Declan D. Sugrue

Coronary artery thrombus as a risk factor for acute vessel occlusion during percutaneous transluminal coronary angioplasty: improving results.

Early experience with percutaneous transluminal coronary angioplasty (from October 1979 to March 1983 inclusive) showed that pre-existing coronary artery thrombus was associated with a significant increase in the incidence of acute coronary occlusion during angioplasty. Acute occlusion occurred in 11 (73%) of 15 patients with pre-existing thrombus compared with 18 (8%) of 223 patients without thrombus. The effect of improved technology (steerable guiding systems) and altered dilatation strategy (full intravenous heparinisation for 24 hours after the procedure and more intensive use of antiplatelet medications) was studied by review of angiograms from 297 consecutive patients without evidence of acute myocardial infarction who underwent angioplasty from April 1983 to March 1985 inclusive. Coronary artery thrombus was present in 34 (11%) patients, eight (24%) of whom had complete occlusion during or immediately after the procedure compared with 34 (13%) of 263 patients without thrombus. Patients with pre-existing coronary artery thrombus continue to be at greater risk of complete occlusion than patients without thrombus, but this risk has declined significantly since the modification of the angioplasty procedure.

Tachycardia induced myocardial dysfunction. A reversible phenomenon

Four patients with myocardial dysfunction related to tachycardia underwent electrophysiological studies, which showed a re-entrant supraventricular tachycardia using an accessory atrioventricular connexion. Serial assessment of left ventricular function by echocardiography before and after control of the tachycardia indicated a variable degree of reversibility. Endomyocardial biopsy in two patients detected non-specific histological changes. Because of the possible role of ischaemia in this condition effective control of prolonged tachycardia is needed to prevent deterioration of myocardial function.

Role of invasive electrophysiologic testing in patients with symptomatic bundle branch block

Electrophysiologic testing was performed in 112 symptomatic patients with bundle branch block. Abnormalities included HV interval 70 ms or longer (35 patients), infra-Hisian block with atrial pacing (6 patients) and sinus node dysfunction (23 patients). Inducible ventricular tachycardia occurred in 47 patients (42%). Therapy was based on the electrophysiologic test result: group I--16 patients with no therapy (normal study results); group II--34 patients with permanent pacing alone; group III--39 patients with antiarrhythmic therapy alone; and group IV--21 patients with both antiarrhythmic therapy and permanent pacing. Cumulative 4-year survival rates were 83% in group I, 84% in group II, 63% in group III and 84% in group IV (mean follow-up 2.5 years). Recurrent syncope occurred in 19% of group I, 6% of group II, 33% of group III and 19% of group IV. In symptomatic patients with bundle branch block and normal electrophysiologic test results, prognosis is good without treatment. In patients undergoing permanent pacing based on electrophysiologic testing, survival is good and rate of symptom recurrence is low. Electrophysiologic testing identifies patients with inducible ventricular tachycardia for whom antiarrhythmic therapy is indicated but who nevertheless have a poor prognosis.

Symptomatic "isolated" carotid sinus hypersensitivity: Natural history and results of treatment with anticholinergic drugs or pacemaker

Because syncope may occur intermittently in patients with carotid sinus hypersensitivity, a knowledge of its natural history is needed as a basis for interpreting the usefulness of therapy. Fifty-six consecutive patients are described (47 men and 9 women; mean age 61 years) with carotid sinus hypersensitivity and syncope in whom 24 hour ambulatory monitoring and intracardiac electrophysiologic study revealed no other cause for the syncope. The mean duration of symptoms was 44 months (range 1 to 480) and the mean number of episodes was 4.0 (range 1 to 20). During a follow-up period of 6 to 120 months (median 40), syncope recurred in 3 of 13 patients who received no treatment, in 2 of 23 patients who received a pacemaker and in 4 of 20 patients who received anticholinergic drugs (incidences corrected for totals available at follow-up: 27, 9 and 22%, respectively). Two-thirds of the patients receiving no treatment were asymptomatic compared with all nine of the patients with syncope and a pure cardioinhibitory response to carotid sinus massage who received an atrioventricular (AV) sequential pacemaker. Although pacing was effective in abolishing syncope, its use should be reserved for recurrent episodes because of the high rate of spontaneous remission of symptoms.

Increased vagal tone as an isolated finding in patients undergoing electrophysiological testing for recurrent syncope: response to long term anticholinergic agents.

Features suggestive of an isolated increase in vagal tone during electrophysiological study were found in 12 patients with recurrent near syncope or syncope. Results at neurological and cardiac evaluation were otherwise normal. The increased tone or heightened sensitivity to vagal tone was manifested by abnormal atrioventricular nodal refractoriness and conduction that were reversed with atropine. The patients underwent long term treatment with an anticholinergic agent (propantheline bromide) and 75% improved. Before treatment they had experienced a median of seven episodes (range 3-28) of near syncope or syncope during 10.5 months (range 1-60). During treatment these episodes decreased to a median of one (range 0-15) during 22.5 months (range 3-67); six patients experienced no further symptoms. Three patients continued to have syncope while on treatment, and one of these required permanent cardiac pacing. No additional cause for syncope was identified in any patient. During electrophysiological assessment of patients with syncope, evidence may be obtained pointing to an increase in vagal tone. In many of these patients treatment with anticholinergic drugs seemed to improve or eliminate the symptoms.

Results of percutaneous transluminal coronary angioplasty for unstable angina pectoris in patients 70 years of age and older

Between November 1980 and November 1985, 54 patients ages greater than or equal to 70 years underwent percutaneous transluminal coronary angioplasty for unstable angina, defined as recent-onset (less than 1 month) angina, new onset of rest angina (greater than or equal to 2 episodes) or accelerating class III or IV angina. In these 20 men and 34 women, disease was 1-vessel in 34 (63%) and multivessel in 20 (37%). The mean (+/- standard deviation) ejection fraction was 0.62 +/- 0.12. Angioplasty was successful in 43 patients (80%). In the 11 unsuccessful cases, emergency coronary artery bypass grafting for acute occlusion was performed in 3 and elective coronary artery bypass surgery in 8. There were no deaths. Two patients (4%) sustained Q-wave myocardial infarctions. The mean duration of follow-up for the total group was 37 months (6 to 73 months). Of the 43 patients with successful dilation, 4 died, 1 had an non-Q-wave myocardial infarction and 8 had symptomatic restenosis (4 underwent successful repeat angioplasty, 1 had repeat percutaneous transluminal coronary angioplasty and then bypass surgery, 1 had repeat bypass surgery alone and 2 had medical therapy). At last follow-up, 3 patients had stable class III or IV angina and 31 patients (72%) were angina-free.

Surgical treatment of accessory atrioventricular pathways and symptomatic tachycardia in children and young adults

Twenty-seven patients aged 21 years or younger (mean 15) with symptomatic tachycardia underwent operation for ablation of an accessory atrioventricular pathway. Six patients had associated Ebsteins malformation of the tricuspid valve. Supraventricular tachycardia had been present for a mean of 5 years. At electrophysiologic study, 4 patients were found to have 2 accessory pathways. Left ventricular free wall pathways were found in 14 patients, right ventricular free wall pathways in 10 and septal pathways in 6. Successful initial ablation of all the pathways was achieved in 26 of the 27 patients. No patient died perioperatively and none had persistent complete heart block. During a mean follow-up of 11 months, no patient had recurrence of an arrhythmia related to the accessory pathway. Thus, the surgical treatment of children and young adults with accessory atrioventricular pathways and symptomatic supraventricular tachycardia is safe and effective. For these patients, unless the tachycardia can be easily controlled with a minimal number of drugs and adverse effects, surgical ablation should be considered early in the clinical course.

Impact of Intracardiac Electrophysiologic Testing on the Management of Elderly Patients With Recurrent Syncope or Near Syncope

Seventy‐five patients, 75 years of age and over, experienced recurrent syncope, with the etiology remaining unclear but presumably cardiogenic, after cardiac and neurologic examinations and noninvasive laboratory testing (including an electrocardiogram and ambulatory electrocardiographic monitoring). The mean number of previous syncopal spells was 14 (range, 1 to 64) over a mean of 36 months (range, 1 to 480 months). These patients underwent invasive electrophysiologic testing and a potential cause for syncope was identified in 68%. Abnormal findings at electrophysiologic testing included: sinus node dysfunction (55%); abnormal His‐bundle conduction (39%); and ventricular tachycardia (14%), with some patients having more than one abnormality. No major complications were associated with the electrophysiologic testing. Patients were subsequently treated with permanent cardiac pacing or antiarrhythmic drugs or both, depending upon results of the electrophysiologic study. Follow‐up examinations (mean of 26 months; range, 1 to 70) were possible in 90% of patients. No further syncope occurred in 84% of patients with an abnormal electrophysiologic study who received subsequent therapy to prevent the identified abnormality. Thus, in this difficult group of patients with recurrent syncope of uncertain etiology, electrophysiologic testing was safe and indicated abnormalities of conduction or rhythm in 68% of patients; treatment to correct these abnormalities prevented recurrent syncope in 84%.

Out-of-hospital cardiac arrest in patients without clinically significant coronary artery disease: comparison of clinical, electrophysiological, and survival characteristics with those in similar patients who have clinically significant coronary artery disease.

Fifty nine survivors of out-of-hospital cardiac arrest unassociated with an acute myocardial infarction were referred for intracardiac electrophysiological study. Thirty patients who had no clinically significant coronary artery disease (group 1) were compared with 29 who did (group 2). Ventricular tachycardia or fibrillation was induced in significantly more patients in group 2 than in group 1 (69% vs 40%). Median duration of follow up, which was achieved in all patients, was 31 months in group 1 and 14 months in group 2. In group 1, an effective treatment was identified electrophysiologically in seven patients, and none died; an arrhythmia was induced, but no effective treatment was identified in five patients, and one patient died subsequently; an arrhythmia was not induced in 18 patients, 15 of whom were treated empirically with anti-arrhythmic drugs, and one died. In group 2, effective treatment was identified electrophysiologically in seven patients and three died (two of pump failure) during follow up. In 13 an arrhythmia was induced but no effective drug was identified, and six died or had a recurrence; in another nine patients without inducible arrhythmias, six subsequently died or had a recurrence. A Cox proportional hazards analysis identified previous myocardial infarction as the only predictor of recurrence. Patients without coronary artery disease who suffer an out-of-hospital cardiac arrest have a low inducibility rate at electrophysiological study and an excellent prognosis compared with patients who have coronary artery disease. Electrophysiological testing seemed to be of value in predicting the response to antiarrhythmic drugs, but non-inducibility of arrhythmias in patients with coronary artery disease was of no predictive value.

Histologic abnormalities of the left ventricle in a patient with arrhythmogenic right ventricular dysplasia

SummaryRight ventricular histologic abnormalities have been described in association with arrhythmogenic right ventricular dysplasia, but the cause of the disease is unknown. Identical abnormalities were noted in endomyocardial biopsy specimens from the right and left ventricles of a 20-year-old male patient with the clinical syndrome of arrhythmogenic right ventricular dysplasia. Left ventricular function was normal at rest and during bicycle exercise. Eighteen months previously, he had shown clinical and serologic evidence of mycoplasmal myocarditis. Arrhythmogenic right ventricular dysplasia may represent predominant involvement of the right ventricle in a generalized cardiomyopathic process, possibly as a consequence of healed myocarditis.