Nishimura, Rick A.

ObjectivesWe aimed to assess the utility of changes in systolic and diastolic function by isoproterenol challenge in predicting symptom resolution post‐myectomy in selected patients with hypertrophic cardiomyopathy (HCM) and labile obstruction.BackgroundIn a subset of symptomatic HCM patients without resting/provocable obstruction on noninvasive assessment, isoproterenol challenge during hemodynamic catheterization may elicit labile left ventricular outflow tract (LVOT) obstruction, and demonstrate the effect of obstruction on diastolic function. These changes may determine whether patients achieve complete symptom resolution post‐myectomy.MethodsBetween February 2003 and April 2009, 18 symptomatic HCM patients without LVOT obstruction on noninvasive testing underwent isoproterenol provocation and septal myectomy due to presence of provocable gradient and were followed for 4 (IQR 3–7) years.ResultsThirteen (72.2%) had complete symptom resolution, while 5 (27.8%) had improved, but persistent symptoms. Those with provoked gradient >100 mm Hg or increase in left atrial pressure (LAP) with isoproterenol had symptom resolution.ConclusionsSymptomatic HCM patients without LVOT gradient on noninvasive testing may demonstrate labile obstruction with isoproterenol. With isoproterenol, patients with high LVOT gradient or increase in LAP concomitant with an increase in gradient achieved complete symptom resolution post‐myectomy. Thus, improved diastolic filling as well as outflow gradient production in patients with HCM may predict symptom response to myectomy. © 2016 Wiley Periodicals, Inc.

Background— Severe primary (degenerative) mitral regurgitation (MR) is repaired with durable results when simple single-scallop disease is addressed. The midterm quality outcomes of minimally invasive repair for complex disease are unknown, however. Methods and Results— From January 2008 to January 2015, 487 patients (56±11 years, 360 men, ejection fraction 65±6%, 98.8% complete follow-up) underwent robotic mitral valve repair for severe nonischemic degenerative MR. Simple pathology was addressed in 289 of 487 (59%) patients, and complex repair (all others) was performed in 198 of 487 (41%). Four patients died during follow-up with a 5-year survival rate 99.5% (99.4% simple; 99.5% complex; hazard ratio, 0.48; 95% confidence interval, 0.05–4.59); and New York Heart Association functional class I/II was documented in 97.9% (477/487). Eight patients had recurrence of moderate-to-severe MR (4 simple, 4 complex), with a 5-year freedom from MR of 94.6% (96.2% simple; 92.7%, complex; P =0.67; hazard ratio, 1.36; 95% confidence interval, 0.34–5.43). Seven patients (2 simple, 5 complex), underwent mitral reoperation, with a 5-year freedom from reoperation of 97.7% (99.1% simple; 95.7% complex; P =0.13; hazard ratio, 3.35; 95% confidence interval, 0.65–17.32). Conclusions— At a large tertiary care referral center, midterm quality outcomes after robotic correction of degenerative MR are excellent, with very high survival, infrequent complications, and a low likelihood of MR recurrence, regardless of mitral valve repair complexity. Awareness of these improvements in outcome is important to inform contemporary decisions regarding high-quality alternatives to conventional and percutaneous mitral repair.

Background— Low-flow, low-gradient aortic stenosis (AS), associated with a poor prognosis, can be caused by a reduced stroke volume despite a preserved ejection fraction (left ventricular ejection fraction). We hypothesized that impaired ventricular diastolic filling secondary to constrictive pericarditis (CP) could contribute to reduced transaortic gradients in patients with AS+CP. We sought to examine the characteristics and outcomes of this unique cohort. Methods and Results— We analyzed 84 patients with different degrees of AS and preserved left ventricular ejection fraction (≥50%): 28 diagnosed with concomitant CP by echocardiography and 56 patients without CP matched by age, sex, and AS severity during 1998 to 2013. Prior mediastinal radiation (32.1% versus 5.4%; P =0.0072) and cardiac surgery (50.0% versus 3.6%; P =0.0016) were more common in AS+CP patients than those with AS only. AS+CP patients had lower left ventricular stroke volume index and mean transaortic gradients. Five-year survival was 34.3% for AS+CP patients and 89.1% for those with AS only ( P <0.001). In univariate analysis, prior mediastinal radiation (hazard ratio, 8.35; 95% confidence interval, 3.38–20.62; P <0.001), reduced left ventricular stroke volume index of <35 mL/m 2 (hazard ratio, 12.52; 95% confidence interval, 3.97–39.48; P <0.001), and concomitant CP (hazard ratio, 13.65; 95% confidence interval, 4.85–38.41; P <0.001) were highly associated with increased mortality. Conclusions— Our findings highlighted the possibility of CP as a pathophysiological mechanism for low-flow, low-gradient AS. Left ventricular stroke volume index and transaortic gradients were commonly reduced in AS in the setting of CP despite a preserved left ventricular ejection fraction, which may result in underestimation of AS severity. Prior mediastinal radiation, lower left ventricular stroke volume index, and concomitant CP were associated with poorer survival in AS patients.

ObjectivesPrior analysis at our institution found that patients with hypertrophic cardiomyopathy (HCM) who experience postprandial symptoms (PPS) are more likely to have resting left ventricular outflow tract (LVOT) obstruction and reduced quality of life. Our objective was to determine whether PPS in patients with HCM vs healthy subjects occur as a result of measurable hemodynamic alterations in the postprandial hemodynamic response.MethodsWe conducted a prospective cross‐sectional study examining 45 patients with HCM and 10 controls who underwent fasting and postprandial 2‐dimensional Doppler echocardiography. Postprandial echocardiographic measurements were obtained at symptom onset or 30 minutes after consumption of a standardized meal, whichever occurred first.ResultsThe HCM population included 18 (40%) patients with PPS and 27 (60%) without PPS. Compared to controls, mean resting peak LVOT gradient was 23.4 ± 17.6 mmHg in HCM patients with PPS and 25.1 ± 33.1 mmHg in those without PPS (P = 0.10). The mean change in peak LVOT gradient after a meal was 0.7 ± 1.1 mmHg for controls, 5.0 ± 8.3 mmHg for HCM patients with PPS, and 1.5 ± 18.2 mmHg for HCM patients without PPS (P = 0.64).ConclusionAlthough the ability to provoke an increased LVOT gradient with a postprandial, upright exercise study protocol was recently reported, the current study suggests that a resting, supine, postprandial protocol does not elicit evidence of LVOT obstruction. Therefore, future investigations should consider whether simply performing an upright postprandial study in HCM patients with PPS will provide evidence of dynamic LVOT or if the addition of an exercise component is necessary.

NISHIMURA, R.A. et al.: Hemodynamic and symptomatic consequences of ventricular pacing. After implantation of a ventricular demand pacemaker (VVI), occasional patients continue to have dizziness, syncope, or near syncope (“pacemaker syndrome”). To identify patients in whom VVI pacing may have deleterious effects, we compared cuff blood pressure responses to VVI pacing with blood pressure responses to atrioventricsler sequential pacing (DVI) or sinus rhythm in 50 consecutive patients. Patients with intact ventriculoatrial conduction had a much greater decrease in systolic blood pressure with VVI pacing (24 ± 11 mm Hg) than those with ventriculoatrial dissociation (−4 ± 15 mm Hg) (P<0.005). Patients who were in heart failure had a lesser decrease in blood pressure with VVI pacing than did those without failure (P<0.05); 13 of the 14 heart failure patients lacked ventriculoatrial conduction. Ten patients had symptomatic dizziness after VVI pacing; the incidence of symptoms was higher in patients with ventriculoatrial conduction (9 of 23) than in those without ventriculoatrial conduction (1 of 27) (P<0.003). We conclude that the presence of intact ventriculoatrial conduction appears to be a crucial determinent of the hemodynamic response to VVI pacing, and its presence may identify patients who are at risk for “pacemaker syndrome.”

In this report, we describe the case of a 41‐year‐old man with hypertrophic cardiomyopathy presenting with right‐sided congestive heart failure symptoms. Noninvasive testing was suggestive, but non‐diagnostic for constrictive pericarditis (CP) and thus invasive hemodynamic catheterization was performed. The unique presence of both hypertrophic cardiomyopathy and constriction in this case led to lack of “modern” echocardiographic and invasive criteria for CP, based upon findings of enhanced ventricular dependence. However, classic hemodynamic criteria of early rapid filling with elevation and end‐equalization of diastolic pressures were present, and the patient ultimately received pericardiectomy with dramatic clinical improvement. © 2015 Wiley Periodicals, Inc.

Confirmation of the presence and magnitude of left ventricular outflow tract (LVOT) obstruction is a critical component of the evaluation of symptoms in patients with hypertrophic cardiomyopathy (HCM). The presence of LVOT obstruction in patients with severe symptoms refractory to pharmacologic therapy identifies a subgroup of HCM patients who may benefit from septal reduction therapy. Two‐dimensional echocardiography with continuous wave Doppler is the main tool for confirming the presence and severity of LVOT obstruction in HCM. However, when uncertainty remains following non‐invasive evaluation, invasive hemodynamics studies are required to confirm and quantify LVOT obstruction. In this manuscript we describe a series of 6 cases in which hemodynamic catheterization is instrumental in supplementing non‐invasive imaging in the assessment of LVOT obstruction in HCM. © 2015 Wiley Periodicals, Inc.