Assessment of the optimal atrioventricular delay in dual chamber-paced patients by a portable scintillation probe (VEST).

BACKGROUND: The optimal atrioventricular delay in dual-chamber pacing differs from patient to patient. The availability of a portable scintillation probe (VEST) enables noninvasive monitoring of left ventricular function. METHODS AND RESULTS: Hemodynamic variations were measured in 10 patients with programmable DDD pacemakers. The ejection fraction, stroke volume, and diastolic and systolic volume were evaluated, programming six different atrioventricular delays ranging from 75 to 200 msec, to determine the most favorable atrioventricular delay. Comparing left ventricular ejection fraction (LVEF), stroke volume, and end-diastolic and end-systolic volume at each DVI mode with a preceding DVI setting of 75 msec, all parameters at 200 msec were statistically different from those at 100 msec. An increase of LVEF and stroke volume and a decrease of end-systolic volume was found. In only five patients a switch of VVI mode to the optimal DVI mode results in an increase of LVEF of more than 5%. CONCLUSIONS: Our study stresses the importance of optimizing atrioventricular delay. The VEST system permits these measurements, increasing the accuracy of the determination of optimal atrioventricular delay, and appears to be valuable in the management of patients with cardiac dual-chamber pacemakers.

Right atrial tumor arising on an atrial septal aneurysm. Assessment by MR imaging.

An elderly women presenting with transient ischemic events underwent transesophageal echocardiography, which detected an aneurysm of the interatrial septum. A tumor protruding from the right atrial aspect of the aneurysm also was found incidentally. Not only was magnetic resonance (MRI) imaging helpful in better characterizing the aneurysm, but also the use of gadolinium diethylaminetriamine pentaacetic acid permitted differentiation between the tumor and adherent thrombus. To the best of our knowledge, this represents the first report of a tumor arising from an atrial septal aneurysm.

In vivo comparison between two tip pressure transducer systems.

Experimental findings are presented of an in vivo comparison between a Sentron catheter and another tip transducer manometer: a Millar microtip catheter. Both catheters have been used simultaneously in the left ventricle of dogs. Pressure variations were elicited by drug infusion. Pressure values and derivatives obtained from both systems were compared. A cross correlation between episodes of the two pressures was computed. Results from this study showed good correlation between left ventricular systolic pressure measured with both manometers (R = 0.992, p < 0.0001), end-diastolic pressure (R = 0.809, p < 0.0001) and between first derivatives: positive derivative (R = 0.993, p < 0.0001) and negative (R = 0.634, p < 0.0001). The mean cross correlation between both pressure signals was 0.61 +/- 0.04. In the frequency domain no statistical difference was found between the location of the maxima of the peaks. It is concluded that a Sentron manometer can be a valid alternative, at a reasonable price, to a cheaper, though less accurate fluid filled catheter and a more expensive 'golden standard' microtip catheter.

The use of intracoronary ultrasound for quantitative assessment of coronary artery lumen diameter and for on-line evaluation of angioplasty results.

UNLABELLED: The value of intracoronary ultrasound for quantitative assessment of minimal coronary arterial diameter and for on-line evaluation of balloon angioplasty result was studied in 42 patients undergoing single vessel coronary angioplasty. Measurement of minimal luminal diameter of 75 matched coronary arterial segments showed a significant correlation between both the ultrasound and angiographic method (r: 0.759; p < 0.001). Furthermore using intravascular ultrasound it was possible to classify the obtained coronary balloon angioplasty results. A preliminary correlation between ultrasound classification and the in-hospital acute rethrombosis as well as late restenosis was attempted in individual patients. CONCLUSIONS: 1) Clinical use of coronary ultrasound is feasible and safe in selected cases. 2) A significant correlation between intracoronary ultrasound and quantitative coronary angiography is demonstrated. 3) Using intracoronary ultrasound seems promising for evaluation of the postangioplasty result, and may finally lead to improved selection of the interventional strategy.

Angiographic assessment of the infarct-related residual coronary stenosis after spontaneous or therapeutic thrombolysis.

The severity of the infarct-related residual coronary stenosis after spontaneous or therapeutic thrombolysis was quantitatively assessed in 91 patients with an acute myocardial infarction who were allocated to treatment in the acute stage with either a thrombolytic agent (100 mg of recombinant tissue-type plasminogen activator given over 3 h, 49 patients) or a placebo (42 patients). Heparin and aspirin were given to both groups until angiography was performed. Digital subtracted images of the infarct-related coronary vessel were obtained 10 to 14 days after hospital admission and were subsequently analyzed with the use of a computer-assisted coronary stenosis measurement system. Neither treatment group differed significantly in age, gender or location of the culprit coronary lesion. Median values (90% range) in the thrombolysis and control groups were, respectively, 1.95 (0.9 to 5.3) mm versus 1.7 (0.9 to 3.4) mm for stenosis length; 1.4 (0.8 to 2.7) mm versus 1.4 (0.9 to 1.8) mm for minimal luminal diameter; 57% (36% to 75%) versus 58% (44% to 71%) for diameter obstruction; 82% (59% to 95%) versus 82% (68% to 92%) for geometric area obstruction; and 78% (58% to 91%) versus 79% (66% to 90%) for densitometric area obstruction. The difference between the two groups was not statistically significant for any of these measurements. Thus, in this study no significant differences in anatomy or severity of residual coronary stenosis could be demonstrated at 10 to 14 days after an acute myocardial infarction in patients with a recanalized infarct-related vessel, whether or not thrombolytic therapy was given on admission. These results indicate that with effective antithrombotic treatment, gradual endogenous fibrinolysis or more rapid lysis induced by the infusion of a thrombolytic agent results in a similar infarct-related coronary lesion at the time of hospital discharge.

Comparison of angiographic methods for the assessment of the extent of experimental anterior myocardial infarction in dog hearts.

Infarction was provoked in the dog by introducing a copper coil into the left anterior descending coronary artery. Eight groups, each of 6 dogs, were studied which received various treatments and were evaluated after 24 hours or 1 week. The anatomical extent of infarction was measured by the triphenyltetrazoliumhydrochloride method; size was evaluated angiographically by the centerline, chord and radial method and by ejection fraction. The extent of infarction was similar in groups studied after 24 hours and 1 week. Angiographical changes were most marked after 24 hours, and the ejection fraction was related to the extent of infarction (r = -0.5; P less than 0.02). Some parameters of the radial and centerline method showed also a relation to the extent of infarction (r = 0.47 to 0.57; P less than 0.05). After one week, the ejection fraction was no longer correlated to the extent of infarction. The correlation between the parameters of the chord, radius and centerline method and the extent of infarction improved to r-values of 0.58 to 0.63 (P less than or equal to 0.01). There was no difference between the 3 methods.

Multivariate survival analysis for the assessment of prognostic factors and risk categories after recovery from acute myocardial infarction: the Belgian situation.

Twenty-one and a half per cent of the patients with acute myocardial infarction, admitted consecutively to the coronary care unit of the University Hospitals of Leuven in the period 1973-1979, died within 28 days. The 1,669 who recovered were followed between three and nine years. The mortality rate was 13.1% during the first year and fell to below 5% in the succeeding yearly intervals. Univariate and life table analysis were performed on noninvasive, clinical data collected during the coronary care unit stay for the total population and various subgroups. The Cox proportional hazards model was applied to the data in order to determine the prognostic factors for long-term survival. Of the 34 initially selected variables, the most dominant factors were age, Killip class III and IV, peripheral vascular disease, abnormal chest x-ray findings, previous infarction, and the use of digitalis or diuretics. The model, which was validated extensively, allowed the establishment of risk categories. Mortality five years after the acute event was 8.2 times more frequent in the highest risk quintile than in the lowest one. From this study one may conclude that multivariate techniques based on noninvasive variables collected during the coronary care unit stay are valuable for the determination of the long-term prognosis of patients with myocardial infarction.

Normalized first derivative ofthe left apex cardiogram in assessment of left ventricular function.

The relation between the left displacement apex cardiogram and the left ventricular pressure during isovolumic contraction was studied in 30 patients with cardiac disease. Using the instantaneous relation between the first time derivative and the magnitude of both the left apex cardiogram and the left ventricular pressure, normalized derivatives were obtained. These noramized velocities were correlated with each other and with several indexes of left ventricular function. The normalized derivatives of the left apex cardiogram (dD/dt/D) and the left ventricular pressure (dP/dt/P) were similar in magnitude, standard deviation and variation coefficient. No such similarity was present when the first time derivatives of each tracing (dD/dt and dP/dt) were compared. A highly significant relation was found between normalized displacement velocity and normalized pressure velocity using both total (r = 0.76, P less than 0.001) and developed (r = 0.75, P less than 0.001) displacement and pressure. Significant correlations with several other indexes of left ventricular function (end-diastolic pressure, peak dP/dt, maximal velocity of the contractile elements at zero load[Vmax]) were also observed. It is concluded that the index dD/dt/D of the left apex cardiogram is an important noninvasive tool for assessing left ventricular function in man.