Left ventricular regional relaxation and its nonuniformity in hypertrophic nonobstructive cardiomyopathy

BACKGROUND. Regional nonuniformity has been suggested to be closely related to left ventricular (LV) relaxation in diseased heart. The purpose of the present study was to assess LV global and regional relaxation in patients with nonobstructive hypertrophic cardiomyopathy (HCM). METHODS AND RESULTS. Left ventriculography was conducted simultaneously with pressure micromanometry in 10 normal control subjects and 11 patients with nonobstructive HCM. LV silhouettes in the right anterior oblique projection were divided into eight regions, and regional wall stress during isovolumic relaxation was computed for six regions from the midventricle to the apex. In HCM patients, isovolumic relaxation time (IRT) and the time constant of LV pressure decrease (Tp) were greater than in control subjects (IRT, 84 +/- 13 versus 66 +/- 6 msec; Tp, 51 +/- 8 versus 36 +/- 5 msec, respectively; p less than 0.01). In HCM patients, the (-)dP/dt upstroke pattern was convex-downward, and dP/dt(20/60), the ratio of dP/dt values 20 and 60 msec after peak (-)dP/dt, was less than in control subjects (1.46 +/- 0.16 versus 2.15 +/- 0.14, p less than 0.01). These findings suggest that there is impaired LV relaxation in HCM patients. End-systolic regional wall stress was lower, and the time constant of regional stress decrease (Tst) was prolonged for each region in HCM patients compared with control subjects. In the HCM group, Tst tended to be more prolonged in regions with increased wall thickness than in regions with normal wall thickness (60 +/- 15 versus 50 +/- 11 msec, p less than 0.01). The coefficient of variation for Tst values in six areas of the left ventricle was calculated in each subject and was greater in HCM patients than in control subjects (13 +/- 7% versus 7 +/- 3%, p less than 0.05), indicating regional nonuniformity in Tst during isovolumic relaxation in HCM patients. CONCLUSIONS. Significant correlations existed between the coefficients of variation for Tst and Tp (r = 0.80, p less than 0.01), IRT (r = 0.79, p less than 0.01), and dP/dt(20/60) (r = -0.67, p less than 0.05) in the HCM group. Thus, regional nonuniformity is closely related to the impairment of LV relaxation in HCM.     

Left ventricular regional wall stress in dilated cardiomyopathy

Left ventriculography with simultaneous pressure micromanometry was performed in 11 normal control subjects and 17 patients with dilated cardiomyopathy (DCM). Left ventricular silhouettes in the right anterior oblique projection were divided into eight areas, and regional wall stress was computed by Janz's method in each area excluding the two most basal areas. Wall stress was higher in DCM patients than in control subjects (p less than 0.01). The percent area changes from end diastole to end systole in each area were lower in DCM patients than in control subjects (mean for six areas, 22 +/- 14% versus 54 +/- 9%, respectively, p less than 0.01), but the coefficient of variation for the percent area changes in the six areas of the left ventricle in DCM patients was greater than that in control subjects (32 +/- 17% versus 15 +/- 4%, respectively, p less than 0.01), indicating regional differences in hypokinesis. There was a significant negative correlation between end-systolic regional wall stress and percent area change (r = -0.60 to -0.86, p less than 0.05) in each area. Thus, excessive regional afterload may play an important role in causing regional hypokinesis in DCM.     

Left ventricular filling in dilated cardiomyopathy: relation to functional class and hemodynamics

Left ventricular systolic function does not correlate well with functional class in patients with dilated cardiomyopathy. To determine whether the correlation is better with Doppler indexes of left ventricular diastolic function, 34 patients with dilated cardiomyopathy (M-mode echocardiographic end-diastolic dimension greater than 60 mm, fractional shortening less than 25%, increased E point-septal separation) were studied. Patients were classified into two groups according to functional class. Group 1 consisted of 16 patients in New York Heart Association functional class I or II; group 2 included 18 patients in functional class III or IV. Left ventricular dimensions, fractional shortening, left ventricular mass, meridional end-systolic wall stress, peak early and late transmitral filling velocities and their ratio, isovolumetric relaxation period and time to peak filling rate were computed from pulsed wave Doppler and M-mode echocardiograms and calibrated carotid pulse tracings. Right heart catheterization was performed in 20 of 34 patients. No differences were observed between groups with regard to age, gender distribution, heart rate, blood pressure and M-mode echocardiographic-derived indexes of systolic function. Peak early filling velocity (72 +/- 13 versus 40 +/- 10 cm/s, p less than 0.001) was higher and atrial filling fraction (27 +/- 4% versus 46 +/- 8%, p less than 0.001) was lower in group 2 than in group 1. The ratio of early to late transmitral filling velocities was higher in group 2 patients (2.3 +/- 0.5 versus 0.7 +/- 0.2, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Left ventricular diastolic reserve during acute pressure loading in hypertrophic cardiomyopathy and dilated cardiomyopathy

To evaluate left ventricular diastolic reserve during acute pressure loading, changes in mitral flow velocity patterns before and after the elevation of blood pressure were analyzed by pulsed Doppler echocardiography in 11 cases of hypertrophic cardiomyopathy (HCM), nine cases of dilated cardiomyopathy (DCM), and 11 control subjects. Systolic blood pressure was elevated 25% above basal values by methoxamine infusion (0.01 mg/kg/min). Before and after methoxamine, left ventricular dimension and mitral flow velocity pattern were obtained by M-mode and pulsed Doppler echocardiography, respectively. The peak velocity in the rapid filling and atrial contraction phases and time-velocity integrals were measured from the flow pattern. After methoxamine, left ventricular diastolic dimension was significantly increased in all groups, from 43.8 +/- 4.7 mm to 47.4 +/- 4.9 mm in the control subjects, from 43.7 +/- 6.3 mm to 47.2 +/- 6.0 mm in HCM, and from 57.9 +/- 6.4 mm to 60.6 +/- 5.9 mm in DCM. Left ventricular systolic dimension was significantly increased from 48.6 +/- 8.4 mm to 52.8 +/- 8.3 mm in DCM, but not in the control subjects or HCM. The peak velocity in the rapid filling phase was significantly increased from 60 +/- 16 cm/sec to 69 +/- 14 cm/sec in the control subjects and tended to be increased from 44 +/- 13 cm/sec to 52 +/- 12 cm/sec in HCM. The extent of this increase tended to be less in HCM. However, the peak velocity in the rapid filling phase tended to decrease in DCM. There were no consistent trends of changes in the peak velocity in the atrial contraction phase in any groups. The mitral velocity integral increased from 502 Hz-sec to 621 Hz-sec in the controls and from 525 Hz-sec to 613 Hz-sec in HCM, but it did not increase in DCM. These findings suggest that there is impaired diastolic reserve during acute pressure loading in HCM and DCM and that the diastolic disturbance might be reflected in the early diastolic phase, rather than in the late diastolic phase.     

Left ventricular mechanics in dilated cardiomyopathy

The influence of altered chamber shape on the evaluation of left ventricular (LV) mechanics in idiopathic dilated cardiomyopathy (IDC) is unknown. Nine patients with IDC and 7 subjects with normal LV function were studied with simultaneous LV pressure and M-mode echographic recordings in order to derive LV meridional wall stress. The major axis of the left ventricle, determined from the left ventriculogram at rest, allowed for derivation of circumferential wall stress. The IDC group was characterized by larger end-diastolic and end-systolic LV volumes, increased LV mass, depressed angiographic ejection fraction and more spherical LV chamber shape. Both end-systolic meridional (114 +/- 30 kdyne/cm2) and circumferential (251 +/- 73 kdyne/cm2) wall stresses were elevated in patients with IDC, although the ratio of these stresses was less than normal (2.2 +/- 0.1 vs 2.7 +/- 0.2, respectively). LV load alteration with phenylephrine or nitroglycerin allowed for construction of end-systolic stress-minor-axis dimension and end-systolic stress-minor-axis shortening relations. Similar mean slopes of the meridional end-systolic stress-dimension relation were noted in IDC and normal subjects, although the line was displaced to the right in IDC. The slope of the circumferential end-systolic stress-dimension relation was, however, decreased in patients with IDC. Moreover, the end-systolic stress-fractional minor-axis shortening relation in patients with IDC was displaced downward from the normal relation supporting depressed contractile function in these IDC patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Left ventricular regional function in patients with dilated cardiomyopathy (computerized echocardiographic data)

Computerized echography was used to assess left-ventricular dysfunction in 40 patients with dilatation cardiomyopathy (DCM). The so-called "floating" system was shown to be the most acceptable model for the correction of DCM-associated superposition. An original system was used for segment division by two- and four-chamber projections. Total left-ventricular hypokinesia and a significant reduction of the total ejection fraction (32.5 +/- 1.9%) were demonstrated.     

Left ventricular structural adaptations to obstructive sleep apnea in dilated cardiomyopathy

RATIONALE AND OBJECTIVES: Obstructive sleep apnea is common among patients with heart failure and exposes the left ventricle to trophic mechanical and adrenergic stimuli. We hypothesized that in heart failure patients with nonischemic dilated cardiomyopathy (a condition characterized by eccentric hypertrophy), those with obstructive sleep apnea would have a higher prevalence of left ventricular hypertrophy by wall thickness criteria (> or = 12 mm), and greater septal thickness than those without obstructive sleep apnea. METHODS AND RESULTS: We performed echocardiography and polysomnography in 47 patients with nonischemic dilated cardiomyopathy. Obstructive sleep apnea was present in 45% of these patients. The prevalence of left ventricular hypertrophy was greater in those with than in those without obstructive sleep apnea (47.6 vs. 15.4%, p = 0.016). Interventricular septal thickness (p < 0.001) and relative wall thickness (p = 0.011) were significantly greater in those with than in those without obstructive sleep apnea. However, there was no significant difference in posterior wall thickness between the groups. The frequency of obstructive apneas and hypopneas during sleep was the only significant independent correlate of septal thickness (p = 0.001). CONCLUSIONS: In patients with nonischemic dilated cardiomyopathy, the presence of obstructive sleep apnea is associated with an increased prevalence of left ventricular hypertrophy. The higher relative wall thickness and interventricular septal thickness in patients with obstructive sleep apnea indicate that the left ventricle is relatively less eccentric than in patients without obstructive sleep apnea, and that such remodeling affects mainly the septum. These structural adaptations may reflect unique nocturnal mechanical and adrenergic stimuli associated with obstructive sleep apnea.     

Left ventricular versus biventricular dysfunction in idiopathic dilated cardiomyopathy

Eighty-five consecutive patients with idiopathic dilated cardiomyopathy were categorized according to the presence (biventricular dysfunction) or absence (left ventricular [LV] dysfunction) of reduced right ventricular ejection fraction (<35%) along with reduced LV ejection fraction (<50%). Compared with the 36 patients with LV dysfunction, the 49 patients with biventricular dysfunction had significantly worse New York Heart Association functional class (2.7+/-0.6 vs 1.9+/-0.5; p <0.001), LV ejection fraction (26+/-10% vs 34+/-8%; p <0.0001), and outcome (transplant-free survival, 55% vs 89%; p <0.001). Thus, dilated cardiomyopathy is frequently characterized by biventricular involvement, which identifies a more severe disease and a worse long-term prognosis.     

Safety and efficacy of inferior vena caval occlusion to rapidly alter ventricular loading conditions in idiopathic dilated cardiomyopathy

To investigate the safety and efficacy of inferior vena caval (IVC) balloon occlusion for preload alteration in humans, 13 patients with dilated cardiomyopathy were studied before and during repeated (total of 78) IVC occlusions. Left and right ventricular (LV and RV) micromanometer pressures were simultaneously measured and M-mode and 2-D echocardiograms were recorded at end expiration. Complications were limited to abdominal discomfort in 2 patients. With IVC occlusion, RV collapse fluoroscopically shifted the heart toward midline and ventricular septal motion was frequently disordered. Significant (p = 0.001) changes occurred in RV and LV systolic peak pressures (from 19 +/- 6 to 12 +/- 5 mm Hg and from 129 +/- 34 to 109 +/- 25 mm Hg, respectively). LV and RV end-diastolic pressures also decreased significantly (from 18 +/- 7 to 6 +/- 6 mm Hg and from 5 +/- 3 to 2 +/- 2 mm Hg, respectively) (both p less than or equal to 0.0055). Similarly, LV end-diastolic diameter decreased 13% (from 61 +/- 11 to 53 +/- 12 mm, p = 0.0002). Mean heart rate did not change significantly (from 76 +/- 19 to 78 +/- 21 beats/min). Thus, IVC balloon occlusion provides a safe method of repeatedly altering loading conditions in humans. This approach allows for acquisition of important information regarding cardiac chamber dynamics while minimizing the effects of reflex mechanisms and avoiding use of pharmacologic agents.     

Left ventricular diastolic function of patients with dilated cardiomyopathy

A study of 79 patients with dilatation cardiomyopathy (DCMP), making use of echo- and angiocardiography and catheterization of various heart compartments, has demonstrated considerable changes in left ventricular diastolic properties, common to this condition: reduced pliancy of heart chamber, increased myocardial rigidity and impaired myocardial relaxation. Reduced left ventricular diastolic pliancy is associated with myocardial hypertrophy and impaired relaxation.     

Left ventricular relaxation and filling in hypertrophic cardiomyopathy. An echocardiographic study.

Echocardiograms showing left ventricular cavity and mitral valve cusps simultaneously were recorded in 36 patients, apex cardiograms being obtained in 26 of them. These were digitised and continuous plots made of left ventricular dimension, its rate of change, and anterior mitral leaflet velocity, and were compared with those in 20 normal subjects. Peak mitral diastolic closure rate was reduced to 120 +/- 80 mm/s, compared with normal (250 +/- 60 mm/s). Peak rate of increase of dimension was normal (13.4 cm/s), though the pattern of filling was disturbed, with the duration of rapid filling prolonged in 5, and shortened in 15, suggesting restriction. Mitral valve opening, normally synchronous with minimum dimension, was delayed by a mean of 76 ms, and during this period there was an abnormal increase in dimension. Dimension also increased by 50 +/- 25 per cent of the total diastolic excursion before the 'O' point of the apex cardiogram compared with 21 +/- 7 per cent in normals, and the timing of peak rate of increase of dimension was delayed by 50 +/- 20 ms instead of being synchronous with the 'O' point as normal. None of these findings correlated with the reduction in peak mitral diastolic closure rate. Noninvasive methods thus show that relaxation may be abnormal in hypertrophic cardiomyopathy. Delay in mitral valve opening and disturbances in the rate, duration, and co-ordination of wall movement during filling suggest the presence of segmental abnormalities of left ventricular function.     

Left ventricular aneurysm in a patient with mildly dilated cardiomyopathy

We describe the case of a patient with mildly dilated idiopathic cardiomyopathy and left ventricular aneurysm, diagnosed in absence of a prior clinical history and anatomo-pathological features of myocardial infarction. To ascertain the diagnosis of idiopathic cardiomyopathy, the patient underwent cardiac catheterization with coronary angiography, that showed the lack of epicardial artery stenosis and a slow run-off of the contrast. An endomyocardial biopsy showed the presence of hypertrophic myocytes and interstitial fibrosis. Moreover, a thoracic high resolution computed tomography showed the features of pulmonary bilateral basal emphysema, interstitial thickening and bronchiectasis. Alfa1-anti-trypsin plasma levels were reduced. The patient, because of worsening of clinical and hemodynamic conditions, underwent at age of 36 a combined heart-lung transplantation. The pathological examination of the native organs confirmed the previous diagnosis. At the moment, this is the second report in the literature concerning the presence of left ventricular aneurysm in a patient with idiopathic cardiomyopathy without an underlying coronary artery disease or prior history of myocardial infarction.     

Left ventricular shape, afterload and survival in idiopathic dilated cardiomyopathy

Because idiopathic dilated cardiomyopathy is characterized by elevated wall stress and a more spherical left ventricle, the relations among shape, afterload and survival were examined. Thirty-six patients with cardiomyopathy were prospectively studied by two-dimensional echocardiography. Data included echocardiographic short- and long-axis cavity dimensions, their ratio and, with cuff systolic blood pressure, meridional and circumferential end-systolic stress and their ratios. Survivors (n = 16) were followed up for 52 months (range 40 to 76); nonsurvivors (n = 20) died an average of 11 months after study. Survivors had a smaller left ventricular end-diastolic short-axis dimension (6.4 versus 7.1 cm, p less than 0.03) but a similar long-axis length (8.6 versus 8.3 cm). However, overall cavity shape or the ratio of short- to long-axis end-diastolic dimensions was more spherical in those with poorer survival (ratio 0.76 versus 0.68, p less than 0.02). Meridional and circumferential end-systolic stresses were similar in the two groups, but stress was more evenly distributed in the long- and short-axis planes in nonsurvivors (meridional/circumferential stress ratio 0.57 versus 0.52 in survivors, p less than 0.05). Improved survival was associated with an end-diastolic short-axis dimension less than 7.63 cm, a short- to long-axis ratio less than 0.76 and a meridional to circumferential stress ratio less than 0.54. Life table analysis revealed a 28% mortality rate in patients with all three of these characteristics compared with 100% in patients with none. Survivors and nonsurvivors did not differ in systolic cavity dimension, wall thickness, relative wall thickness, cavity volume, percent posterior wall thickening or fractional shortening.(ABSTRACT TRUNCATED AT 250 WORDS)     

Right ventricular dilated cardiomyopathy.

Fourteen patients with predominantly right sided dilated cardiomyopathy were studied, of whom five died suddenly. The condition is characterised by male preponderance, syncope, ventricular tachycardia, which typically has a left bundle branch block pattern on the surface electrocardiogram, and right heart failure. The diagnosis should be considered in patients presenting with otherwise unexplained ventricular tachycardia or syncope; the diagnosis may be readily missed because of the nonspecific nature or absence of signs.     

Left ventricular dysfunction due to atrial fibrillation in patients initially believed to have idiopathic dilated cardiomyopathy.

Ten patients aged 22 to 80 years (median 57) with severe left ventricular (LV) dysfunction and atrial fibrillation (AF) with rapid ventricular response were evaluated after therapy. Because most patients were unaware of their arrhythmia, duration was usually unknown. All patients had heart failure symptoms; 9 presented with New York Heart Association class III or IV disability, and 1 with class II disability. Initial LV ejection fraction ranged from 12 to 30% (median 25). No patient had symptomatic coronary artery disease (4 underwent angiography). Myocarditis and infiltrative processes were excluded by biopsy in 5 patients. All patients were considered initially to have idiopathic dilated cardiomyopathy with secondary AF. Ventricular rate was controlled in all patients, with sinus rhythm restored in 5. At follow-up (median 30 months, range 3 to 56), all patients were asymptomatic. LV ejection fraction after treatment ranged from 40 to 64% (median 52). It is concluded that in some patients initially considered to have idiopathic dilated cardiomyopathy, AF with rapid ventricular response may be the primary cause rather than the consequence of severe LV dysfunction. LV dysfunction may be completely reversible with ventricular rate control.     

Left ventricular hypertrabeculation/noncompaction and neuromuscular disorders in idiopathic dilated cardiomyopathy

OBJECTIVE: Our aim was to assess 1) the association of idiopathic dilative cardiomyopathy (IDC) and left ventricular hypertrabeculation/noncompaction (LVHT), 2) the use of cardiac magnetic resonance imaging (CMRI) in IDC and 3) the association of IDC and neuromuscular disorders (NMD). METHODS: Patients in whom coronary heart disease had been excluded by coronary angiography and whose left ventricular end diastolic diameter was > 59 mm and fractional shortening < 25% with no other causes of cardiac dysfunction, were invited to participate. RESULTS: Among 25 patients, 18 refused CMRI (claustrophobia n = 13, inability to lie flat n = 5), thus 7 patients (2 female, 47-66 years) were included. LVHT was found in 5/7 cases. In 4/5 patients who were neurologically investigated, a NMD was found. In 2/7 cases echocardiography failed to visualise the ventricular apex. CONCLUSIONS: Patients with IDC should be investigated neurologically. In IDC patients with poor echocardiographic quality CMRI should be applied.     

Right ventricular filling in dilated cardiomyopathy.

PURPOSE--To assess right ventricular filling in dilated cardiomyopathy. PATIENTS--32 patients with dilated cardiomyopathy and 24 healthy controls. METHODS--Stroke distances were measured by pulsed Doppler echocardiography at left ventricular outflow and left and right ventricular inflow. The inflow tract dimensions of both ventricles and the outflow tract dimension of the left ventricle were measured from two dimensional images. Right and left sided atrioventricular (AV) ring excursions were measured by M mode echocardiography at the tricuspid and mitral rings. Stroke volume was derived as stroke distance multiplied by left ventricular outflow tract area. Total stroke distances were calculated as the sum of AV valve Doppler stroke distances and ring excursion. The effective orifice areas of the two AV valves were thus defined as stroke volumes divided by total stroke distance. RESULTS--Total tricuspid stroke distance was normally less than mitral (6.0 (1.7) v 7.6 (1.7) cm, P < 0.05), implying that effective orifice area of the tricuspid valve was consistently greater (6.6 (1.6) v 4.5 (0.8) cm2, P < 0.01). Total tricuspid ring excursion was normally more than mitral (2.30 (0.30) v 1.62 (0.22) cm, P < 0.01). Total tricuspid stroke distance in dilated cardiomyopathy was also less than mitral (7.8 (2.4) v 9.7 (2.8) cm, P < 0.05). Tricuspid stroke distance was significantly increased in patients with dilated cardiomyopathy compared with that in healthy controls (P < 0.05 v controls), though stroke volume was much smaller (26 (10) v 63 (11) ml, P < 0.01) so that tricuspid effective orifice area was reduced to less than half normal (2.7 (1.2) cm2, P < 0.01). Total tricuspid ring long axis excursion was more than mitral (1.37 (0.6) v 0.74 (0.21) cm, P < 0.01). Right ventricular end diastolic inflow dimension was increased compared with that in healthy controls (3.9 (0.7) v 2.8 (0.5) cm, P < 0.01), correlating inversely with tricuspid effective orifice area (r = -0.71, P < 0.01). Total tricuspid ring excursion was bimodally distributed as a low amplitude group (less than 1.6 cm, n = 23) and a high amplitude group (more than 1.6 cm, n = 9), in which the interval P2 to onset of tricuspid flow was much longer (100 (35) v 50 (14) ms, P < 0.01). CONCLUSIONS--Enlargement of the right ventricular inflow tract in dilated cardiomyopathy, especially to more than 5 cm, is accompanied by a progressive decrease in effective tricuspid orifice area, sometimes to less than 1 cm2 and increased inflow velocities. Right ventricular relaxation was incoordinate in 28% of the patients studied. These disturbances of right ventricular filling are likely to compromise overall cardiac function independently of left ventricular disease.