Zeitschrift für Kardiologie
-
The Fontan operation causes an acute decrease of volume overload of the univentricular heart followed by changes in ventricular geometry. The postoperative increase of myocardial mass-volume-index (MVI) may alter ventricular diastolic function. In this study, we analysed whether the increase in MVI and changes of the ventricular geometry have an effect on the decrease of the exercise capacity in patients with Fontan surgery. ⋯ Myocardial hypertrophy may influence the myocardial performance of the univentricular heart and thereby the physical performance in children and adults with Fontan circulation.
-
Time and frequency domain analysis were conducted during a period of 600 s each. We performed a special protocol consisting of five different "pacing" periods: 1) recording of normal sinus rhythm (SR1); 2) atrial pacing with a rate 15% higher than the intrinsic heart rate; 3) ventricular pacing triggered by atrial activation (VAT, with a short AV-delay of 80 ms); 4) AV-sequential pacing with an atrial rate 15% higher than the intrinsic heart rate and a very short AV delay of 80 ms (DDD); 5) normal sinus rhythm (SR2). Only patients with normal AV-nodal conduction or with AV-block I degrees were included. The influence of a structural heart disease as well as a non-sustained VT on Holter ECG and a depressed EF on HRV parameters were analyzed using a multivariate analysis. All patients were lying in a supine position. Blood pressure was measured continuously and the frequency of breathing was controlled. ⋯ Heart rate variability derived from consecutive RR-intervals is predominantly caused by periodicity in sinus-node impulse formation. A conduction variability of the AV-node exists, but is very low. The presence of a structural heart disease, a non-sustained ventricular tachycardia on Holter ECG, as well as a depressed ejection fraction of less than 0.50 showed no significant influence on the HRV parameters. Therefore, one can apply the calculation of heart rate variability for risk stratification in patients suffering from structural heart disease and moderate AV-nodal conduction disturbances. Attenuation of the oscillation of the heart rate, i. e. heart rate variability (HRV), is associated with an increased risk for mortality in patients with structural heart disease. Many of these patients also suffer from conduction disturbances, e. g. AV-nodal conduction delays. Whether the calculation of HRV in those patients is recommendable has not been investigated yet. Therefore, we conducted a study consisting of 20 consecutive patients in order to determine the formation of HRV, the influence of structural heart disease, the presence of a nonsustained ventricular tachycardia (VT), and a reduced ejection fraction (EF) on the HRV parameters during an elective electrophysiologic study.
-
An infant with myocardial infarction due to congenital stenosis of the left coronary artery with consecutive left ventricular dysfunction and mitral regurgitation developed refractory pulmonary hypertension (PHT) and recurrent PHT crises. Catecholamines to support cardiac function, or pulmonary vasodilators like inhaled nitric oxide showed no effect. Treatment with Levosimendan (Simdax), a new inodilator, combining both inotropic and pulmonary vasodilating effects, improved left ventricular dysfunction, increased cardiac index, decreased pulmonary vascular resistance and reduced frequency and extent of the PHT crises. This case may suggest the use of Levosimendan as a long-term inotropic agent and pulmonary vasodilator in children with depressed cardiac function.