Case report
A 74-year-old man was admitted to our institution for cardiac monitoring after orthopaedic intervention for a medial fracture of the femur secondary to an accidental fall. He reported a history of cyanosis noted a few months after birth. Although Congenital Heart Disease (CHD) was suspected, his underlying anatomy was not comprehensively evaluated until cardiac catheterisation at 18 years. At that time he was diagnosed with dextrocardia, a univentricular heart, transposition of the great arteries, and pulmonary outflow obstruction. Surgical intervention was not offered. His growth and development during infancy and childhood were considered normal, but he reported a history of therapeutic phlebotomies that were performed during the 1960s and 1970s when his haematocrit exceeded 65%.
When he was 58 years old, he experienced an episode of atrial fibrillation successfully treated with electric cardioversion. Oral anticoagulant therapy was not started because of polyglobulia.
Over the years he gradually presented decreased exercise tolerance.
When he was 69 years old, he experienced one episode of heart failure with dyspnoea, worsening of cyanosis, and recurrence of atrial fibrillation. He was treated with diuretics and β-blockers and was begun on dicumarol therapy. Thereafter he was clinically stable, with NYHA grade II.
His physical examination on admission showed O2 saturation 75–80%, digital clubbing, and a 3/6 L right-sided parasternal systolic murmur. The liver and spleen were normal; peripheral oedema was absent. The lungs were clear. Blood pressure was 110/70 mmHg.
His electrocardiogram showed atrial flutter with a ventricular rate of 60–80 beats/minute and inferolateral Q waves, consistent with a dextrocardia pattern. Chest radiography showed enlarged pulmonary arteries without signs of congestion. Laboratory tests after orthopaedic surgery showed haemoglobin 13.9 g/dl, haematocrit 43.3%, and mean corpuscular haemoglobin 25.9 pg.
Echocardiography demonstrated atrial situs solitus, dextrocardia, d-looped ventricles, double inlet left ventricle – two atrioventricular valves connected to a single morphological left ventricle with normal function: ejection fraction 67% and end-diastolic volume 85 ml/mq – a large atrial septal defect ostium secundum, non-restrictive bulboventricular foramen, l-transposed arteries – anterior left-sided aorta arising from a small right ventricular outlet chamber without obstruction and a posterior right-sided pulmonary artery connected to the morphological left ventricle – and moderate subvalvular and valvular pulmonary stenosis with a maximum gradient of about 60 mmHg. A mild-to-moderate regurgitation of the right-sided atrioventricular valve was present.
During hospitalisation, he underwent a rehabilitation programme without cardiac events.
Currently, 1 year later, he is stable.
Discussion
Univentricular heart is a rare congenital anomaly that accounts for about 1% of all CHDs at birth.Reference Steinberg and Dantzker 1 It is defined as the presence of a single ventricular chamber or two ventricular chambers in which one is severely hypoplastic. Associated anomalies are pulmonary stenosis or atresia, subaortic stenosis, coarctation of aorta, and mitral or tricuspid atresia. It is usually associated with transposed great arteries, whereas Holmes’ heart is a rare variety in which the great arteries are normally related.Reference Gabbarini 2
In unoperated univentricular heart patients the survival rate in the 1st year of life is ~30%Reference Samanek 3 and the median survival is 14 years.Reference Moodie, Ritter, Tajik and O’Fallon 4 Survival into late adulthood without surgical repair is rarely reported.
The clinical presentation and long-term outcome depend on the presence of obstruction in the pulmonary blood flow and pulmonary vascular resistance, morphology, and function of the ventricle, obstruction to aortic flow, and morphology and function of the atrioventricular valves.Reference Hager, Kaemmerer, Eicken, Fratz and Hess 5
A moderate pulmonary stenosis is crucial for haemodynamic balance in this CHD: on one hand it limits the pulmonary blood flow, avoiding pulmonary arteriolar disease, and on the other it causes systemic desaturation. Long-term survival is possible with adequate oxygenation and a balanced ventricular load. Pulmonary stenosis limits the left to right shunt that leads to an increased pulmonary flow and ventricular overload, finally protecting from heart failure.
Morphology and function of the single ventricle are also critical for the clinical course in univentricular hearts: there are, in fact, no reports of long-term survival with right morphology or a indeterminate-type single ventricle. This is probably due to the intrinsic capacity of the left ventricle to deal with the systemic resistance.
Survival is positively influenced by characteristics of atrioventricular valves: competent and separated valves are linked to a better outcome.Reference Hager, Kaemmerer, Eicken, Fratz and Hess 5 Incompetent atrioventricular valves impose a volume overload on the ventricle.
We reviewed the literature on unoperated univentricular hearts and found that atrial arrhythmias, such as typical atrial flutter and atrial fibrillation, are the most frequent complications among patients who survive longer, but to our knowledge there is no report on the mean age at onsetReference Dhillon, Li, Gonna and Waed 6 (Table 1). We found 13 patients:Reference Hager, Kaemmerer, Eicken, Fratz and Hess 5 , Reference Dhillon, Li, Gonna and Waed 6 , Reference Restaino, Dirksen and de Ross 13 , Reference Terada, Watanabe, Iino, Kakizaki, Takahashi and Ito 14 three presented with a history of paroxysmal atrial fibrillation/flutter that was medically controlled, two had permanent atrial fibrillation, and one underwent multiple electrical cardioversions and an ablation procedure for intra-atrial re-entry tachycardia, whereas our patient had atrial flutter.
Table 1 Demographic and clinical data and cardiac anatomy of patients with univentricular heart in natural history surviving beyond the age of 50 years.
DILV=double inlet left ventricle; MGA=ventriculoarterial concordance with a left/right position of the aorta; PHT=pulmonary hypertension; PS=pulmonary stenosis; TGA=transposition of the great arteries with a left/right position of the aorta
Dhillon et alReference Dhillon, Li, Gonna and Waed 6 hypothesised that a progressive atrial myopathy, secondary to uncorrected CHD, leads to atrial fibrosis and may contribute to the genesis of arrhythmias in these patients.
The perspective of survival is greater in patients with the following associations:Reference Hager, Kaemmerer, Eicken, Fratz and Hess 5 single ventricle with left ventricular morphology; transposition of the great vessels without flow obstruction; atrioventricular valve working properly; and moderate obstruction to the pulmonary flow, which allows enough pulmonary flow to prevent severe cyanosis and avoid ventricular overload.
To our knowledge the literature reports only 13 patients with a univentricular heart in natural history who survived beyond the age of 50 years; all of them had left ventricular morphology. Compared with those patients, our patient had the same ventricular morphology but he is to date the oldest (maximal age, respectively, 62 versus 74 years).
The “ideal” anatomy seems characterised by left ventricular morphology, good ventricular function, and “well-balanced” circulation, with some degree of pulmonary stenosis that avoids at the same time excessive pulmonary blood flow and severe cyanosis. These anatomic characteristics can allow patients to survive with mild-to-moderate symptomatology and with a good quality of life. Cardiac arrhythmias are the most frequent complications among patients who survive longer. The patient presented here had these anatomic features, enabling him to reach the age of 74 years without surgical intervention.
Acknowledgements
The authors want to thank Dr Luca Ragni for collaboration.
Financial Support
This research received no specific grant from any funding agency, commercial or not-for-profit sectors.
Conflicts of Interest
None.
