Refractory hypertension (RfHTN) is an extreme phenotype of antihypertensive treatment failure defined as lack of blood pressure control with ≥5 medications, including a long-acting thiazide and a mineralocorticoid receptor antagonist. RfHTN is a subgroup of resistant hypertension (RHTN), which is defined as blood pressure >135/85 mm Hg with ≥3 antihypertensive medications, including a diuretic. RHTN is generally attributed to persistent intravascular fluid retention. It is unknown whether alternative mechanisms are operative in RfHTN. Our objective was to determine whether RfHTN is characterized by persistent fluid retention, indexed by greater intracardiac volumes determined by cardiac magnetic resonance when compared with controlled RHTN patients. Consecutive patients evaluated in our institution with RfHTN and controlled RHTN were prospectively enrolled. Exclusion criteria included advanced chronic kidney disease and masked or white coat hypertension. All enrolled patients underwent biochemical testing and cardiac magnetic resonance. The RfHTN group (n=24) was younger (mean age, 51.7±8.9 versus 60.6±11.5 years; =0.003) and had a greater proportion of women (75.0% versus 43%;=0.02) compared with the controlled RHTN group (n=30). RfHTN patients had a greater left ventricular mass index (88.3±35.0 versus 54.6±12.5 g/m; <0.001), posterior wall thickness (10.1±3.1 versus 7.7±1.5 mm; =0.001), and septal wall thickness (14.5±3.8 versus 10.0±2.2 mm;<0.001). There was no difference in B-type natriuretic peptide levels and left atrial or ventricular volumes. Diastolic dysfunction was noted in RfHTN. Our findings demonstrate greater left ventricular hypertrophy without chamber enlargement in RfHTN, suggesting that antihypertensive treatment failure is not attributable to intravascular volume retention.

We report a 28-year-old white female who suffered significant aortic insufficiency (AI) following mitral valve (MV) replacement for endocarditis. The patient had history of rheumatoid arthritis and presented to our emergency department with a 3-month history of dyspnea, orthopnea, fevers and weight loss, worsening over 2 weeks, for which she took intermittent acetaminophen. On admission, vital signs revealed blood pressure of 99/70 mm Hg, heart rate of 120 beats/minute, and temperature of 98.8 °F; her weight was 100 lbs. Physical exam revealed a thin and pale female. Cardiac auscultation revealed regular tachycardic rhythm with a third heart sound, and a short early systolic murmur at the left lower sternal border without radiation. Lungs revealed right lower lobe rhonchi. Initial pertinent laboratory evaluation revealed hemoglobin 9.6 g/dL and white blood cell count 17,500/μL. Renal function was normal, and hepatic enzymes were mildly elevated. Chest radiogram revealed right lower lobe infiltrate. Blood cultures revealed Enterococcus faecalis. Two-dimensional echocardiogram revealed large multilobed vegetation attached to the anterior MV leaflet with severe mitral regurgitation (MR), otherwise normal left ventricular systolic function. She was started on appropriate antibiotics and underwent MV replacement with 25-mm On-X prosthesis. She was noted post-operatively to have prominent systolic and diastolic murmurs. Repeat echocardiogram revealed normal mitral prosthesis function, with new moderately severe AI. Transesophageal echocardiogram revealed AI originating from a tethered non-coronary cusp, due to a suture preventing proper cusp mobility. The patient declined further surgery. She recovered slowly and was discharged to inpatient rehabilitation 4 weeks later. This case highlights the importance of vigilance to this potential serious complication of valve surgery with regard to diagnosis and treatment to prevent long-term adverse consequences.

The utility and role of cardiac magnetic resonance (CMR) as a non-invasive diagnostic imaging modality has been well recognized in the field of cardiovascular disease. Use of late gadolinium enhancement (LGE) has further enhanced CMR's ability to determine structural, functional, and prognostic information in various cardiovascular diseases. The delivery and distribution of gadolinium as an extracellular agent allows the detection of edema, fibrosis, and infiltration in the myocardium. The pattern of LGE in cardiomyopathies enables us to distinguish among various disease processes non-invasively. Additionally, in patients with hypertrophic cardiomyopathy and sudden cardiac death, it helps in decision making in regards to use of implantable cardioverter defibrillator. In the evaluation of cardiac masses, LGE-CMR can often times differentiate between neoplastic and non-neoplastic conditions. In this review, we will discuss the various aspects of gadolinium-based contrast agents, and its application in CMR.

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