Imran S. Syed

Role of cardiac magnetic resonance imaging in the detection of cardiac amyloidosis.

OBJECTIVES Our aim was to evaluate the role and mechanism of late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) in identifying cardiac amyloidosis (CA) and to investigate associations between LGE and clinical, morphologic, functional, and biochemical features. BACKGROUND CA can be challenging to diagnose by echocardiography. Recent studies have demonstrated an emerging role for LGE-CMR. METHODS LGE-CMR was performed in 120 patients with amyloidosis. Cardiac histology was available in 35 patients. The remaining 85 patients were divided into those with and without echocardiographic evidence of CA. RESULTS Of the 35 patients with histologically verified CA, abnormal LGE was present in 34 (97%) patients and increased echocardiographic left ventricular wall thickness in 32 (91%) patients. Global transmural or subendocardial LGE (83%) was most common and was associated with greater interstitial amyloid deposition (p = 0.03). Suboptimal myocardial nulling (8%) and patchy focal LGE (6%) were also observed. LGE distribution matched the deposition pattern of interstitial amyloid. Among patients without cardiac histology, LGE was present in 86% of those with evidence of CA by echocardiography and in 47% of those without evidence of CA by echocardiography. In patients without echocardiographic evidence of CA, the presence of LGE was associated with worse clinical, electrocardiographic (ECG), and cardiac biomarker profiles. In all patients, LGE presence and pattern was associated with New York Heart Association functional class, ECG voltage, left ventricular mass index, right ventricular wall thickness, troponin-T, and B-type natriuretic peptide levels. CONCLUSIONS LGE is common in CA and detects interstitial expansion from amyloid deposition. Global transmural or subendocardial LGE is most common, but suboptimal myocardial nulling and focal patchy LGE are also observed. LGE-CMR may detect early cardiac abnormalities in patients with amyloidosis with normal left ventricular thickness. The presence and pattern of LGE is strongly associated with clinical, morphologic, functional, and biochemical markers of prognosis.

Real-Time Three-Dimensional Transesophageal Echocardiography in the Intraoperative Assessment of Mitral Valve Disease

BACKGROUND The aims of this study were to evaluate the feasibility of real-time 3-dimensional (3D) transesophageal echocardiography in the intraoperative assessment of mitral valve (MV) pathology and to compare this novel technique with 2-dimensional (2D) transesophageal echocardiography. METHODS Forty-two consecutive patients undergoing MV repair for mitral regurgitation (MR) were studied prospectively. Intraoperative 2D and 3D transesophageal echocardiographic (TEE) examinations were performed using a recently introduced TEE probe that provides real-time 3D imaging. Expert echocardiographers blinded to 2D TEE findings assessed the etiology of MR on 3D transesophageal echocardiography. Similarly, experts blinded to 3D TEE findings assessed 2D TEE findings. Both were compared with the anatomic findings reported by the surgeon. RESULTS At the time of surgical inspection, ischemic MR was identified in 12% of patients, complex bileaflet myxomatous disease in 31%, and specific scallop disease in 55%. Three-dimensional TEE image acquisition was performed in a short period of time (60 +/- 18 seconds) and was feasible in all patients, with optimal (36%) or good (33%) imaging quality in the majority of cases. Three-dimensional TEE imaging was superior to 2D TEE imaging in the diagnosis of P1, A2, A3, and bileaflet disease (P < .05). CONCLUSIONS Real-time 3D transesophageal echocardiography is a feasible method for identifying specific MV pathology in the setting of complex disease and can be expeditiously used in the intraoperative evaluation of patients undergoing MV repair.

Three-Dimensional Echocardiographic Assessment of Right Ventricular Volume and Function in Adult Patients With Congenital Heart Disease: Comparison With Magnetic Resonance Imaging

BACKGROUND The aim of this study was to evaluate the accuracy of three-dimensional (3D) ultrasound compared with the standard magnetic resonance imaging method in determining right ventricular (RV) volumes and function in adult patients with congenital heart disease and chronic, severe pulmonary regurgitation (PR). METHODS Twenty-five patients with severe PR secondary to either pulmonary valvotomy or tetralogy of Fallot repair were evaluated using 3D ultrasound and MRI. RESULTS The mean RV ejection fractions were 42 +/- 8% on 3D ultrasound and 44 +/- 7% on MRI (r = 0.89, P < .0001). The mean end-diastolic volumes were 249 +/- 66 and 274 +/- 82 mL and the mean end-systolic volumes 147 +/- 50 and 159 +/- 60 mL on 3D ultrasound and MRI, respectively. Similarly, there were strong correlations of both end-diastolic volume and end-systolic volume on 3D ultrasound and MRI (r = 0.88 and r = 0.89, respectively). CONCLUSIONS Three-dimensional ultrasound was comparable with MRI in determining RV size and function in most patients with complex congenital heart disease. It will be important to study 3D US in a larger population of patients with TOF, which will be possible only through multi-center collaboration.

Isolated Left Ventricular Noncompaction Syndrome

Isolated left ventricular noncompaction (ILVNC) is a rare congenital cardiomyopathy characterized by prominent trabeculae, deep intertrabecular recesses, and thickened myocardium with 2 distinct layers (compacted and noncompacted). Clinical characteristics, outcomes, and appropriate therapies remain poorly defined. Data were collected on patients diagnosed with ILVNC by echocardiographic criteria at the Mayo Clinic from 2001 through 2006. These data were entered prospectively into a clinical database and retrospectively analyzed. All-cause mortality, stroke, and development of atrial fibrillation (AF) were compared to community and nonischemic dilated cardiomyopathic (DC) controls. Implantable cardioverter-defibrillator (ICD) therapies were examined. Thirty patients with confirmed ILVNC were included in analyses (mean age at diagnosis 39 +/- 19.5 years, 60% men). Three patients with ILVNC died during follow-up (mean 2.5 +/- 1.2 years) compared to 5 DC and 1 community controls. No mortality difference was observed among these groups (p = 0.42 and 0.054, respectively). No ILVNC deaths were observed in patients with normal LV ejection fraction. New-onset AF was diagnosed in 2 patients with ILVNC, and none was observed in DC controls. Stroke occurred in 2 DC controls and none was observed in patients with ILVNC. ICDs were implanted in 11 patients with ILVNC. No appropriate therapies were identified during follow-up, but 2 patients underwent inappropriate therapies related to AF. In conclusion, mortality in patients with ILVNC is similar to that in DC patients. Deaths were observed only in patients with decreased LV ejection fraction, suggesting that ICD therapy may be reserved for this subgroup. New-onset AF may lead to inappropriate ICD discharges.

Cardiac Magnetic Resonance Imaging Pericardial Late Gadolinium Enhancement and Elevated Inflammatory Markers Can Predict the Reversibility of Constrictive Pericarditis After Antiinflammatory Medical Therapy A Pilot Study

Background— Constrictive pericarditis (CP) is a disabling disease, and usually requires pericardiectomy to relieve heart failure. Reversible CP has been described, but there is no known method to predict the reversibility. Pericardial inflammation may be a marker for reversibility. As a pilot study, we assessed whether cardiac magnetic resonance imaging pericardial late gadolinium enhancement (LGE) and inflammatory biomarkers could predict the reversibility of CP after antiinflammatory therapy. Method and Results— Twenty-nine CP patients received antiinflammatory medications after cardiac magnetic resonance imaging. Fourteen patients had resolution of CP, whereas 15 patients had persistent CP after 13 months of follow-up. Baseline LGE pericardial thickness was greater in the group with reversible CP than in the persistent CP group (4±1 versus 2±1 mm, P=0.001). Qualitative intensity of pericardial LGE was moderate or severe in 93% of the group with reversible CP and in 33% of the persistent CP group (P=0.002). Cardiac magnetic resonance imaging LGE pericardial thickness ≥3 mm had 86% sensitivity and 80% specificity to predict CP reversibility. The group with reversible CP also had higher baseline C-reactive protein and erythrocyte sedimentation rate than the persistent CP group (59±52 versus 12±14 mg/L, P=0.04 and 49±25 versus 15±16 mm/h, P=0.04, respectively). Antiinflammatory therapy was associated with a reduction in C-reactive protein, erythrocyte sedimentation rate, and pericardial LGE in the group with reversible CP but not in the persistent CP group. Conclusions— Reversible CP was associated with pericardial and systemic inflammation. Antiinflammatory therapy was associated with a reduction in pericardial and systemic inflammation and LGE pericardial thickness, with resolution of CP physiology and symptoms. Further studies in a larger number of patients are needed.

Intracardiac thrombosis and anticoagulation therapy in cardiac amyloidosis.

Background— Primary amyloidosis has a poor prognosis as a result of frequent cardiac involvement. We recently reported a high prevalence of intracardiac thrombus in cardiac amyloid patients at autopsy. However, neither the prevalence nor the effect of anticoagulation on intracardiac thrombus has been evaluated antemortem. Methods and Results— We studied all transthoracic and transesophageal echocardiograms of cardiac amyloid patients at the Mayo Clinic. The prevalence of intracardiac thrombosis, clinical and transthoracic/transesophageal echocardiographic risks for intracardiac thrombosis, and effect of anticoagulation were investigated. We identified 156 patients with cardiac amyloidosis who underwent transesophageal echocardiograms. Amyloidosis was the primary type (AL) in 80; other types occurred in 76 patients, including 56 with the wild transthyretin type, 17 with the mutant transthyretin type, and 3 with the secondary type. Fifth-eight intracardiac thrombi were identified in 42 patients (27%). AL amyloid had more frequent intracardiac thrombus than the other types (35% versus 18%; P=0.02), although the AL patients were younger and had less atrial fibrillation. Multivariate analysis showed that atrial fibrillation, poor left ventricular diastolic function, and lower left atrial appendage emptying velocity were independently associated with increased risk for intracardiac thrombosis, whereas anticoagulation was associated with a significantly decreased risk (odds ratio, 0.09; 95% CI, 0.01 to 0.51; P<0.006). Conclusions— Intracardiac thrombosis occurs frequently in cardiac amyloid patients, especially in the AL type and in those with atrial fibrillation. Risk for thrombosis increased if left ventricular diastolic dysfunction and atrial mechanical dysfunction were present. Anticoagulation therapy appears protective. Timely screening in high-risk patients may allow early detection of intracardiac thrombus. Anticoagulation should be carefully considered.

MR Imaging of Cardiac Masses

Cardiac MR imaging is the preferred method for assessment of cardiac masses. A comprehensive cardiac MR imaging examination for a cardiac mass consists of static morphologic images using fast spin-echo sequences, including single-shot techniques, with T1 and T2 weighting and fat suppression pulses as well as dynamic imaging with cine steady-state free precession techniques. Further tissue characterization is provided with perfusion and delayed enhancement imaging. Specific cardiac tumoral characterization is possible in many cases. When specific tumor characterization is not possible, MR imaging often can demonstrate aggressive versus nonaggressive features that help in differentiating malignant from benign tumors.

Valsalva Sinus Aneurysms: Findings at CT and MR Imaging

Aneurysms of the Valsalva sinus (aortic sinus) can be congenital or acquired and are rare. They are more common among men than women and among Asians than other ethnic groups. Nonruptured aneurysms may be asymptomatic and incidentally discovered, or they may be symptomatic and manifest acutely with mass effect on adjacent cardiac structures. Ruptured Valsalva sinus aneurysms result in an aortocardiac shunt and may manifest as insidiously progressive congestive heart failure, severe acute chest pain with dyspnea, or, in extreme cases, cardiac arrest. Although both ruptured and nonruptured Valsalva sinus aneurysms may have potentially fatal complications, after treatment the prognosis is excellent. Thus, prompt and accurate diagnosis is critical. Most Valsalva sinus aneurysms are diagnosed on the basis of echocardiography, with or without angiography. However, both electrocardiographically gated computed tomography and magnetic resonance (MR) imaging can provide excellent anatomic depiction, and MR imaging can provide valuable functional information.

Myocardial contrast echocardiography in biopsy-proven primary cardiac amyloidosis

Cardiac vasculature is affected in 88-90% of patients with primary cardiac amyloidosis (CA). Myocardial contrast echocardiography (MCE) relies on the ultrasound detection of microbubble contrast agents that are solely confined to the intravascular space, and are therefore useful in the evaluation of flow in the microvasculature. This is the first case report describing the use of MCE during vasodilator stress to evaluate coronary flow reserve in a patient with biopsy-proven primary CA and angiographically normal coronaries. Qualitative MCE demonstrated delayed replenishment of microbubbles during peak stress; quantitative analysis was consistent with a reduction in total myocardial blood flow and reserve values. Comparative imaging modalities including strain and strain rate imaging, magnetic resonance imaging, and myocardial scintigraphy were suggestive to the diagnosis of CA. In conclusion, MCE is a method for recognition of microvascular dysfunction, and might be considered as a useful tool to augment echocardiographic assessment in the early diagnosis of CA.

MR Imaging of the Pericardium

Imaging of the pericardium requires understanding of anatomy and the normal and abnormal physiology of the pericardium. MR imaging is well-suited for answering clinical questions regarding suspected pericardial disease. Pericardial diseases that may be effectively imaged with MR imaging include pericarditis, pericardial effusion, cardiac-pericardial tamponade, constrictive pericarditis, pericardial cysts, absence of the pericardium, and pericardial masses. Although benign and malignant primary tumors of the pericardium may be occasionally encountered, the most common etiology of a pericardial mass is metastatic disease.