Jürgen Apitz

Proton-decoupled myocardial 31P NMR spectroscopy reveals decreased PCr/Pi in patients with severe hypertrophic cardiomyopathy.

Disturbed myocardial energy metabolism may occur in patients with primary hypertrophic cardiomyopathy (HCM). A noninvasive way to gain insight into cardiac energy metabolism is provided by in vivo 31P nuclear magnetic resonance (NMR) spectroscopy. 31P NMR spectroscopy with proton decoupling was performed in 13 patients aged 13-36 years with HCM on a 1.5 T Magnetom with a double resonant surface coil. A 2D chemical shift imaging (CSI) sequence in combination with slice selective excitation was used to acquire spectra of the anteroseptal region of the left ventricle (volume element: 38 mL). The chemical shifts of the phosphorus metabolites, intracellular pHi, and coupling constants J(alphabeta) and J(gammabeta) were calculated. Peak areas of 2,3-diphosphoglycerate (DPG), Pi, and adenosine triphosphate (ATP) were determined and corrected for blood contamination, saturation, and differences in nuclear Overhauser enhancements (NOE). The maximum thickness of the interventricular septum (IVSmax) was determined from tomographic long-axis images and expressed as number of standard deviations above the mean of the normal population (Z score). The patients were then divided into 2 groups: 6 patients with moderate HCM (HCMm, Z score < or = 5) and 7 patients with severe HCM (HCMs, Z score > 5). No differences between both groups and a control group of healthy volunteers (n = 16) were found with respect to phosphocreatine (PCr)/gamma-ATP ratio, pHi, or the coupling constants. Only the PCr/Pi ratio differed significantly from the control group (HCM(all), alpha < 0.05, HCMs, alpha < 0.02, 2-sided U test). The decrease of the PCr/Pi ratio in patients with HCM is probably caused by ischemically decreased oxygen supply in the severely hypertrophied myocardium.

Primary rhabdomyosarcoma of the heart

SummaryA primary rhabdomyosarcoma of the heart, observed in a 3-week-old infant, provides an opportunity to review this rare clinical entity; 61 reported cases are collated. The more common sites are right ventricle, left atrium, and right atrium; the tumour may protrude into the cavity and cause obstruction. Echocardiography can demonstrate the tumour, which may also be seen as a filling defect on angiography.Primary heart tumours seldom occur, especially in infancy and childhood. According to Van der Hauwaert, the most common cardiac tumour in infancy is the rhabdomyoma. No primary malignant tumour was seen in 15 European centres within a 5-year period.

High-resolution cardiac imaging using an interleaved 3D double slab technique

A three-dimensional (3D) gradient-echo sequence with interleaved double-slab excitation was developed and optimized for the requirements in pediatric cardiac imaging. For this purpose high contrast between blood and myocardium signal should be obtained without the use of contrast agents. An acceptable measuring time for a large region examined with high spatial resolution should be achieved as well, especially with regard to the small structures of the heart and vessels of infants. The presented approach works with gradient moment nulling and a short echo time of 5.5 ms resulting in generally high signal intensity and only minor signal losses due to turbulent flow. The sequence allows simultaneous ECG-gated recording of two separately excited slabs with small thickness (10 mm) and with a distance of several centimeters between them. Thus, common effects of presaturation in 3D imaging can be avoided, although a relatively short measuring time is achievable. In order to get a 3D data set with good signal homogeneity of blood and of the other structures across a large volume of interest several double-slab measurements with suitable positions must be performed. The latter aspect is especially important for postprocessing techniques as multiple planar reconstruction and maximum intensity projection. Examples of applications of the new technique and appropriately postprocessed images are presented allowing demonstration even of subtle cardiac malformations.

Linksventrikuläre Tachykardie bei strukturell unauffälligem kardialem Befund

ZusammenfassungWir berichten über die Möglichkeiten der elektrophysiologischen Diagnostik und Therapie in der Behandlung einer medikamentös nicht sicher einstellbaren symptomatischen linksventrikulären Tachykardie bei einem 10jährigen Jungen mit strukturell unauffälligem kardialem Befund. Bei rechtsschenkelblockartig deformierten QRS-Komplexen im Oberflächen-EGK bei der Aufnahme wurde anhand eines anschließend abgeleiteten Ösophagus-EKG die ventrikuläre Genese der Tachykardie bestätigt. Es erfolgte dann eine erste elektrophysiologische Untersuchung, die eine erhöhte linksventrikuläre Vulnerabilität zeigte. Im Rahmen dieser Untersuchung wurde mittels gezielter ventrikulärer Einzelstimulation die Tachykardie terminiert. Anschließend erfolgte eine medikamentöse Einstellung auf Sotalol. Nach der Aufsättigungsphase wurde eine erneute ventrikuläre Stimulation durchgeführt, die keine Schutzwirkung der Sotalolmedikation nachweisen konnte, so daß die Indikation für eine ventrikuläre Katheterablation gestellt wurde. Nach 5 Hochfrequenzapplikationen linksseptal ließ sich keine ventrikuläre Tachykardie mehr induzieren. Der Patient ist im bisherigen Nachbeobachtungszeitraum beschwerdefrei.SummaryWe report about the possibility of electrophysiological diagnosis and therapy in the treatment of a symptomatic left ventricular tachycardia which could not be treated effectively by oral medical therapy in a 10 year old boy with no obvious structural heart disease. By right bundle-bloc-like QRS-complexes in the surface-ECG, the diagnosis of the ventricular origin of the tachycardia was confirmed by transesophageal-ECG. This was followed by the first electrophysiological examination that showed increased leftventricular vulnerability. During this electrophysiological examination the tachycardia was terminated by stimulated singular premature beats. An oral medical therapy with sotalol was started. After the phase of saturation the next ventricular stimulation was done, that showed no sufficient protection of sotalol against VT. So the decision was made for ventricular ablation. After 5 high frequency-applications no furhter ventricular tachycardia could be induced. Since this intervention the patient lives without symptoms