Power allocation for uniform illumination with stochastic LED arrays.

In this paper, a simple heuristic power allocation scheme is proposed for a random LED array to obtain uniform irradiance on the projection surface. This is done by considering a binomial point process (BPP) for modeling the LED location and using the quality factor as a performance metric. Numerical results are provided to validate the proposed model and demonstrate its simplicity over existing LED geometries.

Electrospray ionization tandem mass spectrometric study of protonated and alkali- cationized α/ε-hybrid peptides: differentiation of a pair of dipeptide positional isomers.

A new class of Boc-N-protected hybrid peptides derived from L- Ala and ε6-Caa (L-Ala = L-Alanine, Caa = C-linked carboamino acid derived from D-xylose) have been studied by positive ion electrospray ionization (ESI) ion-trap tandem mass spectrometry (MS/MS). MSn spectra of protonated and alkali-cationized hybrid peptides produce characteristic fragmentation involving the peptide backbone, the tert-butyloxycarbonyl (Boc) group, and the side chain. The dipeptide positional isomers are differentiated by the collision-induced dissociation (CID) of the protonated and alkali-cationized peptides. The CID of [M + H]+ ion of Boc-NH-L-Ala-ε-Caa- OCH3 (1) shows a prominent [M + H - C4H8]+ ion, which is totally absent for its positional isomer Boc-NH-ε-Caa-L-Ala-OCH3 (6), which instead shows significant loss of t-butanol. The formation of the [M + Cat - C4H8]+ ion is totally absent and [M + Cat - Boc + H]+ is prominent in the CID of the [M + Cat]+ ion of Boc-NH-L-Ala-ε-Caa- OCH3 (1), whereas the former is highly abundant and the latter is of low abundance for its positional isomer Boc-NH-ε-Caa-L-Ala-OCH3 (6). It is observed that 'b' ions are abundant when oxazolone structures are formed through a five-membered cyclic transition state in tetra-, penta-, and hexapeptides and the cyclization process for larger 'b' ions led to an insignificant abundance. However, the significant 'b' ion is formed in ε,α-dipeptide, which may have a seven-membered substituted 2-oxoazepanium ion structure. The MSn spectra of [M + Cat - Boc + H]+ ions of these peptides are found to be significantly different to those of [M + H - Boc + H]+ ions. The CID spectra of [M + Cat - Boc + H]+ ions of peptide acids containing L-Ala at the C-terminus show an abundant N-terminal rearrangement ion, [bn + 17 + Cat]+, which is absent for the peptide acids containing ε-Caa at the C-terminus. Thus, the results of these hybrid peptides provide sequencing information, the structure of the cyclic intermediate involved in the formation of the rearrangement ion, and distinguish a pair of dipeptide positional isomers.

Electrospray ionization tandem mass spectrometry of protonated and alkali-cationized Boc-N-protected hybrid peptides containing repeats of D-Ala-APyC and APyC-D-Ala: formation of [b(n-1) + OCH3 + Na]+ and [b(n-1) + OH + Na]+ ions.

RATIONALE: Differentiation and structural characterization of positional isomers of non-natural amino acid hybrid peptides by using electrospray ionization tandem mass spectrometry (ESI-MS(n) ) is desirable because of their fundamental importance from the view point of peptide mass spectrometry and also of their increasing importance in the area of research towards biomedical and material applications; hence, the present study is undertaken. METHODS: Electrospray ionization ion-trap tandem mass spectrometry (ESI-MS(n)) was used to characterize and differentiate three pairs of positional isomers of Boc-N-protected hybrid peptides containing repeats of D-Ala-APyC and APyC-D-Ala (D-Ala = D-alanine and APyC = trans-3-aminopyran-2-carboxylic acid). RESULTS: ESI-MS(n) spectra of protonated and alkali-cationized positional isomeric peptides display characteristic fragmentation involving the peptide backbone, the Boc group, and the side chain. It is observed that abundant rearrangement ions [b(n-1) + OCH(3) + Na](+) or [b(n-1) + OH + Na](+) are formed when D-Ala is present at C-terminus and the presence of APyC at the C-terminus inhibits the formation of rearrangement ions. In addition, abundant b(n-1)(+) ions are formed, presumably with stable oxazolone structures, when the C-terminus of b(n-1) (+) ions possessed D-Ala. CONCLUSIONS: The present study demonstrates that ESI tandem mass spectrometry is very useful for differentiating positional isomers of hybrid peptides containing D-Ala and APyC amino acids. While the protonated peptides give rise to characteristic sequencing ions, the cationized peptides produce additional rearrangement ions ([b(n-1) + OCH(3) + Na](+) and [b(n-1) + OH + Na](+)) which helps distinguish between the presence of D-Ala and APyC amino acids at the C-terminus.

The prevalence of pulmonary embolism in chronically paralyzed subjects: a review of available evidence.

STUDY DESIGN: Qualitative systematic review. OBJECTIVES: To examine the validity of the prevailing notion that pulmonary embolism (PE) is rare in the chronic spinal cord injury (SCI) population. SETTING: USA. METHODS: Review surveys of adult SCI subjects >2 months after injury in which PE has been looked for and its prevalence estimated. RESULTS: A total of 16 surveys of chronic SCI subjects published between 1956 and 2009 offered data on PE prevalence. Two autopsy surveys, 178 subjects paralyzed >2 months, revealed no PE. Eleven surveys of the cause of death, 3193 subjects paralyzed 1-25 years, revealed PE in 2.1%. Two surveys of survivors of SCI, 5761 subjects paralyzed 1-25 years, revealed PE in 0.4%. Our survey of 112 subjects paralyzed 1-50 years before death, revealed PE in 21 (18.7%), based on autopsy, imaging, clinical and electrocardiographic evidence. In 7 (33%) of the 21 subjects with PE, pulmonary hypertension by transthoracic echocardiography was detected, indicating recurrent and/or unresolved PE. CONCLUSION: PE is not infrequent in the chronic SCI subject; but its presentation may be subclinical; and its apparent recurrence may lead to pulmonary hypertension.

Noninvasive monitoring of left ventricular end-diastolic pressure reduces rehospitalization rates in patients hospitalized for heart failure: a randomized controlled trial.

BACKGROUND: In patients admitted for heart failure (HF), unrecognized elevation of left ventricular end-diastolic pressure (LVEDP) at the time of discharge may have a role in the high rehospitalization rate for HF on follow-up. METHODS AND RESULTS: In a small, prospective study (n = 50), patients admitted for HF were randomized to management guided by daily noninvasive estimated LVEDP monitoring (Group I, open) to a target LVEDP of <20 mm Hg or management based on clinical assessment alone without knowledge of the estimated LVEDP (Group II, blinded). Noninvasive estimated LVEDP was measured by the VeriCor monitor, which uses the Valsalva maneuver to derive the LVEDP. The primary endpoints were the reduction of estimated LVEDP at discharge and the HF rehospitalization rate on follow-up. Estimated LVEDP was significantly reduced at discharge in the open group compared with the blinded group (mean estimated LVEDP 19.7 ± 1.3 mm Hg vs 25.6 ± 1.5 mm Hg, respectively, P = 0.01). The rehospitalization rates for HF on follow-up were significantly improved in the open group compared with the blinded group (at 1 month: 0% vs 25%, respectively [P = .05]; at 3 months: 0% vs 32% [P = .01]; at 6 months: 4% vs 36% [P = .01]; at 1 year: 16% vs 48% [P = .03]). CONCLUSIONS: When HF is managed by clinical assessment only, estimated LVEDPs remain high at discharge, resulting in early and frequent rehospitalization for HF. Therapy guided by estimated LVEDP monitoring optimizes filling pressures and reduces HF rehospitalization rates.

Recurrent, massive pulmonary embolism in chronic myelopathy: a case report.

STUDY DESIGN: Case report. OBJECTIVES: The aim of this report was to describe an example of pulmonary embolism (PE), recently suggested to be highly prevalent in persons with chronic spinal cord lesions. SETTING: Veterans Affairs Hospital, Boston, MA, USA. METHODS: Chart review. RESULTS: A 60-year-old man with paraplegia, T10 motor complete, underwent laminectomy for correction of an arteriovenous malformation. After 41 days, he sustained a massive PE-suggested by right bundle branch block (RBBB) on an electrocardiogram (ECG) and diagnosed by perfusion lung scanning. He was treated with anticoagulants, the lung scan and RBBB resolving within 1 month of initiating treatment. After 5 years, he developed vertebral osteomyelitis at L5-S1 and was treated with antibiotics and bed rest. After 7 days, he was mobilized to a wheelchair, and during a transfer back to bed, he developed anxiety, dyspnea, fluctuating consciousness, low blood pressure and RBBB, absent by ECG 4 days earlier. He expired 20 min after onset of symptoms. The autopsy revealed a fresh thromboembolus occluding both main stem branches of the pulmonary artery. CONCLUSION: Massive PE after surgery in a patient with chronic paraplegia recurred 5 years later in association with severe infection and mobilization after bed rest, which resulted in death.

Right bundle branch block as a screening test for pulmonary embolism in chronic spinal cord injury.

OBJECTIVES: To evaluate right bundle branch block (RBBB) on electrocardiograms (ECGs) as a screening tool for the diagnosis of pulmonary embolism (PE) in a chronic spinal cord injury (SCI) population and to determine the prevalence of PE. DESIGN: Retrospective analysis. SETTING: Boston Veterans Affairs Healthcare System. PARTICIPANTS: Consecutive SCI participants (N=112) who were followed at this institution until death between 1999 and 2005 at an average age of 71 years, a duration of paralysis of 31 years, with a tetraplegic level in 62%, and no useful motor function in 84%. INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: PE, as a cause of RBBB, was diagnosed by autopsy, a source of thromboembolism, imaging, or other ECG signs of PE. Chronic obstructive lung disease was diagnosed by pulmonary function tests and myocardial infarction by ECG or echocardiogram. RESULTS: Twenty-nine participants (26%) had RBBB (6 with incomplete RBBB). Evidence that PE caused RBBB was found in 21 (72%), with 4 (3 massive) found by autopsy, 4 by the presence of an embolic source, 3 by imaging, 2 by the intermittent course of RBBB, 1 by abrupt onset of RBBB before death, and 7 by other ECG signs. RBBB represented chronic obstructive lung disease or myocardial infarction in the remaining 8. The onset of RBBB occurred either within months of SCI in 5 (1 before SCI) or years after SCI in 24 (6-50y, median 32y). RBBB was constant in 27 and intermittent in 2. The duration of RBBB ranged from 20 minutes to 31 years, median 4 years. CONCLUSIONS: RBBB may be a useful initial screening test for PE complicating chronic SCI. PE, often recurrent and sometimes fatal, is prevalent in chronic SCI.

Differentiation of three pairs of Boc-beta,gamma- and gamma,beta-hybrid peptides by electrospray ionization tandem mass spectrometry.

A new series of Boc-N-beta(3), gamma(4)-/gamma(4), beta(3)-isomeric hybrid peptides (containing repeats of beta(3)-Caa and gamma(4)-Caa's, Caa = C-linked carbo beta(3)-/gamma(4)-amino acids derived from D-xylose) have been differentiated by both positive and negative ion electrospray ionization (ESI) ion-trap and high resolution quadrupole time-of-flight/tandem mass spectrometry (Q-TOF MS/MS). MS(n) of protonated isomeric peptides and [M+H-Boc+H](+) produce characteristic fragmentation involving the peptide backbone, the Boc-group, and the side chain. The positional isomers are differentiated from one another by the presence of y(n)(+), b(n)(+), and other fragment ions of different m/z values. It is observed that the peptides with beta-Caa at the N-terminus produce extensive fragmentation, whereas gamma-Caa gave rise to much less fragmentation. Peptides with gamma-Caa at the N-terminus lose NH(3), whereas this process is absent for the carbopeptides with beta-Caa at the N-terminus. Two pairs of dipeptide diastereomers are clearly differentiated by the collision-induced dissociation (CID) of their protonated molecules. The loss of 2-methylprop-1-ene is more pronounced for Boc-NH-(R)-beta-Caa-(R)-gamma-Caa-OCH(3) (6) and Boc-NH-(R)-gamma-Caa-(R)-beta-Caa-OCH(3) (12), whereas it is insignificant or totally absent for its protonated diastereomeric pair Boc-NH-(S)-beta-Caa-(S)-gamma-Caa-OCH(3) (1) and Boc-NH-(S)-gamma-Caa-(S)-beta-Caa-OCH(3) (7). Further, ESI negative ion tandem mass spectrometry has also been found to be useful for differentiating these isomeric peptide acids.

Positive and negative ion electrospray tandem mass spectrometry (ESI MS/MS) of Boc-protected peptides containing repeats of L-Ala-gamma4Caa/gamma4Caa-L-Ala: differentiation of some positional isomeric peptides.

High-resolution electrospray ionization (ESI) quadrupole time-of-flight and ion trap tandem mass spectrometry has been used to distinguish the positional isomers of a new class of N-blocked hybrid peptides containing repeats of the amino acids, L-Ala-gamma(4)Caa ((l))/gamma(4)Caa((l))-L-Ala [Caa((l)) = Carbo (lyxose) amino acid, derived from D-mannose]. Both MS/MS and MS(3) of protonated isomeric peptides produce characteristic fragmentation involving the peptide backbone, Boc-group, and the side-chain. It is interesting to observe that the abundant y(n)(+) ions are formed when the corresponding amide -NH does not participate in the helical structures in solution phase and relatively low abundance y(n)(+) ions resulted when the amide -NH involves in the H-bonding. Thus, it was possible to identify the amide -NH hydrogens that participate in the helical structures through H-bonding in solution phase. Further, negative ion ESI MS/MS has also been found to be useful for differentiating these isomeric peptide acids.

Pulmonary embolism after cardiac surgery.

OBJECTIVES: We examined the incidence of pulmonary embolism after cardiac surgery. BACKGROUND: Because venous thromboembolism is considered to be an uncommon complication after cardiac surgery, its incidence was documented in a consecutive series of 1,033 patients who underwent cardiac surgery over a 5-year period. METHODS: Parallel cohorts of patients in a tertiary referral center were evaluated and the incidence of pulmonary embolism was compared in subgroups of patients undergoing coronary bypass surgery, valve surgery and combined procedures. RESULTS: Pulmonary embolism developed in 33 (3.2%) of the 1,033 cardiac surgical patients, within 2 weeks of a coronary bypass operation in most; it did not develop in any patient who had isolated valve replacement surgery (p < 0.05). The diagnosis of pulmonary embolism was established by pulmonary angiography in 24 patients, ventilation/perfusion lung scan in 3, postmortem examination in 5 and clinical examination in 1 patient. Important risk factors for pulmonary embolism included prolonged postoperative recovery, obesity and hyperlipidemia. The mortality rate was 18.7% in patients with in contrast to 3.3% in those without pulmonary embolism (p < 0.01). CONCLUSIONS: Although pulmonary embolism is rare after isolated valve replacement, it is not an uncommon complication after coronary bypass surgery.

Thrombolytic therapy of acute pulmonary embolism: current status and future potential.

Recombinant human tissue-type plasminogen activator (rt-PA), a relatively clot-specific fibrinolytic agent, represents a novel and promising approach to thrombolytic therapy of pulmonary embolism. Therefore, the efficacy and safety of peripheral intravenous rt-PA therapy were assessed in 47 patients with angiographically documented pulmonary embolism. The drug regimen was 50 mg over 2 hours followed by repeat angiography and, if necessary, an additional 40 mg over 4 hours. By 6 hours, 44 of the 47 patients had angiographic evidence of clot lysis that was slight (n = 5), moderate (n = 12) or marked (n = 27). Among the 34 patients with pulmonary hypertension before treatment (mean pulmonary artery pressure exceeding 17 mm Hg), the pressure decreased from 43/17 (mean 27) to 31/13 (mean 19) mm Hg (p less than 0.0001). Fibrinogen decreased 33% from baseline at 2 hours and 42% from baseline at 6 hours. There were two major complications that required surgical control of bleeding: hemorrhage from a pelvic tumor and mediastinal tamponade in a patient 8 days after coronary artery bypass surgery. The initial results demonstrate that, among selected patients, peripheral intravenous rt-PA can rapidly and, for the most part, safely lyse pulmonary embolism within 6 hours.

Differentiation of Boc- alpha,beta- and beta,alpha-peptides and a pair of diastereomeric beta,alpha-dipeptides by positive and negative ion electrospray tandem mass spectrometry (ESI-MS/MS).

Positive and negative ion electrospray ionization (ESI) tandem mass spectral study of a new series of hybrid peptides, viz, BocN-alpha,beta-peptides and BocN-beta,alpha-peptides, synthesized from C-linked carbo-beta3-amino acids [Caa (S)] and L-Ala has been carried out. The alpha,beta-peptides have been differentiated from beta,alpha-peptides by the collision-induced dissociation (CID) of [M + H]+ and [M - H]- ions in positive and negative ion ESI-MS respectively. The fragment ion [M + H - C(CH3)3 + H]+ formed from [M + H]+ ions by the loss of 2-methyl-prop-2-ene in alpha,beta-peptides with L-Ala at the N-terminus is insignificant or totally absent for beta,alpha-peptides which have the Caa (S) at N-terminus. The fragment ion [M - H-C(CH3)3OH - HNCO]- formed from [M - H]- of beta,alpha-peptide acids is totally absent for alpha,beta-peptide acids. This has been attributed to the absence of the beta-methylene group in alpha,beta-peptides, and the participation of the beta-methylene group in the loss of HNCO in beta,alpha-peptide acids is confirmed by the deuteration experiments. The CID of [M + H-Boc + H]+ ions of these peptides also produce characteristic fragmentation. In the CID spectra of alpha,beta-peptides, the b(n)+ ions and the resulting y(n)+ ions occur at a mass difference of 243 and 71 Da corresponding to the successive losses of Caa and L-Ala, whereas a mass difference of 71 and 243 Da is observed for beta,alpha-peptides. In contrast to the CID of protonated peptides, the CID of [M - H]- ions of the alpha,beta- and beta,alpha-peptide acids do not give b(n)- ions and show abundant z(n) (-) ions. Further, a pair of diastereomeric dipeptide esters and acids have been distinguished by the CID of [M + H]+ ions. The loss of 2-methyl-prop-2-ene is more pronounced for Boc-NH-Caa(R)-D-Ala-OCH3 (21) and Boc-NH-Caa(R)-D-Ala-OH (23) with Caa (R) at the N-terminus, whereas it is totally absent for Boc-NH-Caa (S)-D-Ala-OCH3 (22) and Boc-NH-Caa(S)-D-Ala-OH (24) peptides, which have Caa (S) at the N-terminus. Thus, on the basis of our previous and present studies, we propose that the CID of [M + H]+ ions provides a simple and useful method for distinguishing the configuration of Caa (S or R) at the N-terminus of BocN-carbo beta,alpha- and beta,beta-dipeptides.

Is streptokinase safe during menses?

We used intravenous streptokinase to treat a young woman with deep venous thrombosis manifested during her menses. There was no increase in menstrual bleeding, and she was symptom free six months later. Because menstrual endothelium after the first day of menses relies on arteriolar constriction for hemostasis rather than the formation of fibrin, we think that streptokinase may not be contraindicated in thrombotic disorders that occur during menses after the first day.

Clinical use of thrombolytic agents in venous thromboembolism.

The use of thrombolytic agents in venous thromboembolism has been shown to be highly effective. Patients treated with lytic agents show more rapid clot resolution and lung reperfusion and more rapid and greater reversal of the abnormal hemodynamic responses to pulmonary embolism than patients receiving heparin. Moreover, lytic therapy removes thromboemboli more completely from the pulmonary microcirculation, whereas residual thromboemboli tend to accumulate with heparin therapy. In addition, lytic therapy tends to preserve the venous valves, whereas distortion and destruction occur with heparin therapy. Hence, lytic therapy confers a number of short- and long-term benefits not observed with heparin therapy.

Evaluation of a noninvasive system for determining left ventricular filling pressure.

BACKGROUND: Measurement of left ventricular filling pressure (LVFP) provides an accurate assessment of left ventricular failure. Clinical and radiographic methods of estimating LVFP are unreliable. The noninvasive method of analyzing the decline in the arterial pressure during the strain phase of the Valsalva maneuver may be used to directly measure LVFP. OBJECTIVE: To examine the relationship and the level of accuracy of a noninvasive system (VeriCor) in directly determining left ventricular end diastolic pressure (LVEDP) using simultaneously recorded VeriCor and LVEDP measurements obtained during left heart catheterization. METHODS: During elective right and left heart catheterization, LVFP was assessed by measuring pulmonary capillary wedge pressure (PCWP) and LVEDP in 57 patients followed immediately by a Valsalva maneuver using the VeriCor assembly to estimate these pressures noninvasively. RESULTS: VeriCor measurements had a significant correlation with the catheter-measured LVEDP (r = 0.86), comparable to the correlation of the catheter-measured PCWP with LVEDP (r = 0.81). The predictive accuracy of VeriCor for LVEDP, however, appeared to be superior to that of catheter-measured PCWP for LVEDP: 84% of VeriCor measurements compared with only 41% of PCWP measurements were within 4 mm Hg of catheter-measured LVEDP, and 93% of VeriCor measurements compared with only 67% of PCWP measurements were within 6 mm Hg of catheter-measured LVEDP. CONCLUSION: VeriCor is a reliable noninvasive tool for measuring LVFP.

Historical overview of antithrombotic and thrombolytic therapy.

Early attempts to treat thromboembolic disorders focused on the prevention of thrombus formation, along with the prevention of extension and/or embolization of an existing thrombus. Antithrombotic therapy for these conditions included intravenous and oral anticoagulants and later antiplatelet agents, all of which remain in use today. Subsequent research sought a thrombolytic agent that could lyse a clot directly. Intravenously administered streptokinase and urokinase were found to act on the inactive proenzyme plasminogen to produce the active enzyme plasmin that could safely and effectively lyse fresh fibrin clots. These agents have proved effective for the treatment of myocardial infarction and pulmonary embolism, as well as peripheral arterial and venous thromboembolic conditions. Recent efforts have been directed toward a search for clot-specific agents that would avoid the systemic lytic state associated with the use of urokinase and streptokinase. Three clot-specific plasminogen activators are currently being evaluated: recombinant tissue-specific plasminogen activator, anisoylated streptokinase plasminogen activator complex, and pro-urokinase.

Identification of unstable angina patients who have favorable outcome with medical or surgical therapy (eight-year follow-up of the Veterans Administration Cooperative Study).

To identify patients with unstable angina (UA) who have favorable outcomes with medical therapy or surgery, 468 patients who had been randomized in the Veterans Administration Cooperative Study of UA were risk-stratified based on angiographic criteria of the number of coronary arteries diseased and left ventricular ejection fraction (LVEF). Patients at high risk for UA were defined as those with 3-vessel disease or LVEF of < or = 58%, and patients at low risk were those with 1- or 2-vessel disease and LVEF of > 58%. Of the 468 UA patients randomized, 287 patients belonged to the high-risk and 181 to the low-risk category. In the low-risk group, cumulative mortality after 8 years of follow-up was significantly lower in the medically treated patients (16.8%) than in the surgically treated patients (32.2%) (p = 0.022); in the high-risk group, cumulative mortality was significantly lower in the surgically treated patients (24.1%) than in the medically treated patients (35.3%) (p = 0.03). The relative risk of surgery (the ratio of surgical to medical risk) in the low-risk patients was 1.67, indicating a significant survival advantage with medical treatment (p = 0.05), whereas the relative risk of surgery for the high-risk group was 0.71, indicating a significant survival benefit with surgical treatment (p < 0.05). Thus, medical therapy appears to be the preferred therapy for UA patients with only 1- or 2-vessel disease and normal LVEF, and surgery is preferred for UA patients with 3-vessel disease or LVEF in the lowest tercile.

Usefulness and tolerability of hirulog, a direct thrombin-inhibitor, in unstable angina pectoris.

In an open-label pilot study of 20 patients with unstable angina (Braunwald class I-IIIB), hirulog was administered as a continuous intravenous infusion for 5 days in a dose of 0.2 mg/kg/hour to produce an activated partial thromboplastin time of approximately 200% of control. The primary end points of the study were: death, development of a transmural myocardial infarction, and intractable angina needing interventions such as an intraaortic balloon pump insertion, angioplasty and surgery. The secondary end points were the presence of an intracoronary thrombus detected on angiography and hemorrhagic complications during therapy. There was no death or transmural infarction in this study cohort; however, 1 patient developed intractable angina. Intracoronary thrombus was documented in 2 patients. Infusion of hirulog resulted in a steady prolongation of the activated partial thromboplastin time without any hemorrhagic or other adverse effect. Hirulog appears to be an effective antithrombotic agent that is tolerated well and may have advantages over heparin in the management of patients with unstable angina.

Echocardiography in acute and remote myocardial infarction.

Two dimensional echocardiography is just beginning to be used to characterize cardiac damage in patients with acute myocardial infarction. The two dimensional approach allows for a more comprehensive evaluation of cardiac anatomy and is able to detect with high sensitivity changes in regional wall motion that previously were sometimes missed or only found with difficulty using M mode echocardiography. Two dimensional echocardiography appears to offer a basis for quantifying the extent of myocardial damage in acute myocardial infarction and thus may permit objective assessment of therapeutic modalities and prognosis. In addition, the technique facilitates recognition of specific complications in acute myocardial infarction. In particular, the technique offers te ability to distinguish true from false ventricular aneurysm, postinfarction ventricular septal defect from papillary muscle dysfunction and rupture, and right ventricular infarction from cardiac tamponade.