Harbans S. Wasir

Predictors of arterial thrombosis after diagnostic cardiac catheterization in infants and children randomized to two heparin dosages.

Arterial thrombosis is the most frequent major complication of percutaneous arterial catheterization in children. We prospectively studied the effect of randomized dosage of heparin, 50 IU/kg-group I and 100 IU/kg-group II, on the incidence of arterial thrombosis in 366 children and analysed the various factors which may influence the occurrence of this complication. The age of patients ranged from 17 d to 11 yr (mean age 39.5 +/- 40.9 mo) and mean weight was 11.2 +/- 7.8 kg (range 3 to 39 kg). The incidence of arterial thrombosis was 9.8% in group I and 9.3% in group II (P = NS). There was no statistical difference in precatheterization and procedure variables in the two groups and also in the group with absent pulse (n = 35) to the group with pulse present post cath (n = 331). There were 24.9% infants in our study and 14.3% of these had arterial thrombosis. The loss of pulse was more often seen with more number of attempts at arterial puncture (P < 0.001), absence of back bleed at the end of the procedure (P < 0.001), and increased duration of catheterization (P < 0.01). Use of larger sheath size in a given weight and body surface area of children increased incidence of arterial thrombosis. The administration of heparin 50 IU/kg was equally efficacious to heparin 100 IU/kg. Of the patients with arterial thrombosis, 23 responded with intravenous heparin and 12 needed streptokinase. There was no bleeding or haematoma. Thus our study shows that less attempt for arterial puncture, use of smaller sheath size, maintaining shortest procedure time and ensuring back bleed minimises incidence of arterial thrombosis post catheterization.

Thrombolytic therapy for prosthetic valve thrombosis: A study based on serial Doppler echocardiographic evaluation

Sixteen patients with echocardiographic and cinefluoroscopic evidence of Björk-Shiley prosthetic valve obstruction (13 mitral valves and 3 aortic valves) were treated with intravenous streptokinase. Streptokinase was administered as an initial bolus of 250,000 units for 30 minutes, followed by an infusion of 100,000 units/hr. Serial cinefluoroscopy and echocardiography (M-mode, two-dimensional, and Doppler) were performed at 0, 24, 48, and 72 hours of treatment. The end point of treatment was defined as near normalization of clinical, echocardiographic, and fluoroscopic parameters. Successful thrombolysis was achieved in all patients. The average duration of streptokinase therapy was 43 hours (range 2 to 72 hours). Two of 16 patients had minor systemic embolism during therapy. Short-term follow-up has shown sustained benefit in 14 of 16 patients. Two patients have had rethrombosis of the mitral prosthetic valves and have undergone thrombectomy. Our study demonstrates the feasibility, safety, and efficacy of thrombolytic therapy in the treatment of prosthetic valve thrombosis. It also emphasizes the role of serial Doppler echocardiography in guiding the duration of therapy and assessing its efficacy.

Correlation of lipoprotein (a) to angiographically defined coronary artery disease in Indians

Lipoprotein (a) [Lp(a)] levels have been correlated with angiographically defined coronary artery disease (CAD). Pattern of Lp(a) distribution in various racial groups is different. To study this relationship in Indian patients, plasma levels of Lp(a) and other lipid values were assessed in 101 patients undergoing coronary arteriography. Lp(a) concentration was higher in CAD group (n = 77) compared to normal coronary artery group (n = 24) (26.83 +/- 22.09 mg/dl vs. 15.07 +/- 14.61 mg/dl, P < 0.05). Lp(a) values had graded association with CAD. In Lp(a) quartile of < 5 mg/dl, 66.7% patients had CAD; in Lp(a) quartile of 5-25 mg/dl, 69.0% had CAD; Lp(a) quartile of 26-75 mg/dl, 87.5% had CAD; and in Lp(a) quartile of > or = 76 mg/dl, all patients had CAD. High density lipoprotein (HDL) cholesterol was higher in the normal coronary artery group as compared to CAD group (45.25 +/- 8.26 mg/dl vs. 41.83 +/- 16.47 mg/dl; NS). In HDL quartile of < 35 mg/l, 88.9% patients had angiographically defined CAD. Plasma values of total cholesterol, triglycerides (TG), apolipoprotein-A1 (Apo-A1), apolipoprotein-B (Apo-B), low density lipoprotein (LDL) cholesterol, LDL/HDL cholesterol ratio and Apo A1/B ratio were not significantly different in the groups with normal coronary arteries and CAD. Our results indicate that the measurement of Lp(a) provides a better marker for predicting the presence of angiographically defined CAD as compared to traditional measures.

Reversibility of “Tachycardia Induced Cardiomyopathy” Following the Cure of Idiopathic Left Ventricular Tachycardia Using Radiofrequency Energy

We report a cose of incessant ventricular tachycardia with right bundle branch block and left axis deviation morphology resulting in severe LV dysfunction and congestive heart failure. Radiofrequency ablation of the appropriate site in the region of posteroapical part of the LV septum resulted in the cure of the arrhythmia. On a 3‐month follow‐up, the LV size and function returned to normal.

Cardiac involvement in nonspecific aortoarteritis (Takayasu's arteritis)

Fifty-four patients (18 males and 36 females, ages 2 to 37 years) with nonspecific aortoarteritis (NSAA) were studied. Evaluation revealed hypertension in 35, congestive heart failure (CHF) in 24, mild to moderate mitral regurgitation in six, and mild aortic regurgitation in two. Erythrocyte sedimentation rate was raised (greater than 35 mm in the first hour) in 38 patients. The arterial lesions included type I in seven, type II in eight, and type III in 34. Pulmonary artery involvement was present in 4 (type IV) of the 20 patients in whom it was studied. Selective coronary angiography was done in 11 patients and revealed 90% left main stenosis in one patient. Hemodynamic data revealed raised (greater than 7 mm Hg) mean right atrial pressure in nine, raised mean pulmonary artery pressure (greater than 20 mm Hg) in 29, and raised left ventricular filling pressure (greater than 12 mm Hg) in 27 patients. Radionuclide ventriculography revealed reduced (less than 45%) left ventricular ejection fraction (LVEF) in 27 patients. The myocardial morphology as evaluated on right ventricular endomyocardial biopsy revealed normal histology in nine, features of inflammatory myocarditis in 24, and nonspecific changes suggestive of dilated cardiomyopathy in six patients. Marked right ventricular endocardial thickening was present in three. All patients with CHF had some histologic abnormality. We emphasize that myocardial involvement including myocarditis is common in NSAA and may precipitate CHF in these patients.

Comparison of echocardiographic acoustic quantification system and radionuclide ventriculography for estimating left ventricular ejection fraction: Validation in patients without regional wall motion abnormalities

Echocardiographic automated border detection of blood-endocardium interface is made on the basis of the principle of acoustic quantification. The automated border system is capable of providing on-line left ventricular (LV) cavity area and function. Recently, ABD algorithms have been devised to estimate LV volume on line from a long-axis image, calculated by established area-length method or Simpsons formula. To test the clinical validity of this newly developed echocardiographic method, LV volumes and ejection fraction measured by real-time acoustic quantification were compared with radionuclide ejection fraction in 24 subjects on the same day. Patients were included in the study if > or = 75% of their endocardium was visualized with conventional two-dimensional echocardiography. Sixteen (66%) of 24 patients had a technically adequate conventional echocardiogram with a broad range of ventricular dimensions and systolic function. None of the study patients had regional wall motion abnormalities. Echocardiographic measurements were obtained from the LV apical four-chamber, long-axis view. Ejection fraction, determined by the acoustic quantification and by radionuclide ventriculography, showed a strong linear relation (r = 0.92, standard error of the estimate = 4.4, p < 0.05). However, acoustic quantification overestimated the radionuclide ejection fraction with rather wide limits of agreement (3.8% +/- 16.4%; bias +/- 2 SD). Thus echocardiographic automated border detection technique is a reasonably accurate method for on-line assessment of LV function.

Thrombolytic therapy in infants and children

Thrombolytic therapy is being increasingly used to treat various cardiac and other disorders in the pediatric population. The use of thrombolytic therapy in thrombosis following cardiac catheterization, aortic thrombosis, right atrial and caval thrombosis, pulmonary embolism, thrombosed prosthetic valves, thrombosed Blalock-Taussig shunts, and other disorders is delineated. Special issues of the newborn are discussed. A wider appreciation of the indications and contemporary experience would help in optimizing the use of thrombolytic therapy in children.

Comparative study of the efficacy of metoprolol and verapamil in patients with syncope and positive head-up tilt test response

Head-up tilt testing is a reliable diagnostic tool for patients with recurrent unexplained syncope. It has also been used to assess the drug efficacy for the treatment of patients with syncope. The objective of this study was to assess the efficacy of verapamil compared with metoprolol in a randomized crossover design for patients with syncope and a positive tilt test response. Twenty-eight patients with a positive head-up tilt test were randomized to receive either metoprolol or verapamil; the test was repeated after 7 days of therapy. Of the 15 patients initially given metoprolol, 2 (13.3%) did not respond; both were crossed over to verapamil, to which they remained unresponsive. Of the 13 patients who initially received verapamil, 8 (61%) did not respond; after crossing over to metoprolol therapy, 1 remained unresponsive. Overall, 20 of 23 patients receiving metoprolol had negative results on repeat tilt testing, whereas only 5 of 15 patients receiving verapamil had negative results (p < 0.001). In conclusion, the results of this study suggest that verapamil is considerably less efficacious than metoprolol in managing neurocardiogenic syncope.

Myocardial infarction in young Indian patients: Risk factors and coronary arteriographic profile

One hundred four patients (101 men, three women), under 40 years of age, with myocardial infarction (MI), underwent coronary arteriography. Eighty patients had significant obstructive coronary artery disease (CAD) (group 1), 23 had normal coronary arteries (group 2), and one patient had coronary ostial stenosis as a result of nonspecific aortoarteritis (group 3). Coronary risk factors in group 1 included smoking (76.2%), hypercholesterolemia (36.3%), hypertension (32.5%), positive family history (28.7%), and diabetes mellitus (5%). Multiple risk factors were frequent (56.2%). Smoking was common (p less than 0.01) and diabetes mellitus less frequent (p less than 0.05) as compared to older (greater than 40 years) patients with MI and arteriographically proved CAD. The frequency of one-, two-, and three-vessel disease was 33.7%, 26.2%, and 40%, respectively, in group 1. Group 2 patients were almost devoid of coronary risk factors. The only group 3 patient had left coronary ostial stenosis with no risk factors. Similar to their counterparts in developed countries, young Indian patients with MI and obstructive CAD have a high frequency of coronary risk factors, especially smoking and severe multiple-vessel disease. Since normal coronary arteriograms are also frequent in this setting, a detailed evaluation is recommended for purposes of prognosis and management.

Transcatheter alcohol ablation of the septum in a patient of hypertrophic obstructive cardiomyopathy

We performed transcatheter alcohol ablation of the septum in a case of hypertrophic obstructive cardiomyopathy. The patient showed marked reduction in LVOT gradient; however, he developed complete atrioventricular (AV) dissociation following the procedure, requiring AV sequential pacing. This important complication of this novel technique is highlighted.