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Cardiac Contractility is Only One of Various Determinants of Hemodynamics
The 11th Annual Scientific Meeting
JHFS
S7
Symposium 3 S3-1 Cardiac Contractility is Only One of Various Determinants of Hemodynamics MASARU SUGIMACHI Department of Cardiovascular Dynamics, National Cardiovascular Center, Suita, Japan Normal range of hemodynamics, especially blood pressure, cardiac output, and left atrial pressure, is necessary to maintain the survival of patients. Advances in cardiovascular physiology have disclosed the major determinants of cardiac pump function include ventricular contractility, ventricular compliance, heart rate, and vascular resistance. This indicated that the cardiac contractility is only one of the determinants of pump function. In addition, hemodynamic variables are determined not only by pump function but also by blood volume and vascular resistance. We have recently extended Guyton’s framework and developed a simple formula to back calculate pump function, blood volume, and vascular resistance from a single measurement of cardiac output, atrial pressure and blood pressure by, e.g., a SwanGanz catheter. It is essential that cardiovascular medical team should understand how hemodynamics are determined by properties of cardiovascular components. It is also important to know that some conventional indexes of contractility may be affected by factors other than cardiac contractility; ejection fraction decreases with tachycardia or with vasoconstriction, whereas (dp/dt)maxincreases with volume infusion. We have to bear the limitations in mind when we use each of these indexes.
S3-2 Evaluation of Cardiac Function in the Clinical Scene SHIN-ICHI MOMOMURA Cardiovascular Division, Jichi Medical University, Shimotsuke, Japan Pulmonary arterial catheterization (PAC) has been quite often used for bedside evaluation of hemodynamics and cardiac function in Japan. Forrester’s subsets based on hemodynamic data obtained by PAC are widely used to predict patients prognosis and to determine the choice of treatment. However, since PAC is an invasive procedure, new classification by Nohria et al. derived from non-invasive physical examination is rather recommended in recently published guidelines. In routine diagnostic cardiac catheterization, most useful index of systolic function is left ventricular ejection fraction. This index is however, dependent on loading conditions and is not a pure index of contractility. As for the index of LV contractility, peak positive dP/dt and its derivatives are used. High fidelity pressure data obtained by catheter-tip manometer is necessary to calculate these indexes. Emax is the most reliable index of contractility although this is not practical for routine evaluation. As for the indexes of relaxation, peak negative dP/dt and tau are calculated from high fidelity pressure data. The ratio of LVEDP to LVEDV is a simple index for diastolic distensibility. For further evaluation of diastolic function, cubersome plotting of left ventricular pressure and volume data is required.
S3-3 Physical Examination and Echocardiography KIYOSHI YOSHIDA Department of Cardiovascular Medicine, Kawasaki Medical School, Kurashiki, Japan Evaluation of potential causative factors begins with a thorough history and careful physical examination. The most useful diagnostic test in the evaluation of patients
with heart failure is the comprehensive 2-dimensional echocardiogram coupled with Doppler flow studies to determine whether abnormalities of myocardium, heart valves, or pericardium are present and which chambers are involved. A comprehensive echocardiographic evaluation is important, because it is common for patients to have more than 1 cardiac abnormality that contributes to the development of heart failure. Furthermore, the study may serve as a baseline for comparison, because measurement of ejection fraction and the severity of structural remodeling can provide useful information in patients who have had a change in clinical status or who have experienced or recovered from a clinical event or received treatment that might have had a significant effect on cardiac function.
S3-4 Assessment of Exercise Capacity in Patients with Heart Cardiopulmonary Exercise Test with Respiratory Gas Analysis YOICHI GOTO Division of Cardiology, National Cardiovascular Center, Suita, Japan
Failure:
Assessment of exercise capacity in patients with chronic heart failure (HF) is important because exercise capacity directly relates to HF symptoms (such as exertional dyspnea) and quality of life and is a predictor of long-term prognosis. The simplest method of assessing exercise capacity may be a 6-min walking test, which has been shown to predict survival of HF patients. In contrast, the most sophisticated and clinically useful one is cardiopulmonary exercise test (CPX) with respiratory gas analysis. CPX provides variables of exercise capacity (peak oxygen uptake [PVO2] and anaerobic threshold [AT]), ventilatory efficiency (VE/VCO2 slope), and ventilation pattern (ventilatory oscillation). CPX has been used to identify the cause of exertional dyspnea (limitation of cardiac output, ventilatory abnormality or lack of motivation), to determine the treatment strategy (surgery for valvular heart disease, cardiac transplantation for HF), to determine exercise prescription in cardiac rehabilitation, and to assess the treatment effects and long-term prognosis in HF patients. Thus, CPX is a very useful tool in the diagnosis, treatment, and risk stratification of patients with HF. In this presentation, application and interpretation of CPX will be reviewed.
S3-5 Significance of the Endomyocardial Biopsy for Diagnosis of Heart Failure CHIKAO YUTANI Okayama University of Science, Department of Life Science, Okayama, Japan A long-standing doctrine in medicine is that diseases are better understood by knowing the structural changes of the injured tissue, and biopsy of organs for morphological examination remains the diagnostic reliable tools. The majority of diagnostic tools, recently in particular a variety of imagings, available to evaluate cardiovascular diseases emphasize functional physiologic abnormalities and not the underlying pathogenetic mechanism. While the diagnostic usefulness of the endomyocardial biopsy remains to be fully clarified, it has several important applications and is becoming increasingly important in the evaluation of cardiac diseases such as myocarditis, cardiomyopathies, and arrythmias induced cardiac failure. How the endomyocardial findings are currently interpretated and the understandings for endomyocardial biopsy findings are reviewed.
JHFS
S7
Symposium 3 S3-1 Cardiac Contractility is Only One of Various Determinants of Hemodynamics MASARU SUGIMACHI Department of Cardiovascular Dynamics, National Cardiovascular Center, Suita, Japan Normal range of hemodynamics, especially blood pressure, cardiac output, and left atrial pressure, is necessary to maintain the survival of patients. Advances in cardiovascular physiology have disclosed the major determinants of cardiac pump function include ventricular contractility, ventricular compliance, heart rate, and vascular resistance. This indicated that the cardiac contractility is only one of the determinants of pump function. In addition, hemodynamic variables are determined not only by pump function but also by blood volume and vascular resistance. We have recently extended Guyton’s framework and developed a simple formula to back calculate pump function, blood volume, and vascular resistance from a single measurement of cardiac output, atrial pressure and blood pressure by, e.g., a SwanGanz catheter. It is essential that cardiovascular medical team should understand how hemodynamics are determined by properties of cardiovascular components. It is also important to know that some conventional indexes of contractility may be affected by factors other than cardiac contractility; ejection fraction decreases with tachycardia or with vasoconstriction, whereas (dp/dt)maxincreases with volume infusion. We have to bear the limitations in mind when we use each of these indexes.
S3-2 Evaluation of Cardiac Function in the Clinical Scene SHIN-ICHI MOMOMURA Cardiovascular Division, Jichi Medical University, Shimotsuke, Japan Pulmonary arterial catheterization (PAC) has been quite often used for bedside evaluation of hemodynamics and cardiac function in Japan. Forrester’s subsets based on hemodynamic data obtained by PAC are widely used to predict patients prognosis and to determine the choice of treatment. However, since PAC is an invasive procedure, new classification by Nohria et al. derived from non-invasive physical examination is rather recommended in recently published guidelines. In routine diagnostic cardiac catheterization, most useful index of systolic function is left ventricular ejection fraction. This index is however, dependent on loading conditions and is not a pure index of contractility. As for the index of LV contractility, peak positive dP/dt and its derivatives are used. High fidelity pressure data obtained by catheter-tip manometer is necessary to calculate these indexes. Emax is the most reliable index of contractility although this is not practical for routine evaluation. As for the indexes of relaxation, peak negative dP/dt and tau are calculated from high fidelity pressure data. The ratio of LVEDP to LVEDV is a simple index for diastolic distensibility. For further evaluation of diastolic function, cubersome plotting of left ventricular pressure and volume data is required.
S3-3 Physical Examination and Echocardiography KIYOSHI YOSHIDA Department of Cardiovascular Medicine, Kawasaki Medical School, Kurashiki, Japan Evaluation of potential causative factors begins with a thorough history and careful physical examination. The most useful diagnostic test in the evaluation of patients
with heart failure is the comprehensive 2-dimensional echocardiogram coupled with Doppler flow studies to determine whether abnormalities of myocardium, heart valves, or pericardium are present and which chambers are involved. A comprehensive echocardiographic evaluation is important, because it is common for patients to have more than 1 cardiac abnormality that contributes to the development of heart failure. Furthermore, the study may serve as a baseline for comparison, because measurement of ejection fraction and the severity of structural remodeling can provide useful information in patients who have had a change in clinical status or who have experienced or recovered from a clinical event or received treatment that might have had a significant effect on cardiac function.
S3-4 Assessment of Exercise Capacity in Patients with Heart Cardiopulmonary Exercise Test with Respiratory Gas Analysis YOICHI GOTO Division of Cardiology, National Cardiovascular Center, Suita, Japan
Failure:
Assessment of exercise capacity in patients with chronic heart failure (HF) is important because exercise capacity directly relates to HF symptoms (such as exertional dyspnea) and quality of life and is a predictor of long-term prognosis. The simplest method of assessing exercise capacity may be a 6-min walking test, which has been shown to predict survival of HF patients. In contrast, the most sophisticated and clinically useful one is cardiopulmonary exercise test (CPX) with respiratory gas analysis. CPX provides variables of exercise capacity (peak oxygen uptake [PVO2] and anaerobic threshold [AT]), ventilatory efficiency (VE/VCO2 slope), and ventilation pattern (ventilatory oscillation). CPX has been used to identify the cause of exertional dyspnea (limitation of cardiac output, ventilatory abnormality or lack of motivation), to determine the treatment strategy (surgery for valvular heart disease, cardiac transplantation for HF), to determine exercise prescription in cardiac rehabilitation, and to assess the treatment effects and long-term prognosis in HF patients. Thus, CPX is a very useful tool in the diagnosis, treatment, and risk stratification of patients with HF. In this presentation, application and interpretation of CPX will be reviewed.
S3-5 Significance of the Endomyocardial Biopsy for Diagnosis of Heart Failure CHIKAO YUTANI Okayama University of Science, Department of Life Science, Okayama, Japan A long-standing doctrine in medicine is that diseases are better understood by knowing the structural changes of the injured tissue, and biopsy of organs for morphological examination remains the diagnostic reliable tools. The majority of diagnostic tools, recently in particular a variety of imagings, available to evaluate cardiovascular diseases emphasize functional physiologic abnormalities and not the underlying pathogenetic mechanism. While the diagnostic usefulness of the endomyocardial biopsy remains to be fully clarified, it has several important applications and is becoming increasingly important in the evaluation of cardiac diseases such as myocarditis, cardiomyopathies, and arrythmias induced cardiac failure. How the endomyocardial findings are currently interpretated and the understandings for endomyocardial biopsy findings are reviewed.