Rainer Moosdorf

Complications of implantable cardioverter defibrillator therapy in 440 consecutive patients.

Background: Although more than 150,000 implantable cardioverter defibrillators (ICDs) are implanted yearly worldwide, only few studies systematically examined complications of ICD therapy in large patient cohorts.

Complications of Third-Generation Implantable Cardioverter Defibrillator Therapy

To determine the incidence of complications of third‐generation implantable cardioverter defibrillator (ICD) therapy, 144 patients were prospectively studied who underwent first implant of third‐generation devices (i.e., ICD systems with biphasic shocks, ECC storage capability, and nonthoracotomy lead systems). During 21 ± 15 months of follow‐up, 41 (28%) patients had one or more complications. No patient died perioperatively (30 days) and no ICD infection was observed during follow‐up. Complications included bleeding or pocket hematoma (hemoglobin drop > 2 g/dL) in 5 (3%) patients, prolonged reversible ischemic neurological deficit in 1 (1%) patient, postoperative deep venous thrombosis of leg in 1 (1%) patient, pneumothorax in 2 (1%) patients, difficulty to defibrillate ventricular fibrillation intraoperatively in 2 (1%) patients, generator malfunction in 1 (1%) patient, arthritis of the shoulder in 3 (2%) patients, and allergic reaction to prophylactic antibiotics in 2 (1%) patients. A total of seven lead related complications were observed in six (4%) patients including endocardial lead migration in four (3%) patients. Twenty‐three (16%) patients received inappropriate shocks for supraventricular tachyarrhythmias (n = 13), non‐sustained ventricular tachycardia (VT) (n = 7), or myopotential oversensing (n = 3). We conclude that serious complications such as perioperative death or ICD infection are rare in patients with third‐generation ICDs. Lead‐related problems and inappropriate shocks during follow‐up are the most frequent complications of third‐generation ICD therapy. Recognition of these complications should promote advances in ICD technology and management strategies to avoid their recurrence.

The role of mitochondrial membrane potential in ischemic heart failure.

The molecular events occurring during myocardial infarction and cardioprotection are described with an emphasis on the changes of the mitochondrial membrane potential (ΔΨ(m)). The low ΔΨ(m) values of the normal beating heart (100-140 mV) are explained by the allosteric ATP-inhibition of cytochrome c oxidase (CcO) through feedback inhibition by ATP at high [ATP]/[ADP] ratios. During ischemia the mechanism is reversibly switched off by signaling through reactive oxygen species (ROS). At reperfusion high ΔΨ(m) values cause a burst of ROS production leading to apoptosis and/or necrosis. Ischemic preconditioning is suggested to cause additional phosphorylation of CcO, protecting the enzyme from immediate dephosphorylation via ROS signaling.

In vivo determination of elastic properties of the human aorta based on 4D ultrasound data

Computational analysis of the biomechanics of the vascular system aims at a better understanding of its physiology and pathophysiology. To be of clinical use, however, these models and thus their predictions, have to be patient specific regarding geometry, boundary conditions and material. In this paper we present an approach to determine individual material properties of human aortae based on a new type of in vivo full field displacement data acquired by dimensional time resolved three dimensional ultrasound (4D-US) imaging. We developed a nested iterative Finite Element Updating method to solve two coupled inverse problems: The prestrains that are present in the imaged diastolic configuration of the aortic wall are determined. The solution of this problem is integrated in an iterative method to identify the nonlinear hyperelastic anisotropic material response of the aorta to physiologic deformation states. The method was applied to 4D-US data sets of the abdominal aorta of five healthy volunteers and verified by a numerical experiment. This non-invasive in vivo technique can be regarded as a first step to determine patient individual material properties of the human aorta.

Method for Aortic Wall Strain Measurement With Three-Dimensional Ultrasound Speckle Tracking and Fitted Finite Element Analysis

BACKGROUND Aortic wall strains are indicators of biomechanical changes of the aorta due to aging or progressing pathologies such as aortic aneurysm. We investigated the potential of time-resolved three-dimensional ultrasonography coupled with speckle-tracking algorithms and finite element analysis as a novel method for noninvasive in vivo assessment of aortic wall strain. METHODS Three-dimensional volume datasets of 6 subjects without cardiovascular risk factors and 2 abdominal aortic aneurysms were acquired with a commercial real time three-dimensional echocardiography system. Longitudinal and circumferential strains were computed offline with high spatial resolution using a customized commercial speckle-tracking software and finite element analysis. Indices for spatial heterogeneity and systolic dyssynchrony were determined for healthy abdominal aortas and abdominal aneurysms. RESULTS All examined aortic wall segments exhibited considerable heterogenous in-plane strain distributions. Higher spatial resolution of strain imaging resulted in the detection of significantly higher local peak strains (p ≤ 0.01). In comparison with healthy abdominal aortas, aneurysms showed reduced mean strains and increased spatial heterogeneity and more pronounced temporal dyssynchrony as well as delayed systole. CONCLUSIONS Three-dimensional ultrasound speckle tracking enables the analysis of spatially highly resolved strain fields of the aortic wall and offers the potential to detect local aortic wall motion deformations and abnormalities. These data allow the definition of new indices by which the different biomechanical properties of healthy aortas and aortic aneurysms can be characterized.

Cytokines in Pericardial Effusion of Patients with Inflammatory Pericardial Disease

Background. The role of inflammatory and angiogenic cytokines in patients with inflammatory pericardial effusion still remains uncertain. Methods. We assessed pericardial and serum levels of VEGF, bFGF, IL-1β and TNF-α by ELISA in patients with inflammatory pericardial effusion (PE) of autoreactive (n = 22) and viral (n = 11) origin, and for control in pericardial fluid (PF) and serum (n = 26) of patients with coronary artery disease (CAD) undergoing coronary artery bypass graft surgery. Results. VEGF levels were significantly higher in patients with autoreactive and viral PE than in patients with CAD in both PE (P = 0, 006 for autoreactive and P < 0, 001 for viral PE) and serum (P < 0, 001 for autoreactive and P < 0, 001 for viral PE). Pericardial bFGF levels were higher compared to serum levels in patients with inflammatory PE and patients with CAD (P ≤ 0, 001 for CAD; P ≤ 0, 001 for autoreactive PE; P = 0, 005 for viral PE). Pericardial VEGF levels correlated positively with markers of pericardial inflammation, whereas pericardial bFGF levels showed a negative correlation. IL-1β and TNF-α were detectable only in few PE and serum samples. Conclusions. VEGF and bFGF levels in pericardial effusion are elevated in patients with inflammatory PE. It is thus possible that VEGF and bFGF participate in the pathogenesis of inflammatory pericardial disease.

Improved myocardial preservation with short hyperthermia prior to cold cardioplegic ischemia in immature rabbit hearts

OBJECTIVE Recent observations have been shown that the induction and accumulation of heat shock proteins (HSPs) by short exposure to nonlethal whole-body hyperthermia with normothermic recovery are closely associated with transient resistance to subsequent ischemia-reperfusion challanges. Here, this study was performed to investigate whether a shortly heat shock pretreatment affects the left ventricular (LV) function after cold cardioplegic ischemia in reperfused neonatal rabbit hearts. METHODS Hearts from neonatal New Zealand White rabbits were isolated perfused (working heart preparation) and exposed to 2 h of cold cardioplegic ischemia followed by reperfusion for 60 min. To induce the heat shock response neonatal rabbits (n=5, HT-group) were subjected to whole-body hyperthermia at 42.0-42.5 degrees C for 15 min, followed by a normothermic recovery period of 60 min, before harvesting and the onset of global hypothermic cardioplegic arrest. Another set of hearts (n=5, control group) without a heat treatment underwent a similar perfusion and ischemia protocol served as control. The postischemic recovery was assessed by measuring several parameters of LV function. LV biopsies from all control and heat treated animals were taken before ischemia and at the end of reperfusion to examine myocardial HSP levels by Western blot analysis. RESULTS At 60 min of reperfusion the HT-group showed significant better recovery of ventricular function such as LV developed pressure (DP) (74.6+/-10 vs. 52.1+/-8.5%, P<0.05), LV positive dP/dt (910+/-170 vs. 530+/-58 mmHg/s, P<0.01) and LV end-diastolic pressure (LVEDP) (8+/-2 vs. 18.4+/-5 mmHg, P<0.05) than control. Myocardial oxygen consumption (MVO(2)) was significantly higher in the HT-group compared with control (0.054+/-0.006 vs. 0.041+/-0.002 ml/g per min, P<0.05). Significant postreperfusion lower level in lactate production was observed in the HT-group (0.83+/-0.11 vs. 1.67+/-0.8 mmol/l, P<0.05). Also, the recovery of hemodynamic parameters such as aortic flow, coronary flow and cardiac output was significantly superior (P<0.05) in the HT-group. Furthermore, high expression of HSP72(+)/73(+) were detected in the myocardial tissue samples of heat-treated rabbits by immunoblotting, appearing even at 60 min of normothermic recovery after heat stress. CONCLUSIONS These data in the immature rabbit heart indicate that previous shortly heat treatment with high level expression of heat shock proteins (HSP72(+)/73(+)) before hypothermic cardioplegic ischemia provides transient tolerance against myocardial injury and could be an improvement for the postischemic functional recovery of neonatal hearts.

Right ventricular cardiac myxoma. Diagnostic usefulness of cardiac magnetic resonance imaging.

Background:Cardiac myxomas are the most common type of cardiac tumors. About 75–85% of cardiac myxomas originate in the left atrium, 15–20% in the right atrium. Most myxomas arise from the interatrial septum adjacent to the fossa ovalis. Only 3–4% are found in the left and right ventricle each. Although myxomas are histologically benign, they may be fatal because of their strategic position.Case Study:The authors report on a 24-year-old patient with stabbing thoracic pain and dyspnea due to pulmonary thromboembolism that was caused by an atypically localized myxoma at the right ventricular apex originating from the interventricular septum. The diagnosis was based on cardiac magnetic resonance (CMR) imaging. Superior to echocardiography, CMR could strengthen the diagnostic accuracy by additional information on tissue characterization using different imaging sequences. Typically for cardiac myxomas, contrast enhancement was moderate and delayed enhancement was found in the outer circumferential tumor margins only.Conclusion:High spatial resolution and multiplane imaging combined with different acquisition patterns of CMR achieve a global view of the heart that seems to be useful for diagnosing cardiac tumorous masses.ZusammenfassungHintergrund:Myxome sind die häufigsten kardialen Tumoren und zu 75–85% im linken sowie zu 15–20% im rechten Vorhof zu finden. Die linksatrialen Myxome entspringen üblicherweise von der Fossa ovalis. Nur 3–4% sind jeweils rechts- bzw. linksventrikulär lokalisiert. Obwohl Myxome histologisch benigne sind, können sie aufgrund ihrer Lokalisation erhebliche Folgeerscheinungen wie beispielsweise Thromboembolien oder mechanische Herzklappenbeeinträchtigungen, intrakavitäre Obstruktionen oder Herzrhythmusstörungen nach sich ziehen.Fallbericht:Die Autoren berichten den Fall eines 24-jährigen Patienten mit stechenden thorakalen Beschwerden und Dyspnoe, hervorgerufen durch eine Lungenembolie. Ursache war ein atypisch lokalisiertes Myxom im Bereich des rechtsventrikulären Apex mit Ursprung am interventrikulären Septum. Die kardiale Magnetresonanztomographie mit unterschiedlichen Bildgebungssequenzen wurde zur Charakterisierung der Raumforderung herangezogen. Es fand sich eine nur mäßige Kontrastmittelaufnahme in der First-Pass-Perfusion, wie dies für Myxome typisch ist. Ein „delayed enhancement“ 15 min nach Kontrastmittelapplikation wurde im äußeren Randbereich des Myxoms gefunden. Darüber hinaus grenzte sich das Myxom in ödemsensitiven Sequenzen deutlich von seiner Umgebung ab.Schlussfolgerung:Die kardiale Magnetresonanztomographie bietet durch ihre hohe räumliche Auflösung und die Möglichkeiten der multiplanaren Darstellung, kombiniert mit verschiedenen Aufnahmesequenzen, eine gute Möglichkeit zur morphologischen Erfassung und Gewebecharakterisierung kardialer Raumforderungen.

Importance of Real-Time Tissue Oximetry: Relationship to Muscle Oxygenation and Tissue Viability

BACKGROUND There is currently no efficient and reliable clinical means of assessing the degree of ischemia- and reperfusion-associated damage in microvascular transplants. The objective was to study correlation of tissue oxygen tension measurements with tissue oxygen saturation, cytochrome oxidase redox state, and tissue viability. MATERIALS AND METHODS Latissimus dorsi muscle was dissected and mobilized in New Zealand white rabbits (n = 30, 2.5 ± 0.5 kg). Muscles were exposed to warm ischemia in two groups with either 4 or 6 h, followed by reperfusion. Tissue PO(2) was measured with a miniature intramuscular oxygen sensor (Licox microprobe; Integra Neurosciences, Ratingen, Germany) all along with tissue hemoglobin saturation (rSO(2)) and cytochrome oxidase aa3 redox state (CytOx) by in vivo near-infrared spectroscopy. Linear correlation was performed between tissue PO(2) and rSO(2), CytOx and tissue viability. RESULTS After ischemia and reperfusion, tissue PO(2) and CytOx recovery was significantly decreased in both groups compared with control (4 h: P < 0.05; 6 h: P < 0.01). Significant correlations between changes in tissue PO(2) and rSO(2) (r = 0.92; P < 0.01), CytOx (r = 0.90; P < 0.01), wet-to-dry ratio (r = -0.97; P < 0.01), and mitochondrial viability index (r = 0.97; P < 0.01) were found. CONCLUSIONS Tissue oxygen tension measured with microprobes correlated closely with tissue oxygenation, cellular oxygen utilization, and the extent of ischemia reperfusion injury.

Right Ventricular Cardiac Myxoma

Background:Cardiac myxomas are the most common type of cardiac tumors. About 75–85% of cardiac myxomas originate in the left atrium, 15–20% in the right atrium. Most myxomas arise from the interatrial septum adjacent to the fossa ovalis. Only 3–4% are found in the left and right ventricle each. Although myxomas are histologically benign, they may be fatal because of their strategic position.Case Study:The authors report on a 24-year-old patient with stabbing thoracic pain and dyspnea due to pulmonary thromboembolism that was caused by an atypically localized myxoma at the right ventricular apex originating from the interventricular septum. The diagnosis was based on cardiac magnetic resonance (CMR) imaging. Superior to echocardiography, CMR could strengthen the diagnostic accuracy by additional information on tissue characterization using different imaging sequences. Typically for cardiac myxomas, contrast enhancement was moderate and delayed enhancement was found in the outer circumferential tumor margins only.Conclusion:High spatial resolution and multiplane imaging combined with different acquisition patterns of CMR achieve a global view of the heart that seems to be useful for diagnosing cardiac tumorous masses.ZusammenfassungHintergrund:Myxome sind die häufigsten kardialen Tumoren und zu 75–85% im linken sowie zu 15–20% im rechten Vorhof zu finden. Die linksatrialen Myxome entspringen üblicherweise von der Fossa ovalis. Nur 3–4% sind jeweils rechts- bzw. linksventrikulär lokalisiert. Obwohl Myxome histologisch benigne sind, können sie aufgrund ihrer Lokalisation erhebliche Folgeerscheinungen wie beispielsweise Thromboembolien oder mechanische Herzklappenbeeinträchtigungen, intrakavitäre Obstruktionen oder Herzrhythmusstörungen nach sich ziehen.Fallbericht:Die Autoren berichten den Fall eines 24-jährigen Patienten mit stechenden thorakalen Beschwerden und Dyspnoe, hervorgerufen durch eine Lungenembolie. Ursache war ein atypisch lokalisiertes Myxom im Bereich des rechtsventrikulären Apex mit Ursprung am interventrikulären Septum. Die kardiale Magnetresonanztomographie mit unterschiedlichen Bildgebungssequenzen wurde zur Charakterisierung der Raumforderung herangezogen. Es fand sich eine nur mäßige Kontrastmittelaufnahme in der First-Pass-Perfusion, wie dies für Myxome typisch ist. Ein „delayed enhancement“ 15 min nach Kontrastmittelapplikation wurde im äußeren Randbereich des Myxoms gefunden. Darüber hinaus grenzte sich das Myxom in ödemsensitiven Sequenzen deutlich von seiner Umgebung ab.Schlussfolgerung:Die kardiale Magnetresonanztomographie bietet durch ihre hohe räumliche Auflösung und die Möglichkeiten der multiplanaren Darstellung, kombiniert mit verschiedenen Aufnahmesequenzen, eine gute Möglichkeit zur morphologischen Erfassung und Gewebecharakterisierung kardialer Raumforderungen.