Frits W. Bär

The value of the electrocardiogram in the differential diagnosis of a tachycardia with a widened QRS complex.

To determine the value of the electrocardiogram for differentiating aberrant conduction from ventricular ectopy, findings were retrospectively reviewed from patients with a widened QRS complex during tachycardia in whom the site of origin of tachycardia was determined by His bundle electrography. Seventy episodes of sustained ventricular tachycardia from 62 patients and 70 episodes of aberrant conduction during supraventricular tachycardia from 60 patients were available for study. Findings suggesting a ventricular origin of tachycardia were (1) QRS width over 0.14 sec, (2) left axis deviation, (3) certain configurational characteristics of QRS and (4) atrioventricular (A-V) dissociation. Capture or fusion beats resulting from A-V conduction of dissociated atrial complexes during ventricular tachycardia were seen during only four of 33 episodes of sustained tachycardia.

Characteristic electrocardiographic pattern indicating a critical stenosis high in left anterior descending coronary artery in patients admitted because of impending myocardial infarction

In patients admitted to the hospital because of unstable angina, a subgroup can be recognized that is at high risk for the development of an extensive anterior wall myocardial infarction. These patients, who show characteristic ST-T segment changes in the precordial leads on or shortly after admission, have a critical stenosis high in the left anterior descending coronary artery. Of 145 patients consecutively admitted because of unstable angina, 26 (18%) showing this ECG pattern, suggesting that this finding is not rare. In spite of symptom control by nitroglycerin and beta blockade, 12 of 16 patients (75%) who were not operated on developed a usually extensive anterior wall infarction within a few weeks after admission. In view of these observations, urgent coronary angiography and, when possible, coronary revascularization should be done in patients with unstable angina who show this ECG pattern.

Vital exhaustion predicts new cardiac events after successful coronary angioplasty.

&NA; Excessive tiredness is one of the most prevalent premonitory symptoms of myocardial infarction and sudden cardiac death. This state is labelled as vital exhaustion and consists of three components: fatigue, increased irritability, and demoralization. Vital exhaustion has been found to be an independent risk‐indicator of myocardial infarction in one prospective study and several case‐control studies. It is as yet unclear whether the association between vital exhaustion and future myocardial infarction can be explained by confounding of (subclinical) coronary artery disease. Therefore, the present study investigates the predictive value of vital exhaustion for the occurrence of new cardiac events after percutaneous transluminal coronary angioplasty (PTCA), while explicitly controlling for the severity of coronary artery disease. Patients with a successful PTCA were followed during 1.5 years. A new cardiac event was defined as present if one of the following end points occurred: cardiac death, myocardial infarction, coronary bypass surgery, repeat‐PTCA, increase of coronary atherosclerosis, or new anginal complaints with documented ischemia. Vital exhaustion was assessed using the Maastricht Questionnaire two weeks after hospital discharge. Participants of the present study were 127 patients (mean age 55.6 +/‐ 9.1; 105 men, 22 women). Fifteen (35%) of the 43 exhausted patients experienced a new cardiac event, whereas 14 (17%) of the 84 not exhausted patients had a new cardiac event (OR = 2.7; CI = 1.1–6.3; p = .02). Multiple logistic regression analysis revealed that vital exhaustion continued to be of predictive value when other significant risk factors for new cardiac events were controlled for (i.e., severity of coronary artery disease and hypercholesterolemia).(ABSTRACT TRUNCATED AT 250 WORDS)

Angiographic and clinical characteristics of patients with unstable angina showing an ECG pattern indicating critical narrowing of the proximal LAD coronary artery

One hundred eighty of 1260 patients consecutively admitted to the hospital because of unstable angina pectoris had the typical ST-T segment changes suggestive of a critical stenosis in the proximal LAD. In 108 patients the ECG abnormalities were present at the time of admission. In the remaining 72 patients they developed shortly thereafter. The difference between these two groups was a longer duration of anginal complaints in the former (mean 2.3 days). Results of coronary angiography, performed a mean of 4.6 days after the last attack of chest pain, showed 50% or more narrowing in the proximal LAD in all patients. Thirty-three patients had complete occlusion of the LAD and 75 had collateral circulation to the LAD. Results of left ventricular angiography showed abnormal systolic left ventricular wall motion in 137 patients and normal systolic motion in the remaining 43 patients. The difference between these two groups was a shorter mean time interval between the last attack of chest pain and angiography in the former group (p less than 0.001). Twenty-four patients had only abnormal diastolic wall motion. Twenty-one patients had a small increase in the creatine kinase level at the time of admission. Fifteen patients (nine before and six during early revascularization) had an anterior wall myocardial infarction in the hospital; these patients had a patent but severely narrowed LAD and a low incidence of collateral circulation to the LAD.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of Procainamide, Propranolol and Verapamil on Mechanism of Tachycardia in Patients With Chronic Recurrent Ventricular Tachycardia

The effect of short-term intravenous administration of procainamide (12 patients), propranolol (4 patients) and verapamil (4 patients) was studied in 12 patients with chronic recurrent sustained ventricular tachycardia. In all patients tachycardia could reproducibly be initiated and terminated with programmed electrical stimulation of the heart. Procainamide (1) lengthened the effective refractory period of the right ventricle, (2) affected the tachycardia zone, (3) reduced ventricular rate during tachycardia, and (4) lengthened the interval between the tachycardia-initiating premature ventricular beat and the first QRS complex of tachycardia. No effect on the refractory period of the right ventricle or the mechanism of tachycardia was seen after administration of propranolol or verapamil. Apart from their therapeutic implications these data suggest that it may be possible to use drugs to study mechanisms of ventricular tachycardia in the human heart.

Abciximab in the treatment of acute myocardial infarction eligible for primary percutaneous transluminal coronary angioplasty: Results of the glycoprotein receptor antagonist patency evaluation (GRAPE) pilot study

OBJECTIVES We sought to study the effect of early infusion of abciximab on coronary patency before primary angioplasty in patients with acute myocardial infarction. BACKGROUND Glycoprotein IIb/IIIa antagonists have proved to be effective in reducing ischemic events associated with coronary angioplasty. The present study explores whether abciximab alone, without administration of thrombolytic therapy, may induce reperfusion in patients with acute myocardial infarction. METHODS In the Glycoprotein Receptor Antagonist Patency Evaluation pilot study 60 patients with less than 6 h signs and symptoms of acute myocardial infarction eligible for primary angioplasty received in the emergency room a bolus of abciximab 250 microg/kg followed by a 12-h infusion of 10 microg/min. All patients were also treated with an oral dose of 160 mg aspirin and 5,000 IU of heparin intravenously. As soon as possible a diagnostic angiography was performed to evaluate the patency of the infarct-related artery. RESULTS The median time between onset of symptoms and the administration of the abciximab bolus was 150 min (range 45 to 345), and the median time between abciximab bolus and first contrast injection in the infarct-related artery was 45 min (range 10 to 150). In 24 patients (40%, 95% confidence interval 28% to 52%) Thrombolysis in Myocardial Infarction (TIMI) flow grade 2 or 3 was observed at a median time of 45 min (range 10 to 150) after abciximab bolus; TIMI flow grade 3 was observed in 11 patients (18%, 95% confidence interval 9% to 28%). There was no difference in percentage of TIMI flow grade 2 or 3 between patients who received abciximab within 2.5 h after onset of symptoms or thereafter. CONCLUSIONS Abciximab therapy given in the emergency room in patients awaiting primary angioplasty is associated with full reperfusion (TIMI flow grade 3) in about 20% and with TIMI flow grade 2 or 3 in about 40% of the patients at a median time of 45 min. These figures are higher than those in primary angioplasty trials without such pretreatment. Randomized controlled trials of very early infusion of abciximab, either prehospital or in-hospital, in patients eligible for angioplasty are warranted.

Effect of amiodarone in the Wolff-Parkinson-White syndrome

The effect of amiodarone in the Wolff-Parkinson-White syndrome was studied with programmed electrical stimulation of the heart in 15 patients. All 15 patients had circus movement tachycardias; 7 also had atrial fibrillation. Programmed electrical stimulation was performed before and after 14 days of oral administration of amiodarone. The effective refractory period of the accessory pathway lengthened in an atrioventricular direction in all patients and in a ventriculoatrial direction in eight patients. The effective refractory period of the atrium and ventricle lengthened in 14 and 12 patients, respectively. After administration of amiodarone, circus movement tachycardia could no longer be initiated in five patients. The zone of tachycardia narrowed in four patients, did not change in two and increased in seven. The effect of amiodarone on initiation of circus movement tachycardia could be related to differences in effect of the drug and in the mechanism of tachycardia in individual patients. In all patients in whom tachycardias could still be initiated after treatment with amiodarone the heart rate during tachycardia was slower than before treatment. This slowing was caused by a decrease in conduction velocity of the circulatory wave in different parts of the tachycardia circuit. The effect of amiodarone in prolonging the refractory period of the accessory pathway makes this drug especially useful in patients with the Wolff-Parkinson-White syndrome and atrial fibrillation.

Does angiography six months after coronary intervention influence management and outcome

OBJECTIVES This study was performed to assess whether angiography six months after coronary balloon angioplasty or stent implantation has an influence on clinical management and one-year outcome. BACKGROUND The Benestent II study randomized 827 patients to balloon angioplasty or stent implantation. A subrandomization was undertaken allocating patients to six-month clinical follow-up (CF) or clinical and angiographic follow-up (AF). METHODS Seven hundred and six patients (349 CF and 357 AF) had no intercurrent angiography, so that restenosis and disease progression elsewhere remained unknown until the time of six-month follow-up. These two groups, which were well matched at enrolment, were compared with respect to symptoms, medication and major cardiac events defined as death, myocardial infarction and need for revascularization at six and 12 months. RESULTS At six-month follow-up, 53 (15%) of the CF and 76 (21%) of the AF patients had stable angina (p = 0.041), while 5 (1%) and 4 (1%) had symptoms of unstable angina. At 12-month follow-up, 44 (13%) patients in both groups had stable angina, and only 1 patient in the CF group had unstable angina. Seventy-seven patients (27 CF and 50 AF; p < 0.01) had major cardiac events between 6 and 12 months. Of the 349 patients in the CF group, 21 underwent repeat percutaneous transluminal coronary angioplasty or coronary artery bypass graft surgery between 6 and 12 months, compared with 44 of the 357 patients in the AF group (relative risk 2.05 [1.24 to 3.37], p = 0.003). CONCLUSIONS Patients who had AF six months after balloon angioplasty or stent implantation experienced more repeat revascularization procedures than those who had CF. They also had significantly more angina at six-month follow-up but this may be due to bias.

Effect of isoproterenol on the anterograde refractory period of the accessory pathway in patients with the Wolff-Parkinson-White syndrome

To evaluate the effect of beta adrenergic stimulation on the duration of the anterograde refractory period of the accessory pathway, isoproterenol was infused in seven patients with the Wolff-Parkinson-White syndrome. In two patients the effect of isoproterenol was studied during long-term oral amiodarone administration. To avoid rate-related changes induced by isoproterenol, the anterograde refractory period of the accessory pathway was determined using the single test stimulus method at identical basic cycle lengths. Isoproterenol shortened the anterograde refractory period of the accessory pathway in six of the seven patients studied. In two of the three patients with an initial anterograde refractory period of the accessory pathway of equal to or less than 290 ms, shortening measured 30 ms. In three patients having an anterograde refractory period of the accessory pathway of more than 290 ms, isoproterenol abbreviated these values by 30, 60 and 80 ms, respectively. The greatest amount of shortening was observed in patients having the longest initial values for the anterograde refractory period of their accessory pathway. In the two patients receiving oral amiodarone therapy, isoproterenol shortened the anterograde refractory period of the accessory pathway by 180 and 60 ms, respectively, indicating that the effect of isoproterenol can not be prevented by long-term oral amiodarone administration. Our observations may be of importance in patients with the Wolff-Parkinson-White syndrome and atrial fibrillation. They suggest that beta adrenergic stimulation induced by hypotension or anxiety may result in shortening of the anterograde refractory period of the accessory pathway, leading to increased ventricular rates during atrial fibrillation.

Use of ajmaline in patients with the Wolff-Parkinson-White syndrome to disclose short refractory period of the accessory pathway

Ajmaline given intravenously produced complete anterograde block in the accessory pathway of 32 of 59 patients with the Wolff-Parkinson-White syndrome. An electrophysiologic investigation performed 1 day later revealed that failure of ajmaline to produce complete anterograde block in the accessory pathway corresponded to a short refractory period of this pathway (less than 270 ms). The use of ajmaline intravenously is advanced as a reliable and rapid procedure for identifying those patients with the Wolff-Parkinson-White syndrome who have a short refractory period of the accessory pathway and are possible at risk of circulatory insufficiency or sudden death if atrial fibrillation supervenes.