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[Regional ventricular function at rest during exercise before and after bypass surgery (author's transl)]
Insights
Aortocoronary bypass surgery significantly improved cardiac function in patients with coronary heart disease. Successful bypasses enhanced ventricular performance during exercise, improving contractility and ejection fraction, while failed grafts showed no change.
Area of Science:
- Cardiology
- Cardiac Surgery
- Cardiovascular Physiology
Context:
- Coronary heart disease (CHD) significantly impairs left ventricular function, leading to reduced contractility and exercise intolerance.
- Aortocoronary bypass surgery is a common intervention aimed at restoring myocardial perfusion and improving cardiac performance in CHD patients.
- Preoperative assessment of ventricular function is crucial for evaluating surgical outcomes and patient prognosis.
Purpose:
- To evaluate the impact of aortocoronary bypass surgery on isovolumetric contractility indices and ejection phase parameters in patients with coronary heart disease.
- To assess regional and global left ventricular function at rest and during physiological stress (leg raising, exercise) before and after bypass surgery.
- To correlate graft patency with functional recovery and symptom relief in patients undergoing coronary artery bypass grafting.
Summary:
- In patients with coronary heart disease, preoperative assessment revealed impaired left ventricular function, characterized by increased left ventricular end-diastolic pressure (LVEDP) and reduced velocity of fiber shortening, especially during exercise.
- Five weeks after aortocoronary bypass surgery, patients with patent grafts demonstrated significant improvements in ventricular contractility and ejection fraction, with enhanced regional wall motion during leg raising and exercise.
- Patients with occluded grafts or intraoperative complications showed no significant functional improvement compared to preoperative values, highlighting the importance of successful revascularization.
Impact:
- Successful aortocoronary bypass surgery markedly improves cardiac function, enabling patients to tolerate physical exercise without angina and significantly enhancing ejection fraction and contractility.
- The study demonstrates a substantial functional recovery, with improvements up to 500% in individual wall segments, underscoring the efficacy of surgical revascularization in CHD.
- These findings provide critical evidence for the benefits of bypass surgery in restoring myocardial function and improving the quality of life for patients with coronary heart disease.
Abstract:
In 9 patients with coronary heart disease isovolumetric contractility indices and ejection phase parameters were measured simultaneously, using an angiographic catheter with a manometer at the tip (Millar). Regional wall motion at rest, after leg raising and during physical exercise (bicycle ergometer) was analyzed applying the hemiaxis method. Five weeks after aortocoronary bypass surgery the same examinations were repeated. Preoperatively left ventricular enddiastolic pressure (LVEDP) increased from 21 to 37 mm Hg following leg raising. The velocity mean of fiber shortening (Vcf) and of regional fiber shortening in the anterior wall decreased significantly.--All patients discontinued physical exercise due to angina pectoris. LVEDP increased from 21 to 39 mm Hg. Large hypokinetic and akinetic areas developed especially in the anterior wall. Velocity of fiber shortening of the anterior wall decreased from 1.43 to 0.76/s. Enddiastolic volume remained unchanged while endsystolic volume increased significantly. In six patients with patent grafts surgery had a beneficial effect. Comparing angiograms at rest no significant changes were found. After leg raising and physical exercise, however, marked improvement in ventricular function occurred, compared to the preoperative performance. All 6 patients were exercised without complaints at a load of 100 watts for 8 minutes. Velocity of fiber shortening in the anterior wall increased significantly from 0.76 to 2.56/s, mean Vcf from 1.11 to 2.12 circ/s, max dP/dt from 2302 to 4280 mm Hg/s and Vpm from 27.8 to 55.7/s. Functional improvement in individual wall segments amounted to 500% in the mean. Ejection fraction increased from 54 to 76%. Enddiastolic volume remained unchanged while endsystolic volume decreased from 67 to 33 ml/1.37 m2 (p less than 0.002). In three patients the bypass occluded or myocardial infarction occurred intraoperatively. Postoperative findings at rest and during exercise were unchanged as compared to preoperative values. Following successful bypass surgery ventricular function at rest did not change. During exercise, however, a marked improvement in overall and in regional ventricular function was found.