Influence of pacemaker-induced tachycardia with A-V block on left ventricular blood velocity in man.

Phasic instantaneous left ventricular blood velocity was measured by radiotelemetry in 28 subjects with a Doppler ultrasonic flowmeter catheter during atrial pacing and induced A-V block Type I Wenckebach A-V block with conduction ratios of 9:8 or lower generally produced a stepwise reduction of peak left ventricular blood velocity in relation to shortened R-R intervals. Longer Wenckebach periods resulted in little or no blood velocity alteration during 1:1 A-V conduction. Those beats following a blocked atrial depolarization were associated with augmented blood velocities. In three subjects, bigeminal periods of 3:2 A-V block resulted in larger left ventricular blood velocities when compared with 2:1 A-V block, despite identical R-R intervals following the blocked P wave. This latter phenomenon was attributed to diastolic augmentation of left ventricular contraction following the second and hemodynamically ineffective beat during 3:2 A-V block. Three patients manifested true blood velocity alternation during second-degree A-V block and changing R-R intervals. The variations in peak left ventricular blood velocity observed during atrial pacing and A-V block are related to changing inotropic state and cycle length dependent alterations of left ventricular diastolic filling.     

Postoperative recurrence of angina pectoris after aortocoronary venous graft bypass

Fifty-six patients with angina pectoris under-went aortocoronary bypass graft implantation. All subjects had an initial angina-free postoperative period. Twelve patients so operated upon had a return of angina pectoris; their clinical and catheterization findings did not differ in any respect when compared with those in the pain-free group. Eight subjects with occlusion of all aortocoronary grafts denied postoperative angina pectoris. It is concluded that caution should be exercised in attributing the relief of angina pectoris to aortocoronary bypass graft patency.     

Doppler measurement of phasic continuous left ventricular blood flow velocity during ventricular arrhythmias

Phasic instantaneous left ventricular blood velocity was continuously measured by means of the Doppler ultrasonic flowmeter catheter radiotelemetry system in 68 patients with ventricular arrhythmias. Ventricular premature depolarizations reduced peak left ventricular blood velocities in relation to their respective coupling intervals, with R-R intervals less than 0.5 second producing the greatest decline. Ventricular tachycardia in 18 subjects produced a 62 per cent mean decrease in left ventricular blood velocity. In a single subject, performance of the Valsalva maneuver effected ventricular tachycardia and a concomitant marked diminution of phasic left ventricular blood velocity. These findings demonstrate the untoward influence of ventricular extrasystoles and tachycardia on left ventricular blood velocity and provide the underlying basis for reductions of blood velocity previously demonstrated in the regional circulations of man during similar arrhythmias.     

Assessment of aortocoronary saphenous vein bypass function utilizing selective indicator dilution curves

Aortocoronary saphenous graft function was evaluated in 21 postoperative patients with the selective indocyanine green indicator dilution method. Selective indicator injections were made into the aortic root, diseased coronary artery, and saphenous bypass graft with constant sampling at the main pulmonary artery. There were no major electrocardiographic alterations associated with dye injection. Graft, aortic, and coronary dilution curves obtained from such testing were analyzed with respect to corrected appearance time (AT), build-up time (BT), peak amplitude (PA), peak amplitude build-up time ratio ($\text{PA}\text{BT}$), clearance time (CT), and spread ratio (SR). When compared with aortic root indicator dilution curves, characteristic findings were: (1) patent grafts: shorter AT (P<0.001), higher PA (P<0.001), greater $\text{PA}\text{BT}$ (P<0.001), shorter CT (P<0.05), and greater SR (P<0.01), (2) occluded graft: no significant difference in any measurement. There were significant differences in BT (P<0.01), PA (P<0.01), $\text{PA}\text{BT}$ (P<0.001), and CT (P<0.05) when curves from injection of grafts with good and poor angiographic clearance were compared. Where graft flow appeared more satisfactory than bypassed coronary arterial flow there were significant differences between the majority of these measurements.It is concluded that the selective indicator dilution technique is safe and useful for the evaluation of aortocoronary graft function.     

Atrial pacing during selective aortocoronary saphenous vein bypass angiography

Selective aortocoronary bypass graft angiography was performed in 30 postoperative subjects. Thirty-one of 39 patent graft injections resulted in cardiac arrhythmias including sinus bradycardia, premature ventricular depolarizations, sinoatrial arrest and atrioventricular (A-V) block. In contrast, only 2 of 39 graft angiograms performed during right atrial pacing produced arrhythmias. We conclude the following: (1) Routine prophylactic right atrial pacing is a valuable method for preventing certain cardiac arrhythmias during aortocoronary graft opacification; and (2) the potential for rapid institution of right ventricular pacing provides safety in the event that angiographically induced A-V block occurs.     

Non-invasive assessment of left internal mammary-coronary bypass patency using the external Doppler probe.

Non-directional blood velocity of left internal mammary bypass grafts was non-invasively studied with the Doppler ultrasonic probe. Thirteen of 14 subjects had angiographic evidence of bypass graft patency and their Doppler signals demonstrated high amplitude phasic blood velocities. A single patient with proximal left internal mammary arterial graft occlusion manifested marked attenuation of Doppler blood velocity signals. It is concluded that this technic offers a potential for ambulatory and in-office screening of internal mammary artery bypass graft function.     

Non-paroxysmal A-V junctional tachycardia associated with acute myocardial infarction

The hospital records of 48 subjects with acute myocardial infarction complicated by non-paroxysmal A-V junctional tachycardia (NPJT) were reviewed. Fifteen of 48 subjects (31 per cent) so affected died. NPJT was most commonly associated with inferior wall infarction ($\text{24}\text{48}$, 50 per cent). Although ten of 16 (63 per cent) patients with acute anterior wall infarction and NPJT died, 23 of 24 patients with acute inferior wall myocardial infarction survived. Mean heart rates during NPJT were significantly greater in subjects with anterior wall infarction (113.4 ± 35.3 vs. inferior wall 85.4 ± 28.1, P < 0.01). Peak SGOT levels were significantly higher in those patients who died (488 ± 579 vs. survivors 152 ± 114, P < 0.01). NPJT altered the clinical status of only six subjects. It is concluded that NPJT indicates a poor prognosis in subjects with acute anterior wall infarction but is generally associated with a benign clinical course in patients with inferior infarction. These differences may be based on a greater extent of myocardial damage in the former group.     

The echocardiographic correlates of left ventricular hypertrophy diagnosed by electrocardiography.

Echocardiography was performed in 28 consecutive patients who manifested accepted criteria for left ventricular hypertrophy on their electrocardiograms. Four groups of patients were identified: Group 1, nineteen (68%) who had an increase in both interventricular septal and left ventricular posterior wall thickness; Group 2, three patients (11%) with isolated enlargement of the left ventricular internal dimension; Group 3, two subjects (7%) with increased septal thickness, left ventricular posterior wall thickness and left ventricular internal dimension and Group 4, four patients (14%) with normal echocardiographic measurements. It is concluded that increases in both septal and left ventricular wall thickness are the primary echocardiographic correlates of left ventricular hypertrophy as diagnosed on the electrocardiogram.     

Assessment of echocardiographic left atrial enlargement in patients with atrial fibrillation. An electrovectorcardiographic study.

Standard 12 lead electrocardiograms (ECG) and timed Frank vectorcardiograms (VCG) were recorded in 53 subjects with atrial fibrillation. Thirty-eight patients had echocardiographically documented left atrial enlargement (greater than 4.0 cm) and 15 patients had normal atrial dimensions. The magnitude of the largest "f" wave component during an average cycle length was measured in lead V1 of the ECG and the horizontal plane VCG running loop. Relative sensitivies for detection of left atrial enlargement were: VCG, 25/38 (66%) and ECG 10/38 (26%). An enlarged left atrial internal dimension was diagnosed by the VCG alone in 21 of the 38 subjects (55%). In the group of 15 patients with normal echocardiographic left atrial internal dimensions the prevalence of ECG false positive diagnosis for enlarged left atrial size was 6% in contrast with 0% for the VCG. It is concluded that: 1) the timed Frank VCG is superior to the ECG for the detection of echocardiographically demonstrable left atrial enlargement; 2) the timed VCG and ECG represent complementary techniques for identifying patients with abnormally large left atria; and 3) large fibrillatory waves are rarely observed on the ECG or VCG when the left atrial internal dimension is echographically normal.     

Comparison of the electrocardiogram and vectorcardiogram for the diagnosis of left atrial enlargement.

Standard 12 lead electrocardiograms (ECG) and Frank vectorcardiograms (VCG) were recorded in 21 consecutive patients with mitral valvular disease and angiographically documented left atrial enlargement. Comparative sensitivities for the detection of left atrial enlargement were: diagnostic, ECG = 6/21 (29%), VCG = 14/21 (67%); suggestive, ECG = 3/21 (14%), VCG = 2/21 (9%); non-diagnostic, ECG = 12/21 (57%), VCG = 5/21 (24%). It is concluded that the Frank atrial vectorcardiogram is superior to the standard electrocardiogram for the diagnosis of left atrial enlargement.     

Echocardiographic left atrial enlargement. Comparison of vectorcardiogram and electrocardiogram for detection

Standard electrocardiograms (ECG) and Frank vectorcardiograms (VCG) were obtained in 43 consecutive patients in sinus rhythm who had echocardiographic evidence of left atrial enlargement (left atrial internal dimension greater than 4.0 cm; x +/- 1SD = 4.7 +/- 0.5 cm). High gain VCG P loop measurements for the study group were: maximal posterior magnitude, 0.11 +/- 0.03 mv; duration, 106 +/- 14 msec and ratio of maximal posterior to maximal anterior P vector magnitudes, 3.2 +/- 1.4. Thirty of 43 (70%) patients with echocardiographic determined left atrial enlargement had VCGs diagnostic of that condition. Utilizing New York Heart Association criteria for left atrial enlargement, 17 of 43 patients (40%) had ECGs which were diagnostic. Fifteen of 43 (35%) subjects manifested both ECG and VCG criteria for left atrial enlargement and only two patients had diagnostic ECGs and normal VCGs. It is concluded that analysis of high gain VCG P loops provides a 30% higher yield for the diagnosis of echocardiographically determined left atrial enlargement when compared with P wave examination on the standard ECG.     

Bacteroides pericardial effusion and cardiac tamponade in a patient with chronic renal failure

A 31-year-old woman with chronic renal insufficiency and recurrent pericarditis developed and enlarging cardiac silhouette and physical signs of cardiac tamponade. Cardiac catheterization demonstrated pericardial effusion with hemodynamic evidence of cardiac compression. At pericardial exploration, 1.5 L. of foul-smelling purulent material was removed from a distended pericardial sac. Cultures of both the exudate and pericardium revealed pure growth of Bacteroides fragiles. The patient was subsequently treated with intravenous chloramphenicol and has had an uncomplicated clinical course since that time.This represents the first reported case of cardiac tamponade secondary to culturally proved Bacteroides pericarditis in the setting of chronic renal insufficiency.     

Vectorcardiographic study of initial QRS forces in left bundle branch block associated with myocardial infarction, primary myocardial disease and valvular heart disease

Distribution of the initial 10–30 msec QRS forces was determined on the Frank vectorcardiograms (VCGs) of 31 patients with complete left bundle branch block (LBBB). Of nine patients with coronary artery disease, three had all 10–30 msec vectors directed posteriorly in the horizontal plane (HP) and associated inferior or apical left ventricular asynergy. Frontal plane initial 30 msec QRS forces were oriented superiorly in two of these three subjects. In five patients with isolated anterior wall myocardial infarction, the HP 10 msec QRS vectors were anterior, followed by posteriorly directed 20–30 msec QRS vectors. Twelve patients with primary cardiomyopathy had initial QRS vectors distributed as follows: 10–30 msec posterior and left in two; 10–20 msec anterior and left in five; 10 msec anterior and left with the 20–30 msec posterior and left in four. In one patient the 10 msec was posterior and right, and 20–30 msec posterior and left. Of 10 patients with valvular heart disease three manifested posterior 10–30 msec QRS vectors. In four the 10 msec vector was anterior and left and 20–30 msec posterior and left. The 10–20 msec were anterior and left and 30 msec posterior and left in two subjects. There was no correlation between posteriorly directed initial QRS forces and left ventricular hypertrophy in the latter group. We conclude that: 1) posterior orientation of the initial 10 msec QRS vectors in the presence of LBBB is not specific for myocardial infarction; 2) when present in patients with obstructive coronary artery disease such abnormal posterior forces correlate with anterior and probable co-existing infero-apical infarction and, 3) factors aside from left ventricular hypertrophy can produce abnormally directed initial 10–30 msec QRS vectors in subjects with valvular heart disease.     

Left ventricular blood flow velocity in man studied with the Doppler ultrasonic flowmeter

Left ventricular blood flow velocity was recorded in 32 conscious human subjects with the Doppler ultrasonic flowmeter catheter. There are three major left ventricular flow velocity patterns in man: (1) Inflow tract blood velocity is characterized by a predominant diastolic wave related to left ventricular filling succeeded by a smaller systolic component, (2) Midcavity blood flow velocity is triphasic in nature, and (3) Outflow tract blood velocity is manifested by a major systolic wave, resulting from left ventricular ejection.These flow velocity wave-forms parallel the major hemodynamic events occurring at each anatomic site.It is concluded that such study is of value for characterizing blood velocity in the left ventricle of conscious man.