Nicole Aebischer

Prognosis after stroke followed by surgical closure of patent foramen ovale A prospective follow-up study with brain MRI and simultaneous transesophageal and transcranial Doppler ultrasound

Background: The risk of stroke and the long-term prognosis of recurrent strokes in young patients with patent foramen ovale (PFO) are not well known. For this reason, the treatment of these patients remains empirical. An alternative treatment to prolonged antithrombotic therapy may be surgical closure of the PFO. Methods: Thirty patients (20 men and 10 women) with stroke and PFO were prospectively selected among 138 patients with stroke and PFO for a study of surgical closure of PFO at our center. Eligible patients were <60 years old, had negative results of a systematic search for another cause of stroke (first criterion), and met two of the four following criteria: (1) recurrent clinical cerebrovascular events or multiple ischemic lesions on brain MR, (2) PFO associated with an atrial septal aneurysm, (3) >50 microbubbles counted in the left atrium on contrast transesophageal echocardiography (TEE), and (4) Valsalva maneuver or cough preceding the stroke. Patients selected in this manner for surgery were considered to be a subgroup with a higher risk of stroke recurrence. Results: All patients had a direct suture of PFO while under cardiopulmonary bypass without recorded early or delayed significant complication. All patients underwent a new brain MRI and TEE simultaneous with transcranial Doppler ultrasonography after contrast injection at 8 +/- 3 months after surgery. After a mean follow-up of 2 years without antithrombotic treatment, no recurrent cerebrovascular event (stroke or transient ischemic attack [TIA]) and no new lesion on MRI had developed. Postoperative contrast TEE and transcranial Doppler ultrasonography showed that two patients had residual interatrial right-to-left shunting, although much smaller than before surgery, associated with single versus double continuous suture. Conclusions: Our study of 30 selected stroke patients with surgical suture of PFO showed a stroke recurrence rate of 0% and no significant complication. Residual right-to-left shunting may be avoided by double continuous suture of the PFO. In the absence of controlled studies to guide individual therapeutic decisions, our findings show that PFO closure can be done safely and may be considered to avoid recurrence in selected patients with long life expectancy and presumed paradoxic embolism. NEUROLOGY 1996;47: 1162-1166

Acute Hemodynamic Effects of Atrioventricular Pacing at Differing Sites in the Right Ventricle Individually and Simultaneously

We hypothesized that pacing, which provided a rapid uniform contraction of the ventricles with a narrower QRS, would produce a better stroke volume and cardiac output (CO). We sought to study whether pacing simultaneously at two sites in the right ventricle (right ventricular apex and outflow tract) would provide a narrower QRS and improved CO in 11 patients undergoing elective electrophysiology studies. Patients were studied by transthoracic echocardiography measurement of CO using the Doppler flow velocity method in normal sinus rhythm, AOO pacing (rate 80), DOO pacing in the right ventricular apex (AV delay 100 ms). DOO pacing in the right ventricular outflow tract, and DOO pacing at both right ventricular sites simultaneously in random order. The COs were 5.42 ± 1.83, 5.61 ± 1.97. 5.67 ± 1.6. 5.84 ± 1.68. and 5.86 ± 1.52 L/min, respectively (no significant difference by repeated measures analysis of variance [ANOVA]). The QRS durations were 0.09 ± 0.02, 0.09 ± 0.02. 0.13 ± 0.027, 0.13 ± 0.03, and 0.11 ± 0.03 sees respectively. Repeated measures ANOVA showed that the QRS duration significantly increased with right ventricular apex or right ventricluar outflow tract pacing compared to sinus rhythm and AOO pacing (P < 0.001) but then diminished with pacing at both sites (P < 0.01). QRS duration was not correlated with CO, however the change in QRS duration correlated significantly with the change in CO when pacing was performed at the two right ventricular sites simultaneoasly. In conclusion, during DOO pacing, there was a trend for pacing in the right ventricular outflow tract or both sites to improve the CO compared to the right ventricular apex. With simultaneous pacing at both ventricular sites, the QRS narrowed. Further studies will be required to see if this approach has value in patients with poor left ventricular function or congestive heart failure.

Dual Chamber Pacing in Hypertrophic Obstructive Cardiomyopathy: Beneficial Effect of Atrioventricular Junction Ablation for Optimal Left Ventricular Capture and Filling

Clinical improvement with dual chamber pacing bas largely been reported in patients suffering from hypertrophic obstructive cardiomyopathy and mainly attributed to the reduction of the subaortic pressure gradient. To be effective, pacing must induce a permanent and complete capture of the LV. In two patients of our collective, symptoms (angina and dyspnea NYHA Class III and/or syncopes) persisted or relapsed despite pacing. This was related to the inability to obtain full LV capture due to a too‐short native PR interval. RF ablation of the AV junction was therefore performed in botb patients, resulting in permanent AV block in one and prolonged PR interval up to 310 ms in the second. Pacing was thereafter associated with an immediate and significant clinical improvement related to permanent LV capture, whatever the patients activity. After RF ablation, the AV delay was set up to induce the best LV filling, as assessed by Doppler analysis of mitral flow. Our observations suggest that RF ablation or modification of the AV junction can be a successful procedure in some patients with residual or recurrent symptoms, when the latter result from a loss of capture or from the inability to program an AV delay tbat does not compromise the active component to LV filling. Doppler echocardiography is a simple and effective mean to assess the hemodynamic effect of AV interval modulation in this setting.

An echocardiographic and magnetic resonance imaging comparative study of right ventricular volume determination

Assessment of right ventricular volume and function is important in many clinical settings involving heart or lung disease. However, the complexity of the right ventricular anatomy has prevented accurate volume determination by two-dimensional echocardiography. In the present study, 5 models incorporating standard echocardiographic views, were used to determine right ventricular volume in 10 human subjects. Two models were contingent on the true crescentic appearance of the right ventricle, whereas the remaining 3 calculated the right ventricular volume as a pyramid, an ellipsoid or other tapering geometrical figures, respectively. Subsequently, echocardiographic right ventricular volumes were compared to magnetic resonance imaging derived volumes. Correlation analysis and agreement measurement between the echocardiographic and magnetic resonance end-diastolic volume were performed in 10 out of 10 subjects and in 9 out of 10 subjects for the end-systolic volume. The 2 crescentic models resulted in the most reliable estimation of right ventricular volume. Those findings suggest that models based on right ventricular anatomical landmarks are feasible and should be preferred in echocradiographic studies.

Usefulness of the echocardiographic velocity ratio for detection of significant aortic stenosis

In this study, which included 56 patients with aortic stenosis, the predictive value of the fractional shortening velocity ratio was evaluated. This Doppler index allowed detection of significant aortic stenosis (0.53 cm2/m2), with a positive predictive value of 93% and a negative predictive value of 92% for a cutoff value of 0.8.

Ventricular interdependence during valsalva maneuver as seen by two-dimensional echocardiography: New insights about an old method

Two-dimensional echocardiography was used in 15 normal volunteers to assess left (LV) and right ventricular (RV) responses, as well as their interdependence, during the Valsalva maneuver. During the strain phase, LV and RV areas decreased progressively, the RV area decreasing more than the LV area. Immediately after strain release, the RV end-diastolic area increased suddenly and dramatically to 143.3% +/- 9.4% of its baseline value, whereas the LV end-diastolic area decreased further. This transiently overloaded right ventricle and associated septal shift changed LV shape and further reduced the LV cross-sectional area. Thus the resulting momentary drop in the stroke LV area may contribute, along with pulmonary blood pooling, to the abrupt systemic blood pressure drop characteristic of phase III seen in normal subjects. Real-time imaging with echocardiography during respiratory maneuvers is feasible for clinical use. Its application in patients with congestive heart failure might bring further understanding of LV and RV interrelationships in the failing heart.

Reduced Atrial Emptying after Orthotopic Heart Transplantation Masquerading as Restrictive Transmitral Doppler Flow Pattern

Background: An elevated early (E) to late (A) diastolic filling velocities ratio, typically seen in advanced diastolic dysfunction, has also been observed after cardioversion of atrial fibrillation as a consequence of the depressed left atrial (LA) contractility. We hypothesized that the impaired LA contractile function demonstrated after orthotopic cardiac transplantation (OCT) could also lead to this “pseudorestrictive” pattern. Method: E/A ratio related to the tissue Doppler early mitral annular velocity (Ea) as preload‐independent index of LV relaxation was evaluated in all consecutive OCT patients between 2005 and 2007. Results: The study population comprised 48 patients 97 ± 77 months after OCT. Thirty‐two patients (67%) had an E/A ratio > 2. LV systolic function and myocardial relaxation assessed by the Ea velocity were similar compared to patients with normal ratio (61 ± 6% vs. 60 ± 12%, P = 0.854 and 15 ± 4 cm/s vs. 14 ± 3 cm/s, r = 0.15, P = 0.323, respectively). On the other hand, the proportion of the recipient and donor LA cuffs as estimated by the recipient/global LA area ratio and the LA emptying fraction significantly correlated with the E/A ratio (r = 0.40, P = 0.005 and r =−0.33, P = 0.022, respectively). Conclusion: Our study shows that there is a high prevalence of elevated E/A ratio after standard OCT which seems mainly related to reduced LA contractility. Recognition of this “pseudorestrictive” pattern may avoid misdiagnosis of diastolic dysfunction. (Echocardiography 2011;28:168‐174)

Continuing Medical Education Activity in Echocardiography

Article Title: Reduced Atrial Emptying after Orthotopic Heart Transplantation Masquerading as Restrictive Transmitral Doppler Flow Pattern? (Echocardiography 2011;28:167)

Le point sur l’ergométrie en 2012 dans le diagnostic de la maladie coronarienne

L’ergometrie est l’examen de premiere intention en cas de suspicion de maladie coronarienne chez les patients a probabilite pre-test intermediaire.

Treatment of Hypertrophic Obstructive Cardiomyopathy with Pacing

Hemodynamic, metabolic or genetic disorders can lead to hypertrophy of the heart muscle. The hypertrophy is, whatever its cause, the source of symptoms such as dyspnea, syncope, angina or sudden death. Primary hypertrophic cardiomyopathy may present under 3 different forms: apical hypertrophy, diffuse hypertrophy, and asymmetric septal hypertrophy. This last form, when associated with obstruction, is referred as hypertrophic obstructive cardiomyopathy, a disease with a significant morbidity and mortality. The most common causes of mortality, with a reported annual of rate 3 to 8%,1 are sudden cardiac death due to arrhythmias or congestive heart failure. Medical therapy is considered as initial treatment and includes betablockers, calcium antagonists and disopyramid.2, 3 For drug refractory patients, surgical therapy consisting of septal myotomy, myotomy-myectomy and eventually mitral valve replacement or repair has been performed with good results.4 However, morbidity and mortality due to this intervention is not negligible.5