Nishimura, Rick A.

Background— Patients with severe tricuspid regurgitation (TR) frequently present with exertional fatigue and dyspnea, but the hemodynamic basis for exercise limitation in people with TR remains unclear. Methods and Results— Twelve subjects with normal left ventricular (LV) ejection fraction and grade ≥3 TR underwent high-fidelity invasive hemodynamic exercise testing with simultaneous expired gas analysis and were compared with 13 age- and sex-matched controls. At rest, TR subjects had lower pulmonary blood flow (3.6±0.4 versus 5.1±1.9 L/min; P =0.01), increased right atrial pressure (12±5 versus 4±1 mm Hg; P =0.0002), and higher pulmonary capillary wedge pressure (17±5 versus 9±3 mm Hg; P =0.0001). However, LV transmural pressure (pulmonary capillary wedge pressure−right atrial pressure), which reflects LV preload independent of right heart congestion and pericardial restraint, was similar in TR and controls (6±3 versus 4±2 mm Hg; P =0.3). With exercise, TR subjects displayed lower peak V O 2 (10.3±2.8 versus 13.8±4.2 mL/min per kg; P =0.02), lower pulmonary blood flow (6.4±1.3 versus 10.3±3.3 L/min; P =0.001), and less increase in pulmonary blood flow relative to V O 2 (+4.6±1.1vs +6.2±0.7; P =0.001). TR subjects displayed higher pulmonary capillary wedge pressure with exercise, but this was solely because of RA hypertension (27±9 versus 8±3 mm Hg; P <0.0001), because LV transmural pressure dropped with exercise in subjects with TR (−5±6 versus +3±3 mm Hg; P =0.0007), suggesting inadequate LV diastolic filling, despite high pulmonary capillary wedge pressure. Conclusions— Impaired exercise capacity in people with severe TR is related to low cardiac output reserve relative to metabolic needs, coupled with elevated systemic and pulmonary venous pressures. Left heart pressures are elevated with exercise in subjects with TR, despite low LV preload, secondary to enhanced ventricular interaction.

Background Atrial fibrillation ( AF ) is a common sequela of hypertrophic cardiomyopathy ( HCM ), but evidence on its prevalence, risk factors, and effect on mortality is sparse. We sought to evaluate the prevalence of AF , identify clinical and echocardiographic correlates, and assess its effect on mortality in a large high‐risk HCM population. Methods and Results We identified HCM patients who underwent evaluation at our institution from 1975 to 2012. AF was defined by known history (either chronic or paroxysmal), electrocardiogram, or Holter monitoring at index visit. We examined clinical and echocardiographic variables in association with AF . The effect of AF on overall and cause‐specific mortality was evaluated with multivariate Cox proportional hazards models. Of 3673 patients with HCM , 650 (18%) had AF. Patients with AF were older and more symptomatic ( P <0.001). AF was less common among patients with obstructive HCM phenotype and was associated with larger left atria, higher E/e’ ratios, and worse cardiopulmonary exercise tolerance (all P values<0.001). During median (interquartile range) follow‐up of 4.1 (0.2 to 10) years, 1069 (29%) patients died. Patients with AF had worse survival compared to those without AF ( P <0.001). In multivariate analysis adjusted for established risk factors of mortality in HCM , the hazard ratio (95% confidence interval) for the effect of AF on overall mortality was 1.48 (1.27 to 1.71). AF did not have an effect on sudden or nonsudden cardiac death. Conclusions In this large referral HCM population, approximately 1 in 5 patients had AF . AF was a strong predictor of mortality, even after adjustment for established risk factors.

The non‐invasive evaluation of prosthetic valve function is challenging. The effects of flow rate, valvular geometry, leaflet motion, and pressure recovery all impact the Doppler assessment of prosthetic performance. Differentiating prosthesis obstruction from pressure recovery in patients who are found to have high Doppler velocities across an aortic valve prosthesis is critical in order to direct appropriate management. In this manuscript, we present two cases of patients with aortic valve prosthesis with high Doppler velocities and review the pathophysiology and evaluation of prosthesis function. © 2014 Wiley Periodicals, Inc.

Background— Low-gradient severe aortic stenosis with preserved ejection fraction is an increasingly recognized entity, and symptomatic patients may benefit from aortic valve replacement. However, systemic hypertension frequently coexists with low-gradient severe aortic stenosis, which itself may cause elevated left ventricular (LV) filling pressures with resultant symptoms of dyspnea. Methods and Results— Symptomatic patients with hypertension (aortic systolic pressure >140 mm Hg) and low-gradient (mean gradient <40 mm Hg) severe aortic stenosis (aortic valve area <1 cm 2 ) with preserved ejection fraction (ejection fraction >50%) who underwent invasive hemodynamic catheterization of the left and right sides of the heart received infusion of intravenous sodium nitroprusside to reduce blood pressure and arterial afterload. At baseline, patients had severe hypertension (aortic systolic pressure, 176±26 mm Hg), pulmonary hypertension (mean pressure, 39±12 mm Hg), elevated LV end-diastolic pressure (19±5 mm Hg), and reduced stroke volume (33±8 mL/m 2 ). All measures of afterload were reduced with nitroprusside ( P <0.001 for all). Nitroprusside reduced mean pulmonary artery pressure (25±10 mm Hg) and LV end-diastolic pressure (11±5 mm Hg; P <0.001 for both compared with baseline). Aortic valve area (0.86±0.11 to 1.02±0.16 cm 2 ; P =0.001) and mean gradient (27±5 to 29±6 mm Hg; P =0.02) increased with nitroprusside. Conclusions— Systemic hypertension in low-gradient severe aortic stenosis with preserved ejection fraction is associated with elevated LV filling pressures and pulmonary hypertension. Treatment of hypertension with vasodilator therapy results in a lowering of the total LV afterload, with a decrease in LV filling pressures and pulmonary artery pressures. These findings have important implications for the management of patients with low-gradient severe aortic stenosis with preserved ejection fraction and hypertension.

Retroperitoneal fibrosis is a rare condition characterized by the presence of inflammatory and fibrous retroperitoneal tissue that surrounds and often encases abdominal structures. In this report we describe an unusual presentation of retroperitoneal fibrosis and inferior vena cava (IVC) obstruction that was unidentified by noninvasive testing and ultimately diagnosed using exercise right heart catheterization and venography. Exercise hemodynamic catheterization revealed a high pressure gradient across the IVC obstruction during exercise that resulted in reduced preload and inappropriately low cardiac output reserve. The patient ultimately underwent angioplasty and stenting of the obstruction resulting in resolution of his symptoms. © 2013 Wiley Periodicals, Inc.