Dennis A. Tighe

A Syndrome of Transient Left Ventricular Apical Wall Motion Abnormality in the Absence of Coronary Disease: A Perspective from the United States

Background: The syndrome of chest pain associated with characteristic anterior electrocardiographic changes, moderate increases in cardiac enzymes, and a reversible apical wall motion abnormality in the absence of coronary artery disease has been documented in Japan, but has received relatively little attention in other countries. Methods: The clinical and echocardiographic data of 12 patients (11 women, mean age 64 ±14 years) who presented with chest symptoms, electrocardiographic (ECG) changes indicative of an acute anteroapical myocardial infarction, abnormal cardiac enzyme levels and echocardiography showing an apical wall motion abnormality were collected. Coronary angiography was performed in 10 patients. A follow-up echocardiogram was obtained within 2 weeks of the initial diagnosis in most cases. Results: An identifiable, precipitating (‘trigger’) event could be identified in all 12 individuals. Respiratory distress was present in 7, the death of a relative in 3, in 4 a surgical or medical procedure had been performed, and in 1 a panic disorder was diagnosed. The echocardiograms showed a characteristic wall motion pattern of significant apical dysfunction. All of the patients who underwent coronary arteriography had noncritical coronary artery disease. Follow-up echocardiography showed normalization of the LV dysfunction in all instances. Conclusion: We identified a syndrome of chest pain, dyspnea, ECG and enzyme changes mimicking acute myocardial infarction, similar to the ‘Takotsubo’ syndrome described in Japan. It is likely that the widespread use of echocardiography, coupled with increased recognition of this syndrome, will result in this diagnosis being made more commonly.

Direct Ultrasound Measurement of Longitudinal, Circumferential, and Radial Strain Using 2‐Dimensional Strain Imaging in Normal Adults

Current noninvasive techniques used to evaluate left ventricular systolic function are limited by dependence on the angle of insonation (tissue Doppler imaging/TDI) or limited by availability (MRI tagging). We utilized 2‐dimensional speckle strain (ε) imaging (1) to establish normal values for all three ε vectors; (2) to compare circumferential ε values with circumferential shortening (midwall fractional shortening (FSmw); (3) to examine the relationship between left ventricular ε and wall stress; and (4) to compare 2D echocardiographic characteristics by gender. Echocardiography was performed in 60 normal subjects (mean 39 ± 15 years). Small, but significant regional heterogeneity was seen in circumferential ε, but not in radial or longitudinal ε. We found an inverse correlation between circumferential ε and stress (r =−0.29, p<0.05) as well as longitudinal ε and stress (r =−0.11, P < 0.05), though the relationships were not close. We also observed a linear relationship between mean circumferential ε and FSmw (r = 0.29, P < 0.05). In conclusion, (1) 2‐dimensional ε imaging permits measurement of regional systolic ε values in the majority of normal individuals; (2) ε values furnished by this method obey expected stress‐shortening relationships; (3) systolic ε displays minor regional heterogeneity in the circumferential direction; (4) for the first time, a close relationship between FSmw and mean circumferential ε was demonstrated; and (5) there are minor gender‐related differences in LV geometry and function.

Cardiac mechanics in mild hypertensive heart disease: a speckle-strain imaging study.

Background—We hypothesized that abnormalities in regional systolic strain (ϵ) might be present among hypertensive subjects with normal ejection fraction, and, if present, could be used to identify patients at high risk for heart failure. The aim of the current case-control study was to use speckle tracking imaging to identify subclinical global and regional systolic function abnormalities in hypertensive subjects with normal ejection fraction. Methods and Results—Standard 2D Doppler echocardiography, tissue Doppler imaging, and 2D speckle strain imaging were performed in 52 hypertensive subjects with normal ejection fraction and 52 control subjects of similar age. Peak systolic (S′), and diastolic (E′) annular velocities were obtained by tissue Doppler imaging, whereas longitudinal myocardial systolic velocity (Vl) and circumferential, longitudinal, and radial strains (ϵc, ϵl, ϵr) were obtained by speckle tracking. Midwall shortening and peak basal longitudinal strain (ϵl) were used as indices of regional function. Hypertensive subjects had lower velocities—tissue Doppler imaging E′ and S′, and Vl—and evidence of reduced regional function. Surprisingly, however, global ϵ values did not differentiate hypertensive subjects from control subjects. Among hypertensive patients, significant inverse associations were found between left ventricular mass and global longitudinal and circumferential ϵ (both P<0.05). Conclusions—Hypertensive heart disease with normal ejection fraction is associated with reduced myocardial velocities and reduced regional function but normal global ϵ. Our data suggest that velocity abnormalities occur early in hypertension and may be an appropriate target for preventive strategies because they occur before abnormalities in global ϵ.Background— We hypothesized that abnormalities in regional systolic strain (e) might be present among hypertensive subjects with normal ejection fraction, and, if present, could be used to identify patients at high risk for heart failure. The aim of the current case-control study was to use speckle tracking imaging to identify subclinical global and regional systolic function abnormalities in hypertensive subjects with normal ejection fraction. Methods and Results— Standard 2D Doppler echocardiography, tissue Doppler imaging, and 2D speckle strain imaging were performed in 52 hypertensive subjects with normal ejection fraction and 52 control subjects of similar age. Peak systolic (S′), and diastolic (E′) annular velocities were obtained by tissue Doppler imaging, whereas longitudinal myocardial systolic velocity (Vl) and circumferential, longitudinal, and radial strains (ec, el, er) were obtained by speckle tracking. Midwall shortening and peak basal longitudinal strain (el) were used as indices of regional function. Hypertensive subjects had lower velocities—tissue Doppler imaging E′ and S′, and Vl—and evidence of reduced regional function. Surprisingly, however, global e values did not differentiate hypertensive subjects from control subjects. Among hypertensive patients, significant inverse associations were found between left ventricular mass and global longitudinal and circumferential e (both P <0.05). Conclusions— Hypertensive heart disease with normal ejection fraction is associated with reduced myocardial velocities and reduced regional function but normal global e. Our data suggest that velocity abnormalities occur early in hypertension and may be an appropriate target for preventive strategies because they occur before abnormalities in global e. Received September 26, 2008; accepted July 21, 2009. # CLINICAL PERSPECTIVE {#article-title-2}

Acquired long QT syndrome from stress cardiomyopathy is associated with ventricular arrhythmias and torsades de pointes

BACKGROUND Stress cardiomyopathy (SCM) is a syndrome of transient ventricular dysfunction triggered by severe emotional or physical stress, likely resulting from catecholamine-mediated myocardial toxicity. Repolarization abnormalities associated with other hyperadrenergic states can cause QT prolongation and lethal arrhythmia including torsades de pointes (TdP). Despite the development of repolarization abnormalities and QT prolongation in SCM, little is known about the risk of ventricular fibrillation (VF) and TdP. OBJECTIVE The aim of this study was to assess the prevalence and clinical predictors of ventricular arrhythmias in a cohort of patients with SCM. METHODS Data from a registry of consecutive patients with SCM from 2 institutions were reviewed. Patients who developed VF or TdP were identified. Clinical characteristics and outcomes were analyzed and compared with a control group of patients with SCM without VF/TdP. RESULTS Of 93 patients with SCM, 8 (8.6%) experienced VF/TdP. Of these 8 patients, 2 presented with VF and were subsequently diagnosed with SCM. Six other patients experienced pause-dependent TdP or VF after SCM diagnosis in the setting of substantial QT prolongation. Prolongation of the corrected QT interval (QTc) was significantly associated with the occurrence of ventricular arrhythmia (odds ratio 1.28 for each 10 ms increase in QTc, 95% confidence interval 1.10 to 1.50). CONCLUSION SCM can be associated with life-threatening ventricular arrhythmia in over 8% of cases. SCM should be recognized among the causes of acquired long QT syndrome and can be associated with a risk of TdP.

Risk of dysphagia after transesophageal echocardiography during cardiac operations.

BACKGROUND Dysphagia can be a significant complication following cardiac operations. This study evaluates its incidence and relationship to intraoperative transesophageal echocardiography (TEE) for specific indications versus known factors such as stroke or prolonged intubation. METHODS Records of 838 consecutive cardiac surgical patients were reviewed, and categorized into those who received TEE for specific indications versus those who did not (nonTEE). Dysphagia was recorded when symptoms were confirmed by barium cineradiography. Multiple logistic regression identified significant factors causing dysphagia. RESULTS TEE was significantly related to the development of postoperative dysphagia by multiple logistic regression (p < 0.001). After controlling for other significant factors (stroke, left ventricular ejection fraction, intubation time, duration of operation), the odds of dysphagia for TEE patients was 7.8 times greater than for nonTEE patients. CONCLUSIONS TEE may be an independent risk factor for dysphagia following cardiac operations.

Comparison of proximal isovelocity surface area method with pressure half-time and planimetry in evaluation of mitral stenosis.

OBJECTIVES This study sought to 1) compare the accuracy of the proximal isovelocity surface area (PISA) and Doppler pressure half-time methods and planimetry for echocardiographic estimation of mitral valve area; 2) evaluate the effect of atrial fibrillation on the accuracy of the PISA method; and 3) assess factors used to correct PISA area estimates for leaflet angulation. BACKGROUND Despite recognized limitations of traditional echocardiographic methods for estimating mitral valve area, there has been no systematic comparison with the PISA method in a single cohort. METHODS Area estimates were obtained in patients with mitral stenosis by the Gorlin hydraulic formula, PISA and pressure half-time method in 48 patients and by planimetry in 36. Two different factors were used to correct PISA estimates for leaflet angle (theta): 1) plane-angle factor (theta/180 [theta in degrees]); and 2) solid-angle factor [1-cos(theta/2)]. RESULTS After exclusion of patients with significant mitral regurgitation, the correlation between Gorlin and PISA areas (0.88) was significantly greater (p < 0.04) than that between Gorlin and pressure half-time (0.78) or Gorlin and planimetry (0.72). The correlation between Gorlin and PISA area estimates was lower in atrial fibrillation than sinus rhythm (0.69 vs. 0.93), but the standard error of the estimate was only slightly greater (0.24 vs. 0.19 cm2). The average ratio of the solid- to the plane-angle correction factors was approximately equal to previously reported values of the orifice contraction coefficient for tapering stenosis. CONCLUSIONS 1) The accuracy of PISA area estimates in mitral stenosis is at least comparable to those of planimetry and pressure half-time. 2) Reasonable accuracy of the PISA method is possible in irregular rhythms. 3) A simple leaflet angle correction factor, theta/180 (theta in degrees), yields the physical orifice area because it overestimates the vena contracta area by a factor approximately equal to the contraction coefficient for a tapering stenosis.

Influence of image quality on the accuracy of real time three-dimensional echocardiography to measure left ventricular volumes in unselected patients: a comparison with gated-SPECT imaging.

Background: Patient selection, often restricted to those with ideal image quality, and timing of studies in relation to reference methods may limit clinical applicability of cardiac volumes derived from 3D echocardiography. Methods: To test the influence of image quality on LV volumes by real time 3DE (RT3DE), we compared results obtained by RT3DE to those from gated‐SPECT imaging in 64 consecutive patients referred for clinically indicated nuclear perfusion imaging. To minimize hemodynamic effects, RT3DE was performed immediately following G‐SPECT. LV volumes by RT3DE were calculated using at least three orthogonal plane pairs. Image quality was rated as good if 75–100% of the endocardial border was visualized, fair if 60–74% was visualized, and poor if 50–60% was visualized. Results: Image quality was good in 25 (39%), fair in 20 (31%), and poor in 13 (20%) patients. Six patients (9%) were excluded for uninterpretable echo images. For the entire cohort, EDV and ESV agreed closely (all P = NS). When stratified by image quality, the EDV and ESV of those with good and fair image quality agreed closely with minimal bias (average 1 ± 9 mL and 2 ± 7 mL, respectively). Poor image was associated with less strong agreement and much greater bias for EDV and ESV (7 ± 25 mL and 7 ± 20 mL, respectively). Conclusions: When applied to patients studied in routine clinical practice, LV volumes by RT3DE compare favorably to G‐SPECT. RT3DE results are more reliable when >60% of endocardium is visualized.

Systolic and Diastolic Mechanics in Stress Cardiomyopathy

Background— Stress cardiomyopathy (SCM) is a peculiar form of reversible left ventricular dysfunction seen predominantly in women and occurs in response to emotional or physical stress. Because dysfunction in SCM is reversible and that of acute myocardial infarction (MI) is not, we hypothesized that these fundamental mechanistic differences between SCM and MI would be associated with different systolic and diastolic properties. Methods and Results— We examined 3 groups, all women: patients with SCM (n=24; mean age, 63±12 years), those with left anterior (LAD) ST-segment–elevation MI (n=36; mean age, 63±10 years), and referent control subjects (n=30; mean age, 62±8 years). All underwent angiography, ventriculography, and pressure measurements within 48 hours of presentation. Left ventricular volumes, diastolic pressures, and diastolic stiffness were higher in SCM and LAD MI patients than in control subjects but no different from each other. Similarly, left ventricular diastolic pressures and diastolic stiffness were elevated in the SCM and LAD MI groups compared with the control group. Left ventricular ejection fraction in SCM and LAD MI were 40.8±12.3% and 49.6±5.6%, respectively, versus 70.4±9.4% in control subjects (P<0.001), and stroke work less than half the value of control subjects. Indexes of contractility and ventricular-arterial coupling were similarly abnormal in SCM and LAD MI. Conclusions— SCM and LAD MI show severe diastolic dysfunction. At similar left ventricular volumes, their diastolic pressures are more than twice as high as in control subjects, and systolic dysfunction is equally reduced in SCM and LAD MI. Despite a completely different pathophysiology in terms of systolic and diastolic function, SCM is indistinguishable from acute LAD-territory MI.

ST-segment depression during adenosine infusion as a predictor of myocardial ischemia

The incidence and hemodynamic changes associated with ST-segment depression during adenosine stress testing are poorly defined. To examine this, 550 consecutive patients who underwent adenosine perfusion testing were evaluated for the development of ST-segment depression. At least 1 mm of horizontal or downsloping depression developed in 82 patients (15.9%) and was observed with similar frequency in patients with normal scans and those with only fixed defects. ST depression developed in 58 of 242 patients with reversible defects (sensitivity = 24%) and in only 24 of 275 patients without reversible defects (specificity = 91%). Its presence was highly predictive of reversible perfusion defects (predictive accuracy = 71%). Similar findings were observed in patients with and without ECG evidence of left ventricular hypertrophy. Patients with ST depression had perfusion defects in more vessel distributions, had more severe defects, and had a greater increase in heart rate during adenosine infusion. Thus ST-segment depression occurs infrequently during adenosine infusion but is specific for and predictive of myocardial ischemia, as evidenced by reversible perfusion scan defects. Patients with ST depression have more severe disease and develop faster heart rates during infusion, which could result in decreased coronary perfusion during diastole allowing for the development of myocardial ischemia.

Usefulness of the Pulmonary Arterial Systolic Pressure to Predict Pulmonary Arterial Wedge Pressure in Patients With Normal Left Ventricular Systolic Function

Tissue Doppler imaging combined with transmitral Doppler permits estimation of pulmonary artery wedge pressure (PAWP) in many, but not all, patients, whereas pulmonary artery systolic pressure (PASP) and cardiac output (time-velocity integral method) are routinely measured. It was hypothesized that simple Doppler echocardiographic measurements could be used to estimate PAWP in many patients by rearranging the equation for pulmonary vascular resistance ([mean pulmonary artery pressure - (left atrial pressure/cardiac output)] x 80). Data from 69 patients (mean age 59 +/- 15 years) were reviewed, including cardiac output, transmitral mitral E wave velocity, and lateral tissue Doppler imaging mitral annular early diastolic velocity. PAWP was determined in the 2 ways of (1) measured (PAWPm) using the regression equation PAWPm = 1.91 + (1.24 * transmitral mitral E wave velocity/mitral annular early diastolic velocity) developed and validated by Nagueh, and (2) using a nomogram that we developed to predict PAWP when cardiac output and PASP were known. Moderately strong correlation was found between PASP and PAWPm (r = 0.73), and this correlation improved when excluding patients with pulmonary or liver disease and restricting cardiac output to 3.5 to 6.0 L/min (physiologic range; r = 0.81). Furthermore, the relation between PAWPm and PASP allowed for discrimination of high versus low PAWP: 36 of 37 patients with PASP < or =30 mm Hg had PAWPm < or =15 mm Hg (sensitivity 97%, specificity 47%). Conversely, 9 of 9 patients with PASP > or =40 mm Hg had PAWPm > or =12 mm Hg (sensitivity 100%, specificity 70%). Predicted PAWP correlated well with PAWPm (r = 0.63) and improved when patients with liver or pulmonary disease were excluded (r = 0.83). In conclusion, PASP strongly correlated with PAWP, and this principle can be exploited to rapidly detect patients with low or high PAWP.