The cause of ischemic stroke in younger adults is undefined in as many as 35 percent of patients. We studied the prevalence of patent foramen ovale as detected by contrast echocardiography in a population of 60 adults under 55 years old with ischemic stroke and a normal cardiac examination. We compared the results with those in a control group of 100 patients. The prevalence of patent foramen ovale was significantly higher in the patients with stroke (40 percent) than in the control group (10 percent, P less than 0.001). Among the patients with stroke, the prevalence of patent foramen ovale was 21 percent in 19 patients with an identifiable cause of their stroke, 40 percent in 15 patients with no identifiable cause but a risk factor for stroke, such as mitral valve prolapse, migraine, or use of contraceptive agents, and 54 percent in 26 patients with no identifiable cause (P less than 0.10). These results suggest that because of the high prevalence of clinically latent venous thrombosis, paradoxical embolism through a patent foramen ovale may be responsible for stroke more often than is usually suspected.

Arrhythmogenic right ventricular dysplasia (ARVD) is a structural heart disease affecting young adults that leads to cardiac rhythm disorders including supraventricular and mostly ventricular arrhythmias. Sudden death may be the first presentation of the disease. Ablation techniques have been used for the treatment of ventricular tachycardia in cases resistant to drug therapy. Radiofrequency is appropriate as a first approach for ventricular tachycardia ablation in ARVD; however, its effectiveness is less than 40% at the first session. Fulguration is effective for ventricular tachy-cardia ablation and should be used in the same session after ineffective radiofrequency ablation. However, fulguration requires expertise, general anesthesia, and more than one session in half of all patients. Radiofrequency and fulguration plus other common forms of treatment including pacemakers and automatic implantable cardioverter defibrillators provides a clinical success rate of 81% to 93% in a series of 50 consecutive patients studied during 16 years. Earlier poor reputation of fulguration was the result of poorly understood technical problems concerning the physics and biophysics of the procedure under control with presently available methods. This in-depth study of a large population over a long time period demonstrates that fulguration should be rehabilitated.

Patent foramen ovale (PFO) is present in 25-30% of the population. Spontaneously, or with activities implying a Valsalva maneuver, a transient right-to-left shunt occurs. This can now be easily diagnosed with contrast echography. We report 29 cases of paradoxical cerebral embolism with a PFO and compare them with 25 reported cases. There may be clinical evidence suggesting the diagnosis: a Valsalva-inducing activity at the onset of stroke. previous chronic pulmonary hypertension, contemporary pulmonary embolism and evidence of deep vein thrombosis.

Each result of the time- and frequency-domain analyses revealed that both methods had equivalent value. Combining the two domain analyses improved the sensitivity without reducing the specificity. These findings suggest that combining the time- and frequency-domain analyses of the SAECG may be useful as a screening test to detect patients with ARVD.

Electrode catheter ablation (fulguration) is a new technique for the treatment of ventricular tachycardia resistant to medical treatment. It proved effective in our hands in a series of 65 cases of ventricular tachycardia of varied origin. This paper reports the early results in a subgroup of 13 patients suffering from arrhythmogenic right ventricular dysplasia in whom shocks ranging from 160 to 280J, single or multiple, in one or up to three sessions were delivered. In the 11 patients surviving the DC ablation procedure single or multiple monomorphic sustained VT was brought under control. However, four patients (36%) required therapeutic antiarrhythmic treatment following the fulguration therapy. During the learning phase one case of death was related to poor catheter selection and the other to poor protocol. The post-mortem study of the effect of shocks depends on the anatomical structure to which the shocks have been delivered.

The beneficial haemodynamic effects of sequential atrioventricular (AV) pacing have been clearly established and are dependent on the AV delay and pacing rate. However, the optimal AV delay is difficult to determine in each particular patient. We used a modified impedance plethysmographic method to assess variations in stroke volume for different AV delay and pacing rate settings. Impedance measurements showed a good correlation with CO2 rebreathing stroke volume measurements in VVI patients. Impedance variations were then used to set the optimal AV delay at different pacing rates in DDD patients. The inverse relationship between the optimal AV delay and the pacing rate has been accurately identified in most of the patients but is not predictable. In all cases, the cardiac output was higher in DDD mode at the optimal AV delay than in VVI mode. In some patients with a damaged myocardium, the stroke volume appeared to be highly sensitive to multiple AV delay settings. Impedance plethysmography can permit such repetitive non-invasive quick measurements, increasing the accuracy of optimal AV delay determination and is well suited for routine examination of patients with cardiac dual chamber pacemakers.

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SUMMARY Diagnosis of so-called false aneurysms of the left ventricle after infarction is judged to be important because the risk of rupture is high and resection of aneurysms with a narrow orifice is usually successful. Aneurysms with larger communication orifices are less likely to rupture. Echocardiographic and angiographic criteria have been devised to classify left ventricular aneurysms into two distinct types. In four cases of inferior aneurysms the echocardiographic and angiographic criteria were typical of a "false aneurysm" but the defects were diagnosed as true aneurysms after intraoperative and histological examination. These aneurysms were characterised by their site in the inferior wall and by late diagnosis and treatment, which may have influenced their occurrence and determined the development of their characteristic shape.These findings suggest that the classic echocardiographic and angiographic diagnostic criteria for "false" aneurysms may have to be abandoned.Left ventricular aneurysms with narrow communication orifices are more likely to rupture than aneurysms with wider necks. In 1975 Roelandt et al established echocardiographic criteria to differentiate between so-called false and true aneurysms.' Angiographic2 and anatomical criteria3 have also been developed. The four patients we report had an inferior left ventricular aneurysm that developed after myocardial infarction; their echocardiographic and angiographic features were in every respect those that are regarded as being characteristic of a "false" aneurysm. At operation and histological examination, however, these so-called false aneurysms were found to be "true" aneurysms.These findings suggest that the classic diagnostic criteria for "false" aneurysms may have to be abandoned, at least for inferior aneurysms.Requests for reprints to Dr G Lascault, Service