Cardiovascular magnetic resonance in pregnancy: insights from the cardiac hemodynamic imaging and remodeling in pregnancy (CHIRP) study.

BACKGROUND: Cardiovascular disease in pregnancy is the leading cause of maternal mortality in North America. Although transthoracic echocardiography (TTE) is the most widely used imaging modality for the assessment of cardiovascular function during pregnancy, little is known on the role of cardiovascular magnetic resonance (CMR). The objective of the Cardiac Hemodynamic Imaging and Remodeling in Pregnancy (CHIRP) study was to compare TTE and CMR in the non-invasive assessment of maternal cardiac remodeling during the peripartum period. METHODS: Between 2010-2012, healthy pregnant women aged 18 to 35 years were prospectively enrolled. All women underwent TTE and CMR during the third trimester and at least 3 months postpartum (surrogate for non-pregnant state). RESULTS: The study population included a total of 34 women (mean age 29 ± 3 years). During the third trimester, TTE and CMR demonstrated an increase in left ventricular end-diastolic volume from 95 ± 11 mL to 115 ± 14 mL and 98 ± 6 mL to 125 ± 5 mL, respectively (p<0.05). By TTE and CMR, there was also an increase in left ventricular (LV) mass during pregnancy from 111 ± 10 g to 163 ± 11 g and 121 ± 5 g to 179 ± 5 g, respectively (p<0.05). Although there was good correlation between both imaging modalities for LV mass, stroke volume, and cardiac output, the values were consistently underestimated by TTE. CONCLUSION: This CMR study provides reference values for cardiac indices during normal pregnancy and the postpartum state.

The effects of fish oil consumption on cardiovascular remodeling in ApoE deficient mice.

Owing to their spontaneous development of atherosclerosis, apolipoprotein E knockout mice (ApoE(KO)) are one of the best studied animal models for this disease. Little is known about the utility of various omega-3 fatty acid regimens, in particular fish oils, in preventing cardiac disease in ApoE(KO) mice. The purpose of this study was to determine the cardiovascular effects of omega-3 fatty acid supplementation with either safflower oil (control), fish oil, flaxseed oil, or designed oil in ApoE(KO) mice fed a high-fat diet for a total of 16 weeks. In-vivo cardiac function was assessed weekly using murine echocardiography. Blood pressure, plasma lipid levels, and brain natriuretic peptide (BNP) were serially measured. The results show that ApoE(KO) mice fed fish oil demonstrated an increase in left ventricular wall thickness as a result of increased afterload. Despite chronic treatment with fish oil over 16 weeks, blood pressure increased in ApoE(KO) mice by 20% compared with the baseline. Both echocardiographic evidence of left ventricular hypertrophy and biochemical increase in BNP levels confirmed diastolic dysfunction in ApoE(KO) mice fed fish oil. This suggests that high-fat diet supplemented with fish oil may lead to adverse cardiovascular effects in ApoE deficient mice.

The impact of telemetry on survival of in-hospital cardiac arrests in non-critical care patients.

OBJECTIVE: Since the introduction of telemetry over a half century ago, it has expanded to various units and wards within health care institutions outside of the traditional critical care setting. Little is known on whether routine telemetry use is beneficial in this patient population. The aim of this study was to determine the impact of telemetry monitoring on survival of in-hospital cardiac arrests in patients admitted to non-critical care units. METHODS: A retrospective study of cardiac arrests in patients admitted to non-critical care units within the Winnipeg Regional Health Authority from 2002 to 2006 inclusive was performed. Baseline demographic, cardiac arrest, and outcome data were collected. RESULTS: Of the total 668 patients, the mean age was 70±14 years with 404 (61%) males. Patients presenting with asystole or pulseless electrical activity (PEA) demonstrated an increased mortality as compared to those presenting with ventricular tachycardia (VT) or ventricular fibrillation (VF). Overall, 268 of 668 patients (40%) survived their initial arrest, 66 (10%) survived to hospital discharge and 49 (7%) survived transfer to another facility. Patients on telemetry vs. no telemetry had higher survival rates immediately following cardiac arrest (66% vs. 34%, OR=3.67, p=0.02), as well as higher survival to hospital discharge (30% vs. 6%, OR=7.17, p=0.01). Finally, patients with cardiac arrest during the night and early morning benefited proportionally the greatest from telemetry use. CONCLUSION: Regardless of whether cardiac arrest was witnessed or unwitnessed, telemetry use was an independent and strong predictor of survival to hospital discharge.

The role of tissue Doppler imaging in predicting left ventricular filling pressures in patients undergoing cardiac surgery: an intraoperative study.

INTRODUCTION: The perioperative management of patients undergoing cardiac surgery usually requires the accurate assessment of left ventricular filling pressures (LVFP). The gold standard for determining LVFP involves the use of pulmonary artery catheters (PAC). Using tissue Doppler indices (TDI) obtained by transthoracic echocardiography, the ratio of early transmitral filling velocity to the corresponding early mitral annular velocity (E/E') has a strong correlation with pulmonary capillary wedge pressure (PCWP). Little is known, however, on whether this relationship between E/E' and PCWP is valid intraoperatively using transesophageal echocardiography (TEE) during cardiac surgery. OBJECTIVE: The objective of our study was to determine whether TDI obtained by intraoperative TEE during cardiac surgery can accurately estimate PCWP using PAC as the gold standard. METHODS AND RESULTS: A total of 34 patients (26 males, mean age 64 ± 9 years) undergoing cardiac surgery were prospectively enrolled between 2010 and 2011 at a single tertiary care center. Conventional diastolic and tissue Doppler parameters were evaluated using intraoperative TEE with concurrent PAC monitoring before and after cardiopulmonary bypass (CPB) surgery. At both pre- and post-CPB, there was no significant correlation between lateral, septal, and mean E/E' obtained by TEE and PCWP. CONCLUSION: Intraoperative TEE was unable to accurately predict LVFP in patients undergoing cardiac surgery. PAC may continue to be the gold standard in the assessment of LVFP for this patient population.

Multimodality cardiac imaging of a double chambered right ventricle with intrapulmonary shunting: a case report.

BACKGROUND: Double chambered right ventricle (DCRV) is a relatively rare congenital heart disease, characterized by the abnormal division of the right ventricle into a high-pressure inlet and low-pressure outlet by anomalous muscle bundles. Extra-cardiac right-to-left shunts may present with clinical symptoms in adulthood and should be sought in patients with previous cavo-pulmonary shunt procedures. CASE PRESENTATION: We report a case of DCRV in a 29 year old Caucasian male presenting in adulthood with a right-to-left shunt secondary to venous collaterals, following cavopulmonary anastomosis for congenital pulmonary atresia and hypoplastic right ventricle. CONCLUSION: Multimodality cardiac imaging using echocardiography, cardiac CT, cardiac MRI and cardiac catheterization is often required for complete characterization of complex congenital heart anomalies in adulthood.

The impact of repeated marathon running on cardiovascular function in the aging population.

BACKGROUND: Several studies have correlated elevations in cardiac biomarkers of injury post marathon with transient and reversible right ventricular (RV) systolic dysfunction as assessed by both transthoracic echocardiography (TTE) and cardiovascular magnetic resonance (CMR). Whether or not permanent myocardial injury occurs due to repeated marathon running in the aging population remains controversial. OBJECTIVES: To assess the extent and severity of cardiac dysfunction after the completion of full marathon running in individuals greater than 50 years of age using cardiac biomarkers, TTE, cardiac computed tomography (CCT), and CMR. METHODS: A total of 25 healthy volunteers (21 males, 55 ± 4 years old) from the 2010 and 2011 Manitoba Full Marathons (26.2 miles) were included in the study. Cardiac biomarkers and TTE were performed one week prior to the marathon, immediately after completing the race and at one-week follow-up. CMR was performed at baseline and within 24 hours of completion of the marathon, followed by CCT within 3 months of the marathon. RESULTS: All participants demonstrated an elevated cTnT post marathon. Right atrial and ventricular volumes increased, while RV systolic function decreased significantly immediately post marathon, returning to baseline values one week later. Of the entire study population, only two individuals demonstrated late gadolinium enhancement of the subendocardium in the anterior wall of the left ventricle, with evidence of stenosis of the left anterior descending artery on CCT. CONCLUSIONS: Marathon running in individuals over the age of 50 is associated with a transient, yet reversible increase in cardiac biomarkers and RV systolic dysfunction. The presence of myocardial fibrosis in older marathon athletes is infrequent, but when present, may be due to underlying occult coronary artery disease.