Heart rate variability in dilated cardiomyopathy.

Chronic heart failure is associated with excessive neurohormonal activation. Analysis of heart rate variability is considered a valid technique for assessment of the autonomic balance of the heart. Twenty symptomatic patients of dilated cardiomyopathy in NYHA class II-IV symptomatic status and as many normal controls were subjected to 24 hours Holter monitoring to assess the heart rate variability with both time domain and frequency domain analysis. Age of the patients ranged from 12 to 67 years (mean +/- SD 38.6 +/- 7 years), the male-female ratio was 4:1. The left ventricular ejection fraction of the patients was between 18-42 percent (mean +/- SD 30.2 +/- 9%) and all received diuretics, digoxin and angiotensin-converting enzyme inhibitors. Heart rate variability parameters measured included mean heart rate with standard deviation, hourly heart rate with SD and the mean of all normal RR intervals from the 24-hour recording. Time domain measures calculated were SD of all normal RR intervals, SD of 5 minute mean RR intervals and root mean square of difference of successive RR intervals. Using spectral plots, frequency domain subsets of low frequency and high frequency were analysed and expressed in normalised units. Total power was also measured. In the dilated cardiomyopathy patients, mean 24-hour heart rate in beats per minute was significantly higher in comparison to controls (82 +/- 13 vs 72 +/- 8; p < 0.001) whereas mean hourly heart rate with standard deviation (msec) was significantly lower (97 +/- 41 vs 232 +/- 25; p < 0.001), SD of all normal RR intervals (msec) was 85.5 +/- 26.3 vs 139.4 +/- 16.9 in controls (p < 0.001), SD of 5 minute mean RR intervals (msec) was also significantly less in patients in comparison to controls (75.8 +/- 39.6 vs 130.8 +/- 20.3; p < 0.001). However, although root mean square of difference of successive RR intervals (msec) was reduced in patients (30.1 +/- 9.3 vs 37.3 +/- 11.7; p < 0.05), the difference was non-significant. Low frequency power (0.05-0.15 Hz) (normalised units) was reduced in the dilated cardiomyopathy group (0.0721 +/- 0.003 vs 0.136 +/- 0.047 in the control group; p < 0.001). High frequency power (0.35-0.50 Hz) (normalised units) (0.08 +/- 0.05 in patients vs 0.09 +/- 0.02 in controls; p > 0.1) and total power frequency (0.02-0.50 Hz) (normalised units) (0.34 +/- 0.05 in patients vs 0.35 +/- 0.12 in controls; p > 0.1) was non-significantly different in the two groups. Regression analysis showed a significant decrease in SD of all normal RR intervals, SD of 5 minute mean RR intervals, low frequency, high frequency, total power and a non-significant decrease in root mean square of difference of successive RR intervals with a decrease in ejection fraction percent whereas there was a significant decrease in SD of all normal RR intervals, SD of 5 minute mean RR intervals, low frequency and total power and a less significant decrease in root mean square of difference of successive RR intervals and high frequency power with an increase in NYHA class. At 6 months duration, 6 patients were lost to follow-up, 3 patients were readmitted (2 for congestive cardiac failure, one of paroxysmal supraventricular tachycardia). One patient who was NYHA class IV at baseline was readmitted for congestive cardiac failure and showed much lower heart rate variability parameters compared to the average of the patients. We conclude that in symptomatic dilated cardiomyopathy patients, heart rate variability parameters are significantly reduced in comparison to control subjects.

Follow-up results of balloon angioplasty for native coarctation of aorta.

Balloon angioplasty of native discrete (< 1 cm) coarctation of thoracic aorta was performed in 29 patients [aged 13 to 31 years (mean 21.5 +/- 5.8 years), 22 males and 7 females], from March 1993 to December 1995. The patients were followed up for two years. After angioplasty, peak systolic arterial pressure (PSAP) decreased from 173.5 +/- 18.1 mm Hg to 122.5 +/- 9.9 mm Hg (p < 0.001), peak systolic pressure gradient (PSG) decreased by 90.9 percent from 86.2 +/- 15.77 to 7.77 +/- 3.8 mm Hg (p < 0.001) and the coarcted segment diameter increased about three times from 3.7 +/- 1.6 to 10.9 +/- 3.3 mm (p < 0.001). PSG decreased to < 10 mm Hg in 27 patients (93%) whereas in the other two patients PSG was 17 and 13 mm Hg. Restenosis appeared in 2 patients (6.8%); aneurysm in one patient (3.4%) which remained static even after 1.3 years of follow-up; mild dissection in 3 patients (10.3%); temporary femoral artery occlusion in 2 (6.8%) patients who recovered with heparin injection. Though hypertension disappeared after balloon dilatation in all patients, it reappeared in 3 patients (10.3%) within 7 days and in 10 patients (34.5%) within 6 months. In conclusion, balloon angioplasty of CoA is a good alternative to surgical correction.

Studies on prosthetic valve function--a transesophageal echocardiographic assessment.

Haemodynamic assessment was done by colour flow mapping and Doppler interrogation by both Transthoracic (TTE) and Transesophageal echocardiography (TEE) in 40 consecutive patients (mean age 36.6 +/- 12.35 years) with prosthetic valves. There were 30 cases of mitral (MVR) and 12 aortic (AVR) valve replacement. Major purpose of the study was to detect the sensitivity of TEE in detecting prosthetic valve malfunction particularly in comparison to TTE. Pannus was detected in 3 and 8 cases of MVR (p < 0.01) by TTE and TEE respectively; however, TEE was found to be of equal status in detecting pannus over AV (2 cases). Physiological regurgitation in MVR and AVR was detected in 13% and 25% by TTE and 20% and 33% by TEE respectively. Paravalvular leak was detected in 3 cases of MVR by TEE compared to only case by TTE. Though it is difficult to deduce any specific conclusion from this small number of patients, there is definite trend to higher sensitivity in detecting disorders with TEE specially for mitral prostheses.

Intravenous thrombolytic therapy in unstable angina.

One hundred consecutive age and sex-matched patients of 3 different subsets of unstable angina (recent onset angina -65, crescendo angina -20, post-infarct angina-15) were randomized 1:1 after coronary angiography to receive I.V., either 1.5 x 10(6) units of streptokinase (SK) in 200 ml of normal saline or 200 ml of normal saline alone (control) in 1 hour. Repeat angiography was done in those patients having intra-coronary thrombi (37.3%) during the initial angiography. Both groups received optimal doses of heparin followed by warfarin, aspirin and other standard drugs and were followed up for 6 months. Anginal pain subsided significantly in the SK group-41 (82%) vs 25 (50%) (P < 0.005), especially in patients with recent onset angina (92.5% vs 60%, P < 0.005). Incidence of acute myocardial infarction (AMI) was much less in the SKgp (4(8%) vs 17 (34%) (p < 0.05). Four cases of fatal MI and four cases of sudden cardiac death (SCD) occurred in the control group against none in the SKgp. Requirements of mechanical revascularization was significantly less (P < 0.05) in the SK gp. Angiographic evidence of partial or complete clot lysis was noted in 90% of SK gp. vs 4.8% of control (P < 0.01). Echocardiographically assessed LV function improved significantly with SK-therapy in recent onset (P < 0.05) and crescendo angina (P < 0.001) subsets--however, the improvements in post infarct angina subset were not statistically significant. The beneficial outcome with SK therapy was observed in patients irrespective of angiographic evidence of thrombi.(ABSTRACT TRUNCATED AT 250 WORDS)

Anticoagulant therapy in acute myocardial infarction.

In 265 patients of acute myocardial infarction (AMI) heparin followed by warfarin sodium was used routinely whenever there was no contraindication to the drug. Patients were followed up to 2 years with weekly estimation of prothrombin time. Another 265 patients of AMI having identical clinical profiles were taken as control and neither any anticoagulant nor any antiplatelet agent was used in them. Both groups were also treated with identical coronary dilators whenever needed. 2 years cardiac mortality was 11.6% in the control group and 5.9% in the anticoagulant therapy (ACT) recipient group (P less than 0.05). Incidence of reinfarction (RMI) was 14.4% during the period in the control group whereas it was only 6.7% in the ACT group (P less than 0.05). The incidence of intracranial events were also more frequent in control group (8.4%) compared to ACT group (3.1%) (P less than 0.05). However on further analysis of intracranial events, it was found that haemorrhagic intracranial events were slightly more frequent in ACT (2.3%) than in the control group (2%), but this difference was statistically insignificant (P greater than 0.05); non-haemorrhagic intracranial events were however significantly less in ACT group (1.96%) compared to the control group (6%) (P less than 0.05). There was no major or fatal extracranial haemorrhagic complication in either group. Only minor extracranial haemorrhages were more commonly observed in the ACT group (4.3%) compared to the control group (1.2%) (P less than 0.05).

Experience with balloon valvuloplasty in pulmonary stenosis.

Fourteen patients of pure valvular pulmonary stenosis of moderate to severe degree underwent balloon valvuloplasty in the Department of Cardiology, SSKM Hospital, Calcutta. Haemodynamic study revealed that immediately after valvuloplasty, right ventricular pressure dropped down from 125 +/- 17.18 mmHg. to 56.67 +/- 8.72 mmHg. (mean +/- SD). Restudy was done in each case after 4 weeks, which showed that right ventricular systolic pressure had further dropped down to 46.71 +/- 5.06 mmHg. (Mean +/- SD). Patients were further followed up for 6 to 15 months (mean 10 months). During the follow-up period, all the patients remained asymptomatic. Drop of right ventricular systolic pressure was maintained except in one case in which the peak systolic pressure gradient across the pulmonary valve was raised to 61 mmHg. from 24 mmHg., the gradient achieved immediately after valvuloplasty.