The relation between transmitral early filling wave deceleration time and the recovery of atrial contractility after electrical cardioversion of atrial fibrillation.

BACKGROUND: Electrical cardioversion of atrial fibrillation (AF) to sinus rhythm is associated with transient left atrial dysfunction and this phenomenon may lead to thrombus formation and embolic stroke. Delay of atrial mechanical function recovery may be related to ventricular diastolic function. OBJECTIVE: This study examined the effects of left ventricular diastolic function as well as the multiple clinical factors on the recovery of atrial systolic function after cardioversion for atrial fibrillation. METHODS: A total of 44 patients (28 male, 16 female, 61+/-18 years) with chronic AF (> or =1 month) underwent electrical cardioversion. Deceleration time of early filling wave (pre-CV EDT) on transmitral inflow obtained by using Doppler echocardiography before cardioversion and serial transmitral inflow Doppler variables were recorded through a 1 week study period in all patients. Various clinical (age, gender, the duration of AF) and echocardiographic variables (pre-CV EDT, left atrial dimension, left ventricular ejection fraction) were tested for an association with peak atrial filling wave velocity (VA) on day 1, 3 and 7 after cardioversion. RESULTS: EDT measured before cardioversion had a strong linear correlation with peak VA on every echocardiographic evaluation after cardioversion (Regression coefficient (R)=0.69, P<0.001; R=0.78, P<0.001 and R=0.83, P<0.001, on day 1, day 3 and day 7, respectively). The effect of left ventricular ejection fraction on peak VA was weaker than those of EDT. The duration of AF showed an inverse association with the recovery of atrial function, but this lost on multivariate analysis. None of the other parameters significantly correlated with peak VA after cardioversion. CONCLUSION: The recovery of atrial mechanical function after cardioversion, as assessed by peak VA on transthoracic Doppler echocardiography is mainly associated with the left ventricular diastolic function as measured by EDT, whereas the left ventricular systolic function relatively a small effect on this outcome. The duration of AF does not have any association with peak VA, possibly if it is chronic.

Atrial sensing performance of a single-lead VDD pacing system during physical activities.

This study was undertaken to evaluate the atrial sensing performance of a single-lead atrial synchronous-ventricular pacing system during various physical activities on late follow-up. Fourteen patients (mean age 55 +/- 17 years) with a third-degree or high-degree atrioventricular block and normal sinus node function were treated with the single-lead Thera VDD (Medtronic, Inc, Minneapolis, MN) pacemaker system. Mean P-wave amplitude at implantation was 3.2 +/- 1.3 mV. To assess the VDD system performance, P-wave amplitudes during various physical maneuvers (supine, sitting, deep breathing, standing, and exercise; respectively) were measured and atrial sensing was evaluated at a mean follow-up of 11 +/- 4 months. During deep breathing, minimum and maximum P-wave amplitudes (0.8 +/- 0.7, 1.2 +/- 1.0 mV, respectively) were found to be significantly lower than the standing position (minimum, 1.1 +/- 0.9, maximum, 1.4 +/- 1.1 mV P = .02 in both). No significant difference was found during other physical maneuvers. During the testing maneuvers, atrial undersensing was observed in 8 patients (57%) at the nominal atrial sensitivity of 0.5 mV. After increasing the atrial sensitivity (0.25 mV), no sensing failure was observed in these patients. It has been concluded that Medtronic Thera VDD system is a safe and reliable device with an easy implantation technique providing effective atrioventricular synchronization. The sensing problems, which may occur on late follow-up, can be corrected successfully by reprogramming. To achieve an optimal atrial sensing function in patients with a single-lead VDD pacing, we recommend that the atrial sensing capability should be examined in various physical maneuvers.

Replacement of an immobile prosthetic mitral valve: a case report.

A mechanical prosthetic heart valve can become acutely obstructed despite anticoagulation therapy. This can be a life-threatening complication. We report the case of a 38-year-old woman who survived obstruction of her Sorin prosthetic mitral valve. She was admitted to the hospital because of severe pulmonary edema. On auscultation, mechanical valve sounds were absent. Transthoracic echocardiography showed an immobile mechanical valve. The patient suffered a cardiac arrest while being prepared for surgery, but she underwent successful mitral valve replacement after cardiopulmonary resuscitation. When patients with prosthetic mitral valves present with acute dyspnea, the possibility of an obstructed prosthetic valve must be considered in the differential diagnosis.

Comparative methods of repairing left ventricular aneurysms.

Between 1 March 1992 and 31 June 1996, we enrolled 72 patients with left ventricular aneurysms in a prospective, nonrandomized study to compare--by study of cardiac indices, single-plane ejection fractions, and nuclear ventriculograms--the effects of classical aneurysmectomy (group 1, n = 36) with those of endoaneurysmorrhaphy (group 2, n = 36). Preoperative and postoperative cardiac index measurements were, respectively, 1.96 +/- 0.6 and 3.51 +/- 0.53 for group 1, and 1.96 +/- 0.31 and 3.43 +/- 0.41 for group 2. In this regard, there was not any significant difference between the groups preoperatively or postoperatively. Preoperative and postoperative multiple-gated acquisition measurements, were, respectively, 34.3 +/- 7.76 and 43.1 +/- 11.1 for group 1, and 37 +/- 3.88 and 66.5 +/- 5.2 for group 2. Although there was not any significant preoperative difference between the groups (P = 0.34), group 2 had significant postoperative improvement in left ventricular ejection fractions (P < 0.001). Preoperative and postoperative single-plane contrast ventriculographic ejection fractions were, respectively, 43.4 +/- 8.7 and 48.6 +/- 11.2 for group 1, and 43.8 +/- 5.5 and 60.8 +/- 15.1 for group 2. Again, there was not any significant difference between the 2 groups in preoperative left ventricular ejection fractions (P = 0.87), but the postoperative left ventricular ejection fractions of group 2 were significantly better than those of group 1 (P = 0.022). We conclude that left ventricular functional improvement with endoaneurysmorrhaphy is superior to that with classical aneurysmectomy.