Impact of intraventricular conduction delay on coronary haemodynamics: a study with intracoronary Doppler in patients with bundle branch blocks and normal coronary arteries.

AIMS: The impact of right bundle branch block (RBBB) and left bundle branch block (LBBB) on myocardial perfusion is not completely understood as data are often blurred by underlying cardiac disease. The present study investigates whether conduction delays per se affect coronary perfusion-an indirect measure of myocardial oxygen demand. METHODS AND RESULTS: Intracoronary Doppler and ultrasound were performed in 8 patients with RBBB, 10 patients with LBBB, and 10 control subjects. All patients had angiographically normal coronary arteries and normal left ventricular function. Baseline (bAPV) and adenosine-induced hyperaemic average flow velocity and coronary flow velocity reserve (CFVR) were measured in left anterior descending arteries. Intravascular ultrasound showed no difference in lumen cross-sectional area and plaque burden between groups. Patients with RBBB and LBBB had higher bAPV values than controls (19.0 +/- 4.9, 21.9 +/- 5.1, and 14.6 +/- 2.4 cm/s, respectively; ANOVA P = 0.003). There was no difference between patients with LBBB and RBBB compared with controls in CFVR (2.8 +/- 0.5, 3.0 +/- 1.0, and 3.4 +/- 0.7, respectively; ANOVA P = 0.21). CONCLUSION: Bundle branch blocks, in particular LBBB, are associated with an increased coronary flow velocity, which indicates enhanced myocardial oxygen demand on the basis of mechanoenergetic disturbance. This may contribute to the unfavourable outcome of patients with intraventricular conduction delay.

[Mitral valve prolapse: identification of high-risk patients and therapeutic management]. / Mitralklappenprolaps: Identifikation von Patienten mit erhöhtem Risiko und therapeutisches Management.

Mitral valve prolapse shows a wide spectrum from a benign anatomic variant to a progressive disease with severe cardiovascular morbidity and mortality. Echocardiography is the most important tool for diagnosis and risk stratification. Predictors for high risk are significant thickening of mitral leaflet of > 5 mm ("classic" prolapse), moderate to severe mitral regurgitation and reduced left ventricular function. These patients have an increased risk of infective endocarditis, cerebral ischemia and sudden cardiac death. Because of the risk for the development of severe mitral regurgitation requiring surgery short follow-up intervals are necessary. In mitral prolapse syndrome cardiac clinical signs (palpitation, rhythm disorders, syncope, etc.) are associated with a prolapse that can be treated symptomatically with drugs after exclusion of other causes and significant mitral regurgitation requiring surgery.