A novel approach to calculation of mean mitral valve gradient by Doppler echocardiography.

The Doppler-derived mean mitral valve gradient (DeltaP(M)) based on the simplified Bernoulli equation requires computerized integration of the Doppler signal and evaluation by a technician with the use of special equipment. We have noted empirically that the DeltaP(M) can be derived by the equation DeltaP(M) = (P(P) - P(T)) / 3 + P(T). Peak (P(P)) and trough (P(T)) pressures are derived from the simplified Bernoulli equation (P = 4V(2)). This equation can be used by the experienced observer to calculate the mean mitral valve gradient without specialized equipment. The purpose of this study is to validate the above empirically derived equation in patients with mitral stenosis. We retrospectively reviewed 41 consecutive studies done at our institution from October 1, 1997, through September 30, 1998, in which mean mitral valve gradient was assessed. Each study was reviewed and the DeltaP(M), P(P), and P(T) were measured for 3 beats by using the software package on an HP Sonos 2500. DeltaP(M) was also calculated with our formula. A linear regression model was used to compare the results of the measured versus the calculated DeltaP(M). The following sub-categories were also evaluated: transthoracic studies (TTE), transesophageal studies (TEE), native valve gradients (NV), prosthetic valve gradients (PV), sinus rhythm (SR), and atrial fibrillation (AF). The results of the regression analysis of the entire population of mean versus calculated DeltaP(M) are n = 41, r = 0.99, P <.001, and standard error of the estimate (SEE) = 0.67. The regression results for the subgroups are as follows: TTE: n = 30, r = 0.99, P <.001, SEE = 0.51; TEE: n = 11, r = 0.99, P <.001, SEE = 59; NV: n = 26, r = 0.99, P <.001, SEE = 0.59; PV: n = 15, r = 0.98, P <.001, SEE = 0.84; SR: n = 23, r = 0.99, P <.001, SEE = 0.58; and AF: n = 18, r = 0.98, P <.001, SEE = 0.82. In conclusion, the simple formula that we have derived is an accurate method for calculation of mean mitral valve gradient, and it is accurate over multiple subgroups. Furthermore, the formula allows visual verification of mean mitral gradient without specialized software.

Evolving indications for permanent pacemakers.

New indications for permanent cardiac pacing have been developed in recent years, with numerous studies demonstrating improved clinical outcomes in a variety of disorders. Because hypertrophic obstructive cardiomyopathy, dilated cardiomyopathy, heart failure, neurocardiogenic syncope, and atrial fibrillation are common conditions, every clinician should be aware of evolving alternative therapies for them. Observational studies in patients with refractory, symptomatic hypertrophic obstructive cardiomyopathy and significant left ventricular outflow gradient at rest suggest that cardiac pacing may result in symptomatic and hemodynamic improvement. Clinical trials have not shown conclusive evidence regarding the long-term benefit from pacing in these patients, and it is unclear whether pacing will be a preferred treatment option. Preliminary data suggest that pacing is a viable adjunctive therapeutic approach for improving symptoms in patients with dilated cardiomyopathy and heart failure. Mortality benefit has yet to be established, but it is to be hoped that ongoing randomized clinical trials will provide definitive information on that issue. Patients with refractory neurocardiogenic syncope or those who are intolerant of medical treatment may benefit from pacing therapies, especially those that use rate-drop sensor algorithms. Biatrial pacing has emerged as a technique that resynchronizes atrial electrical activity and has been shown to prevent atrial fibrillation. Multisite atrial pacing for the prevention of atrial fibrillation is considered investigational but seems promising. Newer indications for pacing are expected to result in improved clinical outcomes for hypertrophic obstructive cardiomyopathy, dilated cardiomyopathy and heart failure, neurocardiogenic syncope, and the prevention of atrial fibrillation.

Meta-analysis of 143 reported cases of aortic intramural hematoma.

Aortic intramural hematoma (IMH) is a clinical condition that has still not been completely defined. We conducted a meta-analysis of reported cases and analyzed the demographic profiles, imaging modalities, pathologic sites, and treatment strategies in relation to outcome in 143 patients with IMH. We performed an English language search of Medline for manuscripts with the keywords "aortic diseases," "aorta AND hematoma," and "intramural hematoma." Data from 143 reported cases were extracted. IMH of the aorta has a reported incidence of 5% to 20% among patients with acute aortic syndromes and a mortality rate of 21%. Most patients were men (61%) and median age was 68 years (range 15 to 88). Hypertension was a predisposing factor in 53% of the patients. Most patients had chest and/or back pain (80%). Transesophageal echocardiography, computer tomographic scan, or magnetic resonance imaging may be effectively used to diagnose this condition. There is no difference in the overall mortality rates in Stanford type A versus type B patients. Patients with Stanford type A IMH who underwent surgery, compared with those who underwent medical management, had a significantly better prognosis (14% vs 36% mortality, respectively, p < 0.02). Patients in Stanford group A who received medical treatment had a higher mortality rate than those in group B who received medical treatment (36% vs 14% mortality respectively, p < 0.02). In type B patients, medical and surgical outcomes were similar.

Ortner's syndrome in association with mitral valve prolapse.

The case of an 83-year-old woman with a history of hypertension, valvular heart disease, atrial fibrillation, and cardiomegaly is presented. The patient also had progressive hoarseness of her voice and intermittent dysphagia. Ear, nose, and throat examination revealed left vocal cord paralysis. Echocardiography revealed severely dilated left (LA) and right atria (RA), moderate mitral regurgitation, severe tricuspid regurgitation, and prolapse of both these valves. A review of literature of Ortner's or cardiovocal syndrome is presented. Ortner's syndrome due to mitral valve prolapse has not been reported previously.

Cardiac manifestations of acquired immunodeficiency syndrome.

Acquired immunodeficiency syndrome is a serious problem worldwide. Recent advances in the knowledge about human immunodeficiency virus (HIV) replication and the treatment of HIV infection have improved survival in HIV patients. Because of the longer survival in HIV patients, the more manifestations of late-stage HIV infection will be seen, including HIV-related cardiac diseases. The common cardiac manifestations in patients with the acquired immunodeficiency virus are pericardial effusion, myocarditis, dilated cardiomyopathy, endocarditis, pulmonary hypertension, malignant neoplasms, and drug-related cardiotoxicity. This review focuses on these cardiac manifestations in patients with the acquired immunodeficiency syndrome.

Clinical predictors of pulmonary hypertension in patients undergoing liver transplant evaluation.

Clinical prediction of portopulmonary hypertension (PPHTN) is critical in the preoperative evaluation of candidates for orthotopic liver transplantation (OLT) because of its association with significant morbidity and mortality. To determine the clinical, laboratory, and echocardiographic predictors of PPHTN, we retrospectively evaluated 55 candidates before OLT. From those, 8 candidates had pulmonary hypertension ([HTN] group A) and 47 candidates did not (group B). Pulmonary HTN was defined as a mean pulmonary artery pressure (PAP) of 25 mm Hg or greater and either elevated pulmonary vascular resistance or normal pulmonary artery wedge pressure. The significant predictors of PPHTN were (1) systemic arterial HTN (63% in group A v 9% in group B; P <.001), (2) loud pulmonary component of the second heart sound (38% v 2%; P =. 001), (3) right ventricular (RV) heave (38% v 4%; P =.002), (4) RV dilatation by echocardiogram (63% v 0%; P <.001), (5) RV hypertrophy by echocardiogram (38% v 0%; P =.001), and (6) echocardiogram-estimated systolic PAP (SPAP) greater than 40 mm Hg (63% v 2%; P <.001). The sensitivity of these variables for the detection of pulmonary HTN ranges from 37% to 63%, and their specificity from 91% to 100%. We conclude that several clinical and echocardiographic features are significantly associated with pulmonary HTN in patients with cirrhosis. In particular, echocardiogram-estimated SPAP greater than 40 mm Hg is strongly associated with pulmonary HTN and is specific. These predictors, however, are not sensitive enough to identify all the patients with PPHTN. Therefore, the evaluation of a combination of these variables may be useful for the preoperative identification of pulmonary HTN in liver transplant candidates.

Coronary dissection and thrombosis associated with exercise testing three months after successful coronary stenting.

Exercise testing is commonly performed to assess the functional result of coronary revascularization procedures and is usually not associated with any complications. However, this report documents a rare case of coronary dissection and thrombosis, which resulted in an acute myocardial infarction, in a patient who underwent stress testing 3 months following successful coronary stent implantation.

Incidence of bleeding complications associated with abciximab use in conjunction with thrombolytic therapy in patients requiring percutaneous transluminal coronary angioplasty.

The use of abciximab after full-dose failed thrombolytics within 15 hours of acute myocardial infarction significantly increases the risk of major bleeding complications.

Use of stents to treat kinks causing obstruction in a left internal mammary artery graft.

Left internal mammary arteries (LIMA) are used routinely as grafts to the left anterior descending coronary artery (LAD) in selected patients undergoing coronary artery bypass graft (CABG) surgery because of better long-term patency rates. Pathology other than fibrointimal hyperplasia, accelerated atherosclerosis, or thrombus can sometimes cause obstructive lesions in such grafts. This report illustrates a kink in a LIMA graft to the LAD causing an obstructive lesion shortly after surgery and describes the subsequent management of this lesion with intracoronary stents.

Hypoxia due to patent foramen ovale in the absence of pulmonary hypertension.

In most patients with a patent foramen ovale, blood flows from the left atrium to the right atrium in the absence of pulmonary hypertension. Our report describes a patient with a patent foramen ovale in whom flow occurred from the right atrium to the left atrium in the absence of pulmonary hypertension. We discuss hemodynamic findings and present a brief review of the pertinent medical literature regarding this phenomenon. We also discuss the role of transesophageal echocardiography in the diagnosis of this condition and in the elucidation of the underlying mechanisms, and we suggest several mechanisms that may explain the occurrence of this phenomenon in our patient.

Acute ischemic syndromes following coronary artery bypass graft surgery.

Coronary artery bypass graft (CABG) surgery, performed for the control of angina pectoris, leads to postoperative relief from symptoms in most patients. Amelioration of ischemia and improvement in exercise capacity after CABG are well documented. However, patients currently undergoing CABG are more complex than in the past--they are older and are maintained on medical therapy for longer periods. A large number of these patients have had one or more previous myocardial revascularization procedures. The post-operative period would appear to be a time of vulnerability for coronary events. However, previous investigators have focused on the pre- and intraoperative aspects of peri-CABG ischemia. Outcome data suggest that the postoperative interval is at least equally important as a determinant of short- and long-term morbidity and mortality. We discuss the epidemiology, etiology, pathophysiology, and treatment of ischemic syndromes in the postoperative period after CABG. In addition, we review recent data from a series of 14 patients, observed at our institution, who underwent cardiac catheterization and, in some cases, angioplasty of the culprit vessel in the immediate postoperative period.

Atrial fibrillation: preventing thromboembolism and choosing nondrug therapies.

A major consequence of atrial fibrillation (AF) is stroke. For stroke prevention in AF, the American Heart Association recommends aspirin, 325 mg/d, for low-risk patients. For all others, anticoagulation with warfarin to a target INR of 2 to 3 is recommended if warfarin is not contraindicated. Approximately 0.3% of patients receiving warfarin suffer intracranial hemorrhage. For restoration of sinus rhythm in recent AF, direct current cardioversion is the treatment of choice if a trial of antiarrhythmic drug therapy has failed or is contraindicated. Potential complications include thromboembolism, ventricular arrhythmia, and pulmonary edema. Permanent pacemakers can be used to control conduction disturbances such as sick sinus syndrome and to prevent paroxysmal AF. Radiofrequency AV nodal ablation provides symptomatic relief for some patients with chronic or paroxysmal AF. Surgical techniques are also being developed for AF. These include left atrial isolation and the corridor and maze procedures.

Atrial fibrillation: drug therapies for ventricular rate control and restoration of sinus rhythm.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, and its prevalence increases with age. Etiologies include coronary artery disease, hypertension, valvular heart disease, thyrotoxicosis, and other cardiac and noncardiac conditions. AF can lead to reversible impairment of left ventricular (LV) function, LV dilatation, clinical heart failure, angina pectoris, stroke, and increased mortality. Digoxin, beta blockers, or calcium channel blockers are used to control ventricular rate in new-onset AF with hemodynamically stable rhythm and in chronic AF where rhythm cannot be restored. These drugs can be used alone or in combination, depending on the clinical situation. The most complete relief of symptoms occurs when sinus rhythm is restored. Class IA, IC, and III antiarrhythmic agents can be used to restore and maintain sinus rhythm in selected patients.

Evaluation of hemolysis in patients with prosthetic heart valves.

The primary mechanism and most common cause of hemolytic disease in patients with prosthetic heart valves are mechanical trauma to red blood cells and paraprosthetic valvular regurgitation, respectively. Presenting features in patients with this condition include anemia, congestive heart failure, fatigue, jaundice, dark urine, and a regurgitant murmur. Various laboratory studies can be utilized to diagnose hemolytic anemia and to assess the severity of hemolysis. Transthoracic echocardiography, transesophageal echocardiography, and Doppler studies including color Doppler are useful imaging methods to assess valve function. Treatment is usually medical (oral iron); however, in patients with paravalvular regurgitation, surgery is often required to correct the anemia.