Akira Kisanuki

Isolated annular dilation does not usually cause important functional mitral regurgitation: comparison between patients with lone atrial fibrillation and those with idiopathic or ischemic cardiomyopathy.

OBJECTIVES We sought to test whether isolated mitral annular (MA) dilation can cause important functional mitral regurgitation (MR). BACKGROUND Mitral annular dilation has been considered a primary cause of functional MR. Patients with functional MR, however, usually have both MA dilation and left ventricular (LV) dilation and dysfunction. Lone atrial fibrillation (AF) can potentially cause isolated MA dilation, offering a unique opportunity to relate MA dilation to leaflet function. METHODS Mid-systolic MA area, MR fraction, LV volumes and papillary muscle (PM) leaflet tethering length were compared by echocardiography among 18 control subjects, 25 patients with lone AF and 24 patients with idiopathic or ischemic cardiomyopathy (ICM). RESULTS Patients with lone AF had a normal LV size and function but MA dilation (isolated MA dialtion) significant and comparable to that of patients with ICM (MA AREA: 8.0 +/- 1.2 vs. 11.6 +/- 2.3 vs. 12.5 +/- 2.9 cm(2) [control vs. lone AF vs. ICM]; p < 0.001 for both lone AF and ICM). However, patients with lone AF had only modest MR, compared with that of patients with ICM (MR fraction: -3 +/- 8% vs. 3 +/- 9% vs. 36 +/- 25%; p < 0.001 for patients with ICM). Multivariate analysis identified PM tethering length, not MA dilation, as an independent primary contributor to MR. CONCLUSIONS Isolated annular dilation does not usually cause moderate or severe MR. Important functional MR also depends on LV dilation and dysfunction, leading to an altered force balance on the leaflets, which impairs coaptation.

Mechanism of Recurrent/Persistent Ischemic/Functional Mitral Regurgitation in the Chronic Phase After Surgical Annuloplasty Importance of Augmented Posterior Leaflet Tethering

Background— Surgical annuloplasty can potentially hoist the posterior annulus anteriorly, exaggerate posterior leaflet (PML) tethering, and lead to recurrent ischemic/functional mitral regurgitation (MR). Characteristics of leaflet configurations in late postoperative MR were investigated. Methods and Results— In 30 patients with surgical annuloplasty for ischemic MR and 20 controls, the anterior leaflet (AML) and PML tethering angles relative to the line connecting annuli, posterior and apical displacement of the coaptation and the MR grade were measured by echocardiography before, early after, and late after surgery. Early after surgery, grade of MR and AML tethering generally decreased (P<0.01), whereas PML tethering significantly worsened (P<0.01). Nine of the 30 patients showed recurrent/persistent MR late after surgery. Compared with patients without late MR, those with the MR showed similar reduction in the annular area, significant re-increase in posterior displacement of the coaptation, and progressive worsening in PML tethering (P<0.05) late after surgery in comparison to the early phase. Both preoperative MR and late postoperative MR were significantly correlated with all tethering variables in univariate analysis. Although apical displacement of the coaptation was the primary determinant of preoperative MR (r2=0.60, P<0.0001), increased PML tethering was the primary determinant of late MR (r2=0.75, P<0.0001). Conclusions— Whereas both leaflets tethering is related to preoperative ischemic MR, both leaflets tethering but with predominant contribution from augmented and progressive PML tethering is related to recurrent/persistent ischemic/functional MR late after surgical annuloplasty.

Mechanism of Persistent Ischemic Mitral Regurgitation After Annuloplasty Importance of Augmented Posterior Mitral Leaflet Tethering

Background—We hypothesized that surgical annuloplasty for ischemic mitral regurgitation (MR) that displaces the posterior annulus anteriorly can potentially augment posterior leaflet (PML) tethering, leading to persistent MR. Relationships between leaflet configurations and persistent ischemic MR after the annuloplasty were investigated. Methods and Results—In 31 patients with surgical annuloplasty for ischemic MR and 20 controls, posterior and apical displacement of the leaflet coaptation, the anterior leaflet (AML) and PML tethering angles relative to the line connecting annuli, coaptation length (CL), and the MR grade were quantified before and early after surgery in echocardiographic left ventricular long-axis views. Six of the 31 patients showed persistent MR despite annuloplasty. Compared with patients without persistent MR, those with MR showed no improvement in the left ventricular ejection fraction and systolic volume, similar reduction in the annular area, significant increase in posterior displacement of the coaptation (P<0.01), no improvement in AML tethering, greater worsening in PML tethering (P<0.01), and no increase in the CL. All tethering variables were significantly correlated with both preoperative and postoperative MR in univariate analysis, and reduced CL was the primary independent determinant of both preoperative and postoperative MR. Although increased AML tethering was the primary determinant of the preoperative CL (r2=0.46, P<0.0001), increased PML tethering was the primary determinant afterward (r2=0.60, P<0.0001). Conclusion—Although tethering of both leaflets is the major determinant of ischemic MR before surgical annuloplasty, both leaflets tethering but with predominant and augmented PML tethering is related to persistent ischemic MR after the annnuloplasty.

Pseudonormalized Doppler total ejection isovolume (Tei) index in patients with right ventricular acute myocardial infarction.

The Doppler total ejection isovolume (Tei) index is useful for estimating global cardiac function. However, the relation between the right ventricular (RV) Tei index and RV infarction has not been investigated. The relation between the RV Tei index and severity of RV infarction was evaluated in 25 patients with inferior wall acute myocardial infarction (13 with and 12 without RV infarction). RV infarction was diagnosed when right atrial pressure was > or = 10 mm Hg or when right atrial pressure/pulmonary capillary wedge pressure was >0.8 by catheterization. The RV Tei index was significantly increased in patients with RV infarction compared with those without (0.53 +/- 0.15 vs 0.38 +/- 0.14, p <0.05). The RV Tei index in patients with severe RV infarction (right atrial pressure > or = 15 mm Hg) was significantly smaller compared with those with mild/moderate RV infarction (right atrial pressure <15 mm Hg) and showed no significant difference in patients with myocardial infarction but without RV infarction (0.44 +/- 0.09 vs 0.61 +/- 0.16 vs 0.38 +/- 0.14, severe RV infarction vs mild/moderate RV infarction vs no RV infarction, p <0.01). The RV Tei index is generally increased in patients with RV infarction; however, severe RV infarction can be manifested with limited or no increase in the Tei index (pseudonormalization).

Two-dimensional echocardiographic assessment of papillary muscle contractility in patients with prior myocardial infarction

OBJECTIVES This study was performed to assess the length and contractile performance of human left ventricular papillary muscles and to determine the relation between papillary muscle dysfunction and mitral regurgitation. BACKGROUND Assessment of human papillary muscle contractility remains a clinical challenge. METHODS Two-dimensional echocardiographic examinations were performed in 16 normal subjects and 31 patients with prior myocardial infarction. Apical echocardiograms were used to obtain long-axis views of the anterior and posterior papillary muscles. The end-systolic and end-diastolic lengths of the papillary muscles were measured and fractional shortening was calculated. RESULTS Fractional shortening in normal subjects was 27 +/- 8% for the anterior papillary muscle and 30 +/- 8% for the posterior papillary muscle. In patients with prior myocardial infarction, a significant decrease in fractional shortening was observed in proportion to the severity of left ventricular wall motion abnormalities at the site of papillary muscle implantation. Moderate or severe mitral regurgitation was significantly more frequent in patients with combined anterior and posterior papillary muscle dysfunction than in those with isolated anterior or posterior dysfunction or with normal function of both papillary muscles (p < 0.05). CONCLUSIONS Two-dimensional echocardiography is useful for demonstrating abnormal contractility of human left ventricular papillary muscles. Papillary muscle contractility should be analyzed in each case to elucidate the mechanism of mitral regurgitation in patients with papillary muscle dysfunction.

Molecular genetic, biochemical, and clinical studies in three families with cardiac Fabry's disease.

The variant form of Fabrys disease, called cardiac Fabrys disease, which has left ventricular hypertrophy as its main clinical manifestation is not uncommon. Because there has been no pedigree analysis in families with cardiac Fabrys disease, we performed gene analyses, enzyme assays, and cardiac evaluations in 3 distinct families with cardiac Fabrys disease. Gene analyses were performed in all 18 members of 3 families including 3 male probands. Five hemizygotes and 6 heterozygotes were identified. Plasma alpha-galactosidase A activity was measured in all 18 family members. Echocardiography and electrocardiography were performed in the 5 hemizygotes and in 5 of the 6 heterozygotes. The proband and 3 heterozygotes from a pedigree with a mutation in exon 6 of the alpha-galactosidase A sequence leading to a Met296Ile substitution showed a decrease in alpha-galactosidase A activity. In a separate pedigree, a proband and his hemizygous brother, with a mutation in exon 2 leading to a Glu66Gln substitution, had a decrease in alpha-galactosidase A activity, whereas 3 heterozygotes had normal values. In the third pedigree, a decrease in alpha-galactosidase A activity was observed in 2 hemizygotes who have a mutation in exon 1 leading to an Ala2OPro substitution. Although all 5 hemizygotes exhibited left ventricular hypertrophy on echocardiography, all 5 heterozygotes lacked this finding. Because plasma alpha-galactosidase A activity was normal in some heterozygotes with cardiac Fabrys disease, gene analysis is essential for an accurate diagnosis. Patients with cardiac Fabrys disease thus show an x-linked form of hypertrophic cardiomyopathy.

Color doppler echocardiographic assessment of the change in the mitral regurgitant volume

We studied the possibility that a mitral regurgitant Doppler signal area on a two-dimensional color Doppler echocardiogram can reflect changes in mitral regurgitant volume in 24 patients with several types of mitral regurgitation. In 20 patients, mitral regurgitant Doppler signal areas were clear enough to measure. Injections of phenylephrine were given to these patients during the recording of the mitral regurgitant Doppler signal area in the same views and with the same Doppler gains. The mitral regurgitant Doppler signal area, blood pressure, and heart rate were measured before and after phenylephrine provocation. In addition, inhalation of amyl nitrite was performed during the recording of the mitral regurgitant Doppler signal area in the same way. Injection of phenylephrine resulted in an increase in the mitral regurgitant Doppler signal area accompanied by an increase in blood pressure and a decrease in heart rate. On the other hand, inhalation of amyl nitrite resulted in a decrease in the mitral regurgitant Doppler signal area, a decrease in blood pressure, and an increase in heart rate. A positive correlation between the change in blood pressure and that in the mitral regurgitant Doppler signal area was observed. In conclusion, two-dimensional color Doppler echocardiography may be useful in the assessment of the acute change in regurgitant volume in the patient with mitral regurgitation.

Noninvasive pulsed Doppler echocardiographic detection of the direction of shunt flow in patients with atrial septal defect: usefulness of the right parasternal approach.

Noninvasive pulsed Doppler echocardiography combined with two-dimensional echocardiography by the right parasternal approach was performed to detect the shunt flow through the defect in 31 patients with suspected secundum atrial septal defect (ASD). A defect of the interatrial septum was seen on the two-dimensional echocardiograms of 30 of 31 patients. In all the 30 patients, Doppler signals of shunt flow could be recorded by placing the sample volume in the center of the defect on the two-dimensional echocardiogram. Neither a defect nor Doppler signal indicating shunt flow were demonstrated in any of 15 normal control subjects. Cardiac catheterization indicated significant shunt flow in all the 31 patients with suspected ASD. Doppler signals obtained from the center of the defect showed left-to-right and/or right-to-left shunt flow patterns. The direction of the shunt flow was mainly left to right, with its peak in late systole and atrial systole in 28 of 30 patients; mainly right-to-left flow was present in the remaining two patients, who had Eisenmengers syndrome. The direction of flow as predicted by the Doppler signal was confirmed by the coincidence of direction of flow as seen on the contrast two-dimensional echocardiogram. In 22 patients for whom the measurement of the pulmonary-to-systemic flow ratio by oximetry was believed to be reasonably accurate, the ratio was fairly well correlated with Doppler-determined left-to-right shunt flow velocity (r = .71, SEE = 6.7 cm/sec).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac involvement in congenital myopathy

We examined cardiac changes in 8 patients (4 men and 4 women, age 21-43 years) with congenital myopathy proven by skeletal muscle biopsy. Of 8 patients, 4 showed cardiac changes, including 1 with cytoplasmic body myopathy (patient 1), 2 with minimal change myopathy (patients 2 and 3) and 1 with nemaline myopathy (patient 4). Patients 1 and 2 showed left ventricular dilatation with severe global hypokinesis of left ventricular wall. These clinical features were quite similar to those of dilated cardiomyopathy and the patients were in NYHA class 3 or 4. Patient 3 had severe mitral regurgitation with mitral valve prolapse. This patient also had a persistent left superior vena cava and hypoplasia of the aorta, and her cardiac function was in NYHA class 3. Patient 4 showed moderate global left ventricular hypokinesis but the left ventricle was not dilated. This patient also had sino-atrial block and type A Wolff-Parkinson-White syndrome. His cardiac function was NYHA class 1. In conclusion, various types of congenital myopathy are associated with cardiac changes which can result in severe congestive heart failure.

Transesophageal doppler echocardiographic assessment of left coronary blood flow velocity in chronic aortic regurgitation

Assessment of systolic and diastolic coronary blood flow velocities (FVs) in patients with aortic regurgitation (AR) has remained a clinical challenge. We recorded left anterior descending coronary blood FV in 21 patients with chronic AR an in 6 control subjects using transesophageal pulsed Doppler echocardiography. In 7 patients FV was measured 4.0 +/- 5.2 months after aortic valve replacement. Peak and mean FVs during systole and diastole and systolic/diastolic ratios of these FVs were determined. Left ventricular (LV) mass index was calculated by means of standard M-mode echocardiography. In patients with severe AR, peak and mean systolic FVs were significantly increased (34 +/- 8 cm/sec and 21 +/- 6 cm/sec, respectively) compared with FVs in the control group (15 +/- 4 and 12 +/- 3 cm/sec, respectively) and in patients with mild AR (17 +/- 3 cm/sec and 13 +/- 2 cm/sec, respectively). Peak and mean systolic FVs were also significantly increased in severe AR (54 +/- 13 cm/sec and 33 +/- 9 cm/sec, respectively) compared with FVs in the control (30 +/- 8 cm/sec and 21 +/- 5 cm/sec, respectively) and mild AR groups (30 +/- 5 cm/sec and 21 +/- 4 cm/sec, respectively). Peak systolic and diastolic FVs were correlated significantly with LV mass index (r = 0.72 and r = 0.73, respectively). Systolic and diastolic FVs and LV mass index were significantly decreased, normalized or both after aortic valve surgery. In conclusion, LV mass seems to have an effect on the significantly increased systolic and diastolic left coronary blood FV pattern in patients with chronic, severe AR. Increased systolic and diastolic FV appears to be normalized in the late period after surgery.