Biomedical subjects

Thorsten Dill

Publications and source records attributed to Thorsten Dill.

16 recordsLinked to original sources

PubMed2006

Imaging in percutaneous ablation for atrial fibrillation.

Percutaneous ablation for electrical disconnection of the arrhythmogenic foci using various forms of energy has become a well-established technique for treating atrial fibrillation (AF). Success rate in preventing recurrence of AF episodes is high although associated with a significant incidence of pulmonary vein (PV) stenosis and other rare complications. Clinical workup of AF patients includes imaging before and after ablative treatment using different noninvasive and invasive techniques such as conventional angiography, transoesophageal and intracardiac echocardiography, computed tomography (CT) and magnetic resonance imaging (MRI), which offer different information with variable diagnostic accuracy. Evaluation before percutaneous ablation involves assessment of PVs (PV pattern, branching pattern, orientation and ostial size) to facilitate position and size of catheters and reduce procedure time as well as examining the left atrium (presence of thrombi, dimensions and volumes). Imaging after the percutaneous ablation is important for assessment of overall success of the procedure and revealing potential complications. Therefore, imaging methods enable depiction of PVs and the anatomy of surrounding structures essential for preprocedural management and early detection of PV stenosis and other ablation-related procedures, as well as long-term follow-up of these patients.

Atrial Fibrillation↗

PubMed2006

Value of gadolinium-enhanced magnetic resonance imaging in patients with Tako-Tsubo-like left ventricular dysfunction.

We present gadolinium-enhanced cardiac magnetic resonance imaging (CMRI) in Tako-Tsubo-like left ventricular dysfunction showing the findings in acute phase and in follow-up. Gadolinium-enhanced CMRI allows to distinguish between myocardial infarction and other myocardial alterations, e.g., myocarditis. CMRI may thus permit to non-invasively identify patients with Tako-Tsubo syndrome by ruling out myocardial infarction or myocarditis in the setting of wall motion abnormalities (WMA).

Aged↗

PubMed2006

Asymptomatic recurrences of atrial fibrillation after pulmonary vein isolation.

AIMS: The purpose of this study was to determine the occurrence of asymptomatic episodes of atrial fibrillation (AF) and wrong AF perception after pulmonary vein isolation (PVI). We evaluated the success of ablation by using the following measurements: (i) clinical symptoms and duration of symptoms noticed by patients and (ii) synchronous event recording (ER). METHODS AND RESULTS: Eighty patients with paroxysmal AF underwent PVI and were provided repeatedly with a portable ER upon discharge and every 3 months for a year. The ER automatically detects arrhythmias by a detection algorithm and can also be manually triggered by the patient. In 46/80 patients (57.5%), episodes of AF were documented. Asymptomatic AF was detected in 21.3%. In 9/80 patients (11.3%), who reported clinical AF recurrence, no AF could be shown by ER. We compared patients' perception to have suffered AF episodes with the ERs and found a sensitivity of 75% and a specificity of 92%. CONCLUSION: Reliance on perception of AF by patients after PVI results in an underestimation of recurrence of the arrhythmia. We observed a maximal occurrence of silent AF or wrong perception of AF in 26/80 (32.6%) patients.

Analysis of Variance↗

PubMed2005

Primary stenting of the left main coronary artery with anomalous origin from the right sinus of valsalva.

The presence of an aberrant origin of left main coronary artery from the right sinus of valsalva passing between the aorta ascendens and pulmonary trunk is one of the anomalies most frequently associated with malignant clinical events, and surgical treatment is recommended. We report of a 64-year-old patient with a highly increased risk for surgery due to severe chronic obstructive pulmonary disease. This case demonstrates that the use of a drug-eluting stent offers a suitable and valuable alternative.

Abnormalities, Multiple↗

PubMed2005

The value of magnetic resonance imaging for the diagnosis of arrhythmogenic right ventricular cardiomyopathy.

This study evaluated the diagnostic significance of a magnetic resonance imaging (MRI) based scoring model for identification of arrhythmogenic right ventricular cardiomyopathy (ARVC) in patients with MRI evidence of RV abnormalities. Fifty-three patients with RV myocardial abnormalities on MRI were divided into a group with ARVC 1 (n=17) and a group with other RV arrhythmias (n=37). Decision tree learning (DTL) and linear classification (based on a modified ARVC scoring model of major and minor criteria) were used to identify and assess MRI criterion information value, and to induce ARVC diagnostic rules. All major ARVC criteria were more frequent in the ARVC group. Among minor criteria regional RV hypokinesia, mild segmental RV dilatation, and prominent trabeculae were more frequent in the ARVC group while mild global RV dilatation was more frequent in the non-ARVC group. RV aneurysm achieved highest importance in ARVC diagnosis (predictive accuracy 76.8%). Better diagnostic accuracy (sensitivity 93.3%, specificity 89.5%) was achieved when the MRI score for the major and minor criteria reached threshold value of four: two major criteria, or one major and two minor, or four minor criteria. Combinations between major and minor criteria contributed to a statistically valid model for ARVC diagnosis.

Adult↗

PubMed2005

Delayed contrast-enhanced magnetic resonance imaging for the detection of autoimmune myocarditis and long-term follow-up.

MRI proved to be a valuable tool for the evaluation and monitoring of myocarditis. We report the case of a 36 year old caucasian male with an undifferentiated collagenosis who presented first four years ago with unspecific symptoms and impaired exercise capacity. On echocardiography left ventricular function was impaired as well as on MRI. In addition, after administration of Gd-DTPA an intramyocardial pathological signal enhancement was observed on TSE T1 weighted and contrast enhanced FLASH 3D IR sequences. Based on several diagnostic tests including myocardial biopsy an autoimmune myocarditis due to an undifferentiated collagenosis was diagnosed. On long time follow up over almost 3 years with repeated MRI examinations, the delayed hyper enhancement (dHE) decreased or disappeared with successful treatment, respectively. However, in the area of recurrent inflammation, a persisting area of dHE developed with a subsequent perfusion defect. This area represents myocardial fibrosis due to recurrent inflammation.

Adult↗

PubMed2005

A decrease in pulmonary vein diameter after radiofrequency ablation predicts the development of severe stenosis.

A decrease in ostial pulmonary vein (PV) diameter was observed in patients on the day after radiofrequency ablation of atrial fibrillation (AF). This study examined whether a relative reduction in PV diameter on day 1 (RRPVD1) after the procedure predicts the late development of severe PV stenosis (PVS). The study included 104 consecutive patients (mean age = 55 years, range 46-61, 34 women) with drug refractory AF. Pulmonary vein diameter was measured using MR angiography (MRA) on the day before and on day 1 after the ablation procedure. The MRA was repeated every 3 months after the procedure. Severe PVS was defined as a >70% diameter reduction from the initial ostial diameter. The cut-off of RRPVD1 was prespecified as 25% decrease in initial diameter. The data are presented as medians and interquartile range. A total of 357 PV were treated. The RRPVD1 was 0.0% (0.0-11.1%). Severe PVS was found in 18 PV during a follow-up of 12 months (range 6-13). The log-rank analysis confirmed a strong association between a RRPVD1 >/=25% and the development of PVS (hazard ratio: 7.1; 95% confidence interval 3.8-13.5, P < 0.0001). By multivariate Cox regression model, after adjustment of procedure variables, RRPVD1 was the strongest predictor of development of severe PVS. RRPVD1 >/=25% was a strong independent predictor of development of severe PVS.

Aged↗

PubMed2005

Percutaneous pulmonary vein stenting for the treatment of severe stenosis after pulmonary vein isolation.

INTRODUCTION: Pulmonary vein stenosis (PVS) is a potential complication of pulmonary vein isolation (PVI) using radiofrequency energy. The aim of our study was the evaluation of the severity and long-term outcome of primary angioplasty and angioplasty with pulmonary vein stenting for PVS. METHODS AND RESULTS: Twelve patients with 15 PVS (greater than 70% stenosis) were prospectively evaluated. Primary dilation of the stenosis was performed because of clinical symptoms (10 patients) and/or the lung perfusion scans showed a significant perfusion defect (11 patients). Magnetic resonance imaging and lung perfusion scans performed before, directly after, during 3-month, and 6-month follow-up. In the stenting group additional multislice CT-scans directly after, during 6-month, and 12-month follow-up were performed. Within 2 months after primary balloon angioplasty, the PV size parameters were significantly reduced (P < 0.001) with recurrence of PVS in 11 of 15 PVs (73%). Pulmonary vein stenting in 8 patients and 11 PVs resulted in no vein stenosis during 12-month follow-up. Normalization of lung perfusion was noted in 8 of 12 patients. We observed 2 patients with hemoptysis during PV dilation, as severe complications with potential life-threatening character. CONCLUSION: PVS stenting seems to be superior to balloon angioplasty and effective at least over a period of 12 months in treating acquired PVS after pulmonary vein isolation.

Angioplasty, Balloon↗

PubMed2004

N-terminal B-type natriuretic peptide predicts extent of coronary artery disease and ischemia in patients with stable angina pectoris.

BACKGROUND: B-type natriuretic peptide (BNP) and its N-terminal fragment (NT-proBNP) are elevated in patients with acute coronary syndromes and are closely linked to prognosis. Because there is only a small amount of data available concerning NT-proBNP in patients with stable angina pectoris, we aimed to determine whether NT-proBNP is of additional diagnostic value in these patients. METHODS AND RESULTS: Ninety-four patients with stable angina pectoris were prospectively included. All patients underwent exercise testing and coronary angiography, and 91 patients received thallium-201 single-photon emission computed tomography myocardial scintigraphy. NT-proBNP was analyzed at rest and after exercise testing. NT-proBNP was elevated in patients with inducible myocardial ischemia shown by single-photon emission computed tomography (396 +/- 80 pg/mL vs 160 +/- 101 pg/mL; P <.01) closely linked to the extent of coronary artery disease (CAD) (no CAD, 148 +/- 29 pg/mL; 1- or 2-vessel disease, 269 +/- 50 pg/mL; 3-vessel disease 624 +/- 186 pg/mL; P <.01). In a multivariate analysis, NT-proBNP was an independent predictor for CAD. The area under the curve of the receiver operating characteristic curve was 0.72 for NT-proBNP to predict CAD. Using an optimized cut off level of 214 pg/mL, CAD can be predicted with high accuracy. The total test efficiency of exercise testing can be improved from 1.46 to 1.52 when combined with NT-proBNP measurement. CONCLUSION: NT-proBNP is elevated in patients with stable angina pectoris and has a close correlation to disease severity. Combining the measurement of NT-proBNP with exercise testing, the test accuracy for predicting severe CAD can be improved. Our data show an incremental value of NT-proBNP in the diagnostic process of stable angina pectoris.

Aged↗

PubMed2004

Long-term follow-up after the mini-maze procedure.

BACKGROUND: Atrial fibrillation (AF) is associated with significant morbidity and mortality. The standard to treat AF surgically is the Cox maze III procedure but owing to its complexity it is not performed on a regular basis. Meanwhile several maze variants have been developed but their long-term results are still not well known. METHODS: From November 1995 until May 2002 a mini-maze procedure was performed upon 77 patients aged 64 +/- 8.7 years with chronic symptomatic AF. Electrophysiological evaluation, magnetic resonance imaging, echocardiography and electrocardiographic evaluations were performed after 3 and 12 months. After a mean follow-up of 50 +/- 2.6 months a standard questionnaire was sent to all patients. RESULTS: Early and late mortality was 1.2% and 9.3% respectively. Actuarial survival was 91%, 90%, and 87% after 1, 3, and 5 years respectively. Left bundle branch block was an independent risk factor for late death (p = 0.02). Patients who were in sinus rhythm at follow-up had significantly better survival rate as compared with the patients still in AF. Seventy-one percent of patients were in sinus rhythm or paced by an atrial pacemaker. Predictors for restoration of sinus rhythm were absence of preoperative mitral insufficiency (p = 0.03) and larger left atrium (p = 0.04). The presence of preoperative tricuspid insufficiency (p = 0.03) and larger right atrium (p = 0.017) were predictors for postoperative pacemaker implantation. CONCLUSIONS: The mini-maze procedure can be carried out with satisfactory early and long-term results regarding mortality and restoration of sinus rhythm. Prophylactic implantation of biventricular pacemakers in patients with left bundle branch block may decrease late mortality. Every effort should be done to cure AF as it affects long-term survival.

Adult↗

PubMed2004

Decreased pulmonary perfusion in pulmonary vein stenosis after radiofrequency ablation: assessment with dynamic magnetic resonance perfusion imaging.

STUDY OBJECTIVES: The functional impact of pulmonary vein (PV) stenosis on pulmonary perfusion after radiofrequency ablation (RFA) for atrial fibrillation (AF) has not been systematically evaluated previously. Therefore, we correlated magnetic resonance (MR) pulmonary perfusion imaging with single-photon emission CT (SPECT) perfusion and with the degree of PV stenosis (PVS) apparent on MR angiography (MRA) after RF ablation. SETTING: Joint radiology-cardiology collaborative magnetic resonance unit at the Kerckhoff Heart Center. DESIGN AND PATIENTS: This was a cohort study of 110 patients who were routinely examined by MRA after RFA for AF, whereby 51 patients with a PV diameter reduction of > 25% or with clinical symptoms (ie, dyspnea and cough) were enrolled into the study. Patients were examined at follow-up by MR perfusion imaging and MRA, and the results were compared to those from patients who underwent SPECT scanning and from a control group of 26 untreated patients. Twelve patients underwent PVS dilatation as well as 22 sequential follow-up examinations. METHODS: Pulmonary perfusion was evaluated using a dynamic contrast-enhanced three-dimensional MR perfusion sequence (1.5 T, 2.5-s temporal resolution, and 0.05 cm spatial resolution), and high-resolution, contrast-enhanced MRA was performed to measure PV diameter. PV dilatation was performed using an angioplasty catheter that was 8 to 10 mm in diameter. RESULTS: The localization and extent of perfusion defects measured by MRI or SPECT scanning were precisely matched. MR perfusion imaging detected 20 of 21 perfusion defects (sensitivity, 95.2%; specificity, 100%). PVSs and perfusion deficits correlated closely and showed the following threshold: perfusion decreased substantially in PVs 6 mm in diameter. After PVS dilatation, perfusion was restored partially after weeks, and complete normalization was seen in 4 of 12 patients (33%). CONCLUSIONS: PVSs caused severe perfusion deficits, which were reliably demonstrated by MR perfusion imaging. Clinical symptoms correlated better with MR perfusion than they did with MRA. The combination with MRA to assess underlying PVS allowed a "one-stop-shopping" MRI procedure to be carried out. The results led to alterations of RFA techniques, and therefore MRA and MR perfusion imaging may be beneficial in patient follow-up and in evaluating new ablation techniques.

Atrial Fibrillation↗

PubMed2003

Magnetic resonance to assess the aortic valve area in aortic stenosis: how does it compare to current diagnostic standards?

OBJECTIVES: The purpose of the present study was to evaluate whether magnetic resonance (MR) planimetry of the aortic valve area (AVA) may prove to be a reliable, non-invasive diagnostic tool in the assessment of aortic valve stenosis, and how the results compare with current diagnostic standards. BACKGROUND: Current standard techniques for assessing the severity of aortic stenosis include transthoracic and transesophageal echocardiography (TEE) as well as transvalvular pressure measurements during cardiac catheterization. METHODS: Forty consecutive patients underwent cardiac catheterization, TEE, and MR. The AVA was estimated by direct planimetry (MR, TEE) or calculated indirectly via the peak systolic transvalvular gradient (catheter). Pressure gradients from cardiac catheterization and Doppler echocardiography were also compared. RESULTS: By MR, the mean AVA(max) was 0.91 +/- 0.25 cm(2); by TEE, AVA(max) was 0.89 +/- 0.28 cm(2); and by catheter, the AVA was calculated as 0.64 +/- 0.26 cm(2). Mean absolute differences in AVA were 0.02 cm(2) for MR versus TEE, 0.27 cm(2) for MR versus catheter, and 0.25 cm(2) for TEE versus catheter. Correlations for AVA(max) were r = 0.96 between MR and TEE, r = 0.47 between TEE and catheter, and r = 0.44 between MR and catheter. The correlation between Doppler and catheter gradients was r = 0.71. CONCLUSIONS: Magnetic resonance planimetry of the AVA correlates well with TEE and less well with the catheter-derived AVA. Invasive and Doppler pressure correlated less well than those obtained from planimetric techniques. Magnetic resonance planimetry of the AVA may provide an accurate, non-invasive, well-tolerated alternative to invasive techniques and transthoracic echocardiography in the assessment of aortic stenosis.

Adult↗

PubMed2003

Pulmonary vein diameter reduction after radiofrequency catheter ablation for paroxysmal atrial fibrillation evaluated by contrast-enhanced three-dimensional magnetic resonance imaging.

BACKGROUND: Radiofrequency catheter ablation (RFCA) is a promising intervention to treat atrial fibrillation. However, pulmonary vein (PV) stenosis after RFCA has been reported. The aim of this study was to investigate the incidence and time course of pulmonary vein stenosis after RFCA within a period of 3 months. Contrast-enhanced magnetic resonance angiography (MRA) was used to visualize pulmonary veins and was compared with radiographic angiography. METHODS AND RESULTS: Forty-six consecutive patients with symptomatic paroxysmal atrial fibrillation had RFCA in the orifice of 138 pulmonary veins. Comparison of diameters measured in 44 untreated vessels either by radiographic angiography or with MRA established the reliability of MRA (r=0.934). MRA measurements revealed an incidence of relevant diameter reductions of > or =25% or stenosis of > or =50% after RFCA of 25 of 138 (18.1%) treated vessels 1 day and/or 3 months after ablation. A progression of diameter reduction after RFCA was observed in 8.3% (maximum 75%), whereas a regression was observed in 6.3% of treated PVs. Ablation at a radial angle of >180 degrees of a pulmonary vein orifice increased the risk of diameter reduction significantly compared with ablation at a radial angle < or =180 degrees (P=0.002). CONCLUSIONS: The occurrence and progression of PV stenosis is a potential significant complication of RFCA in the orifice of pulmonary veins. These findings may have an impact on the technical performance of this intervention. In addition, long-term studies will be necessary to evaluate lumen reduction over time. MRA is a noninvasive, reproducible imaging modality for this purpose.

Angiography↗

PubMed2002

[Role of atherectomy devices in interventional cardiology].

BACKGROUND: Unsatisfactory results and restenosis rates of up to 70% in complex coronary lesions created the necessity for alternative methods of percutaneous revascularization. Debulking of excess tissue seemed a promising approach in comparison to conventional PTCA. Most frequently used techniques included directional coronary atherectomy (DCA), laser angioplasty (ELCA), and rotational atherectomy (rotablation, RA). Neither of these techniques managed to establish a clear advantage over conventional PTCA so that they are indicated only under special circumstances. Even in a randomized controlled comparison of PTCA and rotablation in the treatment of in-stent restenosis, rotablation failed to show a clear advantage. AIM: This review aims to give an overview over currently used atherectomy techniques and their role in interventional cardiology.

Angioplasty, Balloon, Coronary↗

PubMed2001

Correlation of 3D MR coronary angiography with selective coronary angiography: feasibility of the motion-adapted gating technique.

The aim of this study was to verify the feasibility of a respiratory motion compensation technique (motion-adapted gating, MAG) for visualization of coronary arteries (CA) by correlation with selective coronary angiography (SCA). Fifteen subjects (11 patients, mean age 61.3 years, age range 41-73 years; and 4 healthy volunteers, mean age 32.3 years, age range 31-35 years) were investigated. A Philips Gyroscan ACS-NT was used, operating at 1.5 T, was combined with the PowerTrak 6000 gradient system. An ECG-triggered, respiratory motion-gated 3D turbo field echo sequence was used. The real-time algorithm utilized the concept of k-space weighting in combination with automatic analysis of respiratory motion. The main CA were investigated. Qualitative analysis was performed by three blinded investigators. Visibility was graded on a five-point scale (0=not visualized, 1=insufficient, 2=sufficient, 3=good, 4=excellent). Segments graded 2-4 were defined as adequately visualized. Sixty-two of 88 assessable CA segments in patient, and 22 of 32 in volunteer group were adequately visualized. Visibility of CA was classified as excellent for proximal RCA (avg. 3.6+/-0.5), good for LM, proximal LAD, proximal LCX, middle RCA and sufficient for middle LAD. Sensitivity, specificity, positive and negative predictive values for coronary MRA in detection of CA stenoses with luminal narrowing >/=50% were 88, 94, 83, and 96%, respectively. Magnetic resonance imaging in combination with MAG has proven to be a promising technique for noninvasive imaging of CA due to good image quality and a patient convenient free-breathing technique.

Adult↗

PubMedDate not supplied

Cardiac angiosarcoma diagnosed and characterized by cardiac magnetic resonance imaging.

Primary cardiac malignancies are rare. New imaging methods like cardiac magnetic resonance imaging (MRI) play an important role in the early diagnosis and differentiation of cardiac masses. By presenting the case of a 63-year-old woman with an angiosarcoma of the right atrium and its characteristic findings on cardiac MRI, the role of this new imaging method is emphasized.

Female↗