophageal echocardiography in assessing the genesis of mitral regurgitation and the feasibility of valve repair.

To determine the additional diagnostic value of biplane transesophageal echocardiography (TEE) in patients undergoing mitral valve surgery, we studied 48 patients with severe mitral regurgitation. Transesophageal echocardiographic video recordings were reorganized in separate transverse and longitudinal sections to allow independent evaluation. Mechanism of mitral regurgitation and anatomic abnormalities of the mitral valve were assessed by all 3 transesophageal echocardiographic modalities and were related to surgical findings. Biplane TEE detected increased leaflet mobility with a sensitivity of 91% and a specificity of 84%, and restricted leaflet mobility with a sensitivity of 100% and a specificity of 97%. Biplane TEE was accurate in the diagnosis of most of the anatomic abnormalities associated with these mechanisms. However, the sensitivity for detecting subvalvular abnormalities (including papillary muscle abnormalities) was poor, and measurement of the annular diameter had a poor correlation with annular dilatation. Although the yield of biplane TEE was better than either transverse or longitudinal TEE alone, the differences did not reach statistical significance, because of the size of the patient group. The surgical procedure (either valve repair or replacement) was correctly predicted with transverse TEE in 71%, with longitudinal TEE in 69%, and with biplane TEE in 79% of the patients. All 3 transesophageal echocardiographic modalities are very capable of assessing the anatomic abnormalities and mechanism of mitral regurgitation, as well as predicting the feasibility of valve repair.

Aged↗
PubMed1995

Increased dispersion of refractoriness in the absence of QT prolongation in patients with mitral valve prolapse and ventricular arrhythmias.

BACKGROUND: The mechanism responsible for the reported high incidence of ventricular arrhythmias in mitral valve prolapse is not clear. Electrocardiographic studies show an increased occurrence of repolarisation abnormalities on the 12 lead surface electrocardiogram, indicating regional differences in ventricular recovery. The purpose of this study was to investigate whether dispersion of refractoriness was an arrhythmogenic mechanism. METHODS: QT dispersion was measured in 32 patients with echocardiographically documented mitral valve prolapse and ventricular arrhythmias on 24 hour Holter recordings. QT dispersion was defined as the difference between the maximum and minimum average QT interval in any of the 12 leads of the surface electrocardiogram. QT dispersion corrected for heart rate was calculated by Bazett's formula. The results were compared with the data from 32 matched controls without a history of cardiac disease. Patients taking drugs that influence the QT interval and patients with a QRS duration > 120 ms were excluded. RESULTS: QT dispersion was greater in patients with mitral valve prolapse than in matched controls (60 (20) v 39 (11 ms) respectively, P < or = 0.001) as was corrected QT (64 (20 ms) v 43 (12 ms) respectively, P < or = 0.001). There was no significant difference in minimum or maximum QT intervals between the two groups. CONCLUSIONS: QT dispersion on the 12 lead surface electrocardiogram was greater in patients with mitral valve prolapse with ventricular arrhythmias than in normal controls, but the maximum QT interval was not increased. The results accord with the hypothesis that regional shortening and lengthening of repolarisation times in patients with mitral valve prolapse may account for the increased dispersion of refractoriness.

Arrhythmias, Cardiac↗
PubMed1993

Changes in left and right atrial size after cardioversion of atrial fibrillation: role of mitral valve disease.

OBJECTIVES: The aim of this study was to examine the effect of cardioversion on left and right atrial volume in patients with chronic atrial fibrillation and to determine the influence of mitral valve disease on atrial size. BACKGROUND: Atrial enlargement is a common finding in atrial fibrillation and has been associated with an increased risk for embolic stroke. In addition, atrial enlargement may hamper long-term maintenance of sinus rhythm after cardioversion. METHODS: Forty-one patients with chronic atrial fibrillation (mean duration +/- SD, 45 +/- 62 months) underwent two-dimensional echocardiography before and 6 months after cardioversion to determine left and right atrial dimensions. Underlying heart disease was present in 26 patients: mitral valve disease in 12 (stenosis in 5, regurgitation in 5 and a combination in 2 patients) and other heart diseases in 14. Fifteen patients had lone atrial fibrillation. Patients with sustained sinus rhythm were compared with those who had a relapse of the arrhythmia 6 months after cardioversion. RESULTS: Six months after cardioversion, 28 patients still had sinus rhythm, whereas 13 patients had a relapse of the arrhythmia. In the 28 patients who had sinus rhythm after 6 months, left and right atrial volume decreased from a mean (+/- SD) 72.6 +/- 15.1 to 58.5 +/- 13.8 cm3 (-20%, p < 0.05) and from 68.7 +/- 14.6 to 58.6 +/- 11.6 cm3 (-14%, p < 0.05), respectively. Atrial dimensions also decreased significantly in the subgroup of patients with mitral valve disease. In contrast, no change in atrial size occurred in the 13 patients who had a relapse of atrial fibrillation. Left ventricular function did not change between the two echocardiographic studies, although New York Heart Association class improved in patients who had sinus rhythm after 6 months. CONCLUSIONS: Restoration of sinus rhythm reverts the process of left and right atrial enlargement in patients with chronic atrial fibrillation and mitral valve disease. Therefore, cardioversion may reduce the incidence of thromboembolic complications and prevent the arrhythmia from becoming refractory to medical therapy.

Aged↗
PubMed1989

Efficacy and safety of flecainide acetate in the maintenance of sinus rhythm after electrical cardioversion of chronic atrial fibrillation or atrial flutter.

The efficacy and safety of flecainide were studied in the maintenance of sinus rhythm after electrical cardioversion for chronic atrial fibrillation or atrial flutter. Eighty-one patients were randomized to flecainide treatment or no treatment. Baseline characteristics of both groups were comparable. Compared to previous studies, patients could be classified as difficult-to-treat patients. Multiple regression analysis showed New York Heart Association class I for exercise tolerance (p = 0.0004) and flecainide treatment (p = 0.01) to be the main factors increasing the arrhythmia-free episode. However, Mantel-Cox lifetable analysis did not reveal significant differences between arrhythmia-free survival curves of both treatment groups. In the flecainide-treated group, 9% of patients experienced side effects, mostly related to negative dromotropic effects. The incidence of ventricular proarrhythmia in this group of patients was low. Thus, flecainide may be effective in postponing arrhythmia recurrence, even in difficult-to-treat patients. Caution should be excercised in treating patients with underlying conduction disturbances, sick sinus syndrome or characteristics favoring development of ventricular proarrhythmia.

Adolescent↗