Vikas K Rathi

Physiologic compensation is supranormal in compensated aortic stenosis: does it return to normal after aortic valve replacement or is it blunted by coexistent coronary artery disease? An intramyocardial magnetic resonance imaging study.

BACKGROUND In compensated aortic stenosis (AS), cardiac performance measured at the ventricular chamber is typically supranormal, whereas measurements at the myocardium are often impaired. We investigated intramyocardial mechanics after aortic valve replacement (AVR) and the effects relative to the presence or absence of coronary artery disease (CAD+ or CAD-), respectively. METHODS AND RESULTS Twenty-nine patients (46 to 91 years, 10 female) with late but not decompensated AS underwent cardiovascular MRI before AVR (PRE), with follow-up at 6+/-1 (EARLY) and 13+/-2 months (LATE) to determine radiofrequency tissue-tagged left ventricle (LV) transmural circumferential strain, torsion, structure, and function. At the myocardial level, concentric LV hypertrophy regressed 18% LATE (93+/-22 versus 77+/-17 g/m2; P<0.0001), whereas at the LV chamber level, ejection fraction was supranormal PRE, 67+/-6% (ranging as high as 83%) decreasing to 59+/-6% LATE (P<0.05), representing not dysfunction but a return to more normal LV physiology. Between the CAD+ and CAD- groups, intramyocardial strain was similar PRE (19+/-10 versus 20+/-10) but different LATE, with dichotomization specifically related to the CAD state. In the CAD- patients, strain increased to 23+/-10% (+20%), whereas in CAD+ patients it fell to 16+/-11% (-26%), representing a nearly 50% decline after AVR (P<0.05). This was particularly evident at the apex, where CAD- strain LATE improved 17%, whereas for CAD+ it decreased 2.5-fold. Transmural strain and myocardial torsion followed a similar pattern, critically dependent on CAD. AVR impacted LV geometry and mitral apparatus, resulting in decreased mitral regurgitation, negating the double valve consideration. CONCLUSIONS In AS patients after AVR, reverse remodeling of the supranormal systolic function parallels improvement in cardiovascular MRI-derived regression of LV hypertrophy and LV intramyocardial strain. However, discordant effects are evident after AVR, driven by CAD status, suggesting that the typical AVR benefits are experienced disproportionately by those without CAD and not by those obliged to undergo concomitant coronary artery bypass grafting/AVR.

Contrast-enhanced CMR is equally effective as TEE in the evaluation of left atrial appendage thrombus in patients with atrial fibrillation undergoing pulmonary vein isolation procedure

BACKGROUND Patients with atrial fibrillation (AF) routinely undergo transesophageal echocardiography (TEE) for the evaluation of the left atrial appendage (LAA) to rule out thrombus prior to undergoing pulmonary vein isolation (PVI). Cardiac magnetic resonance (CMR) is now increasingly used for the evaluation of patients with AF to define pulmonary vein (PV) anatomy prior to PVI. OBJECTIVE To hypothesize that a retrospective comparison of 2-dimensional/3-dimensional (2D/3D) contrast-enhanced CMR sequences with TEE for the evaluation of LAA thrombus in patients with AF selected for PVI will demonstrate equivalence. METHODS Ninety-seven (N = 97) consecutive patients with AF underwent near-simultaneous TEE and noncontrast and contrast CMR prior to undergoing an initial PVI procedure. The CMR images were analyzed in 2 categories: (1) the 2D noncontrast cine images and early gadolinium enhancement images showing LAA and (2) 3D contrast source images acquired during PV magnetic resonance angiography. CMR variables evaluated were the presence or absence of LAA thrombus and the quality of images, and they were compared with the results of TEE in a blinded fashion. RESULTS All subjects were analyzed for the presence or absence of LAA thrombus. Thrombus was absent in 98% of the patients on both TEE and CMR and present in 2% on both studies (100% correlation). In 6 subjects, 2D cine CMR images were indeterminate whereas all 2D early gadolinium enhancement images and 3D contrast images were successful in excluding LAA thrombus. There was 100% concordance between CMR and TEE for the final diagnosis of LAA thrombus. CONCLUSIONS In one single examination, CMR offers a comparable alternative to TEE for the complete noninvasive evaluation of LAA thrombus and PV anatomy in patients with AF referred for PVI without obligate need for TEE.

Expanding Role of Cardiovascular Magnetic Resonance in Left and Right Ventricular Diastolic Function

This article focuses on the role of cardiovascular magnetic resonance (CMR) in understanding the physiology of diastolic function and on the future applications of CMR as they relate to diastolic function evaluation. CMR has a demonstrated potential to define diastolic function and quantify its properties, in terms of active and passive stages, and its relaxation and compliance characteristics. CMR is also useful for assessing inflow and myocardial velocities, and untwisting properties of the chamber and myocardium, thus providing insights not fully available in other invasive and noninvasive strategies. CMR, which offers the necessary capabilities to evaluate the complex structure of the right ventricle, can serve in the future as the standard for evaluating diastolic function as it currently does for systolic function.

Correction of temporal misregistration artifacts in jet flow by conventional phase‐contrast MRI

To show that accuracy of jet flow representation by magnetic resonance (MR) phase‐contrast (PC) velocity‐encoded (VE) cine imaging is dominated by error terms resulting from the temporal distribution of data, and to present a generally applicable data interpolation‐based approach to correct for this phenomenon.

Geometria da valva mitral derivada da ressonância magnética cardiovascular na avaliação da gravidade da regurgitação mitral

BACKGROUND Mitral regurgitation is the most common valvular heart disease worldwide. Magnetic resonance may be a useful tool to analyze mitral valve parameters. OBJECTIVE To distinguish mitral valve geometric patterns in patients with different severities of mitral regurgitation (MR) based on cardiovascular magnetic resonance imaging. METHODS Sixty-three patients underwent cardiovascular magnetic resonance imaging. Mitral valve parameters analyzed were: tenting area (mm2) and angle (degrees), ventricle height (mm), tenting height (mm), anterior leaflet, posterior leaflet length and annulus diameter (mm). Patients were divided into two groups, one including patients who required mitral valve surgery and another which did not. RESULTS Thirty-six patients had trace to mild (1-2+) MR and 27 had moderate to severe MR (3-4+). Ten (15.9%) out of 63 patients underwent surgery. Patients with more severe MR had a larger left ventricle end systolic diameter (38.6 ± 10.2 vs 45.4 ± 16.8, p<0.05) and left end diastolic diameter (52.9 ± 6.8 vs 60.1 ± 12.3, p= 0.005). On multivariate analysis, the tenting area was the strongest determinant of MR severity (r= 0.62, p=0.035). Annulus length (36.1 ± 4.7 vs 41 ± 6.7, p< 0.001), tenting area (190.7 ± 149.7 vs 130 ± 71.3, p= 0.048) and posterior leaflet length (15.1 ± 4.1 vs 12.2 ± 3.5, p= 0.023) were larger on patients requiring mitral valve surgery. CONCLUSIONS Tenting area, annulus and posterior leaflet length are possible determinants of MR severity. These geometric parameters could be used to determine severity and could, in the future, direct specific patient care based on individual mitral apparatus anatomy.

Mid wall fibrosis on CMR with late gadolinium enhancement may predict prognosis for LVAD and transplantation risk in patients with newly diagnosed dilated cardiomyopathy—preliminary observations from a high-volume transplant centre

Patients with newly diagnosed dilated cardiomyopathy (DCM) and advanced heart failure have a very high morbidity and mortality with an unpredictable clinical course. We investigated the role of cardiovascular magnetic resonance (CMR) imaging using late gadolinium enhancement (LGE) in this cohort of high‐risk patients. We hypothesized that LGE has high prognostic value in primary DCM patients referred for possible transplantation/left ventricular assist device (LVAD) consideration.BACKGROUND Patients with newly diagnosed dilated cardiomyopathy (DCM) and advanced heart failure have a very high morbidity and mortality with an unpredictable clinical course. We investigated the role of cardiovascular magnetic resonance (CMR) imaging using late gadolinium enhancement (LGE) in this cohort of high-risk patients. We hypothesized that LGE has high prognostic value in primary DCM patients referred for possible transplantation/left ventricular assist device (LVAD) consideration. METHODS Over 49 consecutive months, 61 consecutives DCM patients were referred for standard CMR(1.5T, GE) to interrogate the LV pattern, distribution, and extent of LGE (MultiHance, Princeton, NJ). Inclusion criteria for a primary non-ischaemic DCM and EF <45% were met in 31 patients. DCM patients were categorized into: (i) presence of midwall LV stripe (+Stripe) and (ii) absence of midwall stripe (-Stripe) groups. Primary outcome was defined by the composite of death, need for LV assist device (LVAD), and urgent orthotopic cardiac transplantation (Tx) during a 12-month follow-up period. Kaplan-Meier survival analysis was conducted grouping patients by +Stripe and -Stripe. RESULTS There were no differences between groups for demographics, blood pressure, labs, baseline LVEF, NYHA class, or invasive haemodynamics. There were 18 patients (58%) with +Stripe. Nine events occurred: seven patients required urgent Tx and/or LVAD implantation and two patients died. The +Stripe categorization strongly predicted the need for LVAD, urgent Tx surgery, and death (log-rank = 9, P = 0.002). All the events occurred in the +Stripe patients with no MACE experienced in the -Stripe group. The -Stripe group experienced marked signs of improvement in LVEF (P = 0.01) at follow-up. LVEDD was predictive of need for LVAD/Tx and death by univariate analysis. Otherwise, no common clinical metric such as LVEF, LVEDV, RVEF, RVEDV, or any invasive haemodynamic parameter predicted MACE. CONCLUSIONS The presence of +Stripe on CMR is strongly predictive of LVAD, transplant need, and death during a 12-month follow-up period in DCM patients in this proof of concept study. All -Stripe patients survived without experiencing any events. Incorporating CMR imaging into routine clinical practice may have prognostic value in DCM patients; indicating conservative management in low-risk patients while expectantly managing high-risk patients.

Cardiac Sarcoidosis or Giant Cell Myocarditis? On Treatment Improvement of Fulminant Myocarditis as Demonstrated by Cardiovascular Magnetic Resonance Imaging

Giant cell myocarditis, but not cardiac sarcoidosis, is known to cause fulminant myocarditis resulting in severe heart failure. However, giant cell myocarditis and cardiac sarcoidosis are pathologically similar, and attempts at pathological differentiation between the two remain difficult. We are presenting a case of fulminant myocarditis that has pathological features suggestive of cardiac sarcoidosis, but clinically mimicking giant cell myocarditis. This patient was treated with cyclosporine and prednisone and recovered well. This case we believe challenges our current understanding of these intertwined conditions. By obtaining a sense of severity of cardiac involvement via delayed hyperenhancement of cardiac magnetic resonance imaging, we were more inclined to treat this patient as giant cell myocarditis with cyclosporine. This resulted in excellent improvement of patients cardiac function as shown by delayed hyperenhancement images, early perfusion images, and SSFP videos.

Is cardiovascular MRI equally effective as TEE in evaluation of left atrial appendage thrombus in patients with atrial fibrillation undergoing pulmonary vein isolation

Patients with atrial fibrillation (Afib) routinely undergo a transesophageal echocardiogram (TEE) for evaluation of the left atrial appendage (LAA) to rule out thrombus prior to undergoing cardioversion or pulmonary vein isolation (PVI). Cardiac MRI (CMR) is now increasingly used for evaluation of these patients for defining pulmonary vein anatomy prior to PVI. We hypothesized that 2D and 3D non-contrast and contrast CMR is as effective as TEE in evaluating for LAA thrombus while providing simultaneous comprehensive non-invasive evaluation of the pulmonary vein anatomy within a single exam.

Cardiac magnetic resonance imaging in today's economic climate; a cost effectiveness analysis

In the face of the current health care crisis, significant concerns have been raised about the independent clinical utilities of various cardiac imaging modalities. Particularly, Cardiac Magnetic Resonance (CMR) has been labeled “an expensive pretty picture” by some clinicians as compared to other diagnostic modalities.

1087 Right and left ventricular morphologic and functional differences between patients with severe idiopathic vs. secondary pulmonary hypertension; insights from cardiovascular MRI

Introduction In pts with long standing pulmonary hypertension (PHTN), RV is the primary organ to withstand the increased pressure which overtime leads to insidious right heart failure. However, the effect of decreased preload due to PHTN and the failing RV on LV function and geometry is unknown. Theoretically, the LV should be spared but clinically it is often noted that, despite a small LV, the perception of a hypertrophied LV with abnormal geometry by 1D and 2D techniques is present.