Noninvasive diagnosis and treatment of atrial flutter utilizing previously implanted dual chamber pacemaker.

Patients with previously implanted dual chamber pacemakers (PM) may develop atrial flutter (AFL). The Siemens-Pacesetter AFP and Genesis PM have the capability of noninvasively synchronizing to a standard external electrophysiology (EP) stimulator. Any arrhythmia termination or induction protocol may be used with a refractory period limitation of approximately 127 msec (472 ppm). The PM stimulation sequence is directly controlled by the APS Model 370EP Programmer which acts as an interface between the PM and EP stimulator. All testing is conducted with the PM functioning in a single chamber mode. The external EP stimulation is detected by the programmer and a 37 KHz coded radio frequency transmission is used to control the PM stimulation in a 1:1 fashion. Real-time intracardiac electrograms (IEG) can be recorded from either the atrial (A) or ventricular lead. The IEG can be used for: (1) hard-copy for diagnosis and cycle length determination; (2) monitoring during and after the procedure; and (3) a synchronization signal to the EP stimulator. Two patients presented with three episodes of AFL with A rates ranging from 220-290 bpm. An A-IEG was obtained in each case to document the exact rhythm and rate. Rapid A pacing from 300-340 ppm was accomplished using a standard external rapid A pacemaker in concert with the 370EP programmer and PM. In two episodes, the AFL accelerated to transient A fibrillation followed by spontaneous conversion to sinus rhythm (SR). In the other episode, the AFL converted directly to SR.(ABSTRACT TRUNCATED AT 250 WORDS)

A reappraisal of surgical intervention for acute myocardial infarction.

Eighty-three patients underwent coronary artery bypass during acute evolving myocardial infarction 6.8 +/- 2.8 hours after the onset of symptoms. Linear discriminant analysis of preoperative variables identified predictors of mortality with an accuracy of 84%. Significant predictors in decreasing order of importance were cardiogenic shock, age over 65 years, left ventricular ejection fraction less than or equal to 0.30, cardiac index less than or equal to 2.0 L/min/m2, and absent collateral flow. Time to reperfusion did not influence outcome nor did the infarct-related artery. Hospital mortality was 15.6% (13/83). Among 51 low-risk patients under 65 years of age without cardiogenic shock, there were three deaths (5.9%). Follow-up angiography was performed in 21 patients. The graft patency rate was 94%. Left ventricular ejection fraction improved from 0.39 +/- 0.10 to 0.49 +/- 0.11 (p less than 0.05). Left ventricular end-systolic volume decreased from 53.2 +/- 19.3 ml/m2 to 41.4 +/- 16.8 ml/m2 (p less than 0.05), and end-diastolic volume remained unchanged: 86.2 +/- 21.2 ml/m2 before operation and 78.7 +/- 24.0 ml/m2 after operation (no significant difference). Regional ejection fraction of the infarct area, determined by the centerline method, increased 0.23 +/- 0.15. In contrast, among 215 patients treated by nonsurgical reperfusion (intracoronary thrombolysis or angioplasty, or both), mortality was 13.5%. In this group, reperfusion was successful in 144 patients (67%) and 89 underwent follow-up angiography. Persistent patency of the infarct artery was demonstrated in 73 (82%). Ejection fraction increased from 0.45 +/- 0.10 to 0.50 +/- 0.15 (p less than 0.05). We conclude that preoperative variables enable identification of patients with evolving acute myocardial infarction in whom coronary artery bypass is associated with low operative mortality and improved ventricular performance.

Percutaneous transluminal coronary angioplasty after intracoronary streptokinase in evolving acute myocardial infarction.

To achieve optimal myocardial revascularization and prevent rethrombosis of the infarct-related coronary artery, percutaneous transluminal coronary angioplasty (PTCA) was attempted in 18 patients with evolving acute myocardial infarction (9 anterior and 9 inferior) after administration of intracoronary streptokinase. PTCA was attempted 338 +/- 151 minutes after the onset of symptoms. After thrombolytic therapy, 11 patients had a severe residual stenosis and 7 a persistent total occlusion of the infarct-related coronary artery. PTCA was successful in 13 of 18 patients: in 9 of 11 with coronary stenoses and in 4 of 7 with total coronary occlusions. PTCA reduced the severity of the coronary lesion from 91 +/- 2% to 27 +/- 7% (p less than 0.001), and the transstenotic pressure gradient from 38 +/- 5 to 6 +/- 2 mm Hg (p less than 0.01). One patient in cardiogenic shock died during urgent coronary surgery after unsuccessful PTCA. After PTCA, all patients received heparin and antiplatelet agents. One patient had reinfarction with reocclusion of the infarct-related artery 5 days after PTCA. The other 12 patients had an uneventful hospital course, and cardiac catheterization before hospital discharge (8 to 17 days) revealed reocclusion of the infarct-related coronary artery in 3 and persistent patency in 9. Persistent patency of the infarct-related artery was associated with preservation of left ventricular end-diastolic volume (initial 86 +/- 6 ml/m2, follow-up 91 +/- 6 ml/m2), and improvement in left ventricular ejection fraction in some patients.

Value of early postoperative epicardial programmed ventricular stimulation studies after surgery for ventricular tachyarrhythmias.

The value of early postoperative epicardial programmed ventricular stimulation studies after electrophysiologically-directed surgery for ventricular tachyarrhythmia was assessed in 34 patients who underwent epicardial stimulation within 7 to 30 days (mean 9.8) of surgery and were followed up for at least 6 months. The antiarrhythmic operation performed was an endocardial ventriculotomy (full encircling or limited), an endocardial resection, a wall resection or a combination of these procedures. All these interventions were directed by intraoperative mapping during sinus rhythm. Temporary epicardial wire electrodes left at the time of surgery rather than endocardial catheter electrodes were used to perform the pacing. The stimulation protocol included the introduction of up to three ventricular extrastimuli and incremental burst ventricular pacing performed at twice diastolic threshold (9.2 +/- 5.8 mA for the right ventricle and 6.0 +/- 3.5 mA for the left ventricle). A study was considered positive when ventricular tachycardia, defined as 10 or more consecutive ventricular beats, was induced by any pacing modality. Nineteen patients (Group I) had a negative study: after stimulation of both ventricles in 15 patients and of the left ventricle only in 4. Fifteen patients (Group II) had a positive study: after stimulation of the right ventricle in nine patients and of the left ventricle in six. The two groups were comparable with respect to preoperative clinical status, surgical procedures performed and postoperative ejection fraction. No arrhythmic events were observed in Group I during a mean follow-up period of 19.5 months (range 4 to 37), whereas seven arrhythmic events (47% incidence) occurred (p = 0.0008) in Group II during a mean follow-up period of 17.7 months (range 5 to 39).(ABSTRACT TRUNCATED AT 250 WORDS)

Verapamil therapy in the treatment of supraventricular arrhythmias following open heart surgery.

Certain general conclusions suggest themselves on the basis of our extensive experience with treating arrhythmias in patients following open heart surgery, our specific results with verapamil therapy in the treatment of atrial fibrillation and atrial flutter in patients following open heart surgery, and the results of verapamil therapy administered in other groups of patients. First, verapamil can provide highly effective, rapid, and safe control of the ventricular response in the treatment of atrial fibrillation and atrial flutter in patients following open heart surgery. Usually, it should be used in concert with digitalis therapy. Second, extrapolation from the data of others suggests that verapamil has an important role to play in the treatment of most other supraventricular arrhythmias in patients following open heart surgery, particularly if temporary wire electrodes are not available.

Torsade de pointes: the long-short initiating sequence and other clinical features: observations in 32 patients.

The clinical setting, precipitating factors, electrocardiographic features and response to treatment of 32 patients with torsade de pointes were reviewed. Thirty-one patients had underlying cardiac disease and 30 patients had a previous underlying cardiac arrhythmia. Antiarrhythmic medications, often in association with electrolyte abnormalities (such as hypokalemia and hypomagnesemia) were the most common precipitating factors. In 22 of 26 patients, the serum drug levels of the antiarrhythmic agents were found to be within the therapeutic range. However, before the administration of agents known to prolong the QT interval, 20 of the 32 patients had, either alone or in combination, baseline prolongation of the QT interval, hypokalemia or hypomagnesemia. All patients had QTc interval prolongation (mean 0.59 second) immediately before the development of torsade de pointes. Marked lability of T wave morphology was frequently noted. Cardiac pacing was the only consistently effective mode of therapy. A characteristic long-short ventricular cycle length as the initiating sequence was found in 41 of 44 episodes of torsade de pointes. Reported data support the high frequency of this electrocardiographic feature of torsade de pointes in which its onset could be analyzed. It is suggested that this electrocardiographic characteristic will aid in both establishing the diagnosis of torsade de pointes and distinguishing it from other polymorphic forms of ventricular tachycardia.

Congenital heart malformations: sequential angiographic analysis.

A segmental angiographic analysis of congenital heart malformations has been developed with the intention of making evaluation of complex congenital heart anomalies as comprehensive as possible. Each vascular and cardiac segment is analyzed sequentially, considering morphology, connections, and relations. Additional associated cardiovascular abnormalities such as shunts, stenoses, hypoplasias, and atresias are also considered. Information analyzed and presented in this way has more immediate anatomic and physiologic meaning than ambiguous terms, often with obscure embryologic implications. Disagreements regarding definitions and nomenclature will continue; however, a logical framework that allows clear communication among cardiologists, surgeons, and angiographers is absolutely necessary and is provided by the orderly analysis presented here.

Cineangiography in the diagnosis of aortic dissection.

To assess the ability of biplane cineangiography in the diagnostic evaluation of acute dissection of the aorta, 20 patients with acute dissection were studied within 24 hours of surgery or autopsy, or both. Biplane large film aortic angiography was performed in 11 patients (Group I) and biplane aortic cineangiography in 9 (Group II). The morphology of the aortic valve was defined precisely in 5 (50 percent) of 10 patients in Group I and in all 9 patients (100 percent) in Group II (p less than 0.02). Aortic regurgitation weas diagnosed in all patients in both groups in whom it was present (p = not significant). Intimal tears were localized in 5 (50 percent) of 10 patients in Group I and in 8 (89 percent) of 9 in Group II (p less than 0.07). Intimal flaps were not identified angiographically in three patients in Group I and were identified in four patients (100 percent) in Group II (p less than 0.01). The presence of retrograde dissection was established in three (38 percent) of eight patients in Group I and in four (100 percent) of four patients in Group II (p less than 0.05). There was no difference in the ability to identify a nonclotted false lumen between cine and large film angiography. It is concluded that in addition to improved diagnostic capabilities, technical advantages make cineangiography a good alternative to large film angiography in the diagnostic evaluation of patients with acute dissection of the aorta.

A safe, rapid method of transfemoral retrograde left ventricular catheterization in valvular aortic stenosis.

We report our experience with the use of a standard left Amplatz coronary catheter and a guidewire to cross the aortic valve in 34 patients being evaluated for valvular aortic stenosis. A number of 2 Amplatz left coronary catheter inserted via the femoral artery was positioned above the noncoronary aortic valve cusp with the tip aligned toward the aortic valve. This catheter allowed a soft-tipped, Teflon-coated guidewire to be guided through the aortic valve orifice. The catheter was then advanced over the guidewire into the left ventricle. This technique was successful within six minutes in 32 of 34 patients (94%). The stenotic aortic valve was crossed in less than two minutes in 15 patients (42%) and in less than four minutes in 31 (91%). The aortic valve was not crossed in two patients. Twenty-one patients (62%) had an aortic valve area of less than 0.75 cm2. There were no complications. We conclude that this technique provides a method for safe, rapid transaortic left ventricular catheterization in patients with aortic stenosis of all degrees of severity.