Peter F. Cohn

Clinical significance of coronary arterial ectasia.

In a study group of 2,457 consecutive patients undergoing cardiac catheterization, 30 patients had coronary arterial ectasia, an irregular dilatation of major vessels up to seven times the diameter of branch vessels. The frequency of hypertension, abnormal electrocardiogram and history of myocardial infarction was greater than that in a control group with obstructive coronary artery disease. Patients with ectasia did not differ from patients with obstructive disease in sex, age, prevalence of angina or presence of metabolic abnormalities. Six deaths occurred in the group with ectasia during a mean follow-up period of 24 months (annual rate of 15 percent). Extensive destruction of the musculoelastic elements was evident, resulting in marked attenuation of the vessel wall. The short-term prognosis in this group is the same as in medically treated patients with three vessel obstructive coronary artery disease.

Modification of abnormal left ventricular diastolic properties by nifedipine in patients with hypertrophic cardiomyopathy.

The effect of nifedipine on left ventricular isovolumic relaxation and diastolic filling properties and systemic and left ventricular hemodynamics was studied in 15 patients with hypertrophic cardiomyopathy. After nidefipine (10 mg sublingually), the prolonged left ventricular isovolumic relaxation time assessed by echocardiography decreased from 112 i 26 to 83 ± 23 msec (p < 0.0001), and the left ventricular pressure decay as measured by time constant T improved from 63 + 20 to 49 ± 11 msec (p < 0.05). Left ventricular filling dynamics also improved as assessed by a return toward normal in the depressed peak rate of left ventricular diastolic filling (dimension change 72 ± 37 to 101 ± 39 mm/sec, p < 0.01) and the peak rate of posterior wall thinning (47 ± 31 to 68 + 36 mm/sec, p < 0.001). These changes were accompanied by hemodynamic evidence of improved diastolic function shown as a decrease in left ventricular end-diastolic pressure and a downward shift in the left ventricular diastolic pressure-dimension relationship, suggesting improved left ventricular distensibility. After nifedipine, there was a slight increase in heart rate and a decrease in systemic arterial blood pressure, and no depression of the left ventricular percent fractional shortening or cardiac index. These data indicate that abnormal left ventricular relaxation and diastolic filling rates in hypertrophic cardiomyopathy are dynamic and favorably modified by nifedipine, and that this effect is not related to a depression of left ventricular systolic function.

Left ventricular ejection fraction as a prognostic guide in surgical treatment of coronary and valvular heart disease

The immediate and short-term prognostic values of increased left ventricular end-diastolic pressure, reduced cardiac index and depressed ejection fraction determined during preoperative evaluation were compared in 128 patients undergoing coronary revascularization and 44 patients undergoing cardiac valve replacement. A modification of the New York Heart Association (NYHA) functional classification was used to evaluate pre- and postoperative left ventricular decompensation. One hundred fifty-eight of the 172 patients did well postoperatively (NYHA classes I and II), including the majority of patients with either an abnormal left ventricular end-diastolic pressure (> 15 mm Hg), reduced cardiac Index (< 2.5 liters/min per m2) or depressed ejection fraction (< 0.50). However, of the 14 patients who did not survive surgery or had progressive postoperative deterioration, 10 had a depressed ejection fraction and 7 had combined abnormalities of left ventricular end-dlastolic pressure and cardiac index. Because these latter values may often be borderline, or occur as isolated abnormal findings, the ejection fraction is probably the most useful of the readily obtainable, single hemodynamic measurements in assessing the import of deranged left ventricular function on the outlook for patients undergoing cardiac surgery.

Augmentation of Left Ventricular Contraction Pattern in Coronary Artery Disease by an Inotropic Catecholamine The Epinephrine Ventriculogram

In order to assess potential improvement in abnormal left ventricular (LV) wall motion, eighteen subjects — sixteen with obstructive coronary artery disease and LV asynergy and two with no evidence of organic heart disease — were studied by cardiac catheterization and cineangiography. Ventriculograms were performed at rest and during a constant infusion of l-epinephrine (EPI) at 1-4 &mgr;g/min after an average of nine minutes steady state. EPI infusion induced augmentation of LV contraction pattern in both normal subjects and in all normal zones in the sixteen subjects with asynergy, and in no instance was contraction in a normal zone rendered abnormal. Eleven of sixteen patients showed improved contraction in previously asynergic areas, two of whom also demonstrated paradoxical motion in an abnormal zone. Of a total of forty-four resting asynergic zones, twenty-three exhibited an improved contraction pattern with EPI, one showed depressed contraction, two demonstrated both an increase and deterioration in the same zone (paradoxical motion), and eighteen showed no change. Quantitative motion analysis generally corroborated these qualitative ventriculographic observations. Heart rate, LV systolic pressure and LV end-diastolic pressure increased slightly with EPI, but were not significantly changed from control values. While there was wide variation in end-diastolic volume in the subjects with asynergy, EPI resulted in an increase in both stroke volume and ejection fraction, the latter significantly (P < 0.05). In the four subjects who subsequently underwent aneurysmectomy, preoperative lack of improvement with EPI correlated with a pathologic diagnosis of fibrosis. Other than angina pectoris of brief duration in two subjects, EPI provoked no untoward reactions, arrhythmias or complications. It is concluded that LV motion abnormalities can be improved or changed in certain cases by the inotropic stimulus of EPI, suggesting residual contractile ability; the agent may differentiate between zones of potentially functional cardiac muscle and frank fibrosis.

Left Ventricular End-Systolic Pressure-Dimension and Stress-Length Relations in Normal Human Subjects

Abstract To determine whether the left ventricular end systolic pressure-dimension and end-systolic stress-dimension relations in human beings are linear and sensitive to altered contractility, we studied 13 normal subjects during methoxamine infusion and with postextrasystolic potentiation induced by an external mechanical cardiac stimulator. End-systolic diameter was obtained with echocardiography and end-systolic pressure was estimated in six subjects from the dicrotic notch of a simultaneously recorded carotid pulse tracing, standardized by cuff pressure, whereas in seven subjects intraarterial pressure was recorded. For each subject, the end-systolic pressure-dimension relation was linear ( r = 0.83–0.99) over a range of 76 mm Hg (84 to 160) for end-systolic pressure. The mean slope of the end-systolic pressure-dimension line was 62 ± 22 mm Hg/cm. Peak systolic pressure was also linearly related to end-systolic diameter ( r = 0.82–0.99) over a range of 100 mm Hg (104 to 204). End-systolic stress was a linear function of end-systolic dimension as well ( r = 0.93–0.99) over an end-systolic stress range of 181 g/cm 2 . With postextrasystolic potentiation the potentiated beat had a smaller end-systolic dimension for any given end-systolic pressure and thus shifted the end-systolic pressure-dimension relation to the left. Thus, end-systolic pressure-dimension and stress-dimension relations in human subjects appear to be linear and are sensitive to the inotropic state.

Detection of Residual Myocardial Function in Coronary Artery Disease Using Post-extra Systolic Potentiation

Improved global or segmental wall motion following revascularization suggests potential reversibility of ischemic left ventricular dysfunction in coronary artery disease (CAD). This study evaluates the effectiveness of post-extra systolic potentiation (PESP) to detect latent residual contractile function. Quantitative left ventriculography was performed in 15 patients with CAD (including seven with significant asynergy) and in three normal controls. During the ventriculogram, a single extra-systole was introduced by an R-wave coupled stimulator (R-stimulus interval averaged 398 msec, with an average mA of 2.4). PESP improved segmental axis shortening in 51 of 55 normal axes and 15 of 17 hypokinetic or akinetic axes. It also increased both ejection fraction and mean rate of circumferential fiber shortening in 17 of 18 patients. No significant arrhythmia occurred with this technique. A single interposed beat with PESP in one ventriculogram is a safe, effective method to detect residual potential contractile function in myocardium that may be hypokinetic or akinetic under conditions of the study.

Right ventricular performance in patients with coronary artery disease.

While left ventricular (LV) performance in patients with coronary artery disease (CAD) has been extensively investigated, little attention has been given to right ventricular (RV) function in this disease. For this purpose, a new geometric model for RV volume has been developed and RV end-diastolic volume index (EDVI), end-systolic volume index (ESVI), stroke volume index (SVI) and ejection fraction (EF) have been determined from biplane RV cineangiograms in 26 patients. Eight patients served as normal (control) subjects (group I). Eighteen patients with obstructive CAD comprised two other groups: six who had no significant disease of the right coronary artery (RCA) (group II) and 12 who had a high grade RCA lesion (group III). The mean values for EDVI, SVI and EF in group I were 76 ± 11 ml/m2, 50 ± 6 ml/m2, and 66 ± 6%. The only significant difference between groups I and II was that SVI was lower in group II than in group I (P < 0.01). No measurements in groups II and III were statistically different from each other. However, markedly subnormal values were found in group III (EDVI: 61 ± 16 ml/m2, SVI: 33 ± 10 ml/m2 and EF: 52 ± 7%); all values being significantly lower (SVI and EF: P < 0.001; EDVI: P < 0.05) than in group I. RV end-diastolic pressure was normal in all patients. These findings may be related to 1) reduced RV compliance, 2) distorted LV geometry, 3) possible RV ischemia or 4) reduced Frank-Starling effect.

Effect of nitroprusside on regional myocardial blood flow in coronary artery disease. Results in 25 patients and comparison with nitroglycerin.

SUMMARYThe effect of nitroprusside on regional myocardial specific blood flow (RMBF) was evaluated in 25 patients with the xenon-133 washout technique. Six patients were normal (group 1), six patients had coronary artery disease without collateral vessels (group 2), and thirteen patients had coronary artery disease with collateral vessels (group 3). In group 1, RMBF was unchanged following nitroprusside. RMBF decreased significantly in both group 2 and group 3, including seven patients in group 3 with high-grade collateral vessels. The results were compared to the effect of nitroglycerin in 31 patients previously studied using the same technique. Mean arterial pressure and pressure-rate product were comparably reduced by both drugs. In contrast to the findings with nitroprusside, after sublingual nitroglycerin RMBF decreased markedly in normals and increased in patients with coronary artery disease and high-grade collaterals. The data suggest that nitroprusside may primarily affect resistance vessels within the coronary circulation, as opposed to the effect of nitroglycerin on conductance vessels. Thus, nitroprusside could result in redistribution of blood flow away from ischemic areas and potentially increase ischemic injury in some patients with coronary artery disease.

Ejection fraction image: A noninvasive index of regional left ventricular wall motion

Abstract The clinical value of the ejection fraction image, a computerized radionuclide measurement of regional left ventricular wall motion, was assessed in 34 patients. From gated modified left anterior oblique images of the cardiac blood pool, regional ejection fraction images were created. Left ventricular wall motion was classified with ejection fraction imaging as normal, hypokinetic or akinetic in each of three left ventricular regions. Wall motion was similarly characterized with regional analysis (segmental axis shortening, extent of akinetic segments) of contrast angiograms. Results of ejection fraction imaging were assessed in comparison with angiographic analyses. Seventeen patients had asynergy on contrast ventriculography; the other 17 had normal wall motion. There was agreement between the contrast and radionuclide ventriculograms as to presence of asynergy in 33 of 34 patients. In 92 of 102 (90 percent) left ventricular regions evaluated with both contrast and radionuclide methods, the ejection fraction image and contrast angiogram were in agreement regarding presence or absence of wall motion abnormalities. Of 43 abnormal angiographic wall motion descriptions in 35 ventricular regions (8 regions contained both hypokinetic and akinetic segments), 35 (81 percent) were similarly identified with the ejection fraction image. These results suggest that the ejection fraction image is a sensitive indicator of regional left ventricular wall motion.

Electrocardiographic, arteriographie and ventriculographic correlations in transmural myocardial infarction☆

Abstract To determine if significant interrelations exist between the electrocardiographic diagnosis of transmural myocardial infarction, sites of coronary arterial obstruction, and left ventricular asynergy, 235 patients with angiographically documented coronary artery disease were subdivided according to the electrocardiographic location of the myocardial infarction, the coronary arterial system involved and the site of ventricular asynergy. Of 82 instances of anterior myocardial infarction, the left anterior descending artery demonstrated significant disease in 79 (96 percent). Of 100 instances of inferior myocardial infarction, the right coronary artery was significantly diseased in 87 and the left circumflex in 55. When multiple infarctions were present, multivessel disease was found in 93 percent of patients. Left ventricular asynergy was present in 81 percent, including 84 percent of those with anterior infarction, 74 percent of those with inferior infarction, and 93 percent of those with multiple infarctions. The results of our study suggest that the electrocardiogram is often of value in indicating sites of coronary arterial obstruction and ventricular asynergy in patients with coronary artery disease and transmural myocardial infarction.