MEDAFI-Trial (Micro-embolization during ablation of atrial fibrillation): comparison of pulmonary vein isolation using cryoballoon technique vs. radiofrequency energy.

AIMS: Cerebral embolism is a possible serious complication during catheter ablation of atrial fibrillation (AF). The purpose of this prospective pilot study was to analyse the incidence and possible impact of cryo ablation on cerebral lesions and possible differences to radiofrequency (RF) ablation during pulmonary vein isolation (PVI). METHODS AND RESULTS: Pulmonary vein isolation was performed in 89 patients, either with the cryoballoon technique (n = 45) or with RF ablation (n = 44). Phenprocoumon was stopped 3 days before intervention and replaced by subcutaneous low-molecular-weight heparin. During the catheter procedure, an infusion of unfractionated heparin was maintained to achieve an activated clotting time (ACT) of > 300 s. Cerebral magnetic resonance imaging scans were performed 1 day before and after PVI, and at 3-month follow-up. Chronic lesions were observed in 11 patients (12.3%) before PVI without statistically significant difference between the two groups. None of the patients had neurological symptoms during or following the procedure. Seven patients (7.9%) developed acute lesions 1 day after PVI, without statistically significant difference between the group treated by cryoenergy (8.9%) and RF ablation (6.8%). Patients with acute lesions were significantly older compared with those without acute cerebral lesions. No additional cerebral lesions during follow-up were observed. CONCLUSION: A considerable portion of patients with AF but without any neurological symptoms had chronic cerebral lesions before PVI. Additional acute lesions could be added after the procedure. Both ablation techniques showed additional cerebral acute lesions with no neurological symptoms after PVI.

Immunohistological basis of the late gadolinium enhancement phenomenon in tako-tsubo cardiomyopathy.

AIMS: Tako-tsubo cardiomyopathy is characterized by transient contractile dysfunction after emotional or physical stress. Only few patients show late gadolinium enhancement (LGE) in cardiovascular magnetic resonance imaging (MRI). It was the purpose of this study to elucidate the histological basis of this phenomenon. METHODS AND RESULTS: The study included 15 patients. Tako-tsubo cardiomyopathy was diagnosed by coronary angiography and ventriculography. Cardiac MRI was performed within 24 h of admission. Endomyocardial biopsies were taken during the acute phase and after recovery. The content of fibrosis was determined by immunohistochemical staining of collagen-1. In the acute phase, cardiac MRI revealed LGE in five patients. This was completely reversed at follow-up [14, inter-quartile range (IQR) 11-14.5 days]. All patients showed a significant increase of collagen-1 compared with control tissue. Moreover, the amount of collagen-1 was significantly higher in LGE positive patients (LGE positive: 18.84, IQR 13.82-19.75 AU/microm(2); LGE negative: 7.57, IQR 5.41-9.19 AU/microm(2), P = 0.001). The presence of LGE was not associated with poorer left ventricular function. CONCLUSION: The presence of LGE cannot rule out tako-tsubo cardiomyopathy. Instead it defines a special subgroup of patients with a disproportionate increase of extracellular matrix.

Pulmonary vein stenting for the treatment of acquired severe pulmonary vein stenosis after pulmonary vein isolation: clinical implications after long-term follow-up of 4 years.

INTRODUCTION: Severe pulmonary vein stenosis (PVS) after catheter ablation of atrial fibrillation (AF) is a well-recognized complication with a further reported incidence of 1.3%. The preferred therapy for symptomatic PVS is pulmonary vein (PV) angioplasty, but this treatment modality is followed by restenosis in 44-70%. Whether there is additional long-term benefit from PVS stenting is uncertain. The aim of this study was the evaluation of the long-term success after PV stenting of severe stenosis. METHODS AND RESULTS: Ten patients (pts) with 13 PVS were prospectively evaluated. PV stenting was performed with Palmaz Genesis stents. Magnetic resonance imaging (MRI), lung perfusion scans, and CT-scans were performed before, directly after, and every 12 months thereafter. Primary endpoint of the study was the occurrence of restenosis after PV stenting. After a median follow-up of 47.7 (IQRs 25/75 47.2-48.5) months, the primary endpoint was achieved in 3 out of 13 PVs (23% of the treated PVs). We observed two in-stent restenosis 2 and 4 years after PV stenting. These pts experienced onset of dyspnea some weeks before. After an additional balloon angioplasty, the in-stent restenosis was resolved. In one asymptomatic patient, we observed an occlusion of the PV stent 13 months poststenting. Normalization of lung perfusion was noted 4 years after PV stenting versus directly poststenting in all pts without in-stent restenosis (n = 7). CONCLUSION: PVS stenting with stent sizes >or=10 mm seems to be an adequate therapy modality for treatment of severe acquired PVS. Late in-stent restenosis after PVS stenting can occur. The normalization of the initially disturbed lung perfusion scan is possible and remains stable, even 4 years after PVS stenting.

Detection of relevant coronary artery disease using dual-source computed tomography in a high probability patient series: comparison with invasive angiography.

BACKGROUND: Computed tomography (CT) enables detection of coronary artery stenoses, but its use is limited by deficient evaluation at elevated heart rates. The accuracy of dual-source CT (DSCT) for the detection of coronary artery disease (CAD) was assessed in 76 patients at high probability of CAD without heart rate control and compared with quantitative coronary angiography (QCA). Methods and Results The 76 patients (47 males, mean age 65.5+/-10 years) underwent DSCT without preceding heart rate control. Data sets were evaluated by 2 observers in consensus with respect to stenoses >50% decreased diameter. QCA served as the standard of reference. Mean heart rate during scanning was 68+/-9 beats per min, and the average Agatston score was 337+/-560. Of 1,160 coronary artery segments, all but 3 were visualized artefact-free; 58 coronary stenoses were correctly detected by CT angiography. In the segment-based analysis, sensitivity was 98.3%, specificity 99.2% and accuracy 99%; patient based analysis revealed a sensitivity of 100%, specificity of 83.3% and overall accuracy of 92.1%. Conclusions Even at elevated heart rates, DSCT can reliably detect coronary artery stenoses and the results correlate well with those for invasive coronary angiography.

Image quality on dual-source computed-tomographic coronary angiography.

Multi-detector CT reliably permits visualization of coronary arteries, but due to the occurrence of motion artefacts at heart rates >65 bpm caused by a temporal resolution of 165 ms, its utilisation has so far been limited to patients with a preferably low heart rate. We investigated the assessment of image quality on computed tomography of coronary arteries in a large series of patients without additional heart rate control using dual-source computed tomography (DSCT). DSCT (Siemens Somatom Definition, 83-ms temporal resolution) was performed in 165 consecutive patients (mean age 64 +/- 11.4 years) after injection of 60-80 ml of contrast. Data sets were reconstructed in 5% intervals of the cardiac cycle and evaluated by two readers in consensus concerning evaluability of the coronary arteries and presence of motion and beam-hardening artefacts using the AHA 16-segment coronary model. Mean heart rate during CT was 65 +/- 10.5 bpm; visualisation without artefacts was possible in 98.7% of 2,541 coronary segments. Only two segments were considered unevaluable due to cardiac motion; 30 segments were unassessable due to poor signal-to-noise ratio or coronary calcifications (both n = 15). Data reconstruction at 65-70% of the cardiac cycle provided for the best image quality. For heart rates >85 bpm, a systolic reconstruction at 45% revealed satisfactory results. Compared with earlier CT generations, DSCT provides for non-invasive coronary angiography with diagnostic image quality even at heart rates >65 bpm and thus may broaden the spectrum of patients that can be investigated non-invasively.

Radiation dose exposure in multislice computed tomography of the coronaries in comparison with conventional coronary angiography.

BACKGROUND: Radiation dose exposure is increased in multislice spiral computed tomography (MSCT) compared to conventional coronary angiography (CXA). METHODS: Retrospective data analysis of 56 patients (66+/-8 years, 49 males, body surface area 1.98+/-0.18 m(2), heart rate 64+/-11 bpm) who underwent MSCT and CXA was performed (MSCT: 16-slice scanner, rotation time 0.375 s, 120 kV, ECG-pulsing; CXA: current technique system build in 2003). Ten patients with bypass grafts underwent bypass angiography in CXA and MSCT. To compare the radiation doses of both investigations, the effective dose (ED) was chosen as the analysis variable. RESULTS: The mean ED for MSCT was 9.76+/-1.84 mSv (n=46) for patients without bypass grafts; with calcium scoring the mean ED was 12.46+/-2.23 mSv (n=46). In comparison, the mean ED of CXA was 2.60+/-1.27 mSv (n=46) for patients without bypass grafts; with bypass grafts (n=10) the mean ED for MSCT was 12.95+/-1.75 mSv, for CXA of 6.27+/-4.04 mSv, respectively. In MSCT heart rates of 60 bpm (8.86+/-1.24 mSv versus 10.53+/-1.86 mSv). CONCLUSIONS: MSCT is still associated with a higher radiation dose exposure than CXA. The radiation dose relation is more favorable for MSCT than for CXA in patients with bypass grafts in comparison to patients without bypass grafts. This study emphasizes the importance of dose reduction techniques.

Use of automatic exposure control in multislice computed tomography of the coronaries: comparison of 16-slice and 64-slice scanner data with conventional coronary angiography.

OBJECTIVE: To evaluate the radiation-dose-reduction potential of automatic exposure control (AEC) in 16-slice and 64-slice multislice computed tomography (MSCT) of the coronary arteries (computed tomography angiography, CTA) in patients. The rapid growth in MSCT CTA emphasises the necessity of adjusting technique factors to reduce radiation dose exposure. DESIGN: A retrospective data analysis was performed for 154 patients who had undergone MSCT CTA. Group 1 (n = 56) had undergone 16-slice MSCT without AEC, and group 2 (n = 51), with AEC. In group 1, invasive coronary angiography (ICA) had been performed in addition. Group 3 (n = 47) had been examined using a 64-slice scanner (with AEC, without ECG-triggered tube current modulation). RESULTS: In group 1, the mean (SD) effective dose (ED) for MSCT CTA was 9.76 (1.84) mSv and for ICA it was 2.6 (1.27) mSv. In group 2, the mean ED for MSCT CTA was 5.83 (1.73) mSv, which signifies a 42.8% dose reduction for CTA by the use of AEC. In comparison to ICA, MSCT CTA without AEC shows a 3.8-fold increase in radiation dose, and the radiation dose of CTA with AEC was increased by a factor of 1.9. In group 3, the mean ED for MSCT CTA was 13.58 (2.80) mSV. CONCLUSIONS: This is the first study to show the significant dose-reduction potential (42.8%) of AEC in MSCT CTA in patients. This relatively new technique can be used to optimise the radiation dose levels in MSCT CTA.

Diagnostic value of the 16-detector row multislice spiral computed tomography for the detection of coronary artery stenosis in comparison to invasive coronary angiography.

OBJECTIVES: The aim of this study was to determine the diagnostic accuracy of 16-slice multislice spiral computed tomography (MSCT) of the coronaries and to provide data in a real clinical setting. Previous 16-slice MSCT studies presented data excluding patients with calcification, vessels of < 1.5 or 2 mm, and segments with impaired image quality. By including these data for 16-slice MSCT, a direct comparison with new data from 64-slice MSCT is possible. METHODS AND RESULTS: Sixty two patients with suspected or known coronary artery disease (CAD) were prospectively enrolled and underwent computed tomography angiography (CTA) and invasive coronary angiography (ICA). All vessels were evaluated for the presence of a significant coronary artery stenosis (>50%) using the American Heart Association (AHA) 15-segment model. From the evaluation of 917 segments, sensitivity, specificity, and positive and negative predictive value (NPV) (positive predictive value [PPV] and NPV) for the presence of relevant coronary stenosis were 73, 98, and 71 and 98% per segment and 94, 90, and 91 and 93% per patient, respectively. The influence of age, gender, body surface area (BSA), heart rate (HR), stents, and Ca(2+)-score value was analyzed. High Ca(2+)-score values were the only statistically significant predictor for impaired diagnostic accuracy. CONCLUSIONS: In summary, CTA with evaluation of all vessel segments in a broad spectrum of patients allowed accurate and fast noninvasive coronary artery evaluation, including evaluation of stented segments. These data are very similar to those published recently for 64-slice scanners.

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).

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.