MR guided cardiac ablation: how to build an interventional magnetic resonance suite and what's the role of the imaging.

Magnetic resonance (MR) represents a new interesting imaging approach for guiding electrophysiology (EP)-based ablation procedures of atrial flutter and typical atrial fibrillation. This new approach permits to reach good results if compared with conventional EP ablation. Tissue characterization by MR permits to detect cardiac anatomy and pathological substrate like myocardial scars well visualized with late gadolinium enhancement (LGE) sequences. Intra-procedural imaging is useful to real-time follow the catheter during the ablation procedure and at the same time to visualize cardiac anatomy in addition to understanding if the ablation is correctly performed using oedema sequences. Performing cardiac ablations inside an MR room permits to reduce radiation exposure and occupational illnesses.

Cardiac magnetic resonance in Fabry disease.

Fabry disease (FD) is a rare X-linked inherited lysosomal storage disorder caused by deficient a-galactosidase A activity that leads to an accumulation of glycolipids, mainly globotriaosylceramide (Gb3) and globotriaosylsphingosine, in affected tissues, including the heart. Cardiovascular involvement usually manifests as left ventricular hypertrophy (LVH), myocardial fibrosis, heart failure, and arrhythmias, which limit the quality of life and represent the most common causes of death. Following the introduction of enzyme replacement therapy, early diagnosis and treatment have become essential in slowing down the disease progression and preventing major cardiac complications. Recent advances in the understanding of FD pathophysiology suggest that in addition to Gb3 accumulation, other mechanisms contribute to the development of cardiac damage. FD cardiomyopathy is characterized by an earlier stage of glycosphingolipid accumulation and a later one of hypertrophy. Morphological and functional aspects are not specific in the echocardiographic evaluation of Anderson-Fabry disease. Cardiac magnetic resonance with tissue characterization capability is an accurate technique for the differential diagnosis of LVH. Progress in imaging techniques has improved the diagnosis and staging of FD-related cardiac disease: a decreased myocardial T1 value is specific of FD. Late gadolinium enhancement is typical of the later stage of cardiac involvement but as in other cardiomyopathy is also valuable to predict the outcome and cardiac response to therapy.

Double-chambered left ventricle: An unusual finding in a middle-aged woman.

Double-chambered left ventricle (DCLV) is a rare congenital abnormality and is characterized by the subdivision of the left ventricle into two separate chambers by an abnormal septum or muscle band. This rare congenital entity is usually diagnosed in the neonatal or pediatric age. Nevertheless, it can be asymptomatic and incidentally found in the adulthood. A comprehensive multimodality imaging approach is crucial for the correct final diagnosis.

Complication detection in MRI guided cardiac ablation: Atrial wall damage and hepatic oedema.

Magnetic resonance imaging is a novel imaging technique for guiding electrophysiology based ablation operations for atrial flutter and typical atrial fibrillation. When compared to standard electrophysiology ablation, this innovative method allows for better outcomes. Intra-procedural imaging is important for following the catheter in real time throughout the ablation operation while also seeing cardiac architecture and determining whether the ablation is being completed appropriately utilizing oedema sequences. At the same time, intra-procedural imaging allows immediate visualization of any complications of the procedure. We describe a case of a 67 year old male underwent an isthmus-cavo-tricuspid magnetic resonance-guided thermoablation procedure for atrial flutter episodes. During the procedure we noted an atypical focal thinning of the right atrial wall at the isthmus cava-tricuspidal zone. The post-procedural Black Blood T2 STIR showed an area of hyperintensity at the hepatic dome and glissonian capsule, which was consistent with intraparenchymal hepatic oedema, in close proximity to the atrial finding. Given the opportunity to direct monitoring of adjacent tissues, we aim to highlight with our case the ability of magnetic resonance-guided cardiac ablation to immediately detect peri-procedural complications in the ablative treatment of atrial fibrillation.

Effect of heliox on heart rate kinetics and dynamic hyperinflation during high-intensity exercise in COPD.

Respiratory mechanical abnormalities in patients with chronic obstructive pulmonary disease (COPD) may impair cardiodynamic responses and slow down heart rate (HR) kinetics compared with normal resulting in reduced convective oxygen delivery during exercise. We reasoned that heliox breathing (79% helium-21% oxygen) and the attendant reduction of operating lung volumes should accelerate HR kinetics in the transition from rest to high-intensity exercise. Eleven male ambulatory patients with clinically stable COPD undertook constant work-rate cycle testing at 80% of each individuals' maximum work capacity while breathing room air (RA) or heliox (HX), randomly. Mean response time (MRT) for HR and dynamic end-expiratory lung volume (EELV) were measured. Resting EELV was not affected by HX breathing, while exercise EELV decreased significantly by 0.23 L at isotime during HX breathing compared with RA. During HX breathing, MRT for HR significantly accelerated (p = 0.002) by an average of 20 s (i.e., 17%). Speeded MRT for HR correlated with indices of reduced lung hyperinflation, such as EELV at isotime (r = 0.88, p = 0.03), and with improved exercise endurance time (r = -0.64, p = 0.03). The results confirm that HX-induced reduction of dynamic lung hyperinflation is associated with consistent improvement in indices of cardio-circulatory function such as HR kinetics in the rest-to-exercise transition in COPD patients.

Assessment of interstitial lung disease in systemic sclerosis using the quantitative CT algorithm CALIPER.

Interstitial lung disease (ILD) remains a major cause of morbidity and mortality in systemic sclerosis (SSc). Study aim is to characterize and quantify SSc-ILD by using Computer-Aided Lung Informatics for Pathology Evaluation and Rating (CALIPER). Secondly, our objective is to evaluate which radiological pattern is predictive of lung function decline at 12 months follow-up. In the prospective study (IRB 5435), 66 SSc patients underwent high-resolution computerized tomography (HRCT) at baseline. HRCT was performed according to standard protocol using a CT 64GE light speed VCT power scanner. CALIPER classified lung parenchyma on volume units. Every volume unit was classified into radiological parenchymal patterns (honeycombing, reticular and ground glass). Pulmonary function tests (PFTs) were performed at baseline and after 12 months of follow-up. Cigarette smoking and other lung diseases unrelated to SSc are exclusion criteria. CALIPER analysis showed normal lung parenchyma 87.4 ± 9.8%, ground glass 2.8 ± 5.3%, reticular 4 ± 5.7%, and honeycombing 1 ± 1%. In multiple regression analysis, FEV1 (p < 0.0001), FVC (p = 0.001), and DLCO (p < 0.0001) measurements at baseline showed a negative correlation with the reticular pattern percentage. At follow-up, DLCO reduction showed a positive correlation (p < 0.001) with the percentage of ground glass pattern (r = 0.33, beta coefficient = 0.51). In the ROC curve analysis, ground glass score is a good predictor (0.75, p = 0.009; 95% CI 0.59-0.91) of DLCO worsening, defined as a decrease of more than 10% of DLCO. Using a cutoff ≥ 4.5 for ground glass score, the RR for DLCO worsening is 6.8 (p < 0.01; 95% CI 1.6-29.2). The results of this study show that CALIPER is useful not only for quantifying lung damage but also for assessing worsening PFTs, but larger studies are needed to confirm these preliminary data.Key Points• At baseline reticular pattern showed negative correlation with PFTs• At follow-up ground glass pattern predicts worsening of DLCO• CALIPER is a useful to quantify lung damage.

Minute ventilation and heart rate relationship for estimation of the ventilatory compensation point at high altitude: a pilot study.

BACKGROUND: The ventilatory compensation point (VCP) is an exercise threshold which has been used in the design of training programs in sports medicine and rehabilitation. We recently demonstrated that changes in the slope of the minute ventilation to heart rate relationship (ΔV˙E/ΔHR) can be utilized for estimation of the VCP during incremental exercise at sea level (SL). We hypothesized that in hypoxic conditions, such as high altitude (HA), VCP can be also reliably estimated by ΔV˙E/ΔHR. METHODS: At SL and on immediate ascent to HA (5,050 m), six healthy subjects (42 ± 14 SD years) performed a maximal incremental exercise test on a cycle ergometer; O2 uptake (V˙O2), CO2 output (V˙CO2), V˙E, and HR were measured breath-by-breath. The ΔV˙E/ΔHR method for VCP estimation was compared to the standard method using the ventilatory equivalent for CO2 (V˙E/V˙CO2) and end-tidal PCO2 (PETCO2). The ΔV˙E/ΔHR slope values below (S1) and above (S2) VCP were computed by linear regression analysis. RESULTS: A significant difference between S1 and S2 was observed, at SL and HA, for both the ΔV˙E/ΔHR and V˙E/V˙CO2 methods for VCP estimation. A good agreement between the two methods (ΔV˙E/ΔHR vs. V˙E/V˙CO2) was found for both environmental conditions; the mean difference ± 2 SD of V˙O2 at VCP (VCP-V˙O2) was -22 ± 112 ml/min at SL and 39 ± 81 ml/min at HA. The VCP-V˙O2 was significantly lower at HA compared to SL; in addition, S1 and S2 mean values were significantly higher at HA compared to SL. CONCLUSION: At HA, VCP may be reliably estimated by the ΔV˙E/ΔHR method.

Effect of camptocormia on lung volumes in Parkinson's disease.

Camptocormia is defined as an abnormal flexion of the thoracolumbar spine of 45°, or more, that typically increases during walking or standing and completely disappears in the supine position. Camptocormia may occur in patients with Parkinson's disease; when it does, it is usually associated with greater disease severity. Respiratory complications, which may be secondary to abnormal chest function, are one of the most frequent causes of death in patients with Parkinson's disease. No data on lung volumes are available for Parkinson's disease patients with camptocormia. The aim of this study was to evaluate the effect of camptocormia on lung function. Eleven patients with Parkinson's disease and camptocormia and ten age-matched healthy subjects underwent lung spirometry (in the standing position, inclining the trunk forward at approx. 45° and supine) measurement of arterial oxygen-hemoglobin saturation and heart rate. We found that Parkinson's disease with camptocormia is not associated with major clinical changes in lung volumes.

Validation of a predictive survival model in Italian patients with cystic fibrosis.

BACKGROUND: In 2001 Liou published a 5-year survival model using CFF Registry data. AIMS: To evaluate its validity in predicting survival in Italian CF patients. METHODS: In a retrospective study on 945 patients, the 9 variables selected by Liou were analyzed, vital status on December 2008 recorded and observed and expected deaths compared. To develop a new model, patients were randomly divided into a derivation (n=475) and a validation sample (n=470). RESULTS: A significant difference was found between observed and expected deaths based on Liou's model (62 vs 94), with a 34% reduction in mortality (p<0.05). A new model (based on FEV1, Staphylococcus aureus and Burkholderia cepacia complex infection, number of pulmonary exacerbations/year) was generated, that correctly predicted survival in the validation sample (31 observed vs 29 expected deaths, p=0.660). CONCLUSIONS: The Liou model did not adequately predict 5-year survival in our CF population that, compared to the one in which it was originally tested, could benefit from 10 years of improvement in treatments and practice patterns. A new generated model, based on only four variables, was more accurate in predicting 5-year survival in Italian CF patients.

True posterior tibial artery aneurysm in a young patient: surgical or endovascular treatment?

Aneurysms of tibial arteries are extremely rare. Here we report a case of a true posterior tibial artery aneurysm in a young patient without any associated pathology and discuss surgical and endovascular treatment. A young Caucasian male was admitted to our department for painful and pulsatile swelling of the right calf. Colour Doppler ultrasound scan visualised an aneurysmal dilation of the posterior tibial artery. The patient had no trauma to the area and denied other history of vascular disease. Angio-CT and angio-magnetic resonance imaging showed a larger aneurysm compared to ultrasound scan. We performed an embolisation of the aneurysm because of the risk of rupture, as distal collateral circulation ensured foot vascularisation. Endovascular treatment of aneurysms of small arteries seems to be a safe therapeutic and non-invasive choice, particularly in young patients in whom the presence of collaterals guarantees distal vascularisation.