Clinical presentation and electrocardiographic characteristics of patients with dilated cardiomyopathy

 

Sadanand D Kamble¹, Rajesh R Bobade^2*

 

^1,2Assistant Professor, Department of Medicine, Government Medical College, Latur, Maharashtra, INDIA.

Email: sadakamble@gmail.com

 

Abstract              Background: Dilated cardiomyopathy is being recognized as a significant cause of morbidity and mortalitydue to increased awareness along with improvement in diagnostic techniques. Present study was undertaken to focus on dilated cardiomyopathy in Indian patients and to look for correlation between clinical and electrocardiographic features. Material and Methods: The present study was performed in 50 patients of dilated cardiomyopathy diagnosed by echocardiography either admitted in a teaching hospital or attending cardiology clinic. Detail history and clinical examination was done in each patient. Standard 12 lead electrocardiograms were recorded as 25 mm per second and 1 mV per cm standardization. Results: All ages were affected but elderly and middle aged population were predominantly affected. Etiology could not be found in 42% of patients but alcohol was associated risk factor in 36 % of the patients. Dyspnea was invariably present in all patients followed by fatigability, swelling over feet, cough. Raised JVP, edema over feet, gallop rhythm, systolic murmur, congestive hepatomegaly and respiratory rales were common findings.Left axis deviation, LVH, bundle branch block, atrial fibrillation were common ECG abnormalities. Conclusion: Clinical and ECG characteristics areuseful indicesthat may reflect the severity and progression of DCM.

Key Words: Dilated cardiomyopathy, dyspnea,electrocardiography, left ventricular hypertrophy.

 

INTRODUCTION

Dilated cardiomyopathy (DCM) is a syndrome characterized by cardiac enlargement and impaired systolic function of one or both ventricles. The word dilated is preferred to congestive as earliest abnormality is ventricular dilatation while systolic contractile dysfunction and congestive heart failure developing later¹. With increasing awareness of this condition along with improvement in diagnostic techniques, dilated cardiomyopathy is being recognized as a significant cause of morbidity and mortality. The most striking symptoms are those of left ventricular failure¹.

Dyspnea and palpitation are the most common symptom². Fatigue and weakness are due to diminished cardiac output. Chest pain is not an uncommon symptom and may suggest concomitant ischemic heart disease. Some studies have demonstrated that patients of DCM can be detected in asymptomatic phase before development of symptomatic LV dysfunction and treatment of asymptomatic LV dysfunction reduces the morbidity and mortality associated with overt congestive heart failure^3,4. Aggressive approach to the diagnosis and treatment of asymptomatic patients are advised. DCM usually presents with electrocardiographic (ECG) signs of left ventricular (LV) hypertrophy similar to those seen in hypertensive patients^5,6.

However, to elucidate a more characteristic ECG pattern of DCM, 12-lead ECGs of DCM were analyzed.DCM is a topic of interest of physician, cardiologist, cardiac surgeons and many other group of scientists. Present study was undertaken to focus on dilated cardiomyopathy in Indian patients and to look for correlation between clinical and electrocardiographic features.

 

MATERIAL AND METHODS

The present study was performed in 50 patients of dilated cardiomyopathy diagnosed by echocardiography³either admitted in a teaching hospital or attending cardiology clinic. 30 patients were male and 20 were female. Patients presenting with signs and symptoms of congestive cardiac failure, asymptomatic patients having unexplained cardiomegaly on Chest X-ray, abnormal ECG changes were included and those with signs and symptoms of congestive cardiac failure with cardiomegaly on Chest X-ray due to other diseases like coronary artery disease, rheumatic valvular heart disease, congenital heart disease, pericardial disease were excluded.

After selection of patients, detail history was obtained from each patients. Each patient was specifically asked about dyspnea, palpitation, fatigability, sweating, swelling over feet, abdominal pain, syncope, and chest pain. Dyspnea was classified according to NYHA classification⁷. Patient was asked regarding the major illness like Hypertension, Diabetes Mellitus, Myocardial Infarction, Renal disease, COPD. Personal history of addiction was asked. Patients were considered alcoholic who fulfilled the Diagnostic and Statistical Manual (DSM-IV)⁸ of American Psychiatric Associations.

In females, detailed obstetrical history was asked. Peripartum cardiomyopathy was diagnosed by criteria adapted in a workshop on peripartum cardiomyopathy conducted by National Heart, Lung and Blood Institute and Office of Rare Diseases. Family history suggestive of dilated cardiomyopathy was asked. Complete clinical examination was carried out. On physical examination, special attention was given to presence of raised JVP, edema, gallop rhythm, systolic murmur, respiratory rate and congestive hepatomegaly.

Comprehensive M- mode, two dimensional and Doppler echocardiographic examinations were performed in all patients. Routine laboratory investigations such as BSL profile, Liver function tests, Renal function tests, Serum calcium and phosphorus, and serum cholesterol were done. Standard 12-lead electrocardiograms were recorded as 25 mm per second and 1 mV per cm standardization. Rate, rhythm, P-R interval, QRS interval, QTc interval were measured.QRS axis was determined in frontal plane. Axis directed to the region between 0 counter clockwise to 90 was taken as left axis deviation. P wave abnormalities were noted.

Left atrial enlargement was defined as P terminal force in V1 equal to more negative than -0.04 mm sec or notched P wave with duration of 0.12 second or more. Right atrial enlargement was the presence of peaked P wave with a height of 2.5 mm or more in a lead II, III, and avF. Biatrial enlargement was defined as presence of large diphasic P wave in lead V1 with the initial positive component reading greater than 1.5 mm and the terminal negative component reading 1 mm in amplitude and 0.04 sec. in duration. Left ventricular hypertrophy was defined as per Sokolows criteria⁹ as R-wave in V5 or V6 + S-wave in V1 > 35 mm. Ratio of R wave in V6 and maximum R wave in leads I, II, III (RV6/R max) was calculated to find out the correlation the correlation of this ratio with ventricular dilatation and ejection fraction. ST segment and T wave abnormalities were noted.

 

 

RESULTS

In present study, dilated cardiomyopathy was more common in the middle age, most common in fifth decade. Males were affected more common than female with a ratio of 3:2. In 42% of the patients, no significant risk factor was present, while in 36% of the patients, alcohol was the risk factor (Table 1).

 

 

Table 1: Age and Sex Distribution

 

Dyspnea was present in all patients and majority of patients had higher NYHA class (i.e. Class III or IV). Fatigability (72%), cough (60%), swelling over the feet (56%) and palpitations (50%) were other predominant symptoms. Chest pain, abdominal pain, fever, syncope were uncommon symptoms. None of the patients was asymptomatic (Table 2).

 

 

 

 

 

 

Table 2: Symptomatology of DCM

 

In the present study, in 50 patients, mean pulse rate was 105.3 ± 9.47 per min, systolic BP was 113.44 ± 25.03 and diastolic BP was 73.68 ± 12.28 mm of Hg. On examination, most patients were found to have signs of CCF with edema on feet (86%), raised JVP (96%) and congestive hepatomegaly (90%) (Table 3).

 

Table 3: Clinical Features of DCM

 

Mean ventricular rate in the present study was 107.0±10.51 per min. Most of the patients had sinus tachycardia as they were in congestive heart failure. Range of QRS axis was from – 50⁰ to + 90⁰. Left axis deviation was seen in 22 (44%) patients. PR interval ranged from 0.16 to 0.26 seconds with mean of 0.176 ± 0.0303 seconds. 5 patients (10%) had first degree AV block. No patients had second or third degree AV block. Mean left ventricular QRS voltage (S in V₁ + R in V₅ or V₆) was 32.38 ± 11.08 mm. 22 patients had evidence of LVH on ECG (Table 4).

 

Table 4: ECG Abnormalities in Dilated Cardiomyopathy

 

DISCUSSION

In DCM, electrocardiographic characteristics are not specifically defined, although it is well known that signs of LV hypertrophy commonly exist^5,6. In the present study dilated cardiomyopathy was more common in middle age and elderly but commonest age group affected was 31-70 years. Males were affected more than females. Parale et al¹⁰, Karl et al¹¹ and Rihal et al¹² also reported similar findings. In 42% of the patients, no significant risk factor was present, while in 36% of the patients, alcohol was the risk factor. Fuster et al¹³ in their study of 104 patients of dilated cardiomyopathy found that in 49% of patients no risk factor could be identified. 21% patients gave history of excessive consumption of alcohol. In India, Parale et al¹⁰ found that out of 40 patients of dilated cardiomyopathy, 3 patients had diabetes, 2 were alcoholics and 5 were in peripartum period dilated cardiomyopathy was idiopathic in 30 (75%) of patients. In the present study, dyspnea was invariable and was present in all 50 (100%) patients. Fatigability (72%), cough (60%), swelling over the feet (56%) and palpitations (50%) were other predominant symptoms. None of the patients was asymptomatic. Karl et al¹¹, Parale et al¹⁰ and Grimm et al¹⁴ have reported dyspnea in 100% patients of dilated cardiomyopathy. In the present study, only one patient had syncope. ECG in that patient showed nonsustained ventricular tachycardia. In the present study, in 50 patients, mean pulse rate was 105.3 ± 9.47 per min, systolic BP was 113.44 ± 25.03 and diastolic BP was 73.68 ± 12.28 mmHg. On examination, most patients were found to have signs of CCF with edema on feet (86%), raised JVP (96%) and congestive hepatomegaly (90%).On cardiovascular examination, gallop rhythm was present in 92%, systolic murmurs in 50%, loud P2 in 18% and precordial thrill in 2% of the patients. 74% of patients had respiratory rales and 10% patients had ascites. Rihal et al¹² found in patients of dilated cardiomyopathy, systolic BP was 124 ± 19 and diastolic BP was 80 ± mm of Hg. Andersson et al¹⁵ have found that mean heart rate was 78 ± 16 per min, systolic BP was 124 ± 22 and diastolic BP was 76 ± 11 mm of Hg. Parale et al¹⁰ have found that elevated JVP, peripheral edema, congestive hepatomegaly, third heart sound and cardiomegaly were common signs in dilated cardiomyopathy. In the present study, most of the patients had signs of biventricular failure. Reduced right ventricular compliance, whether by precordial constraint or myocardial restriction may be operative in advanced stages of chronic cardiomyopathy. This concept was supported by Sassoon et al¹⁶ after their study on hepatic pulsations in patients with dilated cardiomyopathy.

Mean ventricular rate in the present study was 107.0 ± 10.51 per min. Most of the patients had sinus tachycardia as they were in congestive heart failure. Tachycardia in patients with dilated cardiomyopathy is also reported by studies done by Werner et al¹⁷ and Wilensky et al¹⁸. In the present study, range of QRS axis was from – 50⁰ to + 90⁰. Left axis deviation was seen in 22 (44%) patients. Parale et al¹⁰ have found left axis deviation in 59% of patients. Techuan Chou⁹ mentions that left axis deviation is seen in 42% of patients of dilated cardiomyopathy. In the present study, PR interval ranged from 0.16 to 0.26 seconds with mean of 0.176 ± 0.0303 seconds. 5 patients (10%) had first degree AV block. No patients had second or third degree AV block.AV blocks are poor prognostic markers in dilated cardiomyopathy and the progress over time with increasing fibrosis and myocyte hypertrophy. In the present study, AV block were seen in 10% of cases comparable to other studies. P waves were absent in 5 patients with atrial fibrillation, 14 (28%) patients had abnormal P waves. Techuan Chou⁹ mentions that in a series of 40 patients, P wave abnormalities were noted in 15 patients. Left atrial enlargement was the most common feature. As reported by others in the present study also left atrial enlargement on ECG was more common than right atrial or biatrial enlargement. In the present study, mean left ventricular QRS voltage (S in V₁ + R in V₅ or V₆) was 32.38 ± 11.08 mm. 22 patients had evidence of LVH on ECG. Results in the present study were comparable with studies by Roberts et al³ and Momiyama et al¹⁹. Techuan Chou⁹ mentions that relative incidence of LBBB in idiopathic dilated cardiomyopathy is higher than in IHD. In patients with cardiomegaly of unknown cause, the presence of LBBB further supports the diagnosis of primary myocardial disease. Abnormal left axis deviation consistent with LAHB also is common, occurring in as many as 42% in some series¹⁶. As reported by Barboso et al²⁰ and Schoeller et al²¹ in the present study also intraventricular conduction abnormalities were common. In DCM, though all ages were affected but elderly and middle aged population were predominantly affected. Etiology could not be found in 42% of patients but alcohol was associated risk factor in 36% of the patients. Dyspnea was invariably present in all patients and majority of patients had severe dyspnea [NYHA class III (48%) and IV (40%)]. Fatigability, swelling over feet and cough were other common symptoms. Raised JVP, edema over feet, gallop rhythm, systolic murmur, congestive hepatomegaly and respiratory rales were common findings. Left axis deviation, LVH, bundle branch block, atrial fibrillation were common ECG abnormalities.

 

REFERENCES

1. Joshua Wynne, Eugene Braunwald. The cardiomyopathy and myocarditis. In: Braunwald'sHeart Disease: A Textbook of Cardiovascular Medicine, 5th edition, Vol. 2, 1404-63.
2. Goodwin JF, Gordon H, Hollman A. et al. Clinical aspects of cardiomyopathy.BMJ 1961; 1:69-79.
3. Robert William C, Siegel RJ, et al. Idiopathic dilated cardiomyopathy: Analysis of 152 Necropsy patients. Am J of Cardiology 1987; 60:1340-55.
4. Dec GW, Fuster V, et al. Idiopathic dilated cardiomyopathy: Medical progress. NEJM 1994; 331(23):1564-75.
5. Riabykina GV, Lobova NM, DauletbaevaSM, et al. Value of electrocardiography and echocardiography for diagnosing ventricular enlargement in dilated cardiomyopathy. Cor Vasa 1987; 29:278.
6. Samdarshi TE, Thakur AK.Echocardiographicand electrocardiographic correlation in casesof congestive cardiomyopathy.IndianHeart J 1989;41:252.
7. Jules Constant. The evolving check list in history taking.Bedside Cardiology – by Jules Constant, fifth edition. 1-16.
8. Schuckit MA. Alcohol and alcoholism.Harrision’s Principles of Internal Medicine, 18^th edition, Vol. 2:3546-52.
9. Techuan Chau. Left ventricular hypertrophy. Electrocardiography in Clinical Practice, Third edition, 37-52.
10. Parale GP, Yadav NA, Kulkarni PM et al. Clinical profile cardiomyopathy in suburban part of Maharashtra. JAPI 2001; 49:182-183.
11. Karl S. Dujardin, ChuwaTei, Tion Cheng Yeo et al.Prognostic values of Doppler index containing systolic and diastolic performance in idiopathic dilated cardiomyopathy. Am J of Cardiology 1998; 82:1071-76.
12. RihalCharanjit S, Aishimura RA et al.Systolic and diastolic dysfunction in patients with clinical diagnosis of dilated cardiomyopathy. Circulation 1994; 90:2772-79.
13. FusterV, Gluliani ER et al.The natural history of idiopathic dilated cardiomyopathy. Am J of Cardiology 1981; 47:525-531.
14. Grimm Wolfram, Steder Ulrike et al.QT dispersion in dilated cardiomyopathy.Am J of Cardiology 1996; 78:458-61.
15. Anderson Bert, Caidahi Kenneth et al.An echocardiographic evaluation of patients with idiopathic heart failure.Circulation 1995; 107:680-689.
16. Sasson, Gupta MK et al.Hepatic pulsation in dilated cardiomyopathy with heart failure due to tricuspid regurgitation.Am J of Cardiology 1993; 71:355-58.
17. Werner GS, Schaefer C, Igulla HR, et al.Prognostic value of Doppler echocardiographic assessment of left ventricular filling in dilated cardiomyopathy.Am J of Cardiology 1993;73:792-98.
18. Wilensky RL, Yudelman P, Cohen A, et al.Serial electrocardiographic changes in idiopathic dilated cardiomyopathy confirmed at necropsy.Am J of Cardiology 1988;62:276-83.
19. Momiyama Y, Mitomura H, et al.ECG characteristics of dilated cardiomyopathy.J of Electrocardiology 1994; 27(4):323-28.
20. Barbosa Fiho J, AlbanseFiho FM, et al. Electrocardiogram in dilated cardiomyopathy.Rev Port Cardiol 1989; 8(ii):769-74.
21. Schoeller R, Anderson D, et al.Atrioventricular block in idiopathic dilated cardiomyopathy. Am J of Cardiology 1993; 71:720-26.