Adenosine induced PR jump on surface ECG to differentiate atrioventricular nodal re-entrant tachycardia from concealed accessory pathway mediated tachycardia: a bedside test.

OBJECTIVE: To evaluate the efficacy of single dose intravenous adenosine in differentiating atrioventricular nodal re-entrant tachycardia (AVNRT) from concealed pathway mediated atrioventricular re-entrant tachycardia (AVRT) using surface ECG at the bedside. METHOD: 12 mg of adenosine was administered to 97 consecutive patients who had documented narrow QRS tachycardia without manifest pre-excitation. The test was labelled positive for AVNRT if surface ECG recordings showed signs of dual atrioventricular (AV) node physiology-namely, PR jump or AV nodal echo. The diagnostic value of this test was evaluated by electrophysiological study as the yardstick. RESULTS: The adenosine test was positive for AVNRT in 48 patients (adenosine induced PR jump in 48, AV nodal echo in 3) and negative in 49 patients. On electrophysiological study, 62 patients had AVNRT and 35 had concealed pathway mediated AVRT. Thus, the test had a sensitivity of 74% and specificity of 94%. The positive predictive value was 96% and the negative predictive value was 67%. CONCLUSION: Single dose (12 mg) intravenous adenosine administered during sinus rhythm can identify dual AV node physiology on surface ECG recording at the bedside. A positive adenosine test identified by a PR jump can differentiate AVNRT from AVRT with a high specificity and positive predictive accuracy.

Measurement of radial artery spasm using an automatic pullback device.

Current evaluation of radial artery spasm (RAS), a frequent finding during the transradial approach for coronary angiography and angioplasty (TRA), is subjective. A quantitative measure of RAS will help in evaluation and comparison of management strategies. The objectives of the study were to assess the feasibility and safety of using an automatic pullback device (APD) for removal of transradial introducer sheaths and to establish a parameter to quantify RAS. In 50 consecutive transradial procedures, the APD was used to measure the force required for sheath removal. The mean maximal pullback force (MPF) was 0.53 +/- 0.52 kg (range, 0.1-3.0 kg). In 48 (96%) cases, the MPF was reached within the first 5 sec of pullback. All patients with clinical RAS (n = 4) had an MPF greater than 1.0 kg, while the remaining had an MPF less than 1.0 kg. All patients with severe pain during sheath removal (n = 3) had an MPF greater than 1.0 kg, while no patient with an MPF less than 1.0 kg had severe pain. It is feasible and safe to remove transradial introducer sheaths using the APD. The MPF is achieved within the first 5 sec of pullback and is a reliable parameter to quantify RAS. An MPF more than 1.0 kg correlates with clinical RAS and is associated with severe pain during sheath removal.

Transcatheter fenestration of a total cavopulmonary connection baffle.

Transcatheter creation of a de novo fenestration of a total cavopulmonary connection baffle has not been previously reported from India. We present our experience with such a procedure in a 4-year-old child with recurrent pleural effusions in the early postoperative period.

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.

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.

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.

Pre-natal echocardiographic diagnosis and neonatal balloon dilatation of severe valvar pulmonic stenosis.

A case is presented below where pre-natal echocardiographic diagnosis of critical pulmonic valvar stenosis was made at 36 weeks of gestation. In view of the severe heart failure, successful balloon valvotomy was performed on day 4 of life. The child was asymptomatic at one month follow-up.

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.

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.