Naeem Merchant

Assessment of Systemic Right Ventricular Function in Patients With Transposition of the Great Arteries Using the Myocardial Performance Index Comparison With Cardiac Magnetic Resonance Imaging

Background—Assessment of systemic right ventricular (RV) function is a key point in the follow-up of patients with transposition of the great arteries (TGA). Current echocardiographic assessment of RV function is at best an estimate, and cardiac magnetic resonance (CMR) is considered the gold standard. However, this technique is expensive, has limited availability, and requires significant expertise to acquire and interpret the images. The myocardial performance index (MPI) has recently been studied for assessment of pulmonary RV function and shows promise as a simple yet powerful tool for assessing patients with RV dysfunction of various origins. We set out to compare MPI and CMR assessment of systemic RV function in patients with TGA. Methods and Results—Data from patients with TGA (11 with congenitally corrected TGA, 18 with surgically corrected TGA) who had CMR within 6 months of their echocardiogram were reviewed. The average systemic RV ejection fraction (RVEF) by CMR was 39.4±11.4%, and the systemic RVMPI for this group was 0.56±0.21. There was a strong negative correlation between the systemic RVMPI and systemic RVEF by CMR (r=−0.82, P<0.01). The systemic RVEF can be estimated from this formula: RVEF=65%−(45.2×MPI). Conclusions—MPI can be used in patients with systemic RVs to assess global function and to estimate an EF with good accuracy.

Pressure Half-time Predicts Hemodynamically Significant Pulmonary Regurgitation in Adult Patients with Repaired Tetralogy of Fallot

Pulmonary regurgitation (PR) is associated with adverse outcomes late after tetralogy of Fallot repair. Accurate assessment of PR in these patients is, therefore, fundamental to their clinical treatment; however, accurate ultrasound markers of severity are as yet poorly defined. This is a prospective study of 34 adult patients with repaired tetralogy of Fallot. Cardiac magnetic resonance imaging was used to assess the PR fraction and its hemodynamic significance on the right ventricular volumes. Regurgitant fractions >/= 20% were associated with significant increases in right ventricular end-diastolic volumes. Echocardiographic continuous wave Doppler profiles of the PR jet were used to calculate pressure half-time. Pulmonary pressure half-time < 100 milliseconds was found to be a good indicator of hemodynamically significant regurgitation. This measure is highly reproducible and easily accessible.

MRI of Hypertrophic Cardiomyopathy: Part I, MRI Appearances

OBJECTIVE We present a two-part review about the use of MRI in patients with hypertrophic cardiomyopathy (HCM). This article, Part 1, focuses on the MRI appearances of HCM. CONCLUSION MRI has proven to be an important tool for the evaluation of patients suspected of having HCM because it can readily diagnose those with phenotypic expression of the disorder and can potentially identify the subset of patients at risk of sudden cardiac death.

MRI of Hypertrophic Cardiomyopathy: Part 2, Differential Diagnosis, Risk Stratification, and Posttreatment MRI Appearances

OBJECTIVE We present a two-part review about the use of MRI in patients with hypertrophic cardiomyopathy (HCM). This article, Part 2, covers the differential diagnosis, risk stratification, and posttreatment MRI follow-up appearances in these patients. CONCLUSION Cardiovascular MRI is a useful imaging tool for the diagnosis of HCM and follow-up of patients after either surgical myomectomy or septal ablation therapy. In addition, MRI can help to discriminate HCM from the differential diagnoses of other cardiomyopathies and cardiac disorders, and it can potentially identify the subset of patients at risk of sudden cardiac death.

Frequency of coronary ostial aneurysms after aortic root surgery in patients with the Marfan syndrome

Coronary ostial aneurysm is a common finding in patients with Marfans syndrome after aortic root surgery, especially in patients who are greater than or equal to35 years of age at time of surgery

Comparison of aortic elasticity in patients with the marfan syndrome with and without aortic root replacement.

In conclusion, MRI enables the assessment of aortic elasticity in patients with Marfans syndrome with elective ARR. Aortic elasticity between Marfan patients with and without aortic root replacement showed no differences.

Anomalous Origin of the Left Coronary Artery From the Main Pulmonary Artery in Adults

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA, or Bland-White-Garland syndrome) occurs once per 300 000 live births, usually as an isolated cardiac lesion. In fetal life, this anomaly is well tolerated because pulmonary pressure equals systemic pressure and oxygen content is identical in the main pulmonary artery (PA) and aorta. Therefore, coronary collateral growth is not especially promoted before birth. After birth, as soon as pulmonary pressure and saturation fall, left ventricular (LV) oxygen demands no longer can be accommodated by the left coronary artery (LCA), and ALCAPA leads to myocardial ischemia. Subendocardial ischemia can occur even in the presence of well-established coronary collateral vessels because of preferential coronary blood flow into the low-pressure pulmonary circulation instead of high-resistance …Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA, or Bland-White-Garland syndrome) occurs once per 300 000 live births, usually as an isolated cardiac lesion. In fetal life, this anomaly is well tolerated because pulmonary pressure equals systemic pressure and oxygen content is identical in the main pulmonary artery (PA) and aorta. Therefore, coronary collateral growth is not especially promoted before birth. After birth, as soon as pulmonary pressure and saturation fall, left ventricular (LV) oxygen demands no longer can be accommodated by the left coronary artery (LCA), and ALCAPA leads to myocardial ischemia. Subendocardial ischemia can occur even in the presence of well-established coronary collateral vessels because of preferential coronary blood flow into the low-pressure pulmonary circulation instead of high-resistance …

Exercise-related neurohumoral activation in adults with repaired tetralogy of fallot: A pilot study

Objectives. To determine the prevalence of pulmonary embali (PE) in asymptomatic adult Fontan patients and identify the risk factors associated with PE. Background. Right atrial thrombi and systemic thromboembolic complications have been reported as a complication after the Fontan procedure. However the frequency of silent PE in this patient population is not known. Methods. All consecutive adult Fontan patients attending the adult congenital clinic over a six-month period underwent ventilation-perfusion (VQ) scanning and bloods for thrombophilia tendency. If the VO scan showed an intermediate or high probability for PE, a spiral computerised tomography scan was performed to confirm the presence of PE. Results. Thirty patients (mean age 26+7 y, 57% male) were included in this study. Five (17%) adult Fontan patients had an intermediate or high probability for PE on VQ scan, all of which were confirmed on spiral CT. No patient had a thrombophilia tendency. PE was not present in any patients (30%) taking warfarin. Late age at time of Fontan operation (19& y vs. 11+6 y, ~~0.012) and lateral tunnel (314, p = 0.001) were associated with increased risk of silent FE. Conclusions. Seventeen percent of adult patients with Fontan procedure have clinically silent PE. The hemodynamic long-term implications of this with respect to Fontan attrition wer time are unknown. Large randomized prospective studies lwking at anticoagulation therapy in all Fontan patients are urgently needed.