Verapamil induced premature ventricular beats before reversion of supraventricular tachycardia

Electrophysiologic characteristics of wide QRS complexes during pharmacologic termination of sustained supraventricular tachycardias with verapamil and adenosine: observations from electrophysiologic study

BACKGROUND

In this study we evaluate wide QRS complexes observed during pharmacologic termination of supraventricular tachycardias.

METHODS

Patients with supraventricular tachycardia, undergoing electrophysiologic study were enrolled. 12 mg of adenosine or 10 mg of verapamil were administered during tachycardia, under continuous monitoring of intaracardiac and surface electrocardiograms. Electrocardiographic features of ventricular ectopy were noted.

RESULTS

Seventy-four patients were enrolled. 48 patients were randomized to adenosine and 26 to verapamil. Five different appearance patterns of ventricular ectopy were observed during termination of tachycardias. All wide QRS complexes were of ventricular origin and all of them were observed during the termination of tachycardia. Adenosine more frequently resulted in appearance of ventricular beats (15.4% vs 41.7%, P = 0.003), and this was more frequently observed in patients with atrioventricular nodal reentrant tachycardia. Patients with ventricular beats were younger than those without, in both, verapamil (47.5 +/- 15.6 vs 65.0 +/- 8.8 years, P = 0.04) and adenosine (40.9 +/- 13.8 vs 49.7 +/- 16.8, P = 0.03) groups. Left bundle branch block (LBBB)/superior axis morphology was most frequent morphology in adenosine group (55%). Two of 4 patients in verapamil group displayed LBBB/inferior axis QRS morphology and another 2 patients displayed LBBB/superior axis morphology.

CONCLUSIONS

Noncatheter induced, five different appearance patterns and four distinct morphologies of ventricular origin were observed. Most of them do not directly terminate tachycardia, but are associated with its termination and are not observed in ongoing tachycardia.

Clinical significance of wide QRS complexes at the termination of paroxysmal supraventricular tachycardias

BACKGROUND

A wide QRS complex is not a rare electrocardiographic phenomenon at the termination of paroxysmal supraventricular tachycardia (PSVT), but no plausible underlying mechanism has yet been proposed. The purpose of the present study was to elucidate the frequency and the underlying mechanism of the wide QRS complexes at the termination of PSVT.

METHODS

We retrospectively reviewed 305 electrocardiograms (ECGs) from 100 patients, on which PSVT termination was recorded. The frequency of the wide QRS complexes was analyzed in 181 ECGs to avoid duplication, because there were 124 ECGs obtained from the same patients with same methods. The 181 ECGs were divided by morphology into three groups: Type A, termination with wide QRS complex without pause; Type B, wide QRS complex following initial pause after termination; Type C, wide QRS complex following the first narrow QRS after termination.

RESULTS

The wide QRS complex was recorded in 81/181 (44.8%) ECGs (Type A; 3/81 (3.7%), Type B; 44/81 (54.3%), Type C; 62/81 (55.6%) ) and its frequency was not dependent on the mechanism of PSVT. It was more frequently observed after a long pause, and was frequently induced by procedures that increase vagal tone, such as intravenous adenosine 5'-triphosphate administration (16/22: 72.7%) and vagal stimulation maneuvers (16/32: 50%). There were a total of 41 wide QRS complexes (44.6%) which had a preceding sinus P wave, out of a total of 92 wide QRS complexes in all three types. These 41 wide QRS complexes included 30/44 (68.2%) Type B wide QRS, and 11 (24.4%) Type C wide QRS complexes.

CONCLUSION

The aberrant conduction or escaped ventricular contraction was suggested to be the underlying mechanism of the majority of wide QRS complexes and ventricular premature contraction is less frequent.

Adenosine versus verapamil in the treatment of supraventricular tachycardia: a randomized double-crossover trial

The safety and efficacy of verapamil and adenosine in the acute termination of supraventricular tachycardia were compared in a randomized double-crossover trial. Of 32 eligible patients with either spontaneous or induced narrow complex tachycardia, seven (22%) patients experienced conversion to sinus rhythm with carotid sinus massage. The other 25 patients were randomly assigned to receive either adenosine (n = 14) or verapamil (n = 11). Relative drug efficacies were 100% for adenosine versus 73% for verapamil, p = NS. Adenosine given at less than or equal to 120 micrograms/kg caused conversion in 12 (86%) of 14 patients. The other two patients required 20 mg adenosine for conversion. After conversion the systolic blood pressure increased significantly in the adenosine group but not in the verapamil group. Reinitiation of tachycardia occurred in two (14%) of 14 patients randomized to the adenosine group. Serious adverse hemodynamic effects were observed in one (9%) of 11 patients randomized to verapamil. The incidence of conversion arrhythmias was similar in both treatment groups (adenosine 57%, verapamil 50%, p = NS).

Efficacy and safety of intravenous sotalol for termination of paroxysmal supraventricular tachycardia. The Sotalol Versus Placebo Multicenter Study Group

A double-blind, placebo-controlled, crossover, multicenter study was conducted to study the efficacy and safety of a single intravenous dose of sotalol (1.5 mg/kg over 10 minutes) in achieving normal sinus rhythm in paroxysmal supraventricular tachycardia (SVT) lasting greater than or equal to 15 minutes. Patients were randomized to either sotalol or placebo as initial treatment, and if the SVT was not terminated a crossover was performed after 20 minutes. A total of 43 patients were enrolled, 38 of whom with spontaneous (n = 14) or induced (n = 24) SVT were analyzed for sotalol efficacy. Most patients (n = 27) had atrioventricular (AV) nodal reentrant tachycardia, and an important subgroup (n = 11) had circus movement tachycardia, using an accessory pathway for retrograde conduction. The number of patients converting to sinus rhythm as a result of the initial treatment was significantly higher in the sotalol group than in the placebo group, for spontaneous (p less than 0.005) as well as for induced tachycardia (p less than 0.001). Sinus rhythm was achieved within 30 minutes in 83% of all patients who received sotalol as the first drug, compared with 16% of the patients first receiving placebo (p less than 0.0001). For sotalol safety analysis, 42 patients were included. A total of 37 patients received sotalol, 19 as the first treatment, and 18 as the second treatment, while 25 patients received placebo. A total of 15 possible adverse effects were reported, occurring in 10 patients with sotalol versus 4 with placebo. The only severe side effect (hypotension) necessitating termination of drug administration occurred with placebo. No proarrhythmic effects were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute management of paroxysmal atrioventricular junctional reentrant supraventricular tachycardia: pharmacologic strategies

A vast array of effective antiarrhythmic agents offers the attending physician attractive options for termination of PJRT. Calcium channel blockers, adenosine compounds, amjaline, and the newer drugs flecainide and propafenone offer an efficacy rate of more than 80% for acute termination of PJRT. Choice should be based on the patient's clinical characteristics including any underlying cardiac or noncardiac pathologic conditions, hemodynamic status, and current medications. Drugs with a very short half-life (adenosine compounds) offer the possibility of repeated administration at increasing dosages or of subsequent administration of a second antiarrhythmic drug without fear of increased adverse effects or drug interactions. Drugs with a long half-life, such as calcium channel blockers, flecainide, and propafenone, have the potential advantage of preventing an immediate recurrence of the arrhythmia. Adenosine compounds are the fastest acting drugs, resulting in termination of PJRT in less than 30 seconds. The cardiac side effects of all antiarrhythmic drugs represent an exaggeration of their intrinsic electrophysiologic and hemodynamic effects. Thus hemodynamic decompensation and bradyarrhythmias resulting from sinus nodal, AV nodal, or infranodal dysfunction are of major concern. Side effects of adenosine compounds are extremely common but very short lasting. Verapamil is both highly effective and safe except in very special circumstances. Guidelines for therapy of PJRT in specific groups of patients are provided.

Comparative clinical and electrophysiologic effects of adenosine triphosphate and verapamil on paroxysmal reciprocating junctional tachycardia

The efficacy, electrophysiologic effects, and side effects of adenosine triphosphate (ATP) and verapamil in the short-term management of paroxysmal reciprocating junctional tachycardia (PRJT) were compared in 20 patients. All patients had inducible sustained PRJT during control electrophysiologic study. Fourteen patients had PRJT involving a retrograde accessory pathway, and six patients had atrioventricular (AV) nodal reentrant tachycardia ("slow-fast" type). ATP, which has a very short half-life, was first administered (10 mg iv over 1 sec) during sustained PRJT. If PRJT did not terminate within 2 min, a bolus of 20 mg ATP was given. Verapamil (5 mg iv over 15 sec) was subsequently administered during sustained PRJT, and if the latter did not terminate within 3 min another bolus of 5 mg verapamil was given. The cycle lengths of PRJT before administration of 10 or 20 mg ATP and 5 mg verapamil were similar. The 10 mg dose of ATP terminated PRJT in 17 of the 20 patients, and 20 mg ATP was required to terminate PRJT in the three remaining patients. The 5 mg dose of verapamil terminated PRJT in 15 patients, whereas an additional bolus of 5 mg terminated PRJT in one of the remaining five patients. The overall efficacy of ATP (20/20, 100%) was significantly greater than that of verapamil (16/20, 80%) (p less than .05); however, there was no significant difference between the conversion rate of PRJT after administration of 10 mg ATP (17/20) and 5 mg verapamil (15/20). ATP terminated PRJT more quickly than verapamil (mean 24 sec vs mean 51 sec; p less than .01). Termination of PRJT by either ATP or verapamil was mainly related to a block in the AV node in patients with accessory pathways and to a block in the antegrade slow pathway in patients with AV nodal reentry. Cycle length alternans before termination of tachycardia was observed more frequently after verapamil than after ATP (7/16 vs 1/20; p less than .01). The total incidence of transient second-degree AV nodal block and various cardiac supraventricular and ventricular arrhythmias was higher after termination of PRJT by ATP than after verapamil (17/20 vs 5/16; p less than .001). A higher incidence of transient but frequently uncomfortable noncardiac side effects was observed after ATP. We conclude that ATP (10 to 20 mg) is more effective and more rapid than verapamil (5 or 5 + 5 mg) in terminating PRJT but results in a higher incidence of cardiac and noncardiac side effects.(ABSTRACT TRUNCATED AT 400 WORDS)

Pirmenol in the termination of paroxysmal supraventricular tachycardia

The effects of pirmenol in terminating paroxysmal supraventricular tachycardia were studied in 25 patients. Pirmenol was administered as 1 or 2 injections of 50 mg to 17 patients during a spontaneous attack, or as a 50-mg bolus followed by steady infusion of 2.5 mg/min in 8 patients during a tachycardia that was induced electrophysiologically. Termination was successful in 11 of 17 patients who had a spontaneous attack and in 3 of 8 patients who had induced tachycardia. Pirmenol was effective in 3 of 5 patients with atrioventricular nodal reentrant mechanism, but in none of 3 patients with a reentrant tachycardia with a retrogradely conducting atrioventricular bypass tract. Conversion to sinus rhythm was achieved in 14 of 25 patients (56%). No hemodynamic adverse effects occurred. Pirmenol increased the atrial effective refractory period, but had little effect on conduction in the atrioventricular node and His-Purkinje system. Reentry was abolished through a block in the retrograde part of the dual atrioventricular nodal pathway, which is typical of class I antiarrhythmic agents.

Effective termination of reentrant supraventricular tachycardia by single dose oral combination therapy with pindolol and verapamil

We evaluated the efficacy of single oral dose combining 20 mg pindolol and 120 mg verapamil in termination of paroxysmal supraventricular tachycardia (SVT) in 12 patients with recurrent symptomatic tachycardia. All had electrically inducible SVT lasting longer than 30 minutes. Patients were administered placebo or crushed pindolol and verapamil on 2 consecutive days after tachycardia was electrically induced and allowed to sustain for 30 minutes. With placebo, SVT lasted 186 +/- 18 minutes (mean +/- SEM); five patients converted spontaneously within 121 to 180 minutes. With pindolol and verapamil, 9 of 12 patients (responders) converted to sinus rhythm within 8 to 74 minutes. The mean duration of SVT in the nine responders was 28 +/- 8 minutes compared with 168 +/- 20 minutes on placebo (p less than 0.001). Before termination, tachycardia rate on pindolol and verapamil slowed significantly from 182 +/- 5 to 164 +/- 7/min (p less than 0.05) compared with no significant change in the rate of SVT on placebo. The mean systolic blood pressure during tachycardia was 97 +/- 5 mm Hg with placebo and 101 +/- 7 mm Hg with pindolol and verapamil. Serum levels of pindolol and verapamil obtained in seven patients at time of spontaneous termination of tachycardia were 66 +/- 13 and 56 +/- 14 ng/ml, respectively. The side effects with pindolol and verapamil included lightheadedness in one patient and symptoms of rapid palpitations in three. A single oral dose of pindolol and verapamil is safe and effective in termination of acute paroxysmal SVT and may be the initial therapy of choice in selected patients.

Pirmenol in termination of paroxysmal supraventricular tachycardia

An assessment was made of the effect of pirmenol in the termination of paroxysmal supraventricular tachycardia (SVT). Sinus rhythm was restored by intravenous administration in 11 of 17 patients during a spontaneous attack. Another 8 patients were studied electrophysiologically. Pirmenol terminated an induced SVT in 3 of 5 patients having an atrioventricular (AV) intranodal re-entry mechanism but in none of 3 patients having an atrioventricular bypass tract as one re-entrant limb. The overall success in restoring sinus rhythm was 14 of 25 patients (56%). The drug was hemodynamically well tolerated even in cases of continued SVT. Pirmenol increased the atrial effective refractory period and had no obvious effect on AH and HV intervals. The functional refractory period of the AV node was decreased, probably by an anticholinergic effect. The effective and functional refractory periods of retrograde atrioventricular conduction via the AV node and bypass tract were increased in some patients. The mechanism terminating the AV intranodal SVT was a block in the retrograde part of the dual AV nodal pathway, a typical antiarrhythmic Class I effect.

Verapamil-induced polymorphous ventricular tachycardia

A 31 year old woman who developed an atypical ventricular tachycardia after administration of intravenous verapamil for control of a recurrent supraventricular tachycardia is presented. Possible explanations for the observed arrhythmia, polymorphous ventricular tachycardia, are discussed. Verapamil must be considered one of the pharmacologic agents that can cause this arrhythmia.

Effects of verapamil on supraventricular tachycardia in patients with overt and concealed Wolff-Parkinson-White syndrome

Verapamil (0.15 mg/kg) intravenously, was administered to 19 patients with recurrent supraventricular tachycardia (SVT) undergoing electrophysiological evaluation. Twelve patients had overt Wolff-Parkinson-White (WPW) syndrome and seven patients had concealed accessory pathways conducting in the retrograde direction only. Verapamil had a significant effect in delaying conduction and prolonging refractoriness in the atrioventricular (AV) node, but no significant actions on any of the other cardiac tissues that formed the tachycardia circuit in these patients. In particular, it had no significant effects on anterograde or retrograde bypass conduction or refractoriness. Sustained SVT was initiated in 15 patients, and was terminated within 60 to 105 seconds of a 30-second injection of verapamil in 13 patients. Cycle length alternation during SVT was seen in six patients prior to reversion, and spontaneous ventricular complexes (VPCs) were observed following verapamil administration in five patients. Two patients with apparently normal sinus node function showed prolongation of their sinus node recovery times immediately following reversion of SVT by verapamil. Echo zones were assessed before and after verapamil, and sustained or self-terminating SVT could still be induced after the drug in 13 of the 15 patients who had sustained SVT beforehand. It was concluded that intravenous verapamil was effective in terminating sustained SVT in the majority of patients with overt or concealed WPW and that, despite a potential for sinus node depression and the initiation of VPCs, it had no clinically significant side effects. The ability to reinitiate SVT following its administration suggests the need for immediate follow-up with maintenance drug therapy.

Electrocardiographic observations on the termination of supraventricular tachycardia by verapamil

The effect of intravenous verapamil on the termination of supraventricular tachycardia (SVT) was studied by continuous electrocardiographic monitoring of 27 episodes of SVT. Progressive increase of the cycle length heralded conversion in eight episodes while cycle-length alternation preceded cessation of the arrhythmia in 13 episodes. In five patients the arrhythmia was either stopped or closely followed by a ventricular premature beat (VPB), followed by further VPBs in three. Runs of bizarre ventricular tachycardia followed initial sinus-beats in two patients. Sinus standstill, lasting 30 seconds, was observed in one patient. The first post SVT beats had an aberrant QRS configuration with a normal P-R interval in four cases and an aberrant QRS complex with a short P-R interval, resembling Wolff-Parkinson-White complexes, in a further seven patients. The possible mechanisms causing this variability of pre- and post-conversion period are discussed. It is suggested that some aspects of verapamil action may be explained by a parasympaticomimetic effect on the myocardium.

Verapamil in the management of supraventricular tachyarrhythmias occurring after a recent myocardial infarction

In 16 patients, a sustained supraventricular tachyarrhythmia occurring less than 72 hours after the first symptom of an acute myocardial infarction was treated with titrated doses of verapamil. The drug was given intravenously in 1 mg increments every minute under continuous monitoring of electrocardiogram and blood pressure. Endpoints for the administration of verapamil were the following: reversion to sinus rhythm; a ventricular rate slower than 100/min; hypotension; a pulmonary capillary wedge pressure rising above 15 mm Hg; signs of intolerance; a maximum dose of 20 mg. Reversion to sinus rhythm was observed in 7/8 patients in atrial flutter and in 1/8 patients in atrial fibrillation; in all the ventricular rate could be slowed below 100/min without untoward effects.

Verapamil: a review of its pharmacological properties and therapeutic use

Verapamil is a novel antiarrhythmic and antianginal agent which, although introduced in 1962, has only recently gained prominence not only as a significant agent in cardiovascular therapeutics but also as a powerful tool to examine the nature of some of the biophysical phenomena at the membrane of cardiac and other excitable tissues. Verapamil is the prototype of those agents which selectively inhibit membrane transport of calcium, an action which accounts for the drug's peripheral and coronary vasodilator properties, its effect on excitation-contraction coupling and hence its negative inotropic propensity, as well as its depressant effects on the sinus node and atrioventricular conduction. Its pharmacological effects are largely independent of the autonomic nervous system. The main therapeutic uses of the drug are in the management of atrial tachyarrhythmias, angina, and possibly hypertension. The overall exp:rimental and clinical data suggest that verapamil will become an important and safe addition to existing drug regimens, especially as an agent of choice for the short-term treatment of most cases of paroxysmal supraventricular tachycardias. The initial experience in other arrhythmias, angina and hypertension, is also sufficiently encouraging to justify further detailed clinical trials to define its potential role in cardiovascular therapeutics.

Effect of verapamil studied by programmed electrical stimulation of the heart in patients with paroxysmal re-entrant supraventricular tachycardia

Atrioventricular (AV) conduction, ventriculoatrial (VA) conduction, and the mechanism of tachycardia, were studied by programmed electrical stimulation before and after the administration of verapamil, in 10 patients with paroxysmal re-entrant supraventricular tachycardia. In 7 patients the tachycardia circuit was confined to the AV node. In 3 patients an accessory pathway conducting only in the ventriculoatrial direction was used during tachycardia. When administered intravenously during tachycardia, verapamil terminated the arrhythmia in 9 patients. Verapamil lengthened the effective and the functional refractory period of the AV node and the AV nodal transmission time in all patients in whom this could be studied. As a result of these changes, it was not possible to initiate tachycardia in 3 patients. The width of the zone of atrial premature beats able to initiate tachycardia (the tachycardia zone) narrowed in 5 patients, and increased in 2 patients. In 6 of these 7 patients the tachycardia zone shifted to longer premature beat intervals. Verapamil resulted in slowing of the heart rate during tachycardia. Apart from slowing in heart rate during tachycardia and termination of tachycardia after intravenous verapamil, the 3 patients with an accessory pathway showed no beneficial effect of verapamil on the mechanism of initiation of tachycardia. Five patients were restudied after 2 to 3 weeks of oral administration of verapamil. Though less, effects were similar to those obtained after intravenous administration.