Influence of a rapid change of left ventricular dimensions on the echocardiographic measurement of left ventricular mass by the Penn convention.

OBJECTIVE: The purpose of this study was to test the robustness of the measurement of left ventricle mass (LVM), using Devereux's formula, in the presence of a rapid change in left ventricular volume induced by nitroglycerin. DESIGN: Forty-eight healthy volunteers with excellent echocardiographic recordings were included. The intrapatient variability of LVM measurement was assessed by two consecutive echocardiograms. The intraobserver reproducibility was assessed by the rereading of 19 echocardiograms by the same observer. The effects of nitroglycerin were compared with those of a placebo in a double-blind random manner on, the left ventricular internal dimension in diastole (LVIDd), the interventricular septum thickness, the posterior wall thickness and the LVM. RESULTS: It was shown that both the intrapatient and the intraobserver reproducibility were high. Nitroglycerin induced a significant decrease in LVIDd compared with placebo (-0.21 +/- 0.24 versus 0.01 +/- 0.21 cm, respectively, P < 0.01) and a non-significant increase in wall thickness. These variations were negatively correlated with each other (r= -0.58, P< 0.01). Despite the change of ventricular dimensions, the variation of LVM induced by nitroglycerin was not significantly different from that induced by placebo (2.0 +/- 16.0 versus 4.7 +/- 17.0 g, respectively, not significant) and close to the intrapatient variability. CONCLUSION: This experiment failed to demonstrate any influence of a rapid variation of ventricle size on the calculation of LVM with the Penn convention and strongly supports the robustness of the method in vivo.

[Predictive factors of induction of ventricular arrhythmia under amiodarone]. / Facteurs prédictifs du déclenchement d'une arythmie ventriculaire sous amiodarone.

A good result of electrophysiological investigations under amiodarone therapy distinguishes a low risk group of patients with malignant ventricular arrhythmias. The authors set out to determine the factors predictive of this response in order to identify patients better protected by amiodarone at an earlier stage. Fourty-five patients with an average age of 56 years, were referred for evaluation of severe ventricular arrhythmias, monomorphic ventricular tachycardia being inducible during electrophysiological investigation in all cases before treatment. Amiodarone was prescribed orally at degressive doses. A control electrophysiological study was performed 4 to 6 weeks later. Eighteen patients (40%) were considered to be responders (absence of inducible ventricular arrhythmia or inducible non-sustained tachycardia or tachycardia with a cycle length increased by over 100 ms with respect to the base-line study). The other 27 patients were considered to be non-responders. No clinical or paraclinical parameter was found to distinguish responders from non-responders. The authors conclude that the data obtained before control electrophysiological investigation under amiodarone does not allow prediction of the response to this drug. The search for early prognosis of the efficacy of amiodarone in preventing ventricular arrhythmias therefore requires electrophysiological investigation after impregnation.

[Thrombosis on the mitral valve prosthesis and disseminated cancer: treatment by fibrinolysis]. / Thrombose de prothèse valvulaire mitrale et cancer disséminé: traitement par fibrinolyse.

The authors report the case of a 63-year-old woman with occlusive thrombosis of a mitral valve prosthesis and cardiogenic shock successfully treated by systemic thrombolytic therapy. This treatment was given despite metastatic hepatic and bone breast cancer. This, and other recently reported cases, argues in favour of widening the indication of thrombolysis as treatment of first intention in cases of obstruction of atrioventricular valve prostheses. Nevertheless, the relative safety of surgical treatment and the risk of systemic thromboembolism of thrombolysis, incites caution and reservation of medical therapy for carefully selected patients.