Pacing from the right ventricular apex may induce adverse hemodynamic effects related to the changes of the spontaneous ventricular activation. In order to determine the effect of long-term ventricular apex pacing on myocardial perfusion and myocardial function, 28 patients implanted with DDD or DDDR pacing with ventricular lead positioned at the apex were included in this study. These patients divided in group 1 with normal myocardial Thallium perfusion (16 patients with mean age 66.3 +/- 5.5) and group 2 with myocardial Thallium defect (12 patients with mean age 64.1 +/- 11.6) underwent exercise Thallium tomography, Doppler-echocardiography and radionuclide ventriculography. All patients had normal coronary angiography. No significant differences between 2 groups were found about age, angina, dyspnea, ventricular threshold, duration of pacing and exercise parameters. The topography of myocardial defects was infero-apical (75%) or apical (50%). These myocardial perfusion defects may lead to septal motion abnormalities (10 patients in group 2 vs 5patients in group 1, with significant difference, p<0.01) and alteration of global left ventricular function (53.1% +/- 5.6 in group 2 vs 63.7% +/- 3.7 in group 1, p<0.005). Myocardial ischemia should be perhaps an explanation of adverse hemodynamic effect of right ventricular apex pacing.

In order to evaluate the frequency of atrial arrhythmias in patients implanted with Ela Medical DDD pacemakers, 76 patients with mean age 68.6 years +/- 10.3 were examined every 6 months with study of statistics event counters and even histograms. The incidence of atrial arrythmias is frequent in patients with AV black (37.2 %) and sick sinus syndrome (45.5 %). The model of atrial lend and the left atrial size are nor a risk factor to induce atrial arrythmias, but atrial pacing prevents atrial arrhythmias. The presence of left ventricular dysfunction is an important factor for the occurrence of atrial arrythmias in the group of AV block.

The influence of ventricular pacing site has not been studied for a long period in patients with dilated cardiomyopathy. 8 patients with mean age 73,8 years +/- 7,4 with severe heart failure unresponsive to optimal medical therapy were implanted with a DDD pacemaker with 2 ventricular leads (in the right ventricular apex and right Ventricular outflow tract) connected in series to the ventricular channel. At medium term follow-up, cardiac output was increased with RVOT pacing versus simultaneous bifocal pacing, and mechanical activation sequence was improved in patients with dilated cardiomyopathy.

In order to evaluate tile influence of the ventricular pacing site on 12 lend electrocardiogram and acute hemodynamic parameters in patients with left ventricular ejection fraction (LVEF) < 30 %. 13 patients with mean age 68,7 years +/- 9,3, mean PR interval = 235 ms +/- 51, mean QRS complex duration = 122 ms +/- 28 and LVEF = 22,3 % +/- 7,3 were included in this study.In all patients, 3 temporary USCI leads were positioned at the right appendage atrium, at the right ventricular outflow tract (RVOT) and at the right ventricular apex (RVAP). QRS complex duration and hemodynamic parameters (PAP, PCWP and cardiac index) were measured during sinus rhythm, RVAP pacing, RVOT pacing and bifocal simultaneous pacing. RVOT pacing and bifocal RVOT + RVAP pacing decreased statistically significantly the duration of QRS complex (135 ms +/- 15, p < 0,0005, 137 ms +/- 18 p < 0,001 respectively) compared to RVAP pacing (151 ms +/- 20). Mean PAP and PCWP remained unchanged with any modes of pacing, but cardiac output increased significantly during RVOT pacing (5,22 l/mn +/- 1,07) and simultaneous pacing (5,23 l/mn +/- 1,04) versus RVAP pacing (4,66 l/mn +/- 0,92, p < 0,005) and sinus rhythm (4,63 l/mn +/- I, p < 0,002). During RVOT pacing, the decrease of V wave was more important (25,6 mmHg +/- 7,5) than with RVAP pacing (28,7 mmHg +/- 8,8) versus in sinus rhythm (31,5 mmHg +/- 8,4). In presence of L.V. dysfunction, this study suggests to implant a RVOT screw-in lead rather than a traditional lead positioned at the apex.

The prevalence of infection of permanent pacing material ranges from 0.13 to 19.9% of patients according to published series. The seriousness of this condition requires early diagnosis and treatment. Transesophageal echocardiography visualised vegetations on the intracardiac pacing lead in all of 11 patients studied, whereas transthoracic echocardiography and polynuclear leucocyte scintigraphy only provided positive diagnoses in 4 cases for each investigation. Three types of vegetation were visualised; no cases of tricuspid valve endocarditis were observed. Treatment was based on explantation of all implanted material by endovascular traction in 7 cases and by surgery in the other 4 cases according to the results of transesophageal echocardiography. There were no deaths or recurrence of infection. Transesophageal echocardiography is the investigation of choice for imaging a vegetation on an endocavitary pacing lead. Complete explanation is essential for a complete recovery of this infection.

Complete spontaneous rupture of a percutaneous caval filter produced two equal parts. Long-term follow-up showed that the filter then remained stable with no complications. This case emphasizes the importance of long-term follow-up of patients with caval filters

The possibility of an intraventricular pressure gradient in patients with aortic stenosis is well known: this entity is associated with a high risk of postoperative complications. The authors carried out a Doppler echocardiographic study of flow in the left ventricle in 51 patients who had recently undergone valve replacement for severe aortic stenosis (valve area < 0.75 cm2). Before surgery, only one patient had significant acceleration of intraventricular systolic flow attaining 3.8 m/s (maximum pressure gradient of 60 mmHg). After surgery, maximum intraventricular systolic velocities of over 2.5 m/s with a typical end systolic peak were observed in 8 patients under basal conditions (gradients of 30 to 115 mmHg), and in 7 others after inhalation of amyl nitrite. Pulsed spectral and color Doppler flow mapping showed that the highest velocities were located at the mitral papillary muscle level. In addition, these patients had significant reduction in cavity size. Only one patient had systolic anterior motion of the anterior mitral leaflet with septal contact. Left ventricular dimensions were measured by TM echocardiography. High intraventricular velocities seemed to be significantly related to the smallest ventricular dimensions, the thickest ventricular walls and the smallest preoperative aortic valve surface area. The highest intraventricular pressure gradients-disappeared with betablocker therapy (4 cases), after correction of hypovolemia (1 case), after drainage of large pericardial effusions (2 cases) or spontaneously (1 case). This study confirms the relatively high prevalence of dynamic intraventricular gradients after surgical cure of aortic stenosis and the value of Doppler echocardiography for the avoidance of certain drugs (inotropic agents, vasodilators, diuretics), which could aggravate the hemodynamic abnormality. From the physiopathological point of view, the intraventricular pressure gradient seems to be different from that of hypertrophic obstructive cardiomyopathy in that systolic anterior motion of the mitral valve is rare, the causal mechanism being obliteration of the cavity or medioventricular obstruction.

OBJECTIVE:The aim of this prospective study was to assess the advantages and limitations of various imaging techniques in identifying problems associated with percutaneous placement of filters in the inferior vena cava.SUBJECTS AND METHODS:One hundred four vena caval filters (65 Filcard, 39 Cardial) were placed in 100 patients (four patients received two filters). Venacavograms, duplex sonograms of the abdomen, abdominal radiographs, perfusion scans of the lung, and impedance plethysmograms were obtained in all patients within 1-2 days and 3 months after filter placement. CT scans of the filter were obtained in 55 patients.RESULTS:In five patients, thrombosis of the inferior vena cava, with retraction of the filter struts in four patients, was noted on venacavograms, CT scans, duplex sonograms, and impedance plethysmograms. Perforation of the inferior vena cava was noted in 36 patients after comparison of findings on venacavograms and CT scans, with an increase in the filter span in 29 patients (apparent on duplex sonograms in only two patients). Four filter tiltings (> 30 degrees) and 25 migrations (> 5 mm) were noted on abdominal radiographs. Trapped thrombi in the filter were shown on venacavograms in nine cases, but on duplex sonograms and unenhanced CT scans in only two cases.CONCLUSION:Our study shows that the major complications of inferior vena caval filters can be detected by noninvasive examinations. Only venacavograms consistently show small trapped thrombi that do not extend above the filter, but the importance of such thrombi is unknown.

The authors report 22 cases of myocardial infarction documented by selective left ventriculography and coronary angiography in women under 45 years of age. The average age in this series was 36 +/- 6.8 years. Two patient groups were identified: Group I (n = 16) with the cardiovascular risk factor of oral contraception (mean age 33.9 +/- 5 years); and Group II (n = 6) comprising older patients (43.8 +/- 1.8 years) with a high prevalence of other risk factors (hyperlipidaemia, hypertension, diabetes). Myocardial infarction tended to be the inaugural event in Group I (9 out of 16 cases, 56.2 %) whereas symptoms of effort angina were commonly observed in Group II (5 out of 6 cases, 83.3 %). Coronary angiography showed more severe coronary lesions in Group II (score 1.5) than in Group I (score 0.75) in which isolated, single vessel disease mainly affecting the left anterior descending artery or normal coronary angiography was observed. Thrombolytic therapy was performed in 8 patients: percutaneous transluminal angioplasty was performed in 4 patients in the first month with a primary success in 3 cases. Coronary bypass surgery was performed in 1 case. The outcome during follow-up lasting 44.5 +/- 4.2 months was mainly favourable as 15 of the 20 patients had no secondary complications. Nevertheless, 2 patients died in the hospital period (1 from cardiogenic shock and 1 from complications of transluminal coronary angioplasty), 2 patients died less than 1 year after acute myocardial infarction (1 sudden death, 1 cardiogenic shock). Although oral contraception was withdrawn in all cases, many women continued to smoke.This series confirms the risk of myocardial infarction in young women taking the pill who continue to smoke cigarettes.

Two cases of severe pulmonary embolism associated with right atrial thrombosis are reported. In the first case, fibrinolytic therapy was administered and was thought to be a causative factor in the death of the patient due to massive pulmonary embolism. In the second case, the patient was referred for surgery and two enormous thrombi were extracted. Unfortunately, the outcome was fatal. These two cases were confronted with the results of the literature. They strongly suggest that echocardiography should be a first-line investigation in severe pulmonary embolism. The detection of right atrial thrombosis modifies the clinical strategy and orientates treatment towards surgical referral when the patient's condition allows it.

Systolic left ventricular flow was studied by pulsed and continuous wave Doppler in 41 patients following aortic valve replacement for severe stenosis (mean valvular area: 0.58 cm2; range 0.3-0.75 cm2). Maximal left ventricular velocities by continuous wave Doppler study, were higher than 2.5 m.s-1 with a sharp peak at end-systole in five patients in basal condition and in four others after amyl nitrite inhalation. Pulsed Doppler study showed that the high velocities started from the apex or mitral papillary muscle level with a marked chamber narrowing at two-dimensional echography. Only one patient had a systolic anterior motion (SAM) of the anterior mitral leaflet with mitral-septal contact. The left ventricular dimensions, as measured by M-mode echography were compared in the various patient groups. High velocities seemed statistically associated with the smaller systolic and diastolic diameters of the left ventricle and outflow tract and the larger relative thickness of the posterior wall. The highest pressure gradients disappeared after correction of hypovolaemia (one patient), clearance of pericardial effusion (one patient), or beta-blocker treatment (three patients). The present study confirms that left intra-ventricular dynamic gradients can occur after clearance of fixed outflow obstruction, for which Doppler examination is a reliable and innocuous diagnostic means. Haemodynamically, this syndrome resembles hypertrophic obstructive cardiomyopathy, but the scarcity of the systolic anterior motion of the mitral leaflets is suggestive of a different mechanism that could be cavity obliteration or mid-ventricular obstruction.

Rapid atrial pacing may reveal myocardial ischemia but the sensitivity for the diagnosis of coronary artery disease is not high enough for routine use. Therefore, the value of atrial pacing coupled with Thallium 201 scintigraphy was evaluated. Sixty-two patients (53 men and 9 women) referred for investigation of angina or chest pain were divided into two groups: a control group of 13 patients (9 men and 4 women, average age: 57.1 years) with insignificant coronary lesions (< 50 %) (N = 5) or normal coronary angiography (N = 8), and a group of 49 patients (44 men and 5 women, average age: 55.5 years) 27 of whom had a history of myocardial infarction (17 posterior, 10 anterior). Coronary angiography showed single vessel disease in 44.9 % of cases, double vessel disease in 34.7 % and triple vessel disease in 18.4 % of cases, and 1 patient with left main stem disease. All 62 patients underwent the same study protocol which comprised: incremental atrial pacing (to the calculated maximal heart rate), Thallium 201 myocardial scintigraphy immediately after pacing and during the redistribution phase, and coronary angiography. The sensitivities of anginal pain (36.7 %) and ECG changes during atrial pacing (57.1 %) were too low for the diagnosis of myocardial ischemia. On the other hand, Thallium 201 scintigraphy with atrial pacing was more sensitive (87.8 %) and specific (84.6 %) for coronary artery disease. Stenosis of the left anterior descending artery was diagnosed with a sensitivity of 96.4 % and that of the right coronary artery with a sensitivity of 90.9 %. However, the sensitivity of detection of left circumflex stenosis was lower (57.9 %). The authors conclude that atrial pacing Thallium scintigraphy may be reserved for patients unable to perform normal exercise stress testing because of peripheral arterial disease, respiratory failure, motor deficits or for those in the immediate post-infarction period (to evaluate residual ischemia).