Long term efficacy and toxicity of amiodarone in the treatment of refractory cardiac arrhythmias.

Amiodarone has remarkable efficacy, but it also has a high incidence of severe side effects. Nevertheless, it is extensively used. The findings of an amiodarone treatment follow-up period of one to 72 months (mean 19 +/- 17) in 95 patients with recurrent life threatening arrhythmias resistant to other antiarrhythmic drugs are described. The mean loading dose of 800 mg/day for one week was followed by an average dose of 600 mg/day for two weeks. The long term daily dose was 400 mg in 80 patients and 200 mg in the remaining 15 patients. Amiodarone was particularly effective in suppressing complex ventricular arrhythmias. It also decreased premature ventricular beats by 83% and atrial premature beats by 41%. Supraventricular tachycardias were completely controlled and the ventricular response to atrial fibrillation was slowed. Twelve of the 95 patients (12.6%) died while taking amiodarone, two of sudden death and 10 of heart failure. Side effects were recorded in 77 (81%) patients. They were generally dose related and subsided with a decrease in dose or discontinuation of the medication. There was a correlation between the concentration of rT3 and the significance of the side effects. Thirty-nine patients stopped taking amiodarone, however, only 14 of these stopped because of toxicity: five developed pulmonary fibrosis; three had neurological toxicity; two had bradyarrhythmias; two developed hepatic dysfunction; one had hypothyroidism; and one patient suffered an aggravation of a pre-existent heart failure. It was concluded that amiodarone is a very effective treatment for supraventricular and ventricular arrhythmias. However, it does have numerous and severe side effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of oral sotalol in suppression of premature ventricular complexes and analysis of its beta-adrenergic blocking activity.

The efficacy of oral DL-sotalol in suppressing premature ventricular complexes was assessed by Holter recordings in 28 patients during short term (two weeks) and long term (two years) trials, and its beta-adrenergic blocking effects were evaluated by heart rate response to the Bruce treadmill stress test and plasma catecholamine increases upon active standing. Sotalol produced a significant decrease (more than 85%) in the number of premature ventricular complexes, during both short term (54%) of patients) and long term (39% of patients) trials. The doses employed in this study (320 mg/day) produced mild to moderate degrees of beta-adrenergic blockade as suggested by: a 20% reduction in the mean heart rate on 48 h Holter monitoring (P less than 0.0005); a 15 to 30% reduction in tachycardia induced by strenuous exercise; and a 12% reduction in standing-induced tachycardia. Under long term sotalol therapy the increase in plasma noradrenaline concentrations in response to active standing was not modified, but the increase in plasma adrenaline concentrations was greater than under baseline conditions (P less than 0.025). Both systolic and diastolic blood pressures significantly increased during long term sotalol administration (P less than 0.005 and P less than 0.025, respectively). However, blood pressure remained within the normotensive range during sotalol therapy. It was concluded that sotalol provides, at effective antiarrhythmic doses, a satisfactory level of beta-adrenergic blockade which during standing was associated with significant changes in adrenaline plasma increments.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of the diagnostic yield of Holter versus transtelephonic monitoring.

OBJECTIVE: To compare the diagnostic yield of transtelephonic monitoring (TTM) with Holter monitoring in patients presenting possibly arrhythmogenic symptoms. DESIGN: A prospective comparison of Holter monitoring with TTM performed sequentially in all subjects. SETTING: Tertiary arrhythmia clinic at Hôpital du Sacré-Coeur de Montréal, Montréal, Québec. PATIENTS: One hundred consecutive patients (34 men and 66 women, mean +/- SD age 55 +/- 16 years) presenting over a two-year period for diagnosis of intermittent palpitations and/or syncope/dizziness. INTERVENTIONS: Subjects first underwent 24 h Holter monitoring and then were provided with TTM for 25 +/- 13 days, with instructions to record during symptomatic episodes and subsequently to transmit the recording at their convenience. MAIN RESULTS: Holter monitoring documented arrhythmia in 30 patients whereas TTM identified arrhythmia in 21. TTM was most useful in excluding arrhythmia during symptoms (34 patients) versus Holter (two patients). Neither method was useful in diagnosing syncope. Frequency of occurrence of palpitations did not predict which method would most likely yield a diagnosis but palpitations lasting longer than 2 mins were likely to be diagnosed by TTM. CONCLUSIONS: Holter and TTM are complementary studies whose combined use increases the diagnostic yield of arrhythmia. Further, TTM is of greatest use in excluding arrhythmia during intermittent symptoms.

Cineangiography of the coronary arteries: clinical function and anatomic correlation in patients with chronic chest pain.

Fifty French-Canadian patients presenting with typical or atypical anginal pain were studied by selective cinearteriography and coronary sinus catheterization, with measurement of myocardial function, oxygen and lactate extraction at rest and during isoproterenol infusion. In 28 of 42 patients all three coronary arteries were involved, but angina pectoris also occurred in patients with single mildly stenotic arterial lesions and even in eight patients with normal cinearteriograms. All patients with severe arterial lesions had typical angina, and the longer the duration of angina, the greater the extent, usually, of anatomic disease. Seventy-nine percent of resting electrocardiograms of patients with documented coronary artery disease were abnormal, with recognizable prior infarction in 18. Two-thirds of the patients experiencing pain during the stressful state had abnormal ventricular function. An abnormal arteriovenous lactate difference in response to isoproterenol occurred in patients in all groups.

Coronary hypertonia and angina.

Coronary hypertonia was observed in a patient with unstable angina. It was possible on one occasion to reproduce the clinical picture, electrocardiographic changes, lactate production and coronary hypertonia by means of atrial pacing. He had a normal left coronary arteriogram when the diffuse spasm was relieved by nitroglycerin. Therefore hypertonia (or spasm) of the left coronary artery was believed to be the cause of his variant angina with subendocardial ischemia.

Wolff-Parkinson-White VCG patterns that mimic other cardiac pathologies: a correlative study with the preexcitation pathway localization.

Vectorcardiograms (VCGs) of 44 patients with a Wolff-Parkinson-White (WPW) syndrome have been analyzed with the aim to correlate the QRS loop patterns with specific preexcitation sites. The VCG QRS loops were analyzed to determine whether conduction abnormalities and myocardial infarction (MI)-like patterns observed in the WPW syndrome could be related to specific preexcitation sites identified by surgery as well as by body surface potential mapping (BSPM). Left bundle branch block pattern was observed with anteroseptal (AS) preexcitation, anterior MI pattern was seen with lateral right ventricle (LRV) preexcitation, left anterior fascicular block was observed with posterior right ventricle (PRV) preexcitation, inferoposterior and strictly posterior MI pattern was found with posteroseptal (PS) and posterior left ventricle (PLV) preexcitation, right bundle branch block was seen in lateral left ventricle (LLV) preexcitation, and right bundle branch block was observed with left posterior fascicular block in anterior left ventricle (ALV) preexcitation. These VCG criteria seem to identify accurately the preexcitation sites as observed by delta wave BSPM and at surgery investigations. Consequently, they could be useful in localizing the preexcitation site in cases of ambiguous delta vector orientation.

[Early and late outcome after aortocoronary bypass: experience in 500 cases]. / Evolution précoce et tardive après pontage aortocoronarien: expérience de 500 cas.

Between 1971 and 1976, 500 patients underwent aortocoronary bypass surgery. There were 15 operative deaths (3%) and the total frequency of perioperative infarction was 7%. The operative mortality was 7.4% in unstable angina, as compared with 1.1% in stable angina (P less than 0.01). The proportion of grafts patent at 2 weeks was 92% and at 18 months 87.6%. Postoperative follow-up was complete for 99% of the patients. There were 15 late deaths (3%) and the rates of survival at 2 and 4 years were 94.4% and 92.1% respectively. The actuarial curve of survival after surgery was not significantly different from that of the general population. After a mean follow-up of 27 months 73% of the patients were completely free of angina and 19% were markedly improved. The rate of recurrence of angina averaged 10% per year and the annual infarction rate was 0.7%. Fourteen patients (3%) underwent reoperation during the follow-up period. Thus, coronary revascularization surgery offers effective and sustained relief of incapacitating angina and might also improve survival if the operative mortality is low.

Myocardial infarction diagnosis with body surface potential mapping, electrocardiography, vectorcardiography and thallium-201 scintigraphy: a correlative study with left ventriculography.

In 35 subjects with typical or atypical angina and/or documented myocardial infarction (MI), body surface potential maps (BSPMs), ECG, VCG and rest Thallium-201 (T1-201) have been compared to left ventriculography (LVG). BSPMs were recorded with 26 ECGs, and BSPM abnormalities for MI cases were considered to be areas of normally positive potentials that have become negative. Subjects with MI were classified according to the segmental localization and degree of asynergy on LVG. Moderate anterolateral and apical asynergy were found to correlate with BSPM diagnosis of anterolateral MI and ischemia, severe anterolateral and apical asynergy with BSPM diagnosis of anterolateral MI and ischemia, and moderate diaphragmatic and/or posterobasal asynergy with BSPM diagnosis of posterior MI. Simultaneous anterior and posterior asynergy were found for BSPM diagnosis of anterior with posterior MI. Subjects with no LVG asynergy had normal BSPMs. BSPM diagnosis had the highest correlation coefficient with the LVG diagnosis (r = 0.88). ECG and VCG showed similar results with r = 0.65 and 0.71 respectively, while T1-201 had r = 0.55. The examination of our BSPMs, as well as the ECG, VCG and T1-201, did not permit to detect apical damage in presence of anterior MI, and posterobasal damage in the presence of inferoposterior MI. It is concluded that BSPMs are slightly superior to ECG and VCG for diagnosis of MI.

Comparative accuracy of the vectorcardiogram and electrocardiogram in the localization of the accessory pathway in patients with Wolff-Parkinson-White syndrome: validation of a new vectorcardiographic algorithm by intraoperative epicardial mapping and electrophysiologic studies.

The scalar electrocardiograms (ECGs) and vectorcardiograms (VCGs) of 41 patients with Wolff-Parkinson-White (WPW) syndrome were used to compare the accuracy of these techniques in the identification of the site of preexcitation. The location of the accessory pathway (AP) was determined by endocavitary electrophysiologic studies in all patients and the location was confirmed during intraoperative epicardial mapping in 28 of them. The ECGs were classified according to Gallagher's criteria and with Milstein's algorithm, whereas the VCGs were classified according to a new two-step algorithm. The presence of multiple accessory pathways and coexisting myocardial infarctions were major limitations in both the VCG and ECG classification procedures. In patients with a single accessory pathway, three AP localizations (right free ventricular wall, posterior, or left free ventricular wall) were identified with the first step of the VCG algorithm, with an overall sensitivity (96.5%), specificity (90.7%), and positive predictive values (80%) that were greater than those obtained with the ECG Milstein algorithm (77.1%, 91.5%, and 75%, respectively). The second step of the VCG algorithm made it possible to identify an AP location in one of the following sites: anterior right, lateral right, posterior right, posterior left, lateral left, or anterior left ventricle. The overall sensitivity, specificity, and positive predictive values were greater for the second step of the VCG algorithm than for the ECG criteria proposed by Gallagher (43.6% versus 39.3%, 92.1% versus 87.4%, and 51.5% versus 33.3%, respectively). It was concluded that the VCG seems to be more specific and sensitive than the ECG in the identification of the preexcitation site and should be given preference in the initial evaluation of the WPW syndrome.

Application of the single moving dipole inverse solution to the study of the Wolff-Parkinson-White syndrome in man.

The single moving dipole (SMD) inverse solution was performed in 28 patients with the Wolff-Parkinson-White preexcitation syndrome to see if the calculated position of the SMD during the initial delta wave could indicate the site of the underlying accessory pathway. This site was first estimated to be at one of eight locations around the atrioventricular ring, from the patient's QRS and ST segment body surface potential maps, as has been described by others. Next, SMD parameters were calculated during the delta wave so as to approximate, on a numerical torso model, the patient's body surface potential map. Visualization of the calculated position of the SMD around the atrioventricular ring was done by projecting it on a plane parallel to this ring. This plane corresponded to the most basal transverse section of a heart model present in the torso model. One limitation was the use of non-varying heart and torso models for all patients. As a result, the SMD technique lacked the precision to separate accessory pathway sites into eight atrioventricular locations. However it was capable of distinguishing between patients belonging to the larger classes of right-sided, posterior, and left-sided preexcitation, formed by combining adjacent atrioventricular accessory pathway locations. With more accurate heart and torso models, it may be possible to increase SMD resolution so as to locate accessory pathway sites deep within the heart. This would represent an advantage over the surface potential map approach which only identifies the site of earliest epicardial breakthrough associated with the accessory pathway.