Since arriving at MGH in 1999 I have had the privilege of training in internal medicine and cardiology, teaching as a chief resident and as a cardiology attending, providing clinical care to patients with a broad range of cardiovascular diseases, and conducting research. As an investigator at MGH I have published over 50 manuscripts in fields ranging from the evaluation of novel therapies for heart failure to mechanisms of exercise intolerance in cardiovascular disease and metabolic response patterns to exercise. I am particularly interested in the role of the lung circulation in mediating exercise intolerance in patients with heart failure. Our team of investigators is also interested in understanding the molecular mechanisms of exercise adaptation through mass spectrometry-based metabolic profiling in collaboration with the Broad Institute and Dr. Robert Gerszten. My clinical interests parallel my research interests and focus on improving cardiac performance in patients with a variety of cardiovascular diseases. As a staff member in the recently established Cardiac Performance Program I look forward to offering state of the art cardiopulmonary exercise testing to a broad spectrum of individuals- from patients with heart failure to athletes- in an effort to further understand and improve cardiac performance. As medical Director of Mechanical CIrculatory Support and the Cardiology Intensive Care Unit I also have a strong interest in treatment of advanced heart failure and other critical illnesses.
ResearchMy background is in biochemistry and cardiopulmonary physiology, and I have formal training in trial design, clinical investigation, and mass spectrometry-based metabolic profiling to study cardiopulmonary performance. A major objective of my current research is to understand mechanisms of exercise intolerance in patients with heart failure and to define physiologic and biochemical signatures of heart failure subphenotypes by using exercise as a physiologic probe.
A major area of focus has been on defining physiologic and metabolomic signatures of right ventricular-pulmonary vascular (RV-PV) interactions during exercise in heart failure. In two recent senior author publications my laboratory was the first to report that periodic breathing during exercise is closely related to right heart performance and that the amplitude and cycle length of ventilatory oscillations are inversely related to cardiac output augmentation during exercise. Through a unique exercise protocol that integrates hemodynamic measurements, ventriculography, gas exchange measurement, and plasma sampling we have also found that the kinetics of oxygen uptake and efficiency of ventilation provide complementary gas exchange signatures of pulmonary vascular function during exercise. Taken together, these easily acquired non-invasive physiologic parameters not only promote recognition of impaired RV-PV function in response to exercise, they also appear to respond favorably to targeted interventions directed at RV-PV dysfunction.
Please see Pubmed for a complete list
Lewis GD, Shah R, Shahzad K, et al. Sildenafil Improves Exercise Capacity and Quality of Life in Patients with Systolic Heart Failure and Secondary Pulmonary Hypertension. Circulation. 2007.116:1555-1562.
Lewis GD, Gona P, Benjamin EJ, et al. Exercise Blood Pressure and the Risk of Incident Cardiovascular Disease: The Framingham Heart Study. Am J Cardiol 2008, Jun 1;101(11):1614-20
Lewis GD, Shah RV, Systrom DM, et al. Determinants of Ventilatiory Efficiency in Heart Failure. Circulation Heart Failure, 2008; 1: 227-233
Lewis GD, Farrell L, Wood MJ, et al. Metabolic Signatures of Exercise in Human Plasma. Science Translational Medicine. 2010;2(33)
Study of 'planned' heart attacks identifies markers that could improve treatment, save lives.
Experts from the Massachusetts General Hospital Institute for Heart, Vascular and Stroke Care present their experience and provide a practical guide to clinical decision making for patients with heart failure, pulmonary embolism and cardiogenic stroke.
Using a system that analyzes blood samples with unprecedented detail, a team led by MGH researchers has developed the first "chemical snapshot" of the metabolic effects of exercise.