Michele Nanna

Dobutamine echocardiography and resting-redistribution thallium-201 scintigraphy predicts recovery of hibernating myocardium after coronary revascularization

The value of dobutamine echocardiography and resting thallium-201 scintigraphy to predict reversal of regional left ventricular wall motion dysfunction after revascularization in patients with chronic coronary artery disease was assessed. Improvement in wall motion during dobutamine echocardiography and normal or mildly decreased uptake on thallium-201 scanning are strong predictors of reversible left ventricular dysfunction. Dobutamine echocardiography and resting thallium-201 scanning are simple and safe methods of assessing hibernating myocardium.

Determination of cardiac output by transcutaneous continuous-wave ultrasonic Doppler computer.

To evaluate the accuracy of a new, portable, continuous-wave Doppler computer (Ultracom) in measuring cardiac output (CO), simultaneous thermodilution CO and Doppler CO were measured in triplicate in 39 selected patients. Technically adequate Doppler CO studies were obtained in 36 patients. Aortic root diameter was measured by echocardiography and the cross-sectional area was calculated. A continuous-wave Doppler transducer was placed in the suprasternal notch, directed toward the ascending aorta and angled until the maximal velocity signal was achieved. The systolic velocity integral was computed using fast Fourier transform technique. The Doppler CO was computed from the equation: CO = aortic cross-sectional area X systolic velocity integral X heart rate. Interobserver and intraobserver variability studies were also performed. CO measured by thermodilution ranged from 1.86 to 10.1 liters/min (mean 5.26 +/- 1.91 [+/- standard deviation]) and CO by the Doppler method ranged from 1.63 to 10.9 liters/min (mean 5.32 +/- 1.83). The correlation coefficient was 0.97 (p less than 0.001) and standard error of the estimate was 0.42. The regression equation showed that Doppler CO = 0.408 + 0.93 X thermodilution CO. The correlation in 29 volunteers for interobserver variability was 0.98 (p less than 0.001) and in 18 volunteers for intraobserver variability was 0.97 (p less than 0.001). Thus, CO can be determined accurately in many patients using this Doppler technique by trained and experienced persons; intra- and interobserver variability is small.

Prognosis of patients with heart failure and unoperated severe aortic valvular regurgitation and relation to ejection fraction

Abstract Massell et al 1 reported that 13 of 14 patients (93%) with unoperated severe chronic aortic regurgitation (AR) died within 2 years after the onset of congestive heart failure (CHF). We reported that left ventricular (LV) ejection fraction was the most important prognostic variable for mortality in elderly patients with CHF associated with coronary artery disease 2 or unoperated severe valvular aortic stenosis. 3 We report the results from a prospective study of elderly patients with CHF associated with unoperated severe valvular AR correlating normal and abnormal LV ejection fraction with cardiac mortality and total mortality.

Cardiovascular response to dynamic exercise in patients with chronic symptomatic mild-to-moderate and severe aortic regurgitation.

Fifteen patients with symptomatic mild-to-moderate and severe chronic aortic regurgitation (AR) performed supine bicycle exercise while measurements of rest and exercise hemodynamics and left ventricular function were obtained. A continuous Doppler method was used to determine the change in distribution of total left ventricular stroke volume between forward stroke volume and regurgitant volume (RgV) with exercise. The pulmonary arterial wedge pressure (PAWP) was lower in the mild-to-moderate AR group than in the severe AR group at rest (8 +/- 1.2 vs 19 +/- 3.6 mm Hg, p = 0.01) and during exercise (15 +/- 3.9 vs 30 +/- 4.3 mm Hg, p = .02). In all patients there were increases in heart rate (78 +/- 4 to 96 +/- 5 beats/min, p less than .001), forward stroke volume (41 +/- 2 to 46 +/- 2 ml/m2), and the cardiac index (3.1 +/- 0.2 to 4.4 +/- 0.3 liters/min-m2, p less than .001), despite a fall in total left ventricular stroke volume index from 84 +/- 5 to 76 +/- 5 ml/m2 (p = .03). The systemic vascular resistance (SVR) decreased with exercise from 1277 +/- 72 to 1031 +/- 64 dynes-sec/cm5 (p less than .001), and the RgV and regurgitant fraction (RgF) both decreased with exercise from 43 +/- 5 ml/m2 to 30 +/- 4 ml/m2 (p = .002) and 0.50 +/- 0.03 to 0.37 +/- 0.03 (p less than .001), respectively. Left ventricular ejection fraction increased on exercise from 0.51 +/- 0.03 to 0.55 +/- 0.03 (p = .02) for the group, but it either decreased or failed to increase by at least 0.05 in seven of 13 patients. The change in ejection fraction on exercise was directly related to the change in SVR (r = .80, p less than .001). We conclude that: in patients with mild-to-moderate AR, the PAWP is generally normal at rest and exercise, in most of those with severe AR, the PAWP is elevated at rest and increases significantly with exercise, which is the likely mechanism for dyspnea on exertion in these patients, the cardiac index in both groups is normal at rest and increases on exercise, the increase in cardiac output results from both an increased heart rate and forward stroke volume, the increase in forward stroke volume results from reductions of RgV and RgF, the RgV and RgF are decreased due to a decreased SVR, and the ejection fraction response to exercise is variable and correlates best with changes in SVR with exercise.

Accuracy of determination of changes in cardiac output by transcutaneous continuous-wave doppler computer

The value of a previously validated portable, continuous-wave Doppler computer was assessed for measuring changes in cardiac output (CO). Simultaneous thermodilution and Doppler CO values were measured in triplicate in 16 patients undergoing clinical intervention with vasodilator therapy. A continuous-wave Doppler transducer was placed in the suprasternal notch and directed toward the ascending aorta and angled until the maximal velocity signal was obtained. The correlation coefficient was 0.92 (standard error of the estimate [SEE] = 0.48 liter/min) at rest; with intervention it was 0.88 (SEE = 0.52 liter/min). Our data indicate that the Doppler computer technique, when used in selected patients, is reliable in detecting changes in CO after vasodilator therapy. It may be of value in clinical situations in which hemodynamic monitoring is impractical.

Internal transcardiac pericardiocentesis for acute tamponade

If the catheter is still in the pericardium when tamponade is recognized during catheterization or electrophysiologic procedures, it can be used for definitive aspiration and relief of tamponade. This is physiologically beneficial to the patient, and psychologically beneficial to both patient and medical staff.

Cross-sectional multiplane transesophageal echocardiographic measurements: comparison with standard transthoracic values obtained in the same setting.

Background: Several algorithms developed for cost‐effective use of transesophageal echocardiography (TEE) propose elimination of “screening” transthoracic echocardiographic (TTE) studies. Cross‐sectional measurements obtained by TTE (left atrial diameter [LAD], left ventricular internal dimensions in diastole and systole [LVIDd, LVIDs], septal and posterior wall thickness in diastole [VSTd, PWTd], LV end‐diastolic and end‐systolic volumes [LVEDV and LVESV], and LV ejection fraction [LVEF]) have not been standardized for TEE. Methods: Forty‐six patients (age 27 to 85 years, 60 ± 13 years, 25 [54%] women) underwent TEE and TTE studies. TTE was performed while the TEE probe was in place and the patient was still sedated. Standard TTE measurements were compared with corresponding TEE values obtained from mid‐esophageal and transgastric views. Results: Standard TTE measurements compared favorably with those obtained by TEE at the mid‐esophageal three‐chamber view for LAD (3.9 ± 0.6 cm vs 4.0 ± 0.7 cm, P = NS) and at the transgastric long‐axis view for LVIDd (4.6 ± 0.8 cm vs 4.7 ± 0.8 cm, P = NS), LVIDs (3.1 ± 0.9 cm vs 3.1 ± 0.9 cm, P = NS), and VSTd (0.95 ± 0.18 cm vs 0.98 ± 0.19 cm, P = NS). Biplane TTE and TEE measurements of LVEDV (106 ± 35 ml vs 112 ± 38 ml, P = NS), LVESV (37 ± 23 ml vs 37 ± 25 ml, P = NS), and LVEF (67 ± 14% vs 69 ± 14%, P = NS) also correlated closely. The negative predictive values of TEE measurements for excluding abnormal LAD, LVIDd, VSTd, PWTd, and LVEF as defined by TTE were 83%, 94%, 95%, 97%, and 97%, respectively. Conclusion: Cross‐sectional TEE measurements as obtained in this study are equivalent to standard TTE dimensions and provide reliable information that may facilitate interpretation of TEE studies in the absence of TTE information.

Value of two-dimensional echocardiography in detecting tricuspid stenosis.

We reviewed the M-mode and two-dimensional echocardiograms of 100 consecutive patients with rheumatic heart disease. All were subsequently studied by cardiac catheterization and angiography. In four patients, cardiac catheterization showed tricuspid stenosis (average mean diastolic gradient 6.2 mm Hg), which was confirmed during cardiac surgery. M-mode echocardiography showed a diminished EF slope in 12 patients (mean 26 mm/sec), including the four patients with tricuspid stenosis. Seven of the eight patients without tricuspid stenosis had significant pulmonary hypertension; the reasons for the diminished EF slope in the other patient could not be identified. Tricuspid stenosis was diagnosed in four patients from two-dimensional echocardiograms on the basis of diastolic doming and restricted leaflet motion of the tricuspid valve. These four patients were the same patients in whom tricuspid stenosis was diagnosed by cardiac catheterization. We conclude that two-dimensional echocardiography is useful in the diagnosis of tricuspid stenosis.

Computer modeling of the effects of aortic valve stenosis and arterial system afterload on left ventricular hypertrophy

The degree of left ventricular hypertrophy is generally thought to reflect the severity of aortic stenosis. However, the compounded influence of arterial system load is poorly understood. We developed a computer model to investigate the effects of aortic valve stenosis in combination with various systemic arterial parameters in the development of left ventricular hypertrophy. Data show that an increased peripheral resistance and/or aortic valve resistance, results in an increase in left ventricular wall thickness and mass, while peak systolic wall stress remains constant. Changing arterial compliance to above normal level would not induce significant changes in wall thickness, while reduction in arterial compliance below normal would cause an increase in ventricular wall thickness. When a double load is imposed on the left ventricle by way of a stenotic valve and an increased arterial afterload, a greater and an aggregated increase in wall thickness results, hastening the hypertrophic process.

Clinical Utility of Intraprocedural Transesophageal Echocardiography during Transvenous Lead Extraction

BACKGROUND Transvenous lead extraction carries a risk of significant complications. Although intraoperative transesophageal echocardiography (TEE) is widely used to monitor cardiac performance and structures, its utility during transvenous lead extraction has not been well described. OBJECTIVE This study evaluates the utility of TEE during transvenous lead extraction. METHODS The records of 108 consecutive patients who underwent transvenous lead extraction with TEE guidance were reviewed. RESULTS Transvenous extraction of 202 leads was attempted; complete extraction was achieved for 174 leads (86%) and partial extraction for 13 leads with clinically acceptable outcomes in 187 leads (93%). Mean age of the patients was 63 +/- 21 (14-99) years and 37% were female. The average number of leads per patient was 1.9 (1-6). Mean implant duration was 71 +/- 57 (1-360) months. Indications for extraction were pocket infection (53 patients), bacteremia (33), atrial J-lead fracture or recall (13), lead malfunction (8), and venous thrombosis (1). TEE identified critical findings that prompted emergency surgical intervention or converted transvenous lead extraction to surgical explantation in 6 patients (two cases with cardiac laceration, 3 cases of cardiac tamponade, and one case with a large vegetation and a patent foramen ovale). TEE eliminated the need for the premature termination of the procedure in 11 patients by excluding significant structural cardiac damage. Overall, TEE provided clinically useful information during transvenous lead extraction in 17 cases (16%). CONCLUSIONS TEE during transvenous lead extraction provides valuable real-time information that improves efficacy and safety.