Narrow Complex Tachycardia - Literature review Example

Narrow Complex Tachycardia Review of Related Literature In a paper by Furlong, et.al., (1995, p. 383), set out to assess the safety and efficacy of using IV (intravenous) adenosine therapy for the emergency treatment of narrow complex tachycardias among patients with an initial diagnosis of presumptive supraventricular ventricular tachycardia (PSVT). This paper was a prospective study conducted in a 10-month period in an urban Emergency Medical Services system with paramedics working with standing orders before physician radio contact (Furlong, et.al., 1995, p. 383). Patients who already had a field diagnosis of PSVT were also included in this paper. The researchers collected demographics on the patients, including history, medications, vital signs, and ECG readings. This study revealed that out of the 41 patients included in this paper, 31 were correctly diagnosed with PSVT, one had sinus tachycardia, and nine had atrial fibrillation (Furlong, et.al., 1995, p. 383). In the 31 cases diagnosed with PSVT, 28 successfully had sinus rhythm after the administration of adenosine. This represents 90.3% of the population being studied (Furlong, et.al., 1995, p. 383). For patients who were converted to sinus rhythm, 16 of them were given a single dose of adenosine, nine of them were given one additional dose of adenosine, and three later required two additional doses of adenosine (Furlong, et.al., 1995, p. 383). None of the patients given adenosine reverted to PSVT after administration of adenosine; there was also no difference in length of asystolic pause or in the outcome which was seen between the actual PSVT and the AF cases receiving adenosine (Furlong, et.al., 1995, p. 383). No significant negative side effects were also seen in the patients given adenosine. This study concluded that adenosine can be an effective emergency treatment of narrow complex tachycardia, and it can also be safely administered without the necessary physician control. The authors recommended that this drug must be used as directed by the manufacturer and it is actually a valuable prehospital diagnostic adjunct in patients with atrial fibrillation (Furlong, et.al., 1995, p. 383). In 2008, a paper by Ertan, et.al. (pp. 386-390) sought to assess the proarrhythmic potential of adenosine in terminating or treating supraventricular arrhythmias otherwise known as narrow complex tachycardia. This study was conducted as a retrospective paper reviewing the records of all patients who underwent adenosine treatment for the termination of supraventricular tachycardia. Patients who registered with continuous ECG readings while undergoing adenosine treatment were also included as respondents in this paper (Ertan, et.al., 2008, p. 386). This paper was able to include 52 supraventricular incidents in 46 patients with continuous ECG readings during the administration of adenosine. The paper was able to establish that incidents of premature ventricular contraction or PVC and ventricular tachycardia or VT were seen in 22 of the patients, and in 26 tachycardia episodes (Ertan, et.al., 2008, p. 386). There were no incidents of VT seen among the patients included in this paper. There were 8 patients who manifested with nonsustained VT representing 17.4% of the population included in this paper; all the ventricular tachycardia episodes registered as polymorphic, short, and self-terminating (Ertan, et.al., 2008, p. 386). The basal and demographic properties of patients with PVC or with VT were not significantly different from those without PVT or VT. This paper concluded that adenosine can safely and effectively terminate narrow QRS complex tachycardia; however it is also likely to induce ventricular tachycardia or PVC, characteristics which are clinically insignificant in the absence of other accompanying heart disease (Ertan, et.al., 2008, p. 386). In a paper by Byerly, et.al. (1991, pp. 552-554), the researchers wanted to describe the occurrence of PSVT (paroxysmal supraventricular tachycardia) on two separate occasions in a woman on her third trimester of pregnancy. This study came about because medical health professionals noticed that PSVT is quite common in the emergency department and most often during pregnancies (Byerly, et.al., 1991, p. 552). Verapamil has been commonly used as the drug of choice in PSVT haemodynamically stable patients with narrow QRS complex; limited studies however on its use among pregnant women have been conducted (Byerly, et.al., 1991, p. 552). Moreover, a limited number of case reports have been conducted on the safety and the efficacy of the drugs in the treatment of maternal or foetal PSVT. Authors speculate that this may be due to the careful assessment needed in the use of medication during pregnancy creates risks for both the mother and the foetus (Byerly, et.al., 1991, p. 552). The fact that verapamil can cross the placenta barrier is cause of concern as it can potentially affect foetal heart rate. This paper presented a case describing the occurrence of PSVT on two separate occasions in a pregnant woman in her third trimester of pregnancy (Byerly, et.al., 1991 p. 552). The study revealed that during both episodes, about 10 mg IV verapamil was given to the pregnant woman, and on both occasions, normal sinus rhythm was successfully restored. Moreover, monitoring of the foetal heart rate during administration did not register any significant change (Byerly, et.al., 1991, p. 552). The authors recommended more studies on the subject matter to be conducted as the current study covered only one patient. The authors set forth that the administration of verapamil among pregnant women registering with PSVT can successfully restore normal sinus rhythm without affecting foetal heart rate. In a paper by Faulds, et.al., (1991, pp. 596-624), they evaluated the use of cardiac diagnostic procedures, and the use of adenosine in the treatment of paroxysmal supraventricular tachycardia. The study explained that adenosine often depresses the atrioventricular nodal conduction and such depression results in transient AV block. Adenosine is an active agent and with ATP, it is converted to adenosine after exogenous administration (Faulds, et.al., 1991, p. 596). Within 30 seconds after administration, adenosine acts to block the anterograde AV limb of a re-entrant circuit and consequently converts most episodes of paroxysmal supraventricular tachycardia. This action is more or less equivalent to the action of verapamil in adults; and more efficient than lanatoside C among children with its faster onset of action (Faulds, et.al., 1991, p. 596). Since the induced conduction block has its effects on the AV node, adenosine is an important diagnostic element in patients who have narrow QRS complex tachycardia as it eliminates arrhythmias which depend on the AV node; it also uncovers supraventricular mechanisms during the transient AV block, almost always having no effect on ventricular tachycardia (Faulds, et.al., 1991, p. 596). The authors mentioned that noncardiac adverse effects such as flushing, dyspnoea, and chest pains may be seen during acute arrhythmia termination. However, such effects are often temporary, lasting less than a minute (Faulds, et.al., 1991, p. 596). The authors point out that adenosine has mild side-effects which often resolve within 1-2 minutes from the discontinuation of adenosine. The study revealed that adenosine is appropriate for diagnosing tachycardias and for managing PSVT within the AV node (all age groups). This is more advantageous because there is no need to deal with the risk of cardiac arrest and hypotension as seen in the administration of verapamil (Faulds, et.al., 1991, p. 596). Moreover, IV adenosine can also be used to induce the vasodilatation of the coronary veins in patients who cannot perform exercise stress tests for 201TI scintigraphy (Faulds, et.al., 1991, p. 596). The researchers De Wolf, and colleagues (1993, pp. 793-796) instituted a study on the effects of using adenosine triphosphate treatment for supraventricular tachycardia in infants. They initially pointed out that adenosine is an endogenous nucleoside which acts on coronary perfusion and myocardial conduction (DeWolf, et.al., 1993, p. 793). Adenosine has been known for its antiarrhythmic effects; however, in recent years, its precursor ATP has renewed interest in adenosine as it has now been established for its termination of supraventricular tachycardia (SVT). This paper studied the use of striadyne, which is basically ATP mixed with other nucleosides, including adenosine, in 22 infants younger than 6 months. This study sought to evaluate the efficiency of striadyne in stopping SVT in this age group (De Wolf, et.al., 1993, p. 793). The study revealed that striadyne terminated SVT in 17 of the 22 cases included in this study; it was also considered diagnostic in 4 other cases. The study revealed a reinitialization of SVT in 10 of the 17 patients; however, most of them were easily controlled (De Wolf, et.al., 1993, p. 793). The paper revealed greater support for the efficiency of ATP in terminating the re-entry type of tachycardia. Also, its diagnostic value and its lack of side effects were also revealed by this paper. The paper concluded that ATP and adenosine play important roles in safely stopping most cases of SVT among infants, thereby allowing their safe transfer to the cardiology department for further treatment (De Wolf, et.al., 1993, p. 793). The extensive use of adenosine in the studies cited above was not widely supported in the study conducted by Innes (2008, pp. 209-215). The study sought to assess the efficacy of adenosine as a pharmacological intervention for SVT and for wide complex tachycardia, including the diagnosis of difficult arrhythmias (Innes, 2008, p. 209). Other factors like the dose, administration, nature, and the frequency of side-effects, including relevant interactions and dose administrations were also assessed by this paper (Innes, 2008, p. 209). This paper conducted a Medline database search from 1950 to 2007, including the Embase database from 1974 to 2007 in order to assess and evaluate related articles. The paper revealed that adenosine is effective in treating and restoring stable SVT, however, its efficacy is more or less similar to cheaper alternatives (Innes, 2008, p. 209). The paper also revealed that adenosine plays a role as a first-line of treatment in unstable SVT; it is also safe when used to treat or diagnose wide complex tachycardia. The administration of adenosine creates a small risk of inducing serious arrhythmias – atrioventricular blockade and ventricular fibrillation. The paper was also able to reveal that the doses being recommended for infants are actually too low, while the dosage for adults and for children is adequate (Innes, 2008, p. 209). The author’s review also established that central venous administration of adenosine requires lower doses; however, no studies were seen addressing the peripheral sites of administration and the size of flushes (Innes, 2008, p. 209). The review also established that there is a need to adjust doses of adenosine while considering the interaction of medications. The author noticed that there were no studies which addressed medication adjustments. The author concluded that extensive evidence established adenosine as a safe and effective in treating SVT, however, it is no more effective or safe than other cheaper alternatives. The author also recommended more studies to be undertaken on other areas of adenosine use (Innes, 2008, p. 209). In a study Ferguson and DiMarco (2003, pp. 1096-1099), they sought to establish the current and contemporary management of paroxysmal supraventricular tachycardia. Their study was conducted as a clinical update on interventions for narrow complex tachycardia. In the course of their study, they revealed that oral antiarrhythmic drug tablets are often not reliably absorbed during PSVT. In some instances, patients respond better to self-administered medications (Ferguson & DiMarco, 2003, p. 1096). The authors pointed out that combining diltiazem and propanolol was much more effective than the administration of placebo and flecainide. The study emphasized that adenosine and non-dihydropyridine calcium antagonists verapamil and diltiazem are the recommended drugs for PSVT (Ferguson & DiMarco, 2003, p. 1096). They also pointed out that although adenosine exhibits with side effects like dyspnoea and chest pain, these often disappear and resolve after a second dose is administered to the patient (Ferguson & DiMarco, 2003, p. 1096). Moreover, the actions of verapamil and diltiazem are also effective in terminating PSVT. Alboni, et.al. (2001, pp. 548-553) conducted a study in an attempt to establish the efficacy and safety of out-of-hospital self-administered single-dose oral drug treatment in the management of infrequent, well-tolerated paroxysmal supraventricular tachycardia. This study attempted to assess the efficacy of two drug treatments – flecainide and propanolol – when administered as a single dose in the treatment of arrhythmic incidents (Alboni, et.al., 2001, p. 548). The authors pointed out that both drugs have not been recommended or have been questioned as first-line drugs for PSVT. Hence, this study which covered 42 eligible patients was conducted. This study revealed that conversion to sinus rhythm was seen within 2 hours in 52% patients on placebo; in 61% patients on fleicanide, and on 94% of patients on diltiazem/propanolol (Alboni, et.al., 2001, p. 548). Four patients registered with hypotension, while four had a sinus rate of Read More