Prognostic implications of complex ventricular ectopy in patients with and without structural heart disease. A study based on programmed electrical stimulation

Fifty-six patients with complex ventricular premature beats (Lown grade IVa, IVb), but no evidence of ventricular tachycardia on 48 hours of continuous monitoring were evaluated by programmed electrical stimulation. Thirty patients had coronary atherosclerotic heart disease, 3 had valvular heart disease, 2 had cardiomyopathy and 21 had no structural heart disease. Programmed stimulation identified two groups of subjects: Group I comprised 11 patients in whom ventricular tachycardia was induced and Group II comprised 45 patients (which included 21 patients without heart disease) in whom no ventricular tachycardia was induced. The incidence of left ventricular dysfunction (ejection fraction less than 40%) was significantly higher in Group I as compared to Group II (P less than 0.001). There was, however, no difference between the grade of ventricular ectopy, HV interval or the incidence of bundle branch block between the 2 groups. Patients with inducible ventricular tachycardia (Group I) were put on laboratory directed anti-arrhythmic drug therapy. Patients without inducible tachycardia (Group II) were not given anti-arrhythmic therapy. The patients were followed up for 34 +/- 10 months. The incidence of sudden death (36.3% vs 6.6%, P less than 0.001) was significantly higher in Group I as compared to Group II. No patients without structural heart disease died during the follow-up. Programmed electrical stimulation fails to induce ventricular tachycardia in patients with complex ventricular ectopy but no structural heart disease. It is, however, possible to define a high risk subset in patients with structural heart disease and complex ectopy. The high risk patients with inducible ventricular tachycardia do not seem to benefit by anti-arrhythmic drugs, which may independently increase the risk of sudden death in treated patients. Patients in whom ventricular tachycardia is not inducible have better left ventricular function, a good long-term prognosis and do not require anti-arrhythmic agents.

Value of physical and pharmacological tests in predicting intrinsic and extrinsic sick sinus syndrome

We studied 13 patients with sick sinus syndrome using various physical (postural reflex testing. Valsalva manoeuvre, carotid sinus massage), pharmacological (intravenous isoprenaline, atropine, neostigmine and total autonomic blockade) and electrophysiological tests in order to identify simple non-invasive markers of intrinsic sick sinus syndrome. Following autonomic blockade, 6 patients had normal and the remaining 7 had an abnormal intrinsic heart rate. Electrophysiological testing revealed abnormal sinus node parameters in 8 (62%) subjects in the basal state and 11 (85%) after autonomic blockade. Carotid sinus massage was abnormal in all patients (100%) with an abnormal intrinsic heart rate, and in only 2 of the 6 (33%) with normal intrinsic heart rate (P less than 0.05). The heart rate response to isoprenaline was abnormal in 5 of the 6 (83%) patients with normal as compared to only 1 of the 7 with abnormal intrinsic heart rate. With isoprenaline there was a significantly (P less than 0.05) higher increase in heart rate in patients with abnormal as compared to those with normal intrinsic heart rate. The other physical and drug tests were not helpful to differentiate between intrinsic and extrinsic mechanisms. Thus, carotid sinus massage and, to some extent, isoprenaline administration appear simple bedside tests which may be helpful in identifying the underlying mechanism of sick sinus syndrome.

Myocardial infarction in young Indian patients: risk factors and coronary arteriographic profile

One hundred four patients (101 men, three women), under 40 years of age, with myocardial infarction (MI), underwent coronary arteriography. Eighty patients had significant obstructive coronary artery disease (CAD) (group 1), 23 had normal coronary arteries (group 2), and one patient had coronary ostial stenosis as a result of nonspecific aortoarteritis (group 3). Coronary risk factors in group 1 included smoking (76.2%), hypercholesterolemia (36.3%), hypertension (32.5%), positive family history (28.7%), and diabetes mellitus (5%). Multiple risk factors were frequent (56.2%). Smoking was common (p less than 0.01) and diabetes mellitus less frequent (p less than 0.05) as compared to older (greater than 40 years) patients with MI and arteriographically proved CAD. The frequency of one-, two-, and three-vessel disease was 33.7%, 26.2%, and 40%, respectively, in group 1. Group 2 patients were almost devoid of coronary risk factors. The only group 3 patient had left coronary ostial stenosis with no risk factors. Similar to their counterparts in developed countries, young Indian patients with MI and obstructive CAD have a high frequency of coronary risk factors, especially smoking and severe multiple-vessel disease. Since normal coronary arteriograms are also frequent in this setting, a detailed evaluation is recommended for purposes of prognosis and management.

Fate of thrombectomized Björk-Shiley valves. A long-term cinefluoroscopic, echocardiographic, and hemodynamic evaluation

Fourteen patients underwent thrombectomy for thrombosis of implanted Björk-Shiley valves (13 in the mitral and one in the aortic position) between January, 1975, and July, 1984. There was no operative mortality or perioperative embolism. Over a follow-up period of 1 to 96 months (average 23.5 months), there was no late mortality. Serial evaluation of valve function by cinefluoroscopy and echocardiography has shown no evidence of rethrombosis or valve dysfunction in any of the patients. Cardiac catheterization and angiocardiography done in 10 patients at various intervals (1 month to 6 years) postoperatively have shown normal valve function in all and normalization of elevated preoperative intracardiac pressures in the majority. Our experience suggests that thrombectomy of thrombosed Björk-Shiley valves provides excellent early and long-term results in terms of patient survival and valve function.

The value of intracardiac electrophysiologic techniques in recurrent syncope of "unknown cause"

We prospectively evaluated and followed-up 45 patients with syncope in whom conventional cardiovascular and neurological investigations did not reveal the cause. All patients underwent electrophysiologic studies to assess the function of the sinus node and the integrity of atrioventricular conduction. These included the ajmaline test and the inducibility of supraventricular or ventricular tachycardia. Seven patients (15.5%) had evidence of sinus node dysfunction, 8 patients (17.7%) had evidence of infra-His atrioventricular block after ajmaline administration and 5 patients (11.1%) had inducible ventricular tachycardia. The remaining 25 patients (55.5%) had non-diagnostic studies. All patients with sinus node dysfunction and inducible infra-His atrioventricular block were asymptomatic during a mean follow-up period of 14.3 +/- 9.5 months after implantation of a permanent pacemaker. Patients with inducible ventricular tachycardia (except 1 with poor left ventricular function who died) were likewise asymptomatic while receiving laboratory guided anti-arrhythmic drug therapy. Twenty-five patients with non-diagnostic studies who were treated empirically are alive but the symptoms persist in 14 (56%). Provocative electrophysiological studies are of diagnostic and therapeutic utility in a significant number of patients with recurrent syncope of "unknown cause".

Ajmaline-induced torsade de pointes

A patient with primary myocardial disease and left bundle-branch block who developed marked QT prolongation and torsade de pointes following an intravenous injection of ajmaline during an electrophysiologic study is reported. The patient could be resuscitated successfully 1 h after the onset of tachycardia.

Thrombotic obstruction of Bjork-Shiley valves--diagnostic and surgical considerations

We have evaluated 12 patients with thrombotic obstruction of the Bjork-Shiley valve since 1975, 11 in the mitral and 1 in the aortic position. During this period 442 patients with 303 mitral (181 plano-convex and 122 convexo-concave) and 205 aortic (112 plano-convex and 93 convexo-concave) Bjork-Shiley valves were available for follow-up. The incidence of thrombosis for the plano-convex model was 1.06% per patient year for the mitral position and 0.19% per patient year for the aortic position. The new convexo-concave model has brought down the incidence to 0.78% per patient year for the mitral (P less than 0.01) and 0% per patient year for the aortic valve. The onset of symptoms was acute (less than 15 days) in 41.7% and subacute (greater than 15 days) in 58.3% patients. All patients presented with pulmonary edema. Evidence of inadequate anticoagulation was present in only 3 (25%) patients. Reduction of prosthetic sounds and appearance of a new murmur was highly suggestive of valve thrombosis. Echocardiography and cinefluoroscopy was very useful for the instant recognition of this condition and had obviated the need for cardiac catheterisation in the last 6 patients. Emergency surgery was obligatory in all. Thrombectomy alone was successful in 9 patients. Three patients required replacement of the prosthesis. There was one operative death (mortality 8.3%). The long-term follow-up of these patients (3-82 months, mean 34 months) is excellent. We conclude that thrombotic obstruction of the Bjork-Shiley valve is often not related to inadequate anticoagulation, and more than half of the patients do not present with abrupt onset of symptoms. The convexo-concave model has significantly reduced this problem. Emergency surgery with thrombectomy is the procedure of choice for clotted prostheses.