DC Shock Research Articles

Sudden cardiac arrest in adolescence: the case of ventricular fibrillation 11 years after presenting with Kawasaki's disease

A previously asymptomatic, 16-year-old male from China presented following a cardiac arrest. He had a past medical history of Kawasaki's disease with no known sequelae. Following 6 min of bystander...

Brugada syndrome: Case report

Brugada syndrome is an arrhythmogenic disease characterized by coved ST segment elevation and J point elevation of at least 2 mm in at least two of the right precordial ECG leads (V1-3) and ventricular arrhythmias, syncope, and sudden death. Risk stratifications of patients with Brugada electrocardiogram are being strongly debated. A 23-year-old man was admitted to the Coronary Care Unit of the Clinical Centre "Bezanijska kosa" due to weakness, fatigue and chest discomfort. The patient suffered from fainting and palpitations. There was a family history of paternal sudden death at 36 years. Electrocardiogram showed a coved ST segment elevation of 4 mm in leads V1 and V2, recognised as spontaneous type 1 Brugada pattern. Laboratory investigations revealed normal serum cardiac troponin T and serum potassium, and absence of inflammation signs. Echocardiographic finding was normal, except for a mild enlargement of the right atrium and ventricle. The diagnosis of Brugada syndrome was made by Brugada-type 1 electrocardiogram and the family history of sudden death <45 years. The patient was considered as a high risk, because of pre-syncope and palpitations. He underwent ICD implantation (Medtronic MaximoVR7232Cx) using the standard procedure. After implantation, noninvasive electrophysiology study was done and demonstrated inducible VF that was interrupted with the second 35 JDC shock. The patient was discharged in stable condition with beta-blocker therapy. After a year of pacemaker check-ups, there were no either VT/ VF events or ICD therapy. Clinical presentation is the most important parameter in risk stratification of patients with Brugada electrocardiogram and Brugada syndrome.

Cryoballoon ablation as first-line therapy of paroxysmal atrial fibrillation: dusk of global warming and the dawn of a new ice age era?

This editorial refers to ‘Isolating the pulmonary veins as first-line therapy in patients with lone paroxysmal atrial fibrillation using the Cryoballoon’ by M. Namdar et al. , on page 197 The introduction of catheter ablation for the treatment of supraventricular arrhythmias in the early 1980s initially with the delivery of intra-cardiac DC shocks and finally in 1987 with the introduction of radiofrequency energy changed forever the management of supraventricular tachycardias.1–3 Despite the safety, reproducibility, and high efficacy rates, catheter ablation of supraventricular tachycardias is still not considered first-line therapy. Similarly, despite many attempts with different energy sources radiofrequency ablation remains the gold standard. The proposal for a catheter-based approach in the mid 1990s for the treatment of atrial fibrillation was met with significant scepticism. Initial attempts using extensive lines trying to reproduce the Cox-Maze approach were associated with mediocre results and untenable procedure and fluoroscopic times.4,5 Nonetheless perseverance and a better understanding of the mechanisms of atrial fibrillation as …

Giant Intramural Left Ventricular Rhabdomyoma in a Newborn

A 1-day-old newborn was referred with prenatal echocardiographic diagnosis of cardiac mass. Born by caesarean section at 38+3 weeks of pregnancy, he presented with cyanosis and bradycardia at birth, requiring immediate intubation and mechanical ventilation. Chest x-ray demonstrated cardiomegaly with a cardiothoracic index of 0.7 (Figure 1). Echocardiographic examination (Figure 2 and Movie I in the online-only Data Supplement) confirmed the diagnosis of a large cardiac mass located at the posterior wall and at the apex of the left ventricle (LV). The child presented with several episodes of paroxysmal supraventricular tachycardia, which were treated with DC shock and various pharmacological agents, such as amiodarone, adenosine, flecainide, digoxin, and metoprolol, and 1 episode of ventricular fibrillation with cardiac arrest requiring resuscitation. MRI showed a single large mass (5.5×5 cm) arising from the left atrioventricular groove and extending to the LV lateral wall and apex, up to the interventricular septum, with no LV inflow or outflow obstruction, and was suggestive …

A sword of Damocles in an asymptomatic man presenting with serendipitously detected ventricular pre-excitation

MOTS CLES Syndrome de WolfA 25-year-old man was admitted to hospital for electrophysiological studies for WolfParkinson-White syndrome, discovered during a medical clearance examination to be a professional soccer referee. This athlete had no medical history, reported no symptoms and his physical examination was normal. A 12-lead electrocardiogram revealed the presence of ventricular pre-excitation, a negative delta wave in leads I and aVL, and right bundle branch-type QRS morphology, consistent with a left lateral accessory pathway (Fig. 1), which persisted during peak exercise. Electrophysiological studies confirmed the presence of a left lateral accessory pathway and the induction of atrial fibrillation by rapid atrial pacing, immediately followed by the development of ventricular fibrillation (Fig. 2a, b), requiring the delivery of two consecutive biphasic 200J DC shocks to restore sinus rhythm (Fig. 3a). The patient

Regional cooling facilitates termination of spiral-wave reentry through unpinning of rotors in rabbit hearts

Moderate global cooling of myocardial tissue was shown to destabilize 2-dimensional (2-D) reentry and facilitate its termination. This study sought to test the hypothesis that regional cooling destabilizes rotors and facilitates termination of spontaneous and DC shock-induced subepicardial reentry in isolated, endocardially ablated rabbit hearts. Fluorescent action potential signals were recorded from 2-D subepicardial ventricular myocardium of Langendorff-perfused rabbit hearts. Regional cooling (by 5.9°C ± 1.3°C) was applied to the left ventricular anterior wall using a transparent cooling device (10 mm in diameter). Regional cooling during constant stimulation (2.5 Hz) prolonged the action potential duration (by 36% ± 9%) and slightly reduced conduction velocity (by 4% ± 4%) in the cooled region. Ventricular tachycardias (VTs) induced during regional cooling terminated earlier than those without cooling (control): VTs lasting >30 seconds were reduced from 17 of 39 to 1 of 61. When regional cooling was applied during sustained VTs (>120 seconds), 16 of 33 (48%) sustained VTs self-terminated in 12.5 ± 5.1 seconds. VT termination was the result of rotor destabilization, which was characterized by unpinning, drift toward the periphery of the cooled region, and subsequent collision with boundaries. The DC shock intensity required for cardioversion of the sustained VTs decreased significantly by regional cooling (22.8 ± 4.1 V, n = 16, vs 40.5 ± 17.6 V, n = 21). The major mode of reentry termination by DC shocks was phase resetting in the absence of cooling, whereas it was unpinning in the presence of cooling. Regional cooling facilitates termination of 2-D reentry through unpinning of rotors.

Rescue Extracorporeal Life Support for Acute Verapamil and Propranolol Toxicity in a Neonate

Extracorporeal life support (ECLS) to manage acute antiarrhythmic drugs toxicity in neonates has never been reported. Here presented is a case of venoarterial extracorporeal membrane oxygenation support in a newborn with refractory low cardiac output as a result of acute Ca-channel and β-receptor antagonist toxicity for treatment of paroxysmal supraventricular tachycardia (SVT). Shortly after onset of ECLS, the baby recovered sinus rhythm and subsequent bouts of SVT were controlled by amiodarone infusion and repeated DC shocks. Weaning was possible on the 5th day after implant, once recovery of the left ventricular function and optimization of the antiarrhythmic medication were achieved. In neonates with severe but potentially reversible cardiac dysfunction caused by drug toxicity, ECLS can maintain cardiac output and vital organ perfusion while allowing time for drug redistribution, metabolism, and clearance.

J Wave: Different Characteristics in Two Cases with Ventricular Arrhythmias

J wave or early repolarization has been associated with the risk of ventricular tachyarrhythmias, and its risk stratification is to be established. Case 1: A 51-year-old man without structural heart disease was admitted because of near syncope due to repeated episodes of very rapid non-sustained monomorphic VT (∼240 bpm). His ECG showed J waves in the inferior and lateral leads, and J waves persisted after the administration and were not affected by pilsicainide or epinephrine. VT was mapped to the free wall of right ventricular outflow tract. Case 2: A 74 year-old man developed ventricular fibrillation after successful coronary artery bypass graft surgery. His preoperative ECG showed small J waves in the inferior and lateral leads. During the stay in ICU, J waves were dramatically augmented and led to VF. After the restoration of sinus rhythm by a DC shock, they decreased. The dynamicity and relation of the influence to J wave on the ventricular arrhythmias may be different.

Successful Radiofrequency Catheter Ablation for Incessant Ventricular Tachycardia in an Infant

Background: Here we report an infant with incessant ventricular tachycardia (IVT) with successful control by radiofrequency catheter ablation (RFCA). Case Report: She was first documented supraventricular tachycardia (SVT) and WPW syndrome just after her delivery. Carteolol and digoxin was successfully control her SVT. She lost her consciousness and referred to the hospital at 7-month-old. Electrocardiogram showed incessant polymorphic wide QRS tachycardia with a rate of 380 bpm. Adenosine triphosphate, propranolol, landiolol, amiodarone and DC shock were used but unsuccessful to terminate her tachycardia. Increased dose of amiodarone, with the use of verapamil, landiolol and lidocaine transiently controlled her tachycardia. She was transferred to our hospital for RFCA of her tachycardia when she was 9-month-old. All the antiarrhythmic medications were discontinued, and RFCA was performed. There was no delta wave and retrograde ventriculo-atrial conduction by ventricular pacing. Tachycardia was initiated spontaneously, and confirmed that IVT. At least 3 types of VT were confirmed from left ventricular (LV) apex, LV anterior wall, and LV lateral wall. All the VTs were successfully controlled after 2 sessions of RFCA, and she was discharged on mexiletine. Conclusion: RFCA should be considered early in their life if the VT was refractory to antiarrhythmic medication.

A Case of J Wave Syndrome Successfully Resuscitated from Cardiac Arrest Followed by Prominent J Wave Augmentation

The presence of J wave is associated with a risk for the sudden death, and termed J wave syndrome. A 37-year-old male was referred to our hospital for an ICD implant for secondary prevention. He did not have a history of syncope or family history of sudden death but experienced an episode of cardiac arrest during deskwork at midnight. Ambulance was called and bystander CPR was performed by his wife while waiting for the arrival. A record of AED showed successful defibrillation of VF by multiple DC shocks. However, the prominent J wave was apparent post-VF. The J wave was augmented during mild hypothermia therapy after admission to the hospital but persisted during his hospital course. He recovered without any neurological deficit and the rest of his clinical course was uneventful. Intensive examination excluded structural heart diseases and VF was not induced by programmed electrical stimulation during EP study. Furthermore, an intravenous administration of pilsicainide did not disclose coved type ST elevation and signal averaged ECG was negative. He had an ICD implant and had no recurrence during 4-year follow up period. This is an interesting case of J wave syndrome whose J wave remained continuously but augmented during VF storm.

Return to normal life after a prolonged cardiopulmonary arrest due to idiopathic ventricular fibrillation

An healthy men, 54 years old, free from cardiovascular risk factors, showd a sudden lost of consciousness. A lay rescuer started a BLS protocol. After 11min an ALS team reached the place and continued the CPR. They found a VF characterized by low voltages with no response to DC shock. After a few minutes the team decided to carry the patient to the emergency department which has been reached after 63min of cardiopulmonary arrest. The rhythm at the ER was a bradycardic PEA with a wide QRS complex.

Ventricular tachycardia secondary to a submitral left ventricular aneurysm diagnosed in emergency department—a case report from Oman

A 60-year-old man presented to our emergency department (ED) with monomorphic ventricular tachycardia (VT) (Fig. 1a) and hypotension, and was cardioverted with DC shock. He had a history of recurrent VT for the past month requiring electrical cardioversion three times at a regional hospital and was awaiting an electrophysiology specialist consultation. The ECG during sinus rhythm showed QS with T inversion in II, III, and AVF (Fig. 1b). On enquiry, he reported a history of myocardial infarction 2 years ago and was asymptomatic except for episodes of VT. His serum electrolytes and troponin T were normal. Using an ultrasound machine, bedside examination of the heart showed a non-dilated left ventricle with a large submitral aneurysm of the inferior wall measuring 4 × 4 cm with a wide neck and a mural thrombus, which was confirmed with a transthoracic echocardiogram (Fig. 1c). Ejection fraction (EF) was 35%. He was admitted and subsequently underwent coronary artery bypass surgery with an aneurysmectomy. There was no recurrence of VT at the 1-year follow-up. Fig. 1 The 12-lead electrocardiogram showing monomorphic ventricular tachycardia (a), QS waves with T inversion in II, III, and AVF (b), and a transthoracic echocardiographic image showing a large submitral inferior wall left ventricular aneurysm with thrombus ... The term left ventricular aneurysm (LVA) (true aneurysm) is generally reserved for a discrete, dyskinetic area of the LV wall with a broad neck [1]. The incidence of LVA in patients with acute myocardial infarction was 7.6% in the Coronary Artery Surgery Study [2], and approximately 15% have symptomatic intractable ventricular arrhythmias. Usual sites of LVA are the apical and anterior segments (80%), and rarely in the inferior wall (5–10%). Ultrasound is a modality well suited to the ED [3]. This case illustrates that LVA can present as VT to emergency physicians, and it should be suspected when there are QS waves in the ECG. This case also highlights the importance of bedside ultrasound examination in detecting causes for emergency clinical presentations.

General anaesthesia for external electrical cardioversion of atrial fibrillation: experience of an exclusively cardiological procedural management

External electrical cardioversion (EC) usually requires brief general anaesthesia involving anaesthetists. The aim of this study was to evaluate the feasibility and safety of inducing anaesthesia for EC of atrial fibrillation (AF) exclusively by the cardiologic team with anaesthetists on-hand. A retrospective analysis of 624 elective EC, over a 6-year period, was made. No patients were excluded due to the severity of pathology or comorbidities. The protocol of the intravenous anaesthesia was 5 mg bolus of midazolam and subsequent increasing doses of propofol starting from 20 mg to achieve the desired sedation level. After delivering DC shock, a direct observation period followed in order to assess the post-sedation recovery and to detect the procedure-related complications. Electrical cardioversion was effective in 98.9% of the cases. General anaesthesia was effective in 100% of cases with a dosage of propofol, ranging between 20 mg to a maximum of 80 mg, after 5 mg of midazolam was administered. All patients generally showed a fast recovery waking up in a few minutes. The anaesthesiology team was never called for assistance. All the procedures were carried out by the cardiologic team as planned. No thrombo-embolic and allergic complications were observed. Arrhythmic complications were uncommon and essentially bradyarrhythmias. A general anaesthesia for outpatient EC of AF can be safely handled by a cardiologist having adequate experience with anaesthetical agents. Moreover, the association of midazolam and a very small dosage of propofol, given their synergic action, is effective and safe in inducing anaesthesia. Arrhythmic complications are rare and limited to bradyarrhythmias.

An observational registry on efficacy and safety of the right ventricular outflow tract as a site for ICD leads: results of the EFFORT (EFFicacy Of Right ventricular outflow Tract as site for ICD leads) registry

Although pacing from the right ventricular outflow tract (RVOT) has been shown to be safe and feasible in terms of sensing and pacing thresholds, its use as a site for implantable cardioverter defibrillator (ICD) leads is not common. This is probably due to physicians' concerns about defibrillation efficacy. To date, only one randomized trial, involving 87 enrolled patients, has evaluated this issue. The aim of this observational study has been to compare safety (primary combined end point: efficacy of a 14-J shock in restoring sinus rhythm, R wave amplitude >4 mV and pacing threshold <1 V at 0.5 ms) and efficacy (in terms of effectiveness of a 14-J shock in restoring sinus rhythm after induction of VF, secondary end point) of two different sites for ICD lead positioning: RVOT and right ventricular apex (RVA). The study involved 185 patients (153 males; aged 67 ± 10 years; range, 28-82 years). Site of implant was left to physician's decision. After implant, VF was induced with a 1-J shock over the T wave or--if this method was ineffective--with a 50-Hz burst, and a 14-J shock was tested in order to restore sinus rhythm. If this energy was ineffective, a second shock at 21 J was administered and--eventually--a 31-J shock followed--in case of inefficacy--by a 360-J biphasic external DC shock. Sensing and pacing thresholds were recorded in the database at implant, together with acute (within 3 days of implant) dislodgement rate. The combined primary end point was reached in 57 patients in the RVOT group (0.70%) and in 81 patients in the RVA group (0.79%). The 14-J shock was effective in 159 patients, 63 in the RVOT group (77%) and 86 in the RVA group (83%). Both the primary and the secondary end points are not statistically different. R wave amplitude was significantly lower in the RVOT group (10.9 ± 5.2 mV vs. 15.6 ± 6.4 mV, p < 0.0001), and pacing threshold at 0.5 ms was significantly higher (0.64 ± 0.25 V vs. 0.52 ± 0.20 V, p < 0.01), but these differences do not seem to have a clinical meaning, given that the lower values are well above the accepted limits in clinical practice. Efficacy and safety of ICD lead positioning in RVOT is comparable to RVA. Even if we observed statistically significant differences in sensing and pacing threshold, the clinical meaning of these differences is--in our opinion--irrelevant.

Biphasic DC shock cardioverting doses for paediatric atrial dysrhythmias

Objective To determine cardioversion doses of biphasic DC shock for paediatric atrial dysrhythmias. Design Prospective recording of energy, pre-shock and post-shock rhythms. Setting Paediatric hospital. Patients Shockable atrial dysrhythmias. Main results Forty episodes of atrial dysrhythmias among 25 children (mean age 6.8 ± 7.1 years, mean weight 28.2 ± 28.5 kg) were treated with external shock. The first shock converted the dysrhythmia to sinus rhythm in 25 episodes. Cardioversion occurred in 2 of 8 (25%) episodes with a dose of <0.5 J/kg, 14 of 16 (88%) with a dose of 0.5–1.0 J/kg and 9 of 16 (56%) with a dose of >1.0 J/kg ( p = 0.01, Fisher's exact test). Ten of 15 initially non-responsive episodes were cardioverted with additional shocks at 1.1 ± 0.6 J/kg (range 0.5–2.1 J/kg). Of the remaining 5 unresponsive episodes, 2 of ventricular fibrillation (induced by unsynchronized shock) were successfully defibrillated, and 3 were managed with cardiopulmonary bypass. Among 11 additional children (mean age 4.3 ± 6.8 years, mean weight 18.1 ± 22.0 kg), 18 episodes of atrial dysrhythmias were treated with internal shock which successfully cardioverted all episodes with one or more shocks at 0.4 ± 0.2 J/kg. Conclusions In rounded doses, recommended initial external cardioversion doses are 0.5–1.0 J/kg and subsequently up to 2 J/kg, internal cardioversion doses are 0.5 J/kg.

MANAGEMENT OF PATIENTS WITH HYPERTENSION AND ATRIAL FIBRILLATION PRESENTING TO THE EMERGENCY DEPARTMENT: PP.1.34

Background: Management in the Emergency Department (ED) of patients (pts) with atrial fibrillation (AF) by the availability of new facilities including an Intensive Observation Unit (IOU) and an Outpatient Clinic (OC) could improve the global treatment strategy. Objective: To prevent admissions by the management with an IOU and an OC, in pts with hypertension and AF. Methods. We compared 2 groups of pts presenting to the ED with AF, when the new facilities were unavailable (Group A, 2006–2007), and after the ED reorganization (Group B, 2008–2009). We considered the clinical characteristics, the presence of mild to moderate comorbidities, the AF duration (hours) and the therapeutic approach (pharmacological or DC shock). Overall, 869 pts (38,8%) presented with hypertension and mild structural heart disease. Endpoint: Primary endpoint was prevention of admission; secondary end-point was detection of characteristic predictive of poor outcome. Results: We enrolled 2,237 pts (group A: 970 pts, age 70 y, 38% with hypertension; and group B: 1267 pts, age 71 y, 39,5% with hypertension; all p = n.s.). Admission rate was significantly reduced when IOU and OC were available (Group A, 38% vs Group B, 23%, p < 0,0001). Group A showed higher percentage of comorbidities (40%) vs Group B (24%; p < 0.0001), and pts with AF lasting >48 hours (43%) vs Group B (27%, p < 0.0001). However, when the presence of comorbidities, AF duration, and group assignment were considered comorbidities (HR: 11, CI:8–13; p < 0.0001) and AF duration > 48 hours (HR:5, CI: 4–6; p < 0.0001) were independent predictor of poor outcome. Hypertension, per se, was not associated with poor outcome or longer length of in-hospital stay. Finally, the new ED reorganization was associated with a better outcome (HR: 0.78, CI: 0.62–0.98; p = 0.035). Conclusions: A new ED organization with IOU and OC significantly reduces hospital admission independently of the presence of hypertension. Mild to moderate comorbidities and AF lasting > 48 hours are independent predictors of hospitalization.

Atrial Fibrillation After Cardiac Surgery: Incidence, Risk Factors, and Economic Burden

To evaluate the incidence of postoperative atrial fibrillation (POAF), the predisposing factors, the results of treatment before discharge, and the impact on duration and costs of hospitalization. A prospective observational study. Patients who underwent cardiac surgery from January 1, 2007 to December 31, 2007. Electrocardiography was continuously monitored after surgery. Patients with symptomatic new-onset atrial fibrillation or lasting >15 minutes were treated with amiodarone and with DC shock in prolonged cases. POAF occurred in 29.7%, with the higher incidence between the 1st and 4th postoperative day. Age (p < 0.001), atrial size >40 mm (p < 0.001), previous episodes of AF (p < 0.001), female sex (p = 0.010), and combined valve and bypass surgery (p = 0.012) were multivariate predictors of POAF at logistic regression. Sinus rhythm was restored by early treatment in 205 of 215 patients. This was associated with a low incidence of cerebrovascular events (<0.5%) and with a limited increase of average length of hospitalization (24 hours) in patients with POAF. The overall incidence of POAF in the authors' center is close to 30%; 95.3% of patients were discharged in sinus rhythm. The increase in length and costs of hospitalization (on average, 1.0 day with a burden of about €1,800/patient) were significantly lower than in previous investigations.

ICD shocks: Not just the “straw that broke the camel's back”

ICD shocks: Not just the “straw that broke the camel's back”

205 ST segment changes after external cardioversion using direct current shock: incidence, characteristics and predeictive factors

DC shock is commonly used for external cardioversion of cardiac arrhythmias. Incidence, characteristics and predictive factors of transient ST-segment changes after DC shock are poorly known. 91 consecutive pts referred for external cardioversion of atrial fibrillation (AFib) (61 men, 69 ± 10 yo) were prospectively included. Duration and amplitude of ST elevation or depression were quantified on12 lead-ECG immediately after the first DC shock. Correlations with DC shock characteristics clinical variables, underlying heart disease, echocardiographic parameters, biological parameters, medications, anesthesic drugs as well with morphological features were made. 18 and 20 pts underwent 200 J or 300 J monophasic and 53 pts 200 J biphasic DC shocks. Immediate success rate was 95%.We found an incidence of 48% for ST segment changes: 35% for ST elevation (0,81 ± 0,44 mV) and 13% for ST depression (0,2 ± 0,07 mV, p<0,0001). ST changes were essentially seen in the right precordial leads. Major ST elevation was observed in 27% which could sometimes display Brugada-like pattern. ST changes durations were similar for ST elevation and ST depression (60 ± 43 vs 50 ± 26 sec, p=ns) and were correlated to the amplitude of ST changes. ST changes did not induce significant cardiac events or alter immediate or late AFib recurrences. ST changes were not related to energy but ST elevation was significantly more often induced by monophasic (76% vs 6%, p<0,0001) and ST depression by biphasic DC shocks (26% vs 3%, p=0,01). Using multivariate analysis, independent predictors for ST elevation were the use of monophasic DC shocks, use of propofol and increased CRP, while a low ejection fraction and use of biphasic DC hocks were independent predictors of ST depression. ST segment changes after external cardioversion with DC shock are common, short living and do not seem to carry clinical significance. They are related to the monophasic or biphasic configuration of DC shock, to the use of propofol, to the ejection fraction and to an increased CRP. Direct membrane injury by electroporation is suspected.

Efficacy of Procainamide and Lidocaine in Terminating Sustained Monomorphic Ventricular Tachycardia - Retrospective Case Series -

The efficacy of antiarrhythmic drugs in terminating sustained monomorphic ventricular tachycardia (SMVT) was assessed in a retrospective manner to provide a basis for recommending their use. The 90 patients were included in this study to evaluate the efficacy to terminate SMVT using procainamide or lidocaine. All patients were alert and responsive. The mean systolic blood pressure was 91+/-25 mmHg (range, 40-150 mmHg). SMVT was diagnosed from ECG recordings and later in an electrophysiologic study. VTs with a cycle length of 329+/-55 and 324+/-61 ms were treated with the mean doses of 358+/-50 mg and 81+/-30 mg of procainamide and lidocaine and were terminated in 53/70 (75.7%) and in 7/20 (35.0%) respectively. The drugs were discontinued if there was no rise in blood pressure after slowing of the tachycardia rate or if there were signs of impending deterioration in consciousness. Though procainamide was effective, blood pressure was often low and DC shock should be available at all times during administration of the drug. Procainamide, the relatively older drug, was more effective than lidocaine in terminating SMVT associated with structural heart diseases. This is a retrospective analysis but can form the basis for formulating guidelines for initial management of SMVT.