The hemodynamic simulation of mitral regurgitation in ventricular septal defect after myocardial infarction

Pulmonary Artery Catheters: An Update

Pulmonary artery (PA) catheters are widely used in the care of the critically ill. Numerous catheter designs are available, and the list of indications for their use is con stantly expanding. Extensive physiological data are sup plied by catheters. Right atrial, right ventricular, PA, and PA wedge pressure waveforms, as well as cardiac output and several derived parameters (e.g., systemic vascular resistance, pulmonary vascular resistance) are easily measured. Clinical application of these data may aid in diagnosis and management of acutely ill patients. Physi cians using catheters need to be aware of the numerous complications associated with their use. Scrupulous at tention to insertion and maintenance techniques will minimize the incidence of many of these complications. The undefined risk/benefit ratio of PA catheterization has caused controversy among physicians. Prospective studies to define better the risks versus benefits of PA catheters are currently being planned. Physicians using PA catheters should recognize that the catheters have no direct therapeutic benefit and that PA catheterization should neither replace bedside clinical evaluation nor delay treatment of the patient.

Hemodynamic profile of a post-infarct ventricular septal defect: left atrial a-waves rather than v-waves may be a prominent feature

The presence of prominent left atrial v-waves following interventricular septal rupture in acute myocardial infarction have been reported in the past. Hemodynamic profile obtained in one particular case highlighted some of the varying aspects of pressure wave, oxygen saturation, and compliance abnormalities that may also be present in such cases. The presence of large left atrial a-waves rather than v-waves was one of the findings.

Predictive value of prominent pulmonary arterial wedge V waves in assessing the presence and severity of mitral regurgitation

Indwelling pulmonary arterial catheters are often used to monitor and to guide therapy in critically ill patients. The magnitude of the V wave recorded from the pulmonary arterial wedge (PAW) position is sometimes used to assess the presence and severity of mitral regurgitation (MR). The present study was performed to assess the relation (or lack thereof) between a "prominent" PAW V wave and qualitative and quantitative estimates of MR. In 903 subjects (445 men and 458 women, aged 49 +/- 13 [mean +/- SD] years) referred for cardiac catheterization, an oximetrically confirmed PAW pressure was recorded with a large-lumen stiff catheter, and a left ventriculogram was recorded. In 646 of these subjects (328 men and 318 women, aged 50 +/- 13 years), forward cardiac output was measured by the Fick principle, and a regurgitant fraction was calculated. Prominent PAW V waves--as defined in several ways--were insensitive and had poor positive predictive value in identifying moderate or severe MR. At the same time, the absence of prominent PAW V waves was relatively specific for the absence of moderate or severe MR, and the negative predictive value of small V waves was very good. Thus, the prominence of a PAW V wave cannot be used to assess the presence or severity of MR.

Interventricular septal rupture complicating acute myocardial infarction: from pathophysiologic features to the role of invasive and noninvasive diagnostic modalities in current management

Rupture of the interventricular septum is a serious complication of acute myocardial infarction, accounting for 5% of deaths due to acute infarction. The septal perforation most frequently occurs during the first week after the infarction. The majority of these patients present with at least two-vessel coronary artery disease, and most cases have a total occlusion of the infarct-related artery. The degree of associated right ventricular damage is clinically important. Unpredictable hemodynamic deterioration can rapidly develop in 80% of the patients, and mortality with medical therapy alone exceeds 90%. Because the preoperative hemodynamic status of these patients appears to be a major determinant for survival, accurate diagnosis, urgent management, and early operative correction are necessary to avoid a catastrophic clinical outcome. Traditionally, diagnostic procedures included first, the insertion of a pulmonary artery catheter for recording of pressures, sequential oximetry, and calculation of the shunt's magnitude and the cardiac output followed by left ventriculography and coronary arteriography for angiographic demonstration of the shunt and the coronary anatomy. Currently, optimal utilization of color flow Doppler and two-dimensional and transesophageal echocardiography offers a significant clinical advantage and can be used to shorten the time spent on diagnosis, evaluation, and management prior to the urgent surgical repair. The elimination of time-consuming diagnostic tests can contribute to further improvement in the survival rate.

Significance of diastolic pulmonary artery pressure peaks

We describe a patient undergoing elective surgery for treatment of an abdominal aortic aneurysm in whom an abrupt change in the contour of the pulmonary artery pressure (PAP) trace indicated the development of an intermediate (20 mm Hg) V wave in the pulmonary artery wedge pressure (PAWP) trace. As the PAP trace is displayed continuously, attention to its contour may allow for early detection of changes to the underlying PAWP trace.

Beyond the wedge: clinical physiology and the Swan-Ganz catheter

The Swan-Ganz catheter was introduced into general clinical medicine in 1970 and quickly gained widespread use in the management of critically ill patients. The device offers highly sophisticated physiologic information; however, in many instances, only the wedge pressure and the cardiac output are utilized when managing acutely ill patients. The purpose of this review is to illustrate and explain the array of physiologic data available from the Swan-Ganz catheter in most circumstances. A basic understanding of the information that can be obtained with the Swan-Ganz catheter is quite useful in the diagnosis and management of a variety of cardiovascular disorders. In addition, the Swan-Ganz catheter can be a helpful tool for teaching cardiovascular pathophysiology.

Hemodynamic abnormalities in acute myocardial infarction

Great strides have been made in the management of patients with acute myocardial infarction since the advent of coronary care units. However, congestive heart failure continues to be the major cause of in-hospital mortality. The accurate diagnosis and classification of hemodynamic abnormalities allow the application of specific therapies for each patient. Because clinicians can now routinely measure left and right ventricular preload, systemic and pulmonary vascular resistance, cardiac output, and arteriovenous oxygen difference, pharmacologic and surgical interventions can be applied in a scientific manner. In addition, mechanical complications can be promptly recognized and aggressively treated. Although the mortality rate for patients with severe left ventricular dysfunction after myocardial infarction remains high, expert management offers an improved prognosis for many patients.

Medical management of the patient with angina pectoris: an overview of the problem

The medical management of angina pectoris requires a comprehensive approach to the patient and his family, including attention not only to established physiologic and pharmacologic principles, but also to the emotional aspects of his illness. When comprehensive management is systematically and rigorously applied to the patient with angina pectoris, excellent relief of the symptoms of angina pectoris can be achieved in a high percentage of patients, although there are significant numbers of patients who are refractory to the most intensive management using presently available drugs. The same fundamental principles of care apply to patients with coronary heart disease who undergo aortocoronary bypass surgery and to those treated medically.

Limitations of pulmonary wedge V waves in diagnosing mitral regurgitation

To study the usefulness of large V waves in pulmonary capillary wedge tracings in establishing the diagnosis of mitral regurgitation, data on 1,021 consecutive cardiac catheterizations were reviewed. Wedge tracings were obtained by Swan-Ganz catheterization in 208 patients, usually because of suspected valve disease. One hundred two patients had no trace of mitral regurgitation angiographically, 69 had mild to moderate and 37 had severe regurgitation. V waves were graded as trivial (less than 5), intermediate (5 to 10) or large (10 or more mm Hg above mean wedge pressure). Of 50 patients with large V waves, 18 (36 percent) had no or trace mitral regurgitation; these included 5 with mitral stenosis, 3 with a mitral valve prosthesis, 4 with coronary disease and congestive failure, 2 with aortic valve disease and congestive failure and 2 with a ventricular septal defect. Of 37 patients with severe mitral regurgitation, 16 (43 percent) had large and 12 (32 percent) had trivial V waves. Thus, mitral regurgitation is the most common cause of large V waves; however, large V waves are neither highly sensitive nor specific for severe regurgitation. Increased left atrial compliance may be associated with trivial V waves in the presence of severe regurgitation. Mitral obstruction, congestive heart failure and ventricular septal defect may all be associated with large V waves in the absence of significant mitral regurgitation.

Giant left atrial V-waves in post-myocardial infarction ventricular septal defect

A 54-year-old man developed a post-myocardial infarction ventricular septal defect with a 4:1 shunt. The first cardiac catheterization showed left atrial V-waves of 70 mm Hg. Assessment of the presence or absence of mitral regurgitation was not possible because of ventricular irritability and rapid runoff from left ventricle to right ventricle. At the second catheterization two months later, the left atrial V-waves had fallen to 34 mm Hg. The absence of mitral regurgitation was shown by observing the time difference in appearance of indocyanine green in the right ventricle and the left atrium after left ventricular injection. The defect was repaired by right ventriculotomy with subsequent normalization of left atrial V-waves. This case shows that very large left atrial V-waves may occur in postinfarction ventricular septal defects without mitral regurgitation and that these V-waves may decrease with time, probably reflecting increased left atrial compliance.