The role of flumazenil in outpatient transesophageal echocardiography

BACKGROUND

Benzodiazepines used for transesophageal echocardiography (TEE) sedation may be associated with postprocedural psychomotor effects that are undesirable.

HYPOTHESIS

We hypothesize that flumazenil can reverse cognitive and motor effects from benzodiazepine, promoting earlier return to baseline function.

METHODS

We prospectively evaluated the cognitive and motor function of patients who did or did not receive flumazenil following TEE. Patients' gait, level of drowsiness, and recall of items learned before and after benzodiazepine administration were evaluated before TEE, as well as immediately and 30 min after the procedure.

RESULTS

Of 207 patients (123 men and 84 women), 93 (45%) were given flumazenil 0.2 or 0.4 mg intravenously, and 113 (55%) were not. The baseline characteristics of the patients who received flumazenil were not significantly different from those who did not receive flumazenil, with the exception of a higher mean dosage of midazolam administered to the flumazenil group. In addition, patients in the flumazenil group appeared more drowsy immediately following TEE. When adjusted for age and midazolam dosage, there were no differences, at any time, between the two groups in gait or recall of items learned prior to sedation. however, at 30 min following TEE, the flumazenil group was able to recall a larger number of new items learned immediately after the procedure (1.92/3 vs. 1.61/3, p = 0.02) than did patients in the group not receiving flumazenil. No adverse effects were encountered in any patient.

CONCLUSION

Flumazenil appears safe and effective in reversing anterograde amnesic effects of benzodiazepine following TEE, but has no effects on retrograde amnesia and does not promote earlier return of motor function to baseline. It is useful in clinical situations where high dosages of benzodiazepine have been used and/or excessive drowsiness is evident following TEE. Routine use of the drug, however, is not necessary.

Intracardiac measurement of pre-ejection myocardial velocities estimates the transmural extent of viable myocardium early after reperfusion in acute myocardial infarction

OBJECTIVES

We hypothesized that wall motion velocity during pre-ejection is proportional to the regional content of viable myocardium after reperfusion for acute myocardial infarction (AMI).

BACKGROUND

Pre-ejection wall motion consists of short and fast inward and outward movement towards and away from the center of the left ventricle (LV) and is altered during regional ischemia. This short-lived event can be accurately quantified by Doppler myocardial imaging (DMI).

METHODS

Fourteen open-chest pigs underwent 60 to 120 min of left anterior descending coronary artery occlusion followed by 30 min of reperfusion. The DMI data were collected using a phased-array intracardiac catheter (LV cavity) from ischemic and nonischemic myocardium encompassed within a plane passing through two epicardial bead markers. Peak tissue velocities during isovolumic contraction (IVC) (peak positive and peak negative), ejection (S) and early filling (E) were measured. The cardiac specimen was sliced through the epicardial markers in a plane approximating the ultrasound imaging plane. The transmural extent of necrosis (TEN) (%) was measured by triphenyltetrazolium chloride staining.

RESULTS

During ischemia, positive IVC velocity was zero in ischemic walls with TEN >20%. At reperfusion, positive IVC velocity correlated better with TEN (r = -0.94, p < 0.0001) than it did S (r = -0.70, p < 0.01) and E (r = -0.81, p < 0.01). Differential IVC (the difference between peak positive and peak negative velocity) highly correlated with TEN, during ischemia (r = -0.78, p < 0.001) and during reperfusion (r = -0.93, p < 0.0001).

CONCLUSIONS

Pre-ejection tissue velocity, as measured by intracardiac ultrasound, allows rapid estimation of the transmural extent of viable myocardium after reperfusion for AMI.

Myocardial contrast echocardiography: texture analysis for identification of nonperfused versus perfused myocardium

This study examined texture analysis for objective identification of nonperfused myocardial segments in myocardial contrast echocardiographic (MCE) images. Short-axis MCE images from six open chest pigs after coronary artery ligation were examined. Six of 26 features (low gray level run emphasis, high gray level run emphasis, sum mean, sum variance, coefficient of variance and diagonal variance) demonstrated a significant texture value difference (P < 0.01) between the nonperfused and perfused segments with minimal statistical distribution overlap between the two groups. This study demonstrates that texture features other than mean gray level can objectively distinguish nonperfused from perfused myocardium in MCE images and may thus augment the diagnostic accuracy of current analysis techniques.

Thromboembolic complications after electrical cardioversion in patients with atrial flutter

PURPOSE

To determine the incidence of thromboembolic complications after cardioversion in patients with atrial flutter.

SUBJECTS AND METHODS

We reviewed 615 electrical cardioversions performed electively in 493 patients with atrial flutter. Embolic complications were evaluated during the 30 days after cardioversion. Follow-up data were obtained by follow-up visits and by contacting the treating physician.

RESULTS

Anticoagulants had been administered in 415 cardioversions (67%). Cardioversion was successful in 570 procedures (93%). Three embolic events (in 3 patients) occurred in the 30 days after 550 successful cardioversions with completed follow-up (0.6% of successful procedures; 95% confidence interval, 0.1% to 1.6%). Two of the 3 patients had not been anticoagulated, whereas the third patient had subtherapeutic oral anticoagulation. No embolic event occurred in procedures performed with adequate anticoagulation. The incidence of embolism in patients regardless of subtherapeutic anticoagulation was 1% (3 of 303 successful cardioversions).

CONCLUSIONS

We observed a low (0.6%) incidence of postcardioversion thromboembolic complications in patients with atrial flutter. Embolic events did not occur in patients with adequate anticoagulation.

Analysis of systolic and diastolic time intervals during dobutamine-atropine stress echocardiography: diagnostic potential of the Doppler myocardial performance index

Systolic and especially diastolic Doppler time intervals may be early markers of myocardial ischemia inducible by dobutamine-atropine stress echocardiography (DASE). We postulated that the Doppler myocardial performance index (MPI) may help differentiate ischemic from nonischemic responses. Hemodynamic and Doppler echocardiography variables were measured prospectively at every stress level of DASE in 32 patients (mean age 67 +/- 13 years). Adequate recordings were obtained in 27 patients; 13 had an ischemic response (group I) and 14 a nonischemic response (group II). Heart rate differed between groups at baseline. At equivalent peak stress, left ventricular wall motion score index was significantly greater and ejection fraction lower in group I patients. Of the Doppler variables, only the MPI consistently differed between groups, irrespective of the number of stress levels compared. The Doppler MPI may be a useful adjunct to wall motion analysis in the detection of myocardial ischemia during DASE.

Paradoxical cerebrovascular embolism associated with pulmonary arteriovenous fistula: contrast transoesophageal echocardiographic diagnosis

We report two cases of paradoxical cerebrovascular embolism associated with intrapulmonary arteriovenous fistulas. In both cases the diagnosis was made by the use of contrast transoesophageal echocardiography, which not only detected the fistulas but also localized the arteriovenous fistula to specific pulmonary vascular beds.

Aortic valve sclerosis and aortic atherosclerosis: different manifestations of the same disease? Insights from a population-based study

OBJECTIVES

The aim of this study was to examine the association between atherosclerosis risk factors, aortic atherosclerosis and aortic valve abnormalities in the general population.

BACKGROUND

Clinical and experimental studies suggest that aortic valve sclerosis (AVS) is a manifestation of the atherosclerotic process.

METHODS

Three hundred eighty-one subjects, a sample of the Olmsted County (Minnesota) population, were examined by transthoracic and transesophageal echocardiography. The presence of AVS (thickened valve leaflets), elevated transaortic flow velocities and aortic regurgitation (AR) was determined. The associations between atherosclerosis risk factors, aortic atherosclerosis (imaged by transesophageal echocardiography) and aortic valve abnormalities were examined.

RESULTS

Age, male gender, body mass index (odds ratio [OR]: 1.07 per kg/m(2); 95% confidence interval [CI]: 1.02 to 1.12), antihypertensive treatment (OR: 1.93; CI: 1.12 to 3.32) and plasma homocysteine levels (OR: 1.89 per twofold increase; CI: 0.99 to 3.61) were independently associated with an increased risk of AVS. Age, body mass index and pulse pressure (OR: 1.21 per 10 mm Hg; CI: 1.00 to 1.46) were associated with elevated (upper quintile) transaortic velocities, whereas only age was independently associated with AR. Sinotubular junction sclerosis (p = 0.001) and atherosclerosis of the ascending aorta (p = 0.03) were independently associated with AVS and elevated transaortic velocities, respectively.

CONCLUSIONS

Atherosclerosis risk factors and proximal aortic atherosclerosis are independently associated with aortic valve abnormalities in the general population. These observations suggest that AVS is an atherosclerosis-like process involving the aortic valve.

Annulus paradoxus: transmitral flow velocity to mitral annular velocity ratio is inversely proportional to pulmonary capillary wedge pressure in patients with constrictive pericarditis

BACKGROUND

The early diastolic velocity of the mitral annulus (E') is reduced in patients with diastolic dysfunction and increased filling pressures. Because transmitral inflow early velocity (E) increases progressively with higher filling pressures, E/E' has been shown to have a strong positive relationship with pulmonary capillary wedge pressure (PCWP) and left ventricular end-diastolic pressure. However, previous studies have primarily involved patients without a pericardial abnormality. In constrictive pericarditis (CP), E' is not reduced, despite increased filling pressures. This study evaluated the relationship between E/E' and PCWP in patients with CP.

METHODS AND RESULTS

We studied 10 patients (8 men; mean age, 64+/-7 years) with surgically confirmed CP. Doppler echocardiography was performed to measure early and late diastolic transmitral flow velocities. Tissue Doppler echocardiography was performed to measure E'. PCWP was measured with right heart catheterization. All patients were in sinus rhythm. Mean E and E' were 91+/-15 cm/s and 11+/-4 cm/s, respectively. Mean PCWP was 25+/-6 mm Hg. E' was positively correlated with PCWP (r=0.69, P=0.027). There was a significant inverse correlation between E/E' and PCWP (r=-0.74, P=0.014). Despite high left ventricular filling pressures, E/E' (mean, 9+/-4) was <15 in all but 1 patient.

CONCLUSIONS

Paradoxical to the positive correlation between E/E' and PCWP in patients with myocardial disease, an inverse relationship was found in patients with CP.

Color M-mode and pulsed wave tissue Doppler echocardiography: powerful predictors of cardiac events after first myocardial infarction

To assess the association between color M-mode flow propagation velocity and the early diastolic mitral annular velocity (E(m)) obtained with tissue Doppler echocardiography and to assess the prognostic implications of the indexes, echocardiography was performed on days 1 and 5, and 1 and 3 months after a first myocardial infarction in 67 consecutive patients. Flow propagation velocity correlated well with E(m) (r = 0.72, P <.0001). The ratio of peak E-wave velocity (E) to flow propagation velocity also correlated well with E/E(m) (r = 0.87, P <.0001). The positive predictive value of E/FPV > or =1.5 to identify patients with Killip class > or =II was 90%, and the negative predictive value 92%. The corresponding values for E/E(m) > or =10 were 70% and 90%. Cox proportional hazards analysis identified E/flow propagation velocity > or =1.5 (relative risk, 12.4 [95% confidence interval, 4.1-37.3]), E/E(m) > or =10 (relative risk, 11.5 [95% confidence interval, 3.8-34.7]), and Killip class > or =II (relative risk, 7.8 [95% confidence interval, 1.6-40.4]) to be predictors of the composite end point of cardiac death and readmission because of heart failure. Thus flow propagation velocity and E(m) are closely related after myocardial infarction and appear to have similar prognostic information.

Pathophysiologic determinants of third heart sounds: a prospective clinical and Doppler echocardiographic study

PURPOSE

We sought to determine the importance of a third heart sound (S(3)) and its relation to hemodynamic and valvular dysfunction.

SUBJECTS AND METHODS

We prospectively enrolled 580 patients who had isolated valvular regurgitation (mitral, n = 299; aortic, n = 121) or primary left ventricular dysfunction with or without functional mitral regurgitation (n = 160). We analyzed the associations between the clinical finding of an audible S(3) (as noted in routine clinical practice by internal medicine physicians) and hemodynamic alterations measured by comprehensive quantitative Doppler echocardiography.

RESULTS

S(3) was more prevalent in patients with primary left ventricular dysfunction (46%, n = 73) than in organic mitral (16%, n = 47) or aortic (12%, n = 14) regurgitation (P <0.001). Patients with an S(3) were more likely to have class III-IV symptoms (55% [74 of 137] vs. 18% [80 of 443] of those without an S(3), P <0.001) and had a higher mean [+/- SD] pulmonary pressure (55 +/- 15 vs. 41 +/- 11 mm Hg, P <0.001). An S(3) was also related to a higher early filling velocity due to a greater filling volume, restrictive filling, or both. An S(3) was a marker of severe regurgitation (regurgitant fraction > or =40%) in patients with primary left ventricular dysfunction (odds ratio [OR] = 2.4; 95% confidence interval [CI]: 1.1 to 5.5), mitral regurgitation (OR = 17; 95% CI: 5.8 to 52), and aortic regurgitation (OR = 7.1; 95% CI: 1.8-28). An S(3) was also associated with restrictive filling in primary left ventricular dysfunction (OR = 3.0; 95% CI, 1.6 to 5.9), marked dilatation in mitral regurgitation (OR = 20; 95% CI: 6.8 to 58), and an ejection fraction (<50%) in aortic regurgitation (OR = 19; 95% CI: 6.0 to 62).

CONCLUSION

An audible S(3) is an important clinical finding, indicating severe hemodynamic alterations, and should lead to a comprehensive assessment and consideration of vigorous medical or surgical treatment.

Radiofrequency spectral analysis of attenuated ultrasound signals in experiments with echo contrast microbubbles

Conventional gray-scale myocardial contrast echocardiography cannot distinguish perfused but attenuated from nonperfused myocardium because both may appear similar at low image intensity. We hypothesized that with radiofrequency spectral analysis of attenuated ultrasound signals, the harmonic-to-fundamental frequency ratio of the peak power spectrum (HFR(P)) could determine the presence of contrast microbubbles. We measured frequency responses of Optison microbubbles at defined degrees of ultrasound signal attenuation with different formulations of silicone (55D, 80A, and 3M); gray-scale intensities of Optison plus water compared with degassed water were analyzed at different attenuation settings (-25, -32, and -44 dB, respectively). HFR(P) values of Optison plus water were significantly higher than reference values of degassed water at each attenuation setting (55D, -14 +/- 2 dB versus -30 +/- 2 dB, P <.001; 80A, -19 +/- 2 dB versus -30 +/- 3 dB, P <.01; 3M, -22 +/- 2 dB versus -30 +/- 3 dB, P <.05), even though conventional videodensitometric analysis could not distinguish them. HFR(P) analysis objectively detects microbubbles in clinically relevant conditions of attenuation.

Shape reconstruction of the left ventricle: accuracy of limited-plane three-dimensional echocardiography

OBJECTIVE

To assess the accuracy of left ventricular cavity shape reproduction from 8 spatially related, apical two-dimensional ultrasonographic images.

METHODS

We scanned 6 dog heart specimens. Left ventricular cavity casts were reconstructed from 48-tomogram (high-density), 8-tomogram (octaplane), and 2-tomogram (low-density biplane) apical data sets. The 48-plane left ventricular cast served as the reference. Spatial shape resolution of 3 mm in radial distance from the rotational axis to the interpolated endocardium was used as the criterion of shape accuracy.

RESULTS

The adjusted limits of agreement for the octaplane and biplane left ventricular casts were +/-2.31 and +/-6.84 mm, respectively.

CONCLUSIONS

The three-dimensional left ventricular cavity shape can be accurately reproduced by using a low-data density apical octaplane echocardiographic examination.

Rapid three-dimensional echocardiography : clinically feasible alternative for precise and accurate measurement of left ventricular volumes

BACKGROUND

Clinical applicability of conventional ultrasonographic systems using mechanical adapters for 3D echocardiographic imaging has been limited by long acquisition and processing times. We developed a rapid (6-s) acquisition technique that collects apical tomograms using a continuously internally rotating transthoracic transducer. This study was performed to examine the clinical feasibility of rapid-acquisition 3D echocardiography to estimate left ventricular end-diastolic and end-systolic volumes using electron-beam computed tomography as the reference standard. Methods and Results-We collected a series of 6 to 11 apical echocardiographic tomograms, depending on heart rate, in 11 patients. There was good correlation, low variability, and low bias between rapid 3D echocardiography and electron-beam computed tomography for measuring left ventricular end-diastolic volume (r=0.96; standard error of the estimate, 21.34 mL; bias, -4.93 mL) and left ventricular end-systolic volume (r=0.96; standard error of the estimate, 14.78 mL; bias, -6.97 mL).

CONCLUSIONS

The rapid-acquisition 3D echocardiography extends the use of a multiplane, internally rotating handheld transducer so that it becomes a precise and clinically feasible tool for assessing left ventricular volumes and function. A rapid-image acquisition time of 6 s would allow repeated image collection during the course of a clinical echocardiographic examination. Additional work must address rapid and automated data processing.

Prognostic value of exercise echocardiography in patients after coronary artery bypass surgery

To assess the prognostic value of exercise echocardiography in patients with prior coronary artery bypass surgery, follow-up was obtained in 718 patients (591 men [82%] and 127 women [18%], aged 67 +/- 9 years) who underwent clinically indicated exercise echocardiography 5.7 +/- 4.7 years after coronary bypass surgery. Resting wall motion abnormalities were present in 479 patients (67%). New or worsening wall motion abnormalities developed with exercise in 366 patients (51%). During a median follow-up of 2.9 years, cardiac events included cardiac death in 36 patients and nonfatal myocardial infarction in 40 patients. The addition of the exercise echocardiographic variables, abnormal left ventricular end-systolic volume response and exercise ejection fraction to the clinical, resting echocardiographic and exercise electrocardiographic model provided incremental information in predicting cardiac events (chi-square 37 to chi-square 42, p = 0.02) and cardiac death (chi-square 38 to chi-square 43, p <0.02). Exercise echocardiography provides prognostic information in patients after coronary artery bypass surgery, incremental to clinical, rest echocardiographic, and exercise electrocardiographic variables.

Real-time strain rate echocardiographic imaging: temporal and spatial analysis of postsystolic compression in acutely ischemic myocardium

Postsystolic compression (PSC) is a sensitive indicator of regional left ventricular ischemic diastolic dysfunction. Quantitative assessment of compression patterns by strain rate imaging could determine the presence and spatial extent of PSC for the detection and analysis of acute ischemic diastolic dysfunction. With the use of a segmental left ventricular model, we evaluated time to compression/expansion crossover (T-CEC) in standard apical views. Data at baseline and after acute left anterior descending coronary artery occlusion were collected from 18 open-chest pigs. We found significant mean prolongation of T-CEC, ranging from 43.9 +/- 48.6 ms to 110.8 +/- 73.8 ms, in all apical segments and in 2 midventricular (anterior and anteroseptal) segments. Analysis of variance demonstrated that the prolonged T-CEC is spatially consistent with perfusion defect. The temporal and spatial analysis of T-CEC with the use of strain rate imaging is a new noninvasive technique for identification and topographic quantitation of ischemic diastolic dysfunction expressed by PSC.

Left atrial volume: important risk marker of incident atrial fibrillation in 1655 older men and women

OBJECTIVE

To evaluate the contribution of left atrial (LA) volume in predicting atrial fibrillation (AF).

PATIENTS AND METHODS

In this retrospective cohort study, a random sample of 2200 adults was identified from all Olmsted County, Minnesota, residents who had undergone transthoracic echocardiographic assessment between 1990 and 1998 and were 65 years of age or older at the time of examination, were in sinus rhythm, and had no history of AF or other atrial arrhythmias, stroke, pacemaker, congenital heart disease, or valve surgery. The LA volume was measured off-line by using a biplane area-length method. Clinical characteristics and the outcome event of incident AF were determined by retrospective review of medical records. Echocardiographic data were retrieved from the laboratory database. From this cohort, 1655 patients in whom LA size data were available were followed from baseline echocardiogram until development of AF or death. The clinical and echocardiographic associations of AF, especially with respect to the role of LA volume in predicting AF, were determined.

RESULTS

A total of 666 men and 989 women, mean +/- SD age of 75.2 +/- 7.3 years (range, 65-105 years), were followed for a mean +/- SD of 3.97 +/- 2.75 years (range, < 1.00-10.78 years); 189 (11.4%) developed AF. Cox model 5-year cumulative risks of AF by quartiles of LA volume were 3%, 12%, 15%, and 26%, respectively. With Cox proportional hazards multivariate models, logarithmic LA volume was an independent predictor of AF, incremental to clinical risk factors. After adjusting for age, sex, valvular heart disease, and hypertension, a 30% larger LA volume was associated with a 43% greater risk of AF, incremental to history of congestive heart failure (hazard ratio [HR], 1.887; 95% confidence interval [CI], 1.230-2.895; P = .004), myocardial infarction (HR, 1.751; 95% CI, 1.189-2.577; P = .004), and diabetes (HR, 1.734; 95% CI, 1.066-2.819; P = .03). Left atrial volume remained incremental to combined clinical risk factors and M-mode LA dimension for prediction of AF (P < .001).

CONCLUSION

This study showed that a larger LA volume was associated with a higher risk of AF in older patients. The predictive value of LA volume was incremental to that of clinical risk profile and conventional M-mode LA dimension.

Safety of electrical cardioversion in patients with previous embolic events

OBJECTIVE

To assess thromboembolic complications in cardioversions in patients with atrial fibrillation or flutter and a previous embolic event.

PATIENTS AND METHODS

The study population consisted of 104 patients with previous embolic events who underwent 128 electrical cardioversions for termination of atrial fibrillation or flutter. The primary outcome measure was successful cardioversion.

RESULTS

Anticoagulants were administered in 118 procedures (92%). Cardioversion was successful in 108 (84%) of the 128 procedures. Only 1 embolic event occurred within 30 days after cardioversion (incidence, 0.9% of successful procedures; 95 % confidence interval, 0.02%-5.3%). The single embolic event was a transient neurologic deficit occurring 22 days after cardioversion in a patient with previous atrial fibrillation. This patient had a sub-therapeutic level of anticoagulation. Transesophageal echocardiography revealed no spontaneous echo contrast or thrombi before the procedure. No thromboembolism was noted in patients who had therapeutic anticoagulation or in those with failed cardioversion.

CONCLUSION

Patients with previous embolism are not at additional risk of thromboembolic complications after cardioversion if anticoagulation is adequate.

Initial experience with a steerable, phased vector array ultrasound catheter in the GI tract

BACKGROUND

EUS requires a significant capital outlay. The ability to perform high-resolution phased array scanning and Doppler interrogation by using a catheter that interfaces with a standard US console could increase the accessibility of EUS. Recently, an electronic phased-array US catheter was developed for intracardiac use. To date, this technology has not been applied to the GI tract. The aim of this study is to determine the feasibility and imaging characteristics of a new phased array scanning US catheter in the GI tract.

METHODS

Swine were placed under general anesthesia. This study used a 100 cm, 10F, torquable catheter with 4-way tip deflection to greater than 90 degrees. The catheter tip houses a phased vector array transducer with variable frequency (5.5-10 MHz) and variable focal distance. It has pulsed/color and power Doppler capability. The probe was passed through a therapeutic flexible sigmoidoscope into the upper GI tract. Acoustic coupling was achieved via a condom filled with water or by gastric water infusion. Needle visualization experiments were performed with a second endoscope (also passed per oral) with a standard EUS-guided fine needle aspiration needle.

RESULTS

Acoustic coupling was easily achieved. Resolution of the GI wall into characteristic layers (esophagus 5, stomach 7) was demonstrated. At 5.5 MHz, tissue resolution and Doppler imaging were excellent to greater than 10 cm from the transducer. A 22-gauge EUS-guided fine needle aspiration needle was easily visualized at depth greater than 4 cm. Flow in gastric, hepatic, and pancreatic parenchymal vessels approximately 1 mm diameter was visualized by using power and color Doppler.

CONCLUSIONS

This 10F array US catheter is capable of high-resolution two-dimensional imaging of the gut wall as well as high-quality Doppler imaging. The Doppler capabilities of this equipment may have new GI applications.

Regional asynchrony during acute myocardial ischemia quantified by ultrasound strain rate imaging

OBJECTIVES

We propose a new method to easily quantify asynchronous wall motion due to postsystolic shortening (PSS). We also studied the relationship of the spatial and temporal extent of PSS to the extent of myocardium at ischemic risk after variable duration of ischemia.

BACKGROUND

Postsystolic shortening is a sensitive marker of asynchrony during ischemia. Current techniques for detection of asynchrony are either subjective, or invasive and time-consuming. Strain rate imaging (SRI) can noninvasively depict PSS as prolonged compression/expansion crossover.

METHODS

Nineteen open-chest pigs were scanned from apical views, before and after left anterior descending coronary artery occlusion. Strain rates were derived offline from tissue Doppler velocity cineloops. The time from electrocardiographic R-wave to the occurrence of compression/expansion crossover (TCEC) was calculated. Prolonged TCEC during ischemia was identified using a standardized analysis and both spatial (% of left ventricle) and temporal extent were quantified. The extent of myocardium at risk was measured in seven animals from dye-stained specimens.

RESULTS

Prolonged TCEC was found in all ischemic segments. There was a good correlation (r = 0.91; p < 0.001) and good agreement between the spatial distributions of prolonged TCEC and myocardium at risk. The extent of myocardium at risk was better approximated by TCEC measurement (36 +/- 7% vs. 39 +/- 8%, respectively; p = NS) than by wall motion analysis (47 +/- 17%, p < 0.05). The duration of occlusion did not prolong TCEC.

CONCLUSIONS

Prolonged TCEC consistently occurs in ischemic myocardium and is apparently not affected by the duration of ischemia. Standardized analysis of TCEC in SRI closely quantifies the extent of ischemic myocardium. This new method may be a useful tool in other cardiac conditions associated with regional diastolic asynchrony.

Myocardial dysfunction associated with brain death: clinical, echocardiographic, and pathologic features

BACKGROUND

The sequelae of severe brain injury include myocardial dysfunction. We sought to describe the prevalence and characteristics of myocardial dysfunction seen in the context of brain-injury-related brain death and to compare these abnormalities with myocardial pathologic changes.

METHODS

We examined the clinical course, electrocardiograms, head computed tomography scans, and echocardiographic data of 66 consecutive patients with brain death who were evaluated as heart donors. In a sub-group of patients, we compared echocardiographic findings with pathologic findings.

RESULTS

Echocardiographic systolic myocardial dysfunction was present in 28 (42%) of 66 patients and was not predicted by clinical, electrocardiographic, or head computed tomographic scan characteristics. Ventricular arrhythmias were more common in the patients with, compared to those without, myocardial dysfunction (32% vs 0%; p < 0.001). Myocardial dysfunction was segmental in all 8 patients with spontaneous subarachnoid or intracerebral hemorrhage. In these patients, the left ventricular apex was often spared. Myocardial dysfunction was either segmental or global in 17 patients who suffered head trauma and in 3 patients who died of other central nervous system illnesses. In 11 autopsied hearts, we found poor correlation between echocardiographic dysfunction and pathologic findings.

CONCLUSIONS

Systolic myocardial dysfunction is common after brain-injury-related brain death. After spontaneous subarachnoid or intracerebral hemorrhage, the pattern of dysfunction is segmental, whereas after head trauma, it may be either segmental or global. We found poor correlation between the echocardiographic distribution of dysfunction and light microscopic pathologic findings.

Effect of losartan on degree of mitral regurgitation quantified by echocardiography

The objective of this study was to determine the effect of oral losartan on the degree of mitral regurgitation (MR). The regurgitant volume and effective regurgitant orifice were quantified using 3 methods (flow convergence, quantitative Doppler, and quantitative 2-dimensional echocardiography) in 32 patients (26 men, mean age 67 +/- 14 years) with MR, both at baseline and 4 hours after losartan (50 mg orally). Twenty-eight patients were also reevaluated after 1 month of continued treatment with losartan (50 mg/day). With treatment, systolic blood pressure decreased from 143 +/- 16 to 130 +/- 18 mm Hg and left ventricular end-systolic wall stress from 173 +/- 46 to 156 +/- 44 g/cm2 (both p < 0.001). With treatment, regurgitant volume decreased (from 77 +/- 28 to 64 +/- 26 ml, - 18 +/- 10%; p < 0.001) in direct relation to the effective regurgitant orifice change (from 43 +/- 16 to 37 +/- 15 mm2, -17 +/- 10%; p < 0.001) but without significant change in regurgitant gradient or duration. Wide individual variability in response was observed unrelated to the magnitude of blood pressure changes. Larger reduction in regurgitant volume was observed in patients with a marked decrease in wall stress (r = 0.47, p = 0.01) and higher baseline end-diastolic volume index (r = -0.38, p = 0.03) and regurgitant volume (r = -0.45, p = 0.01). Acute improvements were sustained and unchanged at 1 month (all p > 0.15). Treatment of MR using the angiotensin receptor antagonist losartan produces a significant and sustained decrease in the degree of MR, with decreases in regurgitant volume and effective regurgitant orifice. However, the changes are of modest and variable magnitude.

Association of atrial fibrillation and aortic atherosclerosis: a population-based study

OBJECTIVE

To examine the association between atrial fibrillation (AF) and aortic atherosclerosis in the general population.

SUBJECTS AND METHODS

Transesophageal echocardiography was performed in 581 subjects, a random sample of the adult Olmsted County, Minnesota, population (45 years of age or older) participating in the Stroke Prevention: Assessment of Risk in a Community (SPARC) study. The frequency of aortic atherosclerosis was determined in 42 subjects with AF and compared with that in 539 subjects without AF (non-AF group).

RESULTS

Subjects with AF were significantly older than non-AF subjects (mean +/- SD age, 82+/-10 vs 66+/-13 years, respectively; P<.001) and more commonly had hypertension (28 [66.7%] vs 288 [53.4%], respectively; P=.10). The 2 groups were similar in sex and frequency of diabetes mellitus, hyperlipidemia, or smoking history (P>.10). The odds of aortic atherosclerosis (of any degree) were 2.87 times greater (95% confidence interval [CI], 1.41-5.83; P=.004) and the odds of complex atherosclerosis (protruding atheroma >4 mm thick, mobile debris, or plaque ulceration) were 2.71 times greater (CI, 1.13-6.53; P=.03) in the AF group than in the non-AF group. Age was a significant predictor of aortic atherosclerosis (P<.001). After adjusting for age, the odds of atherosclerosis and complex atherosclerosis were not significantly different between the 2 groups (P=.13 and P=.75, respectively).

CONCLUSIONS

In the general population, AF is associated with aortic atherosclerosis, including complex atherosclerosis. This association is related to age since both AF and aortic atherosclerosis are more frequent in the elderly population.

Outcome of reoperation for aortic valve prosthesis-patient mismatch

We report a single center's 10-year experience with 21 consecutive cases of repeat aortic valve replacement for prosthesis-patient mismatch (P-PM) in which there was no hospital mortality among 12 patients treated for isolated P-PM. With an overall survival of 92% at a median follow-up of 4.5 years and functional class I symptoms in most survivors (73%), we conclude that repeat surgery for isolated P-PM has a relatively low mortality and a good intermediate-term clinical outcome.

Diagnostic value of echocardiography in cardiac tamponade

Cardiac tamponade is a life-threatening condition. Accurate diagnosis and prompt intervention are necessary to prevent adverse outcomes. Clinical features of tamponade such as pulsus paradoxus, tachycardia, elevated jugular venous pressure, and hypotension are important clues to the diagnosis, but are non-specific. Echocardiography allows rapid confirmation of the presence or absence of an effusion, and enables assessment of its hemodynamic impact. Decisions regarding treatment must take into account the clinical presentation and echocardiographic findings. Echocardiographically-guided pericardiocentesis with catheter drainage is the primary treatment strategy of choice for most large or hemodynamically significant effusions. In contemporary clinical practice, echocardiography is the gold standard for diagnosis of tamponade and is essential for directing treatment.

Effects of sildenafil citrate (Viagra) combined with nitrate on the heart

BACKGROUND

Sildenafil citrate (Viagra) is indicated for the treatment of erectile dysfunction. Large and sudden decreases in systemic blood pressure were reported in a substantial number of patients taking sildenafil citrate combined with nitroglycerin. We studied the effect of sildenafil citrate on the relationship between changes in systemic blood pressure and coronary blood flow.

METHODS AND RESULTS

Healthy male beagles were used to assess systemic blood pressure, pulmonary arterial pressure, and flow in the left circumflex artery (in which a critical stenosis was established) and left anterior descending coronary artery. After measurement of the hemodynamic variables, 2 mg/kg sildenafil citrate was administered via a nasogastric tube. Hemodynamic changes were monitored for 1 hour. Subsequently, the acute effect of nitrate combined with sildenafil citrate was studied by the bolus injection of 0.2 mg isosorbide dinitrate before and after sildenafil citrate. Systemic blood and pulmonary arterial pressures and circumflex flow did not change during this study; however, left anterior descending coronary arterial flow increased from 16.0+/-5.8 to 24.6+/-8.7 mL/min 1 hour after administration of sildenafil citrate. The prolongation of systemic blood pressure decrease and the circumflex flow decrement induced by isosorbide dinitrate after sildenafil citrate were significantly larger and longer than those before sildenafil citrate.

CONCLUSIONS

Sildenafil citrate had the effect of vasodilation in a normal coronary artery; however, a combined effect with nitrate resulted in large and protracted decreases in systemic blood pressure and coronary blood flow in vessels with critical stenosis.

A rapid stress-testing protocol for the detection of coronary artery disease: comparison of two-stage transesophageal atrial pacing stress echocardiography with dobutamine stress echocardiography

OBJECTIVES

We compared a new two-stage transesophageal atrial pacing stress echocardiography (TAPSE) protocol with a standard dobutamine stress echocardiography (DSE) protocol.

BACKGROUND

Transesophageal atrial pacing stress echocardiography has been proposed as an efficient alternative to DSE.

METHODS

Two-stage TAPSE (85% and 100% of age-predicted maximum heart rate) and DSE (5 to 40 microg/kg/min at 3-min stages with or without atropine) were both performed, in random sequence, in each patient of a study group of 36 patients. Regional wall-motion analysis, patient acceptance (1 = low, 5 = high), hemodynamics and duration for performing and interpreting tests were compared.

RESULTS

Transesophageal atrial pacing stress echocardiography was successful in 35 of the 36 patients (feasibility 97%). More TAPSE than DSE studies were called "ischemic" (37% vs. 14%; p = 0.005). Peak heart rate was higher with TAPSE (144 +/- 18 vs. 129 +/- 15 beats/min, p = 0.0001). Peak cardiac index (4.6 +/- 2.1 vs. 5.1 +/- 1.9 liters/min/m2, p = 0.14), patient acceptance score (4.2 +/- 0.7 vs. 3.8 +/- 1.3, p = 0.17) and study duration (14.2 +/- 9.3 vs. 13.3 +/- 3.3 min, p = 0.59) were similar. Recovery time (7.1 +/- 7.6 vs. 16.2 +/- 15.9 min, p = 0.0003) and interpretation time (9.1 +/- 2.8 vs. 13.5 +/- 4.4 min, p = 0.0001) were shorter for TAPSE than for DSE.

CONCLUSIONS

Two-stage TAPSE permits rapid evaluation of cardiac patients. Peak cardiac index and patient acceptance scores were similar for TAPSE and DSE. Ischemia was detected more often with TAPSE; this result was attributed to the higher peak heart rate obtained with this protocol.

Transthoracic Doppler echocardiographic comparison of left internal mammary grafts to left anterior descending coronary artery with ungrafted right internal mammary arteries in patients with and without myocardial ischemia by dobutamine stress echocardiography

To characterize Doppler flow patterns of the grafted left internal mammary artery (LIMA) in patients with and without dobutamine stress induced wall motion abnormalities in the graft distribution, we studied 29 patients who underwent coronary artery bypass surgery using LIMA grafts to the left anterior descending coronary artery (LAD). The ungrafted right internal mammary artery (RIMA) was used as a control. RIMA Doppler flow pattern was predominantly systolic in all patients. In patients without ischemia in the LAD distribution, LIMA flow was predominantly diastolic. In patients with ischemia, LIMA flow was predominantly systolic. In the grafted LIMA, a ratio of diastolic to systolic time-velocity integral of > 1.5 best showed absence of ischemia in the graft distribution. In summary, characterization of the Doppler flow pattern in the internal mammary arteries is feasible. In the grafted LIMA, ratios of diastolic to systolic flow are less in patients with an ischemic response in the subtended vascular bed than in those without ischemia.

Independent association of high blood pressure and aortic atherosclerosis: A population-based study

BACKGROUND

Atherosclerosis of the thoracic aorta is associated with stroke. The association between hypertension, a major risk factor for stroke, and aortic atherosclerosis has not been determined in the general population.

METHODS AND RESULTS

Transesophageal echocardiography was performed in 581 subjects, a random sample of the Olmsted County (Minnesota) population aged >/=45 years participating in the Stroke Prevention: Assessment of Risk in a Community (SPARC) study. Blood pressure was assessed by multiple office measurements and 24-hour ambulatory blood pressure monitoring. The association between blood pressure variables and aortic atherosclerosis was evaluated by multiple logistic regression, adjusting for other associated variables. Among subjects with atherosclerosis, blood pressure variables associated with complex aortic atherosclerosis (protruding plaques >/=4 mm thick, mobile debris, or ulceration) were determined. Age and smoking history were independently associated with aortic atherosclerosis of any degree (P:</=0.001) and with complex atherosclerosis (P:=0.002), whereas sex, diabetes mellitus, and body mass index were not. Multiple systolic and pulse pressure variables (office and ambulatory), but none of the diastolic blood pressure variables, were associated with atherosclerosis and complex atherosclerosis, adjusting for age and smoking. Among subjects with atherosclerosis, the odds of complex atherosclerosis increased as ambulatory out-of-bed systolic blood pressure increased (odds ratio 1.43 per 10 mm Hg increase, 95% CI 1. 10 to 1.87) and with hypertension treatment, adjusting for age and smoking history.

CONCLUSIONS

High blood pressure is independently associated with aortic atherosclerosis. Among subjects with atherosclerosis, high blood pressure is associated with complex atherosclerosis.

Left atrial appendage flow velocities in subjects with normal left ventricular function

The objectives of this study were to establish reference values and define the determinants of left atrial appendage (LAA) flow velocities in the general population. LAA flow velocities (contraction and filling velocities) were assessed by transesophageal echocardiography in 310 subjects aged > or = 45 years, sampled from the population-based Stroke Prevention: Assessment of Risk in a Community study. All subjects were in sinus rhythm, with preserved left ventricular systolic function (ejection fraction > or = 50%), and without valvular disease. Values of LAA contraction and filling velocities were established for various age groups in the population. Age was negatively associated with LAA contraction and filling velocities, which decreased by 4.1 cm/s (p < 0.001) and 2.0 cm/s (p < 0.01) for every 10 years of age, respectively. Contraction velocities were 5 cm/s higher in men than in women (p < 0.05). After adjusting for age and sex, heart rate was independently associated with LAA contraction velocities (p < 0.001; nonlinear association). Body surface area, left atrial size, left ventricular mass index, and a history of previous cardiac disease or hypertension showed no significant association with LAA flow velocities (p > 0.05). Furthermore, detailed analysis of 24-hour ambulatory blood pressure data (available in 253 subjects) showed no association between various blood pressure parameters (systolic and diastolic blood pressure, out-of-bed and in-bed measurements) and LAA flow velocities (all p > 0.05). In summary, the present study establishes the reference values for LAA flow velocities in a large sample of the general population. LAA flow velocities progressively decline with age in subjects with preserved left ventricular systolic function.

Determinants of the degree of functional mitral regurgitation in patients with systolic left ventricular dysfunction: A quantitative clinical study

BACKGROUND

Functional mitral regurgitation (FMR) occurs with a structurally normal valve as a complication of systolic left ventricular dysfunction (LVD). Determinants of degree of FMR are poorly defined; thus, mechanistic therapeutic approaches to FMR are hindered.

METHODS AND RESULTS

In a prospective study of 21 control subjects and 128 patients with LVD (defined as ejection fraction <50%, mean 31+/-9%) in sinus rhythm, we quantified simultaneously by echocardiography the effective regurgitant orifice (ERO) of FMR by using 2 methods: mitral deformation (valve and annulus) and left ventricular (LV) global (volumes, stress, function, and sphericity) and local (papillary muscle displacements and regional wall motion index) remodeling. A wide range of ERO (15+/-14 mm(2), 0 to 87 mm(2)) was observed, unrelated to ejection fraction (P:=0.32). The major determinant of ERO was mitral deformation, ie, systolic valvular tenting and annular contraction in univariate (r=0.74 and r=-0.61, respectively; both P:<0.0001) and multivariate (both P:<0. 0001) analyses, independent of global LV remodeling. Systolic valvular tenting was strongly determined by local LV alterations, particularly apical (r=0.75) and posterior (r=0.70) displacement of papillary muscle, with confirmation in multivariate analysis (both P:<0.0001), independent of LV volumes, function, and sphericity.

CONCLUSIONS

The presence and degree of FMR complicating LVD are unrelated to the severity of LVD. Local LV remodeling (apical and posterior displacement of papillary muscles) leads to excess valvular tenting independent of global LV remodeling. In turn, excess tenting and loss of systolic annular contraction are associated with larger EROs. These determinants of FMR warrant consideration for specific approaches to the treatment of FMR complicating LVD.

Usefulness of the myocardial performance index for assessing right ventricular function in congenital heart disease

Quantitative assessment of ventricular function in patients with congenital heart disease is often challenging due to distorted ventricular geometry. A myocardial performance index (MPI) has been reported in adults and children that is a Doppler-derived nongeometric measure of ventricular function. The MPI measures the ratio of isovolumic time intervals (isovolumic contraction time and isovolumic relaxation time) to ventricular ejection time. The effects of altered ventricular preload or afterload on the MPI have yet to be determined. This study assesses the impact of altered preload or afterload on right ventricular (RV) function and the RV MPI in the clinical setting of congenital heart disease. Patient groups were compared with normal pediatric and adult populations before and after repair of their congenital heart lesion. Patients with large atrial septal defects (ASDs) represented the clinical setting of increased ventricular preload, whereas patients with isolated pulmonary valve stenosis represented increased RV afterload. Patients with congenitally corrected transposition of the great arteries (CC-TGA) with severe left atrioventricular valve regurgitation represented a combined increase in RV preload and afterload. The RV MPI in 152 normal children (ages 3 to 18 years) and 37 adults (ages 18 to 51 years) was 0.32 +/- 0.03 and 0.28 +/- 0.04, respectively. In pediatric patients (n = 45) and adult patients (n = 40) with ASD, the RV MPI was 0.35 +/- 0.09 (p = NS) and 0.38 +/- 0.04 (p < 0.01 compared with normal adults), respectively. Patients with pulmonary stenosis (n = 21, ages 1 day to 19 years) had a RV MPI of 0.32 +/- 0.06 (p = NS). CC-TGA patients had a RV MPI of 0.72 +/- 0.17 (p < 0.001). No significant change in the RV MPI was seen in any postoperative patient group despite relief of RV volume or pressure overload. Thus, the MPI is a quantitative measure of RV performance that is appears to be relatively independent of changes in preload or afterload in the clinical setting.

Value of the Doppler index of myocardial performance in the early phase of acute myocardial infarction

Prospective assessment of a nongeometric Doppler-derived index of combined systolic and diastolic myocardial performance was performed in 64 patients with acute myocardial infarction (MI) within 1 hour after their arrival to the hospital and in 39 age-matched healthy subjects. The index is defined as the sum of isovolumetric contraction time and relaxation time divided by ejection time, and is obtained by Doppler measurement from the mitral inflow and left ventricular outflow velocity-time intervals. The index was significantly higher in patients with MI compared with healthy subjects (P <.0001). In patients with MI and in-hospital congestive heart failure (CHF), the index was significantly higher compared with patients without CHF. In a multivariate regression analysis, the index >0.45 was the strongest independent predictor of the development of CHF. This simply obtained nongeometric Doppler index, assessed in the early phase of MI, detected and graded left ventricular dysfunction and identified patients at risk for the development of CHF.

Assessment of severity of aortic regurgitation using the width of the vena contracta: A clinical color Doppler imaging study

BACKGROUND

The width of the vena contracta (VC-W), the smallest area of regurgitant flow, reflects the degree of valvular regurgitation and is measurable by color Doppler imaging, but this method has not been validated in aortic regurgitation (AR).

METHODS AND RESULTS

We prospectively examined 79 patients with isolated AR and 80 patients without regurgitation. The VC-W was measured from the long-axis parasternal view and compared with 2 simultaneous reference methods (quantitative Doppler and 2D echocardiography). In patients without regurgitation, the agreement between methods was excellent. In patients with AR, good correlations (all P<0.0001) were obtained between VC-W and effective regurgitant orifice (ERO) area and regurgitant volume recorded by quantitative Doppler (r=0.89 and 0.90, respectively) and 2D echocardiographic (r=0.90 and 0.89, respectively) methods. These correlations were similar with eccentric or central jets (all P>0.60). The other methods used showed good correlations of VC-W with aortographic grading of AR (n=8, r=0.82, P=0.01), with the proximal flow convergence method (n=53, r=0.85, P<0.0001), and with left ventricular end-diastolic volume (r=0.81, P<0.0001). Sensitivity and specificity of VC-W >/=6 mm for diagnosing severe AR (ERO >/=30 mm(2)) were 95% and 90%, respectively.

CONCLUSIONS

For assessment of the degree of AR, VC-W shows good correlations with simultaneous quantitative measures (regardless of jet direction), shows good correlations with other methods of assessment of AR, and provides a high diagnostic value for severe AR. VC-W is a simple, reliable method that can be used clinically as part of comprehensive Doppler echocardiographic assessment of AR.

Intracardiac echocardiography: newest technology

Intracardiac echocardiography, defined as ultra-sonographic navigation and visualization within large blood-filled cavities or vessels of the cardio-vascular system, has recently undergone refinement as a clinical tool through technologic advances in transducer miniaturization. Intra-cardiac ultra-sound catheters image at lower frequencies than current conventional intravascular ultrasound catheters used for intracoronary imaging. The lower imaging frequency enables greater tissue penetration, permitting whole-heart evaluation from a right-sided catheter position. Newer devices are steerable, have variable imaging frequency (5.5 to 10 MHz), and full Doppler capability (pulsed, continuous wave, and tissue Doppler). These advances have made intracardiac high-resolution imaging as well as hemodynamic assessment possible. A historical perspective, current capabilities and limitations, and potential clinical and research applications of this new imaging technique are discussed.

Evaluation of coronary flow reserve in hypertensive patients by dipyridamole transesophageal doppler echocardiography

This study evaluates the coronary flow reserve (CFR) in hypertensive patients with and without left ventricular (LV) hypertrophy. CFR was assessed by transesophageal Doppler echocardiography in 15 normal subjects (group I), 21 hypertensive patients without LV hypertrophy (group II), and 27 hypertensive patients with LV hypertrophy (group III). All hypertensive patients were complaining of typical anginal pain and had normal coronary angiograms. The sample volume was placed at the bifurcation of the left main and left anterior descending coronary arteries. Coronary blood flow velocities were evaluated at rest, 2 minutes after dipyridamole infusion, and 2 minutes after intravenous aminophylline. The ratios of dipyridamole to rest peak diastolic and systolic velocities were considered as indexes of CFR. Peak diastolic velocity ratio was significantly lower in group III than in groups I and II (1.6 +/- 0.2, 2.7 +/- 0.4, and 2.1 +/- 0.2, respectively; p <0.05), and it was significantly lower in group II than I (p <0.05). The peak systolic velocity ratio was significantly lower in group III than in groups I and II (1.7 +/- 0.3, 2.8 +/- 0.3, and 2.1 +/- 0.2, respectively; p <0.05), and it was significantly lower in group II than I (p <0.05). The peak diastolic velocity ratio was inversely related to systolic blood pressure, diastolic blood pressure, and LV mass index (r = -0.48, -0. 51, and -0.37 respectively) in hypertensive patients. It is concluded that CFR is significantly impaired in hypertensive patients, especially those with LV hypertrophy, compared with healthy subjects. The degree of impairment of CFR is related to LV mass index.

Contrast transesophageal echocardiography in the diagnosis and localization of diffuse pulmonary telangiectasias

Pulmonary arteriovenous fistulas are rare, usually related to the Rendu-Osler-Weber syndrome, and are detected by chest CT scan or pulmonary angiography. In a 14-year-old boy without Rendu-Osler-Weber syndrome, but with clinical evidence of a right-to-left shunt, ancillary diagnostic studies were negative for pulmonary arteriovenous fistulas, and the final diagnosis was made by contrast transesophageal echocardiography. Saline echo-contrast medium injected peripherally was seen emerging from each pulmonary vein and filling the left chambers. These findings, in light of other negative test results, established the diagnosis of diffuse telangiectasias at the capillary level in both lungs. After 6 years of medical therapy, the patient remains cyanotic but functions well.

Myocardial contraction maps using tissue Doppler acceleration imaging

OBJECTIVE

To evaluate the tissue Doppler acceleration imaging (TDAI) data which can be used to determine the intramural site of origin of myocardial contraction in response to electrical stimulation.

METHODS

Six open-chest pigs with left ventricle (LV) pacing were evaluated with TDAI. An epicardial surface scanning method was used to collect short-axis views of the left ventricle. The electrode was implanted from the epicardium through the anterior free wall to an intramural position.

RESULTS

During pacing, the intramural onset of myocardial acceleration occurred within 33 ms after electrical stimulation and always surrounded the embedded subendocardial end of the pacing needle. The observed short-axis diameter of the area of initial myocardial acceleration ranged from 2.9 mm to 5.0 mm (4.2 +/- 0.9 mm, n = 6). The onset of myocardial acceleration allowed appreciation of the initial intramural myocardial contraction. The spatial size and acceleration magnitude of the initial myocardial acceleration distribution were irregular.

CONCLUSION

Two-dimensional myocardial acceleration mapping can show the intramural site of origin of myocardial contraction in response to paced electrical stimulation. The location of myocardial acceleration conformed to the site of initial electrical stimulation. The delay to the earliest regional myocardial contraction, 33 ms after paced electrical stimulation, was related to the frame rate of image acquisition.

Quantification of tricuspid regurgitation by measuring the width of the vena contracta with Doppler color flow imaging: a clinical study

OBJECTIVE

We sought to evaluate the vena contracta width (VCW) measured using color Doppler as an index of severity of tricuspid regurgitation (TR).

BACKGROUND

The VCW is a reliable measure of mitral and aortic regurgitation, but its value in measuring TR is uncertain.

METHODS

In 71 consecutive patients with TR, the VCW was prospectively measured using color Doppler and compared with the results of the flow convergence method and hepatic venous flow, and its diagnostic value for severe TR was assessed.

RESULTS

The VCW was 6.1+/-3.4 mm and was significantly higher in patients with, than those without, severe TR (9.6+/-2.9 vs. 4.2 +/- 1.6 mm, p<0.0001). The VCW correlated well with the effective regurgitant orifice (ERO) by the flow convergence method (r = 0.90, SEE = 0.17 cm2, p<0.0001), even when restricted to patients with eccentric jets (r = 0.93, p < 0.0001). The VCW also showed significant correlations with hepatic venous flow (r = 0.79, p < 0.0001), regurgitant volume (r = 0.77, p<0.0001) and right atrial area (r = 0.46, p< 0.0001). A VCW > or =6.5 mm identified severe TR with 88.5% sensitivity and 93.3% specificity. In comparison with jet area or jet/right atrial area ratio, the VCW showed better correlations with ERO (both p<0.01) and a larger area under the receiver operating characteristic curve (0.98 vs. 0.88 and 0.85, both p<0.02) for the diagnosis of severe TR.

CONCLUSIONS

The VCW measured by color Doppler correlates closely with severity of TR. This quantitative method is simple, provides a high diagnostic value (superior to that of jet size) for severe TR and represents a useful tool for comprehensive, noninvasive quantitation of TR.

Personal ultrasound imager: abdominal aortic aneurysm screening

BACKGROUND

Miniaturized ultrasonographic machines (2.5-MHz curved-array transducer connected to a compact 2.6-kg console), termed personal ultrasound imagers (PUIs), may enable detection of occult abdominal aortic aneurysms (AAAs).

OBJECTIVES

Our goals were to determine whether a PUI is capable of screening for AAAs and to compare the results with an established screening examination with standard echocardiography (SE).

METHODS

One hundred twenty-five patients (aged >70 years) with hypertension who were referred for transthoracic echocardiography were enrolled. After SE, a focused screening with a PUI examination was performed by a blinded sonographer. An AAA was defined as a focal enlargement of the aorta >30 mm. Results and the length of time to image the aorta were compared for both tests.

RESULTS

We studied 64 men and 61 women (aged 76.8 +/- 5 years; mean blood pressures: systolic 145.7 +/- 18 and diastolic 78.6 +/- 10; body surface area 1.9 +/- 0.2 m(2)). The mean time for SE was 2.9 +/- 1.5 minutes and for the PUI examination was 4.6 +/- 2.3 minutes. By using SE as the gold standard, the sensitivity and specificity of the PUI were 91% and 96%, respectively. The positive predictive value of the PUI was 71%, and the negative predictive value was 99%.

CONCLUSION

A PUI can be used to screen for occult AAAs as an extension of the physical examination. Results are comparable to an established screening strategy that uses more expensive, nonportable echocardiographic equipment.

Clinical profile and outcome of idiopathic restrictive cardiomyopathy

BACKGROUND

Idiopathic restrictive cardiomyopathy is a poorly recognized entity of unknown cause characterized by nondilated, nonhypertrophied ventricles with diastolic dysfunction resulting in dilated atria and variable systolic function.

METHODS AND RESULTS

Between 1979 and 1996, 94 patients (61% women) 10 to 90 years old (mean, 64 years) met strict morphological echocardiographic criteria for idiopathic restrictive cardiomyopathy, mainly dilated atria with nonhypertrophied, nondilated ventricles. None had known infiltrative disease, hypertension of >5 years' duration, or cardiac or systemic conditions associated with restrictive filling. Nineteen percent were in NYHA class I, 53% in class II, and 28% in class III or IV. Atrial fibrillation was noted in 74% of patients and systolic dysfunction in 16%. Follow-up (mean, 68 months) was complete for 93 patients (99%). At follow-up, 47 patients (50%) had died, 32 (68%) of cardiovascular causes. Four had heart transplantation. The death rate compared with actuarial statistics was significantly higher than expected (P<0.0001). Kaplan-Meier 5-year survival was 64%, compared with expected survival of 85%. Multivariate analysis using proportional hazards showed that the risk of death approximately doubles with male sex (hazard ratio [HR] = 2.1), left atrial dimension >60 mm (HR = 2.3), age >70 years (HR = 2.0), and each increment of NYHA class (HR = 2.0).

CONCLUSIONS

Idiopathic restrictive cardiomyopathy or nondilated, nonhypertrophic ventricles with marked biatrial dilatation, as defined morphologically by echocardiography, affects predominantly elderly patients but can occur in any age group. Patients present with systemic and pulmonary venous congestion and atrial fibrillation and have a poor prognosis, particularly men >70 years old with higher NYHA class and left atrial dimension >60 mm.