Antazoline in the Treatment of Cardiac Arrhythmias S. S. SHAH C. H
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Postgrad Med J: first published as 10.1136/pgmj.48.559.304 on 1 May 1972. Downloaded from Postgraduate Medical Journal (May 1972) 48, 304-307. Antazoline in the treatment of cardiac arrhythmias S. S. SHAH C. H. VAIDYA M.D. M.D. H. V. DOSHI M.D. M. P. Shah Medical College and Irwin Group of Hospitals, Jamnager, Gujarat State, India Summary ventricular tachycardia. However, the drug was Antazoline was administered in sixty-five episodes of found to be ineffective in atrial flutter and fibrillation. various types of cardiac arrhythmia. Further clinical studies by Reynolds, Baird & A complete suppression of the ectopic beats was Clifford (1964), Kiger (1964), Herbst (1965) and achieved in five out of six episodes of premature atrial Herrmann et al. (1964) confirmed the efficacy of this systoles and in twenty-one of the twenty-four episodes agent in the treatment of various cardiac arrhyth- of ventricular premature systoles. mias. Recently Srinivas & Antani (1971) and Antani Conversion to sinus rhythm was observed in seven (1971) tried the drug in forty and fifty cases respec- out of ten and four out of five episodes of paroxysmal tively and reported similar favourable results. The of this is to our atrial and nodal tachycardia respectively. purpose paper present experiencecopyright. Six out of ten episodes of ventricular tachycardia with antazoline in the management of various types were controlled by intravenous therapy. However, the of cardiac arrhythmia. drug proved to be ineffective in cases of atrial fibrilla- tion. Materials and methods The side-effects were few and transitory, consisting The material of this report consists of sixty-five of nausea, vomiting and drowsiness. arrhythmic episodes treated with antazoline. All the patients were admitted to the Irwin Group of Introduction Hospitals, Jamnagar. In some cases the arrhythmia http://pmj.bmj.com/ Following the reports of Graham (1947) and was the reason for admission to hospital while in Craver, Barrett & Cameron (1951) antazoline 2- others the arrhythmia developed in hospital. (N-benzylanilinomethyl)-2-imidazoline was intro- Occasionally patients were counted more than once duced as an antihistamine and still is in use though in the series because of different arrhythmias occur- almost completely replaced by newer antihistamines. ring during the same hospitalization. All the patients Dutta (1948) reported that antazoline antagonized were subjected to complete clinical examination with the depressant action of acetycholine on rabbit particular reference to their cardiovascular status and on September 25, 2021 by guest. Protected atrium and decreased the maximum rate of electrical the underlying disease triggering the cardiac arrhyth- stimulation to which atrial muscle could respond. mia. A control 12 lead electrocardiogram with a Furthermore, it appeared to be about twice as potent long strip of leads II and VI was recorded to as quinidine in its ability to prolong the refractory establish the type of arrhythmia. All anti-arrhythmic period of the atrium. drugs except maintenance doses of digitalis were In 1952, McKechnie first demonstrated a great omitted prior to administration of antazoline. Sup- reduction in the number of ventricular premature portive therapeutic measures like oxygen, vaso- contractions in man after intravenous and oral pressor drugs, bronchodilators etc. were used when antazoline. Brown (1962) demonstrated the effective- indicated. Before attempting conversion, anti- ness of antazoline in the prevention of ventricular coagulant therapy was instituted in cases with atrial fibrillation during cooling and rewarming experi- fibrillation. ments in dogs. Dreifus, Rabbino & Watanabe (1963) In all cases of ventricular tachycardia antazoline reported in their study of 143 episodes of arrhythmia phosphate was administered intravenously in doses that antazoline was effective in the suppression of of 50 mg at intervals of 5 min till termination of atrial and ventricular premature systoles and arrhythmia or a maximum dose of 10 mg/kg body useful in the termination of paroxysmal atrial and weight had been administered. An ECG was taken Postgrad Med J: first published as 10.1136/pgmj.48.559.304 on 1 May 1972. Downloaded from Antazoline in treatment of cardiac arrhythmias 305 before injecting each fresh dose till conversion arrhythmia as a terminal event in uraemia with occurred, and repeated after 12 hr and every 24 hr hyperkalemia and two patients developed supraven- in successful cases. After the reversion ofthe arrhyth- tricular tachycardia postoperatively. mia an effective concentration was maintained by In six patients with atrial premature beats, com- antazoline hydrochloride 100 mg orally 4-hourly for plete suppression was obtained in five (Fig. 1) and 2 weeks. ectopic contractions were reduced by 70% in the re- In all other cases antazoline hydrochloride was maining one. administered by mouth first in doses of 100 mg 4- Of twenty-four episodes of ventricular premature hourly; if this regimen was not effective within 24 hr, beats, twenty-one were completely suppressed within the dose was increased to 200 mg every 4 hr for a 24 hr (Fig. 2) while there was 70% suppression in further six doses and further increased to 300 mg three. Following the withdrawal of antazoline there every 4 hr in unsuccessful cases. Absence of response was a recurrence in only two patients, both ofwhom to this dosage within 24 hr was taken as failure. were suffering from myocardial infarction. Antazo- The effectiveness of antazoline was considered line was re-administered and premature beats were good when all ectopic beats were abolished or an again eliminated. All the fourteen episodes of ven- ectopic tachycardia had been converted to sino- tricular premature beats due to digitalis responded atrial rhythm. The results were recorded as satisfac- to antazoline. tory when 70% of the ectopic beats had been cleared Conversion to regular sinus rhythm in the present and when an interrupted paroxysm had not recurred series was achieved in seven out of ten and four out within 12 hr. After the arrhythmia had been conver- of five episodes of paroxysmal atrial and nodal ted, antazoline was administered in the same doses tachycardia respectively (Fig. 3). One case ofparoxys- for 48 hr and then reduced to half for another 48 hr mal atrial tachycardia with thyrotoxic heart disease and then suspended. did not respond to antazoline, while there was a recurrence in one case after 48 hr when the antazoline Results dosage was halved. Sixty-five episodes of various cardiac arrhythmias All the patients who had atrialfibrillation demon- copyright. in fifty-six patients were included in the present strated no significant change in ventricular rate. The series. There were thirty-one males and twenty-five atrial mechanism remained unchanged and in no females, with ages ranging from 13 to 65 years, mean case was sinus rhythm restored. All these cases had 40-2. As shown in Table 1 there were six episodes of atrial fibrillation of more than 3 years' duration. premature atrial systoles, twenty-four episodes of Termination of paroxysmal ventricular tachy- premature ventricular systoles, fifteen of paroxysmal cardia by intravenous administration of antazoline supraventricular tachycardia, ten of auricular phosphate was fairly successful (Fig. 4). Out of ten fibrillation and ten of ventricular tachycardia. Out of episodes so treated there was termination of the http://pmj.bmj.com/ fifty-six patients, fifty had organic heart disease; of attack in six. Two cases had advanced uraemia with these, twenty-five had rheumatic heart disease, hyperkalemia; though included as failures in this twenty had acute myocardial infarction, four had series they died only after four and six doses of 50 congenital heart disease and one had thyrotoxic mg each of antazoline had been injected. Both of heart disease. Two cases developed a cardiac them developed atrial standstill; the ventricular rate on September 25, 2021 by guest. Protected TABLE 1. Showing the results of conversion of arrhythmias with antazoline therapy Response Sr. Type of arrhythmia Total no. no. of episodes Good Satisfactory Poor % of good response 1 Atrial ectopic beats 6 5 1 - 83-3 2 Ventricular ectopic beats 24 21 3 87-5 3 Paroxysmal supraventricular tachycardia 15 11 2 2 73-3 (a) Atrial 10 7 1 2 70-0 (b) Nodal 5 4 1 80-0 4 Atrial fibrillation 10 - - 10 5 Ventricular tachycardia 10 6 1 3 60-0 Postgrad Med J: first published as 10.1136/pgmj.48.559.304 on 1 May 1972. Downloaded from 306 S. S. Shah, C. H. Vaidya and H. V. Doshi Discussion The reported results with antazoline in the various types of cardiac arrhythmias are compared in Table :- ali~jE ':'i-- 2. those an excellent re- |< j:c32..,i;.W3? R...:.:ij'^'.;~....., :": Only episodes exhibiting eif ii!iiii ;.·^·¢..|.\<.'...; .........:, >wah ,:2 ,fi~iil 'ij sponse are included in the table for comparison. As shown in Table 1, five out of six patients having i:·tBS! Ciitq: i;iSsiiB ~iZ'i ;. .i : Ei: :. ';:"" i; i. 2°° beats and out .....:i'.;t.^8S:~;. ....;;;;;-; : ...... atrial premature twenty-one of twenty- *w: .i~;::...x:i ·:. } . ::: ..i{.. four having ventricular premature beats were treated successfully in this series. Similar results were re- ported by various workers (Kline et al., 1962; FIG. 1. ECG (lead 11) of a patient with atrial extra- Dreifus et al., 1963; Kiger, 1964; Herrmann et al., systoles. (a) Before and (b) after conversion with antazo- 1964; Srinivas & Antani, 1971; Antani, 1971). It line. appears from this that antazoline is effective in con- atrial 951M. @ trolling and ventricular premature beats re- W......... gardless of aetiology. Similarly, antazoline was found to be effective in paroxysmal atrial and nodal tachy- ...:i~l~i·:i cardias. About 70% of episodes of supraventricular ....:i....:····. ..~ tachycardia in the present series were converted to .. sinus rhythm with oral antazoline. Dreifus et al. (1963) treated thirteen cases of paroxysmal atrial FIG. 2. ECG (lead II) of a patient with ventricular tachycardia with intravenous antazoline with only extrasystoles.