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Abstract: Background: Lack of increase in left ventricular (LV) stroke volume (SV) during low-dose dobutamine stress (LDD) is attributed to exhausted cardiac contractile reserve in failing heart. However, the role of the afterload and preload in SV changes is underestimated. The aim of the study was to investigate the effects of LDD on preload reserve and afterload in patients with non-ischemic heart failure. Methods: 58 patients (age 62years) underwent LDD (up to 20μg/kg/min) using cardiac magnetic resonance. Results: LV-SV increased by 27% in 24 patients (p<0.001) (SV+), while decreased by 19% in 22 patients (p<0.001) (SV−). The LDD-to-rest reduction in preload, as defined by LV end-diastolic volume (EDV), was more pronounced in SV− than SV+ (24% and 8% respectively, p<0.05). The LLD-to-rest increase in systolic blood pressure to LV end systolic volume ratio, an index of LV contractility, was higher but not statistically different in SV+ in comparison to SV− (70% vs 48%, p=ns). Systemic vascular resistance during LDD tended to be higher in SV− (23%, p=ns), while it was significantly reduced in SV+ (9.5%, p<0.011), whereas arterial elastance (Ea) increased in SV− (30%, p<0.001) but decreased in SV+ (0.5%, p=0.04). At multivariable regression models LV-EF, LV-EDV and Ea significantly contributed to LV-SV changes in all patients. Also among SV+ and SV− LV-EDV and Ea revealed significant contribution to LV-SV change. Conclusions: At similar contractile reserve response, the lack of LDD-induced increase in LV-SV, can be related to reduced preload reserve as well as to increased afterload. [Copyright &y& Elsevier]

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Objectives: We investigated whether the presence of right ventricular (RV) abnormalities detected by cardiovascular magnetic resonance (CMR) predict adverse outcome in patients presenting with frequent premature ventricular complexes (PVCs) of left bundle branch block (LBBB) morphology. Background: CMR is a component of the diagnostic workup for the differential diagnosis between arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) and idiopathic RV tachycardia. RV abnormalities evaluated by CMR could have prognostic importance. Methods: Four hundred forty consecutive patients with >1,000 PVCs of LBBB morphology (minor diagnostic criterion of ARVC/D) and no other pre-existing criteria were prospectively enrolled. RV wall motion (WM), signal abnormalities, dilation, and reduced ejection fraction evaluated by CMR were considered imaging criteria of ARVC/D. Follow-up was performed evaluating an index composite end point of 3 cardiac events: cardiac death, resuscitated cardiac arrest, and appropriate implantable cardiac-defibrillator shock. Results: Subjects with multiple RV abnormalities (RVA-2 group) had worse outcome than the no-RVA group (hazard ratio [HR]: 48.6; 95% confidence interval [CI]: 6.1 to 384.8; p < 0.001). Of the 61 patients in the RVA-2 group, only 6 had a definite diagnosis of ARVC/D applying the Task Force Criteria. Also, subjects with a single imaging criterion (RVA-1 group) had worse outcome than the no-RVA group (HR: 18.2; 95% CI: 2.0 to 162.6; p = 0.01). Patients with only WM abnormalities had higher prevalence of cardiac events than no-RVA (HR: 27.2; 95% CI: 3.0 to 244.0; p = 0.03). Conclusions: In subjects with frequent PVC of LBBB morphology, CMR allows risk stratification. RV abnormalities were associated with worse outcome. [ABSTRACT FROM AUTHOR]

Background: Cardiovascular Magnetic resonance (CMR) with the late gadolinium enhancement (LGE) technique allows the detection of myocardial fibrosis in Hypertrophic cardiomyopathy (HCM). The aim of this study was to compare different methods of automatic quantification of LGE in HCM patients. Methods: Forty HCM patients (mean age 48 y, 30 males) and 20 normal subjects (mean age 38 y, 16 males) underwent CMR, and we compared 3 methods of quantification of LGE: 1) in the SD2 method a region of interest (ROI) was placed within the normal myocardium and enhanced myocardium was considered as having signal intensity >2 SD above the mean of ROI; 2) in the SD6 method enhanced myocardium was defined with a cut-off of 6 SD above mean of ROI; 3) in the RC method a ROI was placed in the background of image, a Rayleigh curve was created using the SD of that ROI and used as ideal curve of distribution of signal intensity of a perfectly nulled myocardium. The maximal signal intensity found in the Rayleigh curve was used as cut-off for enhanced myocardium. Parametric images depicting non enhanced and enhanced myocardium was created using each method. Three investigators assigned a score to each method by the comparison of the original LGE image to the respective parametric map generated. Results: Patients with HCM had lower concordance between the measured curve of distribution of signal intensity and the Rayleigh curve than controls (63.7±12.3% vs 92.2±2.3%, p < 0.0001). A cut off of concordance < 82.9% had a 97.1% sensitivity and 92.3% specificity to distinguish HCM from controls. The RC method had higher score than the other methods. The average extent of enhanced myocardium measured by SD6 and Rayleigh curve method was not significant different but SD6 method showed underestimation of enhancement in 12% and overestimation in 5% of patients with HCM. Conclusions: Quantification of fibrosis in LGE images with a cut-off derived from the Rayleigh curve is more accurate than using a fixed cut-off. [ABSTRACT FROM AUTHOR]

Background: Left ventricular hypertrophy (LVH) may be due to different causes, ranging from benign secondary forms to severe cardiomyopathies. Transthoracic Echocardiography (TTE) and ECG are the first-level examinations for LVH diagnosis. Cardiac magnetic resonance (CMR) accurately defines LVH type, extent and severity. Objectives: to evaluate the diagnostic and prognostic role of CMR in patients with TTE and/or ECG evidence of LVH. Methods: We performed CMR in 300 consecutive patients with echocardiographic and/or ECG signs of LVH. Results: Overall, 275 patients had TTE evidence of LVH, with initial suspicion of hypertrophic cardiomyopathy (HCM) in 132 (44%), cardiac amyloidosis in 41 (14%), hypertensive LVH in 48 (16%), aortic stenosis in 4 (1%), and undetermined LVH in 50 (16%). The initial echocardiographic diagnostic suspicion of LVH was confirmed in 172 patients (57.3%) and changed in 128 patients (42.7%, p < 0.0001): the diagnosis of HCM increased from 44% to 71% of patients; hypertensive and undetermined LVH decreased significantly (respectively to 4% and 5%). CMR allowed for a diagnosis in 41 out of 50 (82%) patients with undetermined LVH at TTE. CMR also identified HCM in 17 out of 25 patients with apparently normal echocardiography but with ECG criteria for LVH. Finally, the reclassification of the diagnosis by CMR was associated with a change in survival risk of patients: after CMR reclassification, no events occurred in patients with undetermined or hypertensive LVH. Conclusions: CMR changed echocardiographic suspicion in almost half of patients with LVH. In the subgroup of patients with abnormal ECG, CMR identified LVH (particularly HCM) in 80% of patients. This study highlights the indication of CMR to better characterize the type, extent and severity of LVH detected at echocardiography and suspected with ECG. [ABSTRACT FROM AUTHOR]

Prolonged breath hold (BH) represents a valid model for studying the cardiac adaptation to acute hypoxemia in humans. Cardiac magnetic resonance (CMR) allows a three-dimensional, high-resolution, noninvasive, and nonionizing anatomical and functional evaluation of the heart. The aim of the study was to assess the adaptation of the cardiovascular system to prolonged BH in air. Ten male volunteer diving athletes (age 30 ± 6 yr) were studied during maximal BH duration with CMR. Four epochs were studied: I, rest; II and Ill, intermediate BH; and IV, peak BH. Oxygen saturation (So2), heart rate (HR), blood pressure (BP), systemic vascular resistance (VR), end-diastolic (EDV) and end-systolic volumes (ESV), stroke volume (SV), cardiac output (CO), ejection fraction (EF), maximal elastance index (EL), systolic wall thickening (SWT), and end-systolic wall stress (ESWS) of the left ventricle (LV) were measured in all four BH epochs. Average BH duration was 3.7 ± 0.3 min. So2 was reduced (1: 97 ± 0.2%, range 96–98%, vs. IV: 84 ± 2.0%, range 76–92%; P < 0.00001). BP, EDV, ESV, SV, CO, and ESWS linearly increased from epochs Ito IV, whereas EF, EL, and SWT showed an opposite behavior, decreasing from resting to epoch IV (all trends are P < 0.01). During prolonged BH in air, a marked enlargement of the LV chamber occurs in healthy diving athletes. This response to acute hypoxemia allows SV,CO, and arterial pressure to be maintained despite the severe reduction in LV contractile function. [ABSTRACT FROM AUTHOR]

The article presents an abstract on a paper titled "Progression of Myocardial Fibrosis and Functional Clinical Status in Hypertrophic Cardiomyopathy: A Study With Cardiac Magnetic Resonance," presented at the 2011 Society for Cardiovascular Magnetic Resonance (CMR)/Euro CMR Joint Scientific Sessions held in France.

Background Few studies have explored prognosis in patients with previous myocardial infarction (MI) with mild-moderate (MM) left ventricular (LV) dysfunction (D). The aim of our study was to investigate whether combining LV parameters obtained by cardiac magnetic resonance (CMR) improves risk stratification of patients with previous MI and MM-LV-D. Methods In 418 consecutive patients (63.3 ± 11.3 years old, female 12.9%) with previous MI, we quantified LVEF, volumes and wall motion score index (WMSI) and measured the infarct extent by late gadolinium enhancement (LGE). According to LVEF, patients were considered with normal LVEF (> 55%), MM-LV-D (LVEF > 30 and ≤ 55%) and severe (S) LV-D (LVEF ≤ 30). Results During follow-up (median, 39.7 months) cardiac events (cardiac death or appropriate intra-cardiac defibrillator shocks) occurred in 17/99 of patients with S-LV-D, in 15/201 with MM-LV-D, and in only 1/118 of those with normal LV-EF. After adjustment for age, an extent of LGE > 11.3%, a dilated LV (male > 112 ml/m 2 ; female > 92 ml/m 2 ) and a WMSI > 1.59 were associated with adverse cardiac events in patients with MM-LV-D. In patients with MM-LV-D, when each of these 3 factors was observed, the prognosis was worse respect to those with 1–2 factors and no factor ( p = 0.035 and p = 0.004, respectively). Prognosis was similar ( p = 0.61) between MM-LV-D patients with all 3 factors and those with S-LV-dysfunction. CONCLUSIONS. A multiparametric CMR approach, which includes LGE, dilated LV and WMSI, permits to identify post MI patients with MM-LV-D with a risk of cardiac events similar to those with S-LV-D. Further multicenter studies are needed to confirm our data. [ABSTRACT FROM AUTHOR]

Background In the absence of confounding electrocardiographic features, a prominent R wave in leads V1-V2 reflects a lateral myocardial infarction (MI). We hypothesized that repolarization abnormalities in V1-V2 could also reflect a lateral MI. Methods We retrospectively selected a group of 57 patients with a recent or previous first Q-wave MI involving left ventricular (LV) inferior and/or lateral wall at contrast-enhanced cardiac magnetic resonance (CMR). The location and extent of the MI at CMR were compared with electrocardiographic features. Results The infarction was located in the inferior wall in 12 patients (21%), in the lateral wall in 8 (14%), and in both walls in 37 patients (65%). Infarct size corresponded to 16.8 (SD 9.0%) of LV myocardium. Infarct extent in the inferior and lateral wall (8.3%, SD 7.2% vs. 8.4%, SD 7.5% of LV myocardium) did not differ significantly. Using multiple linear regression analysis, inferior Q-waves and inferior negative T waves were directly associated with infarct extent in the inferior wall (p = 0.014 and p = 0.010, respectively). A prominent R wave in V1 and a prominent anterior T wave (expressed by the T wave amplitude in V2 minus its amplitude in V6) were directly associated with MI extent in the lateral wall (p = 0.008 and p = 0.018), while inferior negative T waves were negatively associated (p = 0.006). Conclusions In patients with MI of the inferior and/or lateral wall, a prominent T wave in V2 with respect to V6 reflects greater infarct extent in the lateral wall. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the prevalence and correlates of right ventricular (RV) noncompaction (RVNC), RV systolic dysfunction, and RV myocardial fibrosis in patients with isolated left ventricular (LV) noncompaction (LVNC). For this purpose, cine and contrast-enhanced cardiac magnetic resonance imaging (MRI) was used. A total of 56 consecutive patients with isolated LVNC were included in the study. The diagnosis of isolated LVNC was based on the presence of standard cardiac MRI and clinical criteria. For each patient, cine and contrast-enhanced cardiac MR images were analyzed to evaluate the prevalence and correlates of RVNC, RV dysfunction, and late gadolinium enhancement (a surrogate of myocardial fibrosis) involving the RV. Mean age of the patient population was 45 ± 19 years; 35 patients (63%) were men. RVNC was observed in 5 patients (9%). Impaired RV systolic function was observed in 9 patients (16%). Late gadolinium enhancement was not observed in any RV segment. No association was found between wall motion abnormalities and noncompaction at RV segmental level (4 coefficient 0.041, p = 0.26). At multivariate analysis, LV ejection fraction was the only variable independently related to RV ejection fraction (β = 0.62, p <0.001). In conclusion, RV systolic dysfunction is present in a non-negligible proportion of patients with isolated LVNC; LV systolic function is the only variable independently related to RV systolic function. [ABSTRACT FROM AUTHOR]

Objectives: This study sought to assess the rate of progression of fibrosis by 2 consecutive cardiac magnetic resonance (CMR) examinations and its relation with clinical variables. Background: In hypertrophic cardiomyopathy (HCM) myocardial fibrosis, detected by late gadolinium enhancement (LGE), is associated to a progressive ventricular dysfunction and worse prognosis. Methods: A total of 55 HCM patients (37 males; mean age 43 ± 18 years) underwent 2 CMR examinations (CMR-1 and CMR-2) separated by an interval of 719 ± 410 days. Extent of LGE was measured, and the rate of progression of LGE (LGE-rate) was calculated as the ratio between the increment of LGE (in grams) and the time (months) between the CMR examinations. Results: At CMR-1, LGE was detected in 45 subjects, with an extent of 13.3 ± 15.2 g. At CMR-2, 53 (96.4%) patients had LGE, with an extent of 24.6 ± 27.5 g. In 44 patients, LGE extent increased significantly (≥1 g). Patients with apical HCM had higher increments of LGE (p = 0.004) and LGE-rate (p < 0.001) than those with other patterns of hypertrophy. The extent of LGE at CMR-1 and the apical pattern of hypertrophy were independent predictors of the increment of LGE. Patients with worsened New York Heart Association functional class presented higher increase of LGE (p = 0.031) and LGE-rate (p < 0.05) than those with preserved functional status. Conclusions: Myocardial fibrosis in HCM is a progressive and fast phenomenon. LGE increment, related to a worse clinical status, is more extensive in apical hypertrophy than in other patterns. [Copyright &y& Elsevier]

Abstract: Objectives: We investigated the prognostic role of myocardial fibrosis by delayed enhancement (DE) cardiovascular magnetic resonance (CMR) in nonischemic dilated cardiomyopathy (NICM) patients with no or mild symptoms of heart failure (HF). Methods: A prospective cohort of 125 NICM patients (82 males, age 59±14years, mean±SD) with echocardiographic evidence of left ventricular (LV) systolic dysfunction (mean ejection-fraction 33±10%), without (stage B) or with history of mild HF symptoms (stage C, NYHA classes I–II) was enrolled. The end-point was a composite of cardiac death and HF hospitalization. Results: Fifty (40%) patients showed myocardial DE, representing 12±7% of LV mass. During a median follow-up of 14.2months, 16 (32%) patients with DE experienced a composite event versus only 6 (8%) patients without DE (Kaplan–Meier survival curve, p=0.001). After correction for age, CMR-derived LV and right ventricular volumes, echocardiographic measurements of LV diastolic function and Doppler-estimated systolic pulmonary artery pressure, the presence of DE remained a strong and independent predictor of cardiac death or HF hospitalization (hazard ratio: 5.32, 95% confidence intervals 1.60 to 17.63, p=0.006). Conclusions: In NICM patients with no or mild HF symptoms, the presence of myocardial DE is a strong predictor of worse clinical outcome even after correction for other established prognostic determinants. Contrast-enhanced CMR may be useful in prognostic stratification from the early stages of NICM. [Copyright &y& Elsevier]

Bicuspid aortic valve (BAV) is frequently associated with aortic wall abnormalities, including dilation of the ascending aorta and even dissection. We propose 2 new indexes of aortic wall biophysical properties, the maximum rates of systolic distension and diastolic recoil (MRSD and MRDR, respectively), in patients with BAV and matched control subjects. We evaluated 53 consecutive young patients with BAV (36 males, mean age 16 ± 4 years) with mild aortic valve disease and a control group of 22 age- and gender-matched healthy volunteers. All subjects underwent a cardiac magnetic resonance imaging study that included phase velocity mapping and cine acquisition at several aortic levels. The MRSD and MRDR were measured in the ascending aorta in both patients with BAV and controls. Of the 53 patients with BAV, 26 had enlarged ascending aortas (dilated BAV), and 27 had a normal aortic diameter (nondilated BAV). Compared to controls, the MRSD was significantly lower in the whole BAV group (4.37 ± 1.1 vs 9.1 ± 2.1), in patients with dilated BAV (4.5 ± 1.1 p <0.0001), and in those with nondilated BAV (4.3 ± 1.0, p <0.0001). The MRDR was greater in the whole BAV group (−4 ± 1.2 vs −7.6 ± 2.7, p <0.0001), in the dilated BAV group (−3.9 ± 1.3, p <0.0001), and in the nondilated BAV group (−4.1 ± 1.2, p <0.0001). A receiver operating characteristic curve analysis of MRSD distinguished BAV from controls with 100% sensitivity and 95% specificity. In conclusion, MRSD and MRDR were slower in the patients with BAV than in the controls, regardless of the dimensions of the ascending aorta. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate, in patients with hypertrophic cardiomyopathy (HC), the association between late gadolinium enhancement and clinical end points, such as nonsustained ventricular tachycardia, arrhythmic risk factors, New York Heart Association class, symptoms, and left ventricular functional parameters. A total of 20 normal subjects (mean age 38 years, 16 men) and 100 patients with HC (mean age 46 years, 70 men) were enrolled in the present study. In the late gadolinium enhancement images, the extent of unenhanced, mildly enhanced, and higher enhanced myocardium was measured. Higher enhancement was present in 80% of the HC population and was significantly greater in patients with a New York Heart Association class >1. Mild enhancement was present in all the patients with HC. Receiver operating characteristic analysis revealed that a cutoff of >4.9% of mild enhancement had 100% sensitivity and 86% specificity to predict the occurrence of nonsustained ventricular tachycardia, and a cutoff of >2.4% of hyperenhancement had 77% sensitivity and 96% specificity. In conclusion, late gadolinium enhancement was associated with nonsustained ventricular tachycardia, arrhythmic risk factors, and worse New York Heart Association class. [Copyright &y& Elsevier]