Evaluation of M-mode echographic estimates of left ventricle function: Relationship of selected ultrasonic and hemodynamic parameters

We examined the relationship between echocardiographic and hemodynamic parameters in 48 patients with left ventricular ejection fractions < 50% without primary vaivular disease. Pulmonary wedge pressure (PWP) correlated with the PR-AC interval (r = ?0.62) and with left atrial dimension (r = 0.64) but not with left ventricular diastolic dimension. A PR-AC interval ≤ 60 msec was observed in 26 of 29 (90%) patients with a PWP ≥ 14 mm Hg versus 1 of 10 (10%) patients with a PWP < 14 mm Hg. The correlation between PWP and the PR-AC interval was substantially better in patients with a PR interval ≤ 200 msec (r = ?0.79) than in patients with a PR interval > 200 msec (r = ?0.55). The PR-AC interval also correlated with the ejection fraction (r = 0.47). A left atrial dimension ≥4.0 cm was observed in 29 of 35 (83%) patients with a PWP ≥ 14 mm Hg versus 0 of 9 (0%) patients with a PWP < 14 mm Hg. Stroke volume (SV) correlated with aortic root excursion (r = 0.71) and with SV calculated from formulas based on mitral valve motion (r = 0.76) or aortic valve motion (r = 0.62). However, no echo formula provided valid estimates of cardiac output. We conclude that M-mode echocardiography provides a relatively useful noninvasive method of assessing left ventricular filling pressure in patients with reduced ejection fraction and no valvular disease.     

Aneurysmectomy and endocardial resection for ventricular tachycardia: Favorable hemodynamic and antiarrhythmic results in patients with global left ventricular dysfunction

Sixty-two patients underwent aneurysmectomy and endocardial resection for control of recurrent sustained ventricular tachycardia (VT). Forty patients also had coronary artery bypass grafting (CABG) (1.5 grafts per patient). The mean preoperative left ventricular end-diastolic pressure (LVEDP) was 18 ± 8 mm Hg, cardiac index (Cl) was 2.7 ± 0.7 L/min/m², and ejection fraction (EF) was 28 ± 10%. In a subset of 32 patients with clearly demarcated aneurysmal and contracting ventricular sections, the mean EF of the residual contracting section (CSEF) was 35 ± 13%, and 26 of these patients had a CSEF < 45%. There were five operative deaths (8%). No hemodynamic findings distinguished the patients who died during surgery. Patients with an LVEDP above the group mean or an overall EF below the group mean had an operative mortality of 10% and 7%, respectively. In the subgroup of 26 patients with a CSEF < 45%, the operative mortality was 12%. In the surgical survivors as a whole the LVEDP decreased from 17 ± 8 to 14 ± 5 mm Hg (p < 0.005) and the overall EF increased from 28 ± 9% to 39 ± 10% (p < 0.001) while the normal CI did not change. Linear regression analysis revealed that patients with the highest preoperative LVEDPs and the lowest overall EFs were most likely to have improvement in these parameters postoperatively. Patients with a preoperative CSEF < 45% had similar postoperative changes in their LVEDP (17 ± 6 to 15 ± 4 mm Hg) and overall EF (24 ± 7% to 38 ± 11%). In addition, the incidence of inducible VT postoperatively was similar in patients with a preoperative CSEF < 45% (4 of 23) and in the rest of the group (8 of 34, p = NS). We conclude that: (1) patients with ventricular aneurysms and medically refractory VT often have marked dysfunction of the residual contracting LV section; (2) aneurysmectomy and endocardial resection is an effective mode of therapy for VT and can be performed with a low operative mortality in this patient population; and (3) postoperatively the angiographic EF usually increases and the LVEDP often decreases, especially in patients with the most marked preoperative LV dysfunction.     

Familial congenital valvular pulmonic stenosis

This is an account of the only known parent-child pair with classic isolated congenital valvular pulmonic stenosis. Both patients had phonocardiograms, electrocardiograms, vectorcardiograms, chest x-rays, cardiac catheterization, and angiocardiography. In addition, genetic information was sought from fingerprints, palm prints, hair and iris color, facial characteristics, colorblindness tests, blood typing and antigens, and degree of kinship existing in the family tree.     

Long-term results of endocardial resection for sustained ventricular tachycardia in coronary disease patients

Sixty patients with recurrent sustained ventricular tachycardia (VT) refractory to medical therapy underwent subendocardial resection. There were 52 men and 8 women, ranging in age from 39 to 74 years, all of whom had coronary disease. Each patient had had a prior infarction 1 week to 11 years prior to surgery and 52 had left ventricular aneurysms. The mean ejection fraction was 27%. All 60 patients underwent endocardial resection with or without aneurysmectomy guided by intraoperative and/or catheter endocardial mapping. Thirty-seven endocardial resections were from the interventricular septum, 14 from the interoposterior free wall, and 16 were from the enteroapical or anterolateral free wall. There were five (8%) surgical deaths. The 55 survivors underwent programmed stimulation in the control state 28 days following the operation. VT was not inducible in 42 patients (group A) and was inducible in 13 patients (group B). The group B patients underwent drug testing and were discharged on the antiarrhythmic agent that made the VT noninducible or more difficult to induce. There have been only four recurrences of sustained VT with a follow-up of 19 ± 11 months. There have also been nine late nonarrhythmic deaths. The actuarial survival curve predicted 62% survival at 40 months. We conclude that activation guided endocardial resection provides long-term effective therapy for drug-resistant ventricular tachycardia.     

Electrophysiologic effects of intravenous metoprolol

We evaluated the electrophysiologic effects of intravenous metoprolol, a selective beta-1-blocking agent, in 12 patients. Electrophysiologic parameters were measured during the control period, immediately following, and 4 to 6 hours after infusion of 0.15 mg/kg. Metoprolol serum concentration was serially measured in 6 of the 12 patients. Immediately after metoprolol infusion, the sinus cycle length increased by 20% from 738 +/- 166 msec to 885 +/- 181 msec (p less than 0.01), AH interval during sinus rhythm increased by 34% from 83 +/- 27 msec to 112 +/- 37 msec (p less than 0.01), and antegrade atrioventricular (AV) nodal Wenckebach cycle length increased by 20% from 360 +/- 188 msec to 432 +/- 199 msec (p less than 0.01). Sinus node recovery time and sinoatrial conduction time did not become abnormally prolonged in any patient. His-Purkinje conduction was unaltered. High atrial and ventricular refractory periods were modestly increased (less than 15 msec); the increase in refractoriness reached statistical significance when repeat measurements were made at 4 to 6 hours. No adverse effects were noted. Metoprolol serum concentration at the time of peak measured electrophysiologic effect was 54.6 +/- 15.2 ng/ml. We conclude that at this dose, intravenous metoprolol significantly prolongs sinus cycle length and AV nodal conduction, may modestly increase atrial and ventricular refractoriness, and appears to have electrophysiologic potency similar to propranolol. It is well tolerated following intravenous administration and may be of particular value in the acute treatment of supraventricular tachycardia when beta-receptor selectivity is desired.     

Relation between site of origin of ventricular tachycardia and relative left ventricular myocardial perfusion and wall motion

To assess the relation between the site of origin of ventricular tachycardia (VT) and relative myocardial perfusion and wall motion, 18 patients with a history of recurrent sustained VT underwent cardiac catheterization, invasive electrophysiologic study with endocardial mapping, and resting radionuclide ventriculography. In addition, 6 patients had exercise and redistribution thallium-201 scintigraphy, whereas the remaining 12 patients had resting thallium scans. The site of origin of VT (determined by catheter and intraoperative endocardial mapping) was correlated with relative myocardial perfusion (thallium) and left ventricular (LV) wall motion. All patients had significant (>50% narrowing) coronary artery disease and 16 had LV aneurysms.Twenty sites of origin of VT (28 morphologies) were identified in these 18 patients. Of the 9 patients with multiple VT morphologies, the VT originated at disparate sites in 2 patients. All 18 patients had thallium defects at rest and 3 patients had additional reversible (ischemic) defects on exercise. Of the 20 sites of origin of VT, 16 were at the periphery of the thallium defect, 1 was adjacent to it, and 3 were in the center of it. In the 16 patients with LV aneurysm, there were 18 sites of origin: 15 at the border of the aneurysm, 1 adjacent to it, and 2 within it.The data suggest that in patients with VT and coronary artery disease the site of origin is usually the periphery of a resting thallium defect, and in patients with LV aneurysm the site is the border of the aneurysm.     

Sequential changes in regional coronary flow during pacing-induced angina pectoris: Coronary flow limitation precedes angina

To investigate the sequence of changes in regional myocardial perfusion which precedes stress-induced angina, we measured great cardiac vein flow (GCVF), draining the anterior left ventricle, during incremental atrial pacing in 10 patients with normal anterior perfusion (group I) and in 11 patients with ≥ 50% diameter stenosis of the left main or proximal left anterior descending coronary artery (group II). Pacing produced angina in 11 of 11 and regional lactate production in 9 of 11 group II patients. Both groups had comparable resting GCVF (group I = 62 ± 7 ml/min vs group II = 76 ± 9 ml/min; p = NS) and both exhibited progressive increases in GCVF with pacing. However, the entire flow-demand relationship was displaced downward in group II, as evidenced by a reduction in the percent increase in GCVF both following the first 20-beat pacing increment (group I = 46 ± 6% vs group II = 16 ± 4%; p < 0.001) and at angina (group I = 113 ± 16% vs group II = 44 ± 9%; p < 0.001). The first 20-beat pacing increment increased the heart rate to only 77 ± 2 bpm in group II whereas angina and ECG changes did not occur until a pacing rate of 117 ± 6 bpm. These data indicate that regional flow abnormalities precede the onset of pacing-induced angina in patients with coronary disease (CAD) and that these flow abnormalities frequently are detectable at heart rates substantially below the anginal threshold.     

Two dimensional echographic imaging of the left ventricle: Comparison of mechanical and phased array systems in vitro

To determine the reliability of two dimensional echographic images of the left ventricle with different two dimensional echographic instruments, two dimensional echographic images of the left ventricle were compared in vitro using two phased array and two mechanical systems to image 22 short axis slices of three postmortem human hearts (one with infarction, one with left ventricular aneurysm, one with mitral regurgitation). Total left ventricular area and left ventricular cavity area were determined with planimetry and myocardial area was derived by subtraction. Comparison of total, myocardial and cavity areas with calibrated photographs of each slice showed excellent correlations for each echographic system (r = 0.93 to 0.97 for total area; 0.90 to 0.94 for cavity area; 0.89 to 0.95 for myocardial area). For total left ventricular area, the ratio of echographic to photographic image size was close to unity (0.95 to 1.08) for one mechanical and two phased array systems, but significantly lower for mechanical system 2 (0.71, p < 0.001). For myocardial area the echographic/photographic ratio was also close to unity (0.96 to 1.15) for two phased array systems and mechanical system 1 but significantly lower for mechanical system 2 (0.77, p < 0.005). In contrast, all systems underestimated left ventricular cavity area with lower, more variable echographic/photographic ratios (0.48 to 0.78), with mechanical system 2 again giving significantly lower values (p < 0.02) than the other systems. Underestimation of left ventricular cavity area appears to result from inaccurate endocardial display. We conclude that accurate left ventricular image quantitation is possible with either phased array or mechanical systems if each variable studied is calibrated against an independent reference standard and echographic results are corrected by the resultant regression equation.     

Antianginal effects of nitroglycerin patches

Nitroglycerin (NTG) patches provide potentially therapeutic NTG blood levels for 24 hours, but their effects on exercise tolerance (ExT) in patients with angina have not been well characterized. Therefore, blinded, randomized trials were performed of the acute effects of both low-dose and maximal-toler-ated-dose NTG patches and placebo on ExT in 14 patients with coronary artery disease and typical exertional angina. The bicycle exercise protocol of the National Institutes of Health was used and sublingual NTG administered as a positive control. In 7 subjects, low-dose patches produced no statistically significant effect on ExT at 4, 8 or 24 hours after administration. Comparable doses of sublingual and oral isosorbide dinitrate, NTG ointment and transmucosal NTG in previous studies have produced effects similar to those of conventional doses of sublingual NTG. Maximally tolerated doses of 2 types of NTG patches were then tested. The first (n = 8, mean NTG dose delivered 25 mg) produced increases in ExT of 82 and 72 seconds at 4 and 8 hours, respectively (both p<0.01), but was ineffective at 24 hours. The second patch type (n = 5, mean NTG dose delivered 22 mg) was also ineffective at 24 hours. Furthermore, even at maximal doses, peak effects on ExT were about half of those of sublingual NTG. Thus, NTG patches, even at maximal doses, appear to have smaller therapeutic effects than other long-acting nitrates and are ineffective at 24 hours. These results suggest rapid attenuation of NTG effect during prolonged maintenance of constant blood levels.     

The electrophysiologic demonstration of atrial ectopic tachycardia in man

Three patients with almost continuous atrial tachycardia were studied in an attempt to delineate the mechanism responsible for their cardiac arrhythmia. During cardiac catheterization intracardiac electrograms and specific atrial stimulation sequences revealed: (1) episodes of tachycardia were initiated by atrial premature depolarizations (APD's) which exhibited no increased delay in AV nodal conduction, (2) during tachycardia atrial cycle length was not a direct function of AV nodal conduction, (3) initial cycles of tachycardia showed progressive shortening in cycle length, (4) APD's introduced during tachycardia resulted in resetting of the atrial cycle, and (5) single APD's and atrial overdrive during tachycardia failed to interrupt it. The electrophysiologic behavior of the arrhythmia was consistent with the hypothesis that it was initiated and was sustained by an ectopic rapidly firing automatic atrial pacemaker.     

Isolated dextroversion of the heart with asymmetric septal hypertrophy.

Dextroversion of the heart is an uncommon congenital anomaly characterized by situs solitus (normal position) of thoracic and abdominal viscera with right cardiac apex. Isolated dextroversion, i.e., without associated congenital heart disease, is rare, but its occurrence permits adult survival, setting the stage for late development of acquired heart disease. The patient herein reported was known since childhood to have a right thoracic heart that represented isolated uncomplicated dextroversion. He presented in the sixth decade with a new murmur that proved to be due to asymmetric septal hypertrophy (ASH) with obstruction. This combination of anomalies is possible only if dextroversion exists without ventricular inversion, since aortic-anterior mitral leaflet continuity is obligatory for obstructive ASH. This paper presented clinical, phonocardiographic, vectorcardiographic, echocardiographic, hemodynamic, angiocardiographic, and intracardiac electrophysiologic information on the unique combination of isolated dextroversion of the heart with obstructive asymmetric septal hypertrophy.     

The value of thallium exercise testing in patients with coronary artery disease

Exercise thallium scanning can be employed in many clinical situations; it is important that the physician formulate the question he wishes to have answered and assess the utility of the procedure to answer the question.For the noninvasive detection of coronary artery disease, exercise thallium scanning is most helpful in patients with uninterpretable stress electrocardiograms (due to baseline ST-T wave abnormalities) or those with nondiagnostic stress electrocardiograms (i.e., negative at less than 85% predicted heart rate). It is also useful in patients strongly suspected of having “false positive” exercise electrocardiograms. In all of these situation, exercise thallium scanning is more appropriate in a patient with an intermediate probability of coronary artery disease (e.g., atypical chest pain).In the evaluation of patients who are known to have coronary artery disease, exercise thallium scanning is most helpful in evaluating the physiologic significance of a known coronary stenosis, detecting multivessel coronary artery disease and/or residual viable myocardium in patients with prior myocardial infarction, and in evaluating the effects of surgical or other therapies.When properly utilized, this expensive procedure will prove to be cost-effective in managing many different subgroups of patients with coronary artery disease.     

Spontaneous gap phenomenon in atrioventricular conduction produced by His bundle extrasystoles.

A gap in atrioventricular conduction is a zone within the cardiac cycle during which premature impulses are blocked in the conduction system, while impulses of greater or lesser prematurity are conducted. This has previously been produced only by atrial or ventricular stimulation techniques. This report demonstrates a spontaneous gap produced by His extrasystoles.     

Heparin therapy: A randomized prospective study

Eighty patients were assigned randomly either to continuous or to intermittent heparin therapy, with control by the Lee-White Clotting Time (LWCT). Major bleeding complications occurred in 7.5 per cent and minor complications in 18 per cent of the entire group. The incidence of major bleeding complications in the continuous group (5 per cent) did not differ significantly from the incidence in the intermittent group (10 per cent). In contrast, bleeding complications were significantly more frequent in patients with soft-tissue trauma due to such procedures as thoracenteses and cut-downs, vascular damage due to other causes, and LWCTs over 35 minutes for 2 consecutive days.The incidence of bleeding complications appear to be the same in patients receiving intermittent as in those receiving continuous heparin therapy. Thoracenteses, cut-downs, and other forms of soft-tissue injury predispose to bleeding complications while laboratory monitoring with the LWCT may help to reduce bleeding complications.     

Acute effects of bovine growth hormone on renal calcium and phosphate excretion

To evaluate the acute effects of bovine growth hormone upon renal hemodynamics and urinary electrolyte excretion, clearance studies were performed in intact and thyroparathyroidectomized dogs, receiving either vehicle alone or bovine growth hormone. Growth hormone had no effect when compared to controls upon glomerular filtration rate, renal plasma flow, or clearance of sodium, calcium, and phosphate either in the presence or absence of parathyroid hormone. It is concluded that acute changes in circulating growth hormone levels do not play an important role in calcium and phosphate homeostasis. The data suggest that previously described antiphosphaturic and hypercalciuric actions of growth hormone are not due to direct acute renal tubular effects but may be the result of indirect effects of chronic growth hormone administration.     

Superficial accessory pathway in the Wolff-Parkinson-white syndrome—Electrophysiological, surgical and histologic demonstration

A superficial accessory pathway was demonstrated by electrophysiologic techniques and surgical histopathology in a 30-year-old male with Wolff-Parkinson-White syndrome, severe mitral valve disease and medically uncontrollable arrhythmias. In this patient, electrode catheter studies in the cardiac catheterization laboratory revealed antegrade and retrograde function of an accessory pathway between the anterior right atrium and the right ventricle. During surgery, electrophysiologic mapping confirmed the anterior location of this pathway. Blunt dissection in the fat pad of the A-V groove between the right atrium and ventricle revealed the accessory pathway which consisted of tissue strands superficial to the A-V ring. These were removed and on histological examination were composed of ordinary myocardial cells. Concomitant recarried out. Postoperatively, there was complete regression of the preexcitation and arrhythmias.