Left Ventricular Outflow Tract Gradient Variability in Hypertrophic Cardiomyopathy

Abstract

Background:The presence and magnitude of left ventricular outflow tract (LVOT) obstruction directs the management algorithm in symptomatic patients with hypertrophic cardiomyopathy (HCM). Although it is well known that the degree of LVOT obstruction is dynamic and dependent upon ventricular load and contractility, the magnitude and potential impact of the day-to-day variability seen in practice has not been well appreciated. Hypotheses: We hypothesized that LVOT gradient variability in HCM has an impact on clinical decision-making. Methods: A total of 100 HCM patients (mean age, 58 ± 13 years; 47% male) underwent comprehensive 2-dimensional Doppler transthoracic echocardiography and cardiac catheterization with transseptal measurement of left-sided pressures. All studies were performed within 48 hours of one another. Results: The correlation of LVOT gradients from both methods performed at different times had a wide scatter with the 95% confidence limits of agreement being ±84 mm Hg. For classifying patients as having severe LVOT obstruction on the basis of either method (<30 vs ≥30 mm Hg), discrepant results occurred in 21% of patients. To confirm the accuracy of Doppler measurements, 15 studies were performed with simultaneous measurement of LVOT gradient, which revealed a very strong correlation (r = 0.98, p < 0.0001) with 95% confidence limits of agreement ±12 mm Hg. Conclusions: In patients with HCM, LVOT gradient measurements are routinely obtained to characterize the severity of obstruction. However, these data demonstrate the marked variability of the LVOT obstruction, which must be considered when determining appropriate therapy in symptomatic patients.

Analog Simulation of Aortic Stenosis

“…In patients with aortic stenosis in exercise the latter compensatory mechanism is more likely to occur. It is clear that simulation data agree well -qualitatively, sometimes even quantitativelywith data obtained in patients (Anderson et al, 1969;Bache et al, 1971;Diver et al, 1988;Huber et al 1981;Peterson et al, 1978;Vanoverschelde et al, 1992) or in patients with hypertrophic cardiomyopathy and outflow tract gradient (Geske et al, 2007(Geske et al, , 2009Sorajja et al 2008). Exhaustion of LV sympathethetic drive and mild LV failure is simulated in Fig.…”

2011 ACCF/AHA Guideline for the Diagnosis and Treatment of Hypertrophic Cardiomyopathy: Executive Summary

“…Patients may have little or no obstruction of the LVOT at rest but can generate large LVOT gradients under conditions such as exercise, the strain phase of the Valsalva maneuver, or during pharmacologic provocation. 40,41 There is often large spontaneous variation in the severity of the gradient during day-to-day activities or even with food or alcohol intake 225 ; exacerbation of symptoms during the postprandial period is common. Importantly, it has been well established that LVOT obstruction contributes to the debilitating heart failure-related symptoms that may occur in HCM, 40,41 and is also a major determinant of outcome.…”

“…64,307 A limitation to using LVOT obstruction as an independent risk marker is that the obstruction in HCM is dynamic and highly variable. 225,344 …”

O diagnóstico da obstrução da via de saída do ventrículo esquerdo na cardiomiopatia hipertrófica

“…There is no typical morphological pattern, although asymmetric forms prevail, presenting septum/posterior wall of the LV > 1.3, and anterior and posterior septum impairment, extending or not to the free wall 15,22 . With smaller frequency, there are cases of concentric or isolated hypertrophy of the LV posterior septum, anterior lateral wall or apex The gradient estimated by Doppler echocardiogram shows a strong correlation with that one measured simultaneously by hemodynamic study 36 . Spontaneous change of gradient at rest of ± 32 mmHg was observed in consecutive measurements, with continuous Doppler, along five days 37 .…”