Faculty Bibliography

Supraventricular arrhythmias, often seen in patients after cardiac surgery, may be associated with scars produced in the atria at the time of surgery. Double potentials, found in the presence of functional or anatomical block, can define the limits and critical regions of a reentrant circuit associated with the atriotomy scars. We describe six patients with seven distinct atrial tachycardias in whom atriotomy scars were successfully mapped during intraatrial reentry utilizing the presence and interelectrogram relationship of observed double potentials. The reentrant circuit was mapped in all patients by following the relationship between double potentials along the surgical scar, assuming that they would be widely split in the middle of the scar and merge into a single continuous fractionated potential at the apex of the scar. At this site, atrial pacing was performed to entrain the tachycardia and confirm the participation of the atriotomy scar in the clinically relevant atrial tachycardia. Radiofrequency ablation was performed from the site of electrogram fusion to the nearest anatomical obstacle. Five of seven atrial tachycardias were successfully ablated utilizing this technique over a mean follow-up of 10 months. We proposed that these double potentials and their interelectrogram relationship are an effective means of mapping atriotomy scars and guiding successful radiofrequency ablation

The biatrial approach to exposing the mitral valve during surgery has the potential for improving visualization of the valve with minimal cardiac manipulation. This procedure, involving a right atriotomy and an extended transseptal incision, may isolate the sinus node from its normal blood supply and autonomic innervation. Thirty-eight consecutive patients undergoing this procedure were examined. Twenty-two of these patients (58%) were admitted in normal sinus rhythm and 15 (40%) were in atrial fibrillation (AF) or atrial flutter. Of the 22 patients admitted in normal sinus rhythm, only 3 patients remained in this rhythm at discharge. Fourteen of the 22 patients were discharged in a slow, low atrial rhythm. All of the patients admitted in AF were discharged in AF. Of the 14 patients discharged in a low atrial rhythm, the rhythm persisted in eleven patients (80%) at a mean of 6-month follow-up. The routine use of this transseptal approach to mitral valve surgery needs further assessment in light of the predictable loss of the sinus mechanism

Surgical treatment of left ventricular aneurysms have recently focused on maintaining normal left ventricular geometry by using a circular patch repair to exclude the aneurysmal cavity (endoaneurysmorrhaphy). We describe two patients who underwent this procedure and were subsequently found by echocardiography and angiography to have a residual communication between the left ventricular cavity and the aneurysm which contained thrombus. This finding may have implications regarding the optimal hemodynamic result of the surgery and the risk of thromboembolism

BACKGROUND: Recent advances in surgical techniques for the repair of left ventricular aneurysms (LVAs) include the use of an endoventricular patch to exclude the aneurysm cavity. This technique has replaced conventional linear plication of the aneurysm. The endoventricular patch technique remodels the left ventricular cavity to a more physiological geometry that improves function. METHODS AND RESULTS: From December 1989 through November 1993, 45 patients underwent an LVA repair with an endoventricular patch. This procedure was performed in association with coronary artery bypass grafting in 40 patients. Twenty-eight patients (62.2%) also had nonguided encircling subendocardial incisions. Operative procedures included 7 emergency operations, 3 concomitant valve procedures, and a mean of 2.2 bypass grafts per patient. Eight patients had previous cardiac operations. Hospital mortality was 15.6% (7/45) for all patients and 9.1% (3/33) for nonemergent revascularization and LVA repairs. Ejection fraction improved from a mean of 25.8% preoperatively to 37.8% postoperatively; the mean New York Heart Association classification improved from 3.5 to 1.5. Of patients known to have preoperative arrhythmias (inducible or sudden death), 69% were not inducible postoperatively without antiarrhythmic medication. Survival from late cardiac death (including death of unknown origin) was 86.5% at 2 years. Freedom from documented ventricular arrhythmias was 94.3% at 2 years. CONCLUSIONS: These results indicate that the patch endoaneurysmorrhaphy technique can provide an excellent functional and physiological outcome in patients with LVAs and severely impaired ventricular function

The purpose of this study was to compare transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) in the evaluation of the coronary sinus and its blood flow. Forty patients were studied by TTE and TEE. The distal coronary sinus and its right atrial communication could be identified in 21 of 40 by TTE, and in all patients by TEE. Coronary sinus diameter measurement at the right atrial communication was possible by TTE in 16 of 40, and in all patients by TEE (maximal diameter 6 to 14 mm, mean 9 +/- 2). Flow velocity measurement by pulsed Doppler was possible in 25 of 40 patients (63%) by TEE, and in none by TTE. The flow velocity pattern was similar to central vein flow velocity, with systolic and diastolic antegrade waves, and a small retrograde end diastolic wave. The coronary sinus cross-sectional area was measured in 5 patients by intravascular ultrasound. It varied in size and shape during the cardiac cycle, reaching a maximum (0.3 to 1.5 cm2) at end diastole, and decreasing by 40% to 70% at end systole. TEE is superior to TTE in the evaluation of the coronary sinus and its blood flow velocity. However, because of the variability in cross-sectional area size and shape, measurement of coronary sinus blood flow may be inaccurate

Baseline AV conduction properties (antegrade and retrograde) are often used to assess the presence of dual AV nodal physiology or concealed AV accessory pathways. Although retrograde conduction (RET) is assumed to be a prerequisite for AV nodal reentrant tachycardia (AVNRT), its prevalence during baseline measurements has not been evaluated. We reviewed all cases of AVNRT referred for radiofrequency ablation to determine the prevalence of RET at baseline evaluation and after isoproterenol infusion. Results: Seventy-three patients with AVNRT underwent full electrophysiological evaluation. Sixty-six patients had manifest RET and inducible AVNRT during baseline atrial and ventricular stimulation. Seven patients initially demonstrated complete RET block despite antegrade evidence of dual AV nodal physiology. In 3 of these 7 patients AVNRT was inducible at baseline despite the absence of RET. In the other four patients isoproterenol infusion was required for induction of AVNRT, however only 3 of these 4 patients developed RET. One of these remaining patients had persistent VA block after isoproterenol. Conclusions: The induction of AVNRT in the absence of RET suggests that this is not an obligatory feature of this arrhythmia. Therefore, baseline AV conduction properties are unreliable in assessing the presence of AVNRT and isoproterenol infusions should be used routinely to expose RET and reentrant tachycardia

Left atrial to femoral arterial bypass was evaluated as a means of supporting patients who were considered to be at high risk for the performance of percutaneous transluminal coronary angioplasty. A 20 French drainage catheter was inserted percutaneously into the left atrium via a modified transseptal technique. Blood was withdrawn from the left atrium and returned through a femoral arterial cannula using a roller pump. Thirteen patients were treated in this fashion with excellent circulatory support. Pump flows varied from 1.5 to 3 liters per minute and bypass time ranged from 27 to 106 min (mean = 43 +/- 17). Aortic mean pressure was well supported during balloon inflation. No significant complications were encountered. Neither an oxygenator nor a perfusionist is required. The ability to obtain direct left ventricular decompression offers a major potential advantage. Further evaluation of this technique for the support of such patients is indicated