Radiofrequency ablation for accessory pathways: success and variants.

INTRODUCTION: Radiofrequency ablation (RFA) is currently being advocated as the first line of therapy for symptomatic and drug refractory arrhythmias mediated by accessory pathways (APs). However, a large database on RFA for APs from India is still lacking. METHODS: Four hundred thirty-four patients (298 males, (69%)), with APs who underwent RF ablation between January, 1998 and May, 2001 were included. The success and variants were evaluated retrospectively from the data. RESULTS: The mean age was 36 +/- 11 years. There were 314 (73%) patients with WPW syndrome while the other 120 (27%) had concealed APs. Documented tachycardia was noted in 406 (91%) patients. Forty-six (11%) patients had associated structural heart disease (Ebstein's anomaly in 18). The procedure was successful in 414 (97%) of 425 patients in whom it was attempted. Of those unsuccessful, five had epicardial APs, four had multiple APs and two had immediate recurrence of APs. RFA was not attempted in nine parahissian pathways. Additional mechanisms were seen in 48 (11%) patients with WPW syndrome (14 (4.4%) AV nodal reentrant tachycardias, 16 (5%) additional concealed APs and 18 (5.7%) multiple APs). Coronary sinus diverticulum were detected in 23 (7.3%) patients, and Mahaim-like APs were diagnosed in 24 (6\8%) patients. The procedural and fluoroscopy time was 96 +/- 41 and 19 +/- 13 minutes, respectively. There were no deaths; three patients developed pericardial tamponade, which was promptly treated by pericardiocentesis. CONCLUSION: Radiofrequency ablation is a safe and effective treatment for AP mediated tachycardia, especially for younger patients and children in whom life-long drug therapy may not be best option.

Pre-excitation with syncope: a false lead?

An 18-year-old girl with pre-excitation presented with a history of recurrent syncope preceded by palpitation. The accessory pathway, which had a relatively long antegrade effective refractory period of 340 ms, was mapped and successfully ablated in the left lateral region. However, after ablation, she had reproducible sustained polymorphic ventricular tachycardia, which was found to be the cause of her syncope. Thus, alternate mechanisms of tachycardia need to be considered in patients with pre-excitation when the presentation is atypical.

Restenosis after coronary stenting--incidence and predictors.

OBJECTIVE: To determine the intermediate term outcome after coronary artery stenting. METHODS: The six month angiographic and clinical follow-up of 92 consecutive patients (94 lesions) undergoing successful coronary stenting was performed. Multiple variables were analyzed for predicting restenosis. RESULT: The mean age was 49.7 +/- 8.5 years. There were 73 males and 19 females. Coronary artery involvement was left anterior descending artery (LAD) in 67%, left circumflex artery (LCx) in 16.5% and right coronary artery (RCA) in 16.5%. The pre-procedure mean reference diameter was 3.1 +/- 0.38 mm, minimal luminal diameter (MLD) was 0.47 +/- 0.28 mm and percentage diameter stenosis (DS) was 85 +/- 9%. Post procedure MLD improved to 3.1 +/- 0.4 mm with an acute gain of 2.6 +/- 0.4 mm and residual DS of only 3 +/- 3%. Clinical and angiographic variables were correlated with restenosis assessed as both binary and continuous variables. Angiographic follow-up could be obtained in 55 out of 92 patients (60%) and 86 patients (88%) had a clinical follow-up. Angiographic restenosis (> 50% diameter stenosis) was present in 12 (22%) patients, seven of whom required a repeat angioplasty procedure. There was no death. At follow-up, the MLD was 2.1 +/- 0.93 and the DS was 32 +/- 29% with a lumen loss of 0.92 +/- 0.84 mm. Only 14 (16%) of patients had angina and stress test was positive in 21 (23%). Hypercholesterolemia (p < 0.001) and female gender (p < 0.05) were independently associated with high lumen loss. CONCLUSION: Intracoronary stenting in an unselected patient group is associated with a 22% restenosis rate. Hypercholesterolemia and female gender are associated with higher restenosis.

Adenosine-induced ventricular fibrillation.

The use of adenosine has been suggested as a diagnostic tool in the evaluation of wide ORS complex tachycardia. However, adenosine shortens the antegrade refractoriness of accessory atrioventricular connections and may cause acceleration of the ventricular rate during atrial fibrillation. We observed ventricular fibrillation in 2 patients who presented to the emergency department with pre-excited atrial fibrillation and were given 12 mg of adenosine.

L-carnitine moderately improves the exercise tolerance in chronic stable angina.

OBJECTIVES: To study the safety and efficacy (with reference to exercise ECG testing) of oral L-carnitine in chronic stable angina. METHODS: Forty-seven patients, 30 men and 17 women, aged 56 +/- 8 years, were randomized to receive L-carnitine (n = 28) or placebo (n = 19) in the dose of 2 g/day for 3 months. The adjuvant treatment was not changed during the study. Patients were evaluated by computerized stress test (CST) done at the beginning and end of the trial. The parameters assessed were exercise duration, time to onset of ST changes, total ST score at peak exercise, rate-pressure product at peak exercise, and time needed for the ST changes to recover to baseline. RESULTS: The two groups were comparable at the beginning of the study. There was no change in the CST parameters in the placebo group at the end of 3 months. In the L-carnitine group there was a statistically significant improvement in the exercise duration from 7.8 +/- 2.2 min to 8.6 +/- 1.8 min (p = 0.006) and in the time needed for the ST changes to revert to baseline from 7.2 +/- 3.9 min to 5.7 +/- 3.8 min (p = 0.019). No change was noted in the time to onset for ST depression, ST score and double product. There were no systemic adverse effects or coronary events in either group. CONCLUSION: Oral L-carnitine is safe and moderately improves the duration of exercise and time to recovery of ST changes in patients with chronic stable angina.

Is dietary fiber beneficial in chronic ischemic heart disease?

OBJECTIVES: To evaluate the benefit of a dietary fiber preparation (Fibernat) in patients with chronic ischemic heart disease (IHD). METHODS: From January 1997 to March 1998, 114 consecutive patients with chronic IHD were enrolled in this prospective double blind randomized placebo controlled trial. The fiber (F) and placebo (P) groups were comparable at baseline. All patients were given advice regarding dietary and lifestyle modifications. Concomitant drug therapy was not altered. The drug (consisting of soluble and insoluble fibers obtained from fenugreek, guar gum and wheat bran) and placebo were administered for six months (10 grams twice daily). RESULTS: The following parameters improved in both groups: HDL cholesterol (32 to 39 mg/dl, p < 0.0009 in F and 33 to 38, p < 0.007 in P), total: HDL cholesterol ratio (6.7 to 5.6, p < 0.0007 in F and from 7.0 to 6.0, p < 0.01 in P) and weight (64.0 to 63.0 kg, p < 0.002 in F and 60.3 to 59.5, p < 0.002 in P). The Apolipoprotein B increased (101 to 129 mg/dl, p < 0.00001 in F and 98 to 127, p < 0.0008 in P). The following parameters improved only in group F: LDL cholesterol (146 to 134, p < 0.027), Apolipoprotein A-1 (105 to 139, p < 0.001), body mass index (24.9 to 24.5, p < 0.03) and waist circumference (37.2 to 36.7, p < 0.03). Total cholesterol, VLDL cholesterol, triglycerides, hip circumference, W:H ratio, exercise time and blood sugar were unchanged in both groups. CONCLUSIONS: Fibernat is well tolerated, safe and had favorable effects on LDL cholesterol, Apolipoprotein A-1, body mass index and waist circumference.

Atrial fibrillation: how effectively can sinus rhythm be restored and maintained after balloon mitral valvotomy?

Atrial fibrillation, commonly associated with rheumatic mitral stenosis, worsens the prognosis. We studied the efficacy of achieving and maintaining sinus rhythm in patients with chronic atrial fibrillation who underwent a successful balloon mitral valvotomy. Fifty-four patients (26 men, 28 women; age 36+/-8 years) received amiodarone 200 mg thrice daily in the first week, and thereafter a maintenance dose of 200 mg once daily. Electrical cardioversion was attempted at 1 and 3 months and patients were followed up at 6, 12 and 18 months. At the end of 1, 3, 6, 12 and 18 months 81 percent, 72 percent, 60 percent, 54 percent and 49 percent of patients, respectively, were in sinus rhythm. Only one patient had a severe adverse effect (hypothyroidism). Univariate analysis revealed that lower age, shorter duration of atrial fibrillation and smaller left atrial size was associated with successful restoration to sinus rhythm. On multivariate analysis, the duration of atrial fibrillation was the only significant predictor of long-term maintenance of sinus rhythm. Amiodarone seems safe and reasonably effective in restoration and maintenance of sinus rhythm in patients of atrial fibrillation with rheumatic heart disease.

Anthropometry, lipid profile and dietary pattern of patients with chronic ischaemic heart disease.

The anthropometry, lipid profile and dietary characteristics of 114 patients with chronic ischaemic heart disease (IHD) were evaluated. There were 91 (80%) men and the mean age was 56 +/- 9 years. The body mass index was near normal (24.4 +/- 3.4), but the waist: hip ratio was high (0.94 +/- 0.06) suggesting central obesity. This was well in accordance of the step II recommendations of the NCEP guidelines as regards their caloric intake and its break-up in terms of carbohydrate, protein and fat (including saturated, mono-unsaturated and poly-unsaturated fatty acids) content. Their daily cholesterol intake (31 +/- 32 mg/day, range 4-180) was very low. The total cholesterol (212 +/- 37 mg%) was marginally elevated, HDL cholesterol (33 +/- 7.5 mg%) was low, LDL cholesterol (148 +/- 39 mg%) was high and the total: HDL ratio (6.8 +/- 2.0) was significantly abnormal. The serum triglyceride level (154 +/- 68 mg%) was on the higher side of normal. These observations give further credence to the recently evolving view that there are different and hitherto unrecognised risk factors of IHD in Indians, who seem to have the highest incidence of IHD amongst all ethnic groups of the world despite consuming a diet low in fat and cholesterol content.

Does radiofrequency ablation increase creatine kinase and troponin-T?

Radiofrequency ablation produces a focal area of myocardial necrosis. Creatine kinase (total & MB fraction) and troponin-T were analysed in 54 patients who underwent electrophysiological study and radiofrequency ablation for atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia and idiopathic ventricular tachycardia. The age of the patients was 36 +/- 12 years; 17 patients underwent slow pathway modification for atrioventricular nodal reentrant tachycardia, 26 patients underwent accessory pathway ablation and 11 patients underwent ablation for idiopathic ventricular tachycardia. There was no significant rise in creatine kinase, creatine kinase total & MB fraction and troponin-T in the patients who underwent slow pathway ablation for atrioventricular nodal reentrant tachycardia. In patients with atrioventricular reentrant tachycardia, there was no significant rise in creatine kinase and creatine kinase total & MB fraction levels, while troponin-T levels rose from 0.13 +/- 0.06 to 0.29 +/- 0.16 eta g/ml (p < 0.05). There was an increase in creatine kinase, creatine kinase total & MB fraction and troponin-T levels after idiopathic ventricular tachycardia ablation from 68.4 +/- 44.9 to 138.0 +/- 81.7 IU (p < 0.05), 2.77 +/- 3.34 to 25.2 +/- 19.8 IU (p < 0.05) and 0.09 +/- 0.04 to 0.34 +/- 0.08 eta g/ml (p < 0.001) respectively. Radiofrequency ablation of atrioventricular nodal reentrant tachycardia does not cause any significant myocardial damage to raise any cardiac enzymes. Ablation of atrioventricular reentrant tachycardia results in only minor injury causing rise in only troponin-T levels. However, ventricular tachycardia ablation results in significant myocardial injury raising all the cardiac enzymes.

Electrocardiographic differentiation between right coronary and left circumflex coronary arterial occlusion in isolated inferior wall myocardial infarction.

The presence of atrioventricular block and ST segment elevation in lead V4R accurately predicts right coronary artery occlusion in patients with inferior wall myocardial infarction. However, these electrocardiographic signs are absent in the majority of patients with inferior myocardial infarction. We studied ST segment elevation in leads II and III, ST segment in lead I and T wave polarity in lead V4R in order to differentiate between right coronary artery and left circumflex coronary artery occlusions in 104 patients with inferior myocardial infarction who subsequently underwent coronary angiography. The ST segment elevation was greater in lead III than in lead II when the right coronary artery was the culprit vessel and vice versa when the left circumflex was the culprit vessel (p < 0.001). An upright T wave in lead V4R and ST segment depression in lead I was common when the right coronary artery was the culprit vessel and not seen with left circumflex occlusion (p < 0.001). ST segment elevation in lead III was higher than in lead II with a sensitivity of 99 percent and a specificity of 100 percent for diagnosing right coronary artery as the culprit vessel. ST segment elevation in lead II was higher than in lead III with a sensitivity of 93 percent and a specificity of 100 percent in identifying the left circumflex as the culprit vessel. Thus, these signs are very useful in identifying the culprit vessel in inferior myocardial infarction.

Age at onset, gender distribution and intraarterial blood pressure changes in atrioventricular node-dependant tachycardias.

OBJECTIVE: Atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT) utilising accessory pathways constitute the vast majority of paroxysmal supraventricular tachycardia (SVT). We studied the age at onset, the gender distribution and the intraarterial hemodynamics of these tachycardias. METHODS: The data of 224 patients who underwent electrophysiology study (EPS) and radiofrequency ablation was analysed. The age at onset of tachycardia was assessed by a careful history. The intraarterial BP was noted during sinus rhythm (SR), immediately after tachycardia onset (T0) and 15 seconds after the onset of tachycardia (T15). RESULTS: The age at onset of tachycardia was a decade later for AVNRT (48 +/- 10 years) than for AVRT (37 +/- 11 years). There was no gender preponderance in the AVNRT group (60 males, 56 females) while a male preponderance was seen in the AVRT group (71 males, 37 females, p < 0.01). There was a marked fall in the intraarterial systolic BP in both groups at the onset of tachycardia, from 143 +/- 24 mm Hg to 108 +/- 16 mm Hg (p < 0.05) for AVNRT and from 139 +/- 25 mm Hg to 107 +/- 18 mm Hg (p < 0.05) for AVRT. There was no correlation between the rate of tachycardia and the extent of fall of BP. CONCLUSION: Hospital-based data in an Indian setting found a similar pattern of age of onset of AV node-dependant tachycardia as in Western literature. However, unlike in Western studies, no female preponderance was seen in the AVNRT group. The fall in systolic BP at the onset of tachycardia is significant, similar in the two groups and independent of the rate of tachycardia.

Arrhythmogenic right ventricular dysplasia: electrophysiologic and morphologic features in nine patients.

Arrhythmogenic right ventricular dysplasia is a potentially life-threatening disorder, not previously well described in India. We analysed the electrocardiographic, electrophysiologic, angiographic, signal-averaged electrocardiogram and magnetic resonance imaging features of nine patients having arrhythmogenic right ventricular dysplasia at our centre. There were seven males and two females, aged 25 to 55 years. Eight patients presented with sustained monomorphic ventricular tachycardia. The electrocardiogram showed prolonged QRS duration in four, T inversion in leads V2-V3 in four, and epsilon wave in two patients. Abnormal late potentials were present in eight patients. During electrophysiologic study in seven patients, 13 different VTs were induced. Seven patients had right ventricular dilatation and dysfunction and left ventricular involvement was seen in three patients. Eight patients were treated with amiodarone, including one who received an implantable cardioverter-defibrillator. At a follow-up of 8.6 +/- 5.3 months, there was no death, while one patient had recurrence of ventricular tachycardia. Arrhythmogenic right ventricular dysplasia seems to predominantly affect middle-aged men, the presentation most often being sustained monomorphic ventricular tachycardia. Depolarisation and/or repolarisation abnormalities in the electrocardiogram are commonly present. Multiple ventricular tachycardia morphologies during electrophysiologic study and abnormal right ventricular angiograms are usually observed.

Scope and efficacy of complex radiofrequency ablation.

Radiofrequency ablation is an effective treatment for various tachycardias. In some patients undergoing radiofrequency ablation, there are additional complexities. Of 254 consecutive patients (161 males, 93 females, aged 38 +/- 15 years) who underwent radiofrequency ablation, two groups were identified. Patients with structural heart disease, multiple accessory pathways, multifocal idiopathic ventricular tachycardia, parahisian accessory pathways, and multiple mechanisms of tachycardia were considered as complex radiofrequency ablation (Group I) and the remaining as non-complex radiofrequency ablation (Group II). There were 23 patients in Group I. The overall success rate was not different in the two groups: 20/23 (87%) vs 208/231 (90%) in groups I and II, respectively. The procedure and fluoroscopy time (212 +/- 91 min vs 136 +/- 45 min; p = 0.0001; and 55 +/- 31 min vs 31 +/- 21 min; p = 0.001, respectively) were significantly longer in Group I. There was a higher recurrence rate in Group I (6/20, 30% vs 20/208, 9.6%; p = 0.02); repeat radiofrequency ablation was successfully performed in four patients with recurrence in Group I. Complications were rare in both the groups. There was no mortality. Thus radiofrequency ablation in complex situations was effective, though more demanding than non-complex radiofrequency ablation and associated with higher recurrence.